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A New Comprehensive Short-form Health Literacy Survey Tool for Patients in General

Open AccessPublished:February 11, 2017DOI:https://doi.org/10.1016/j.anr.2017.02.001

      Summary

      Purpose

      To validate a conceptual short-form health literacy 12 items questionnaire (HL-SF12) in patient populations.

      Methods

      A cross-sectional study was conducted via a convenient sample of 403 patients from three departments of a community general hospital in the northern Taiwan. Patients’ health literacy was assessed with a validated HL-SF12, derived from the full scale, the European Health Literacy Survey Questionnaire (HLS-EU-Q), as well as a single-item from Chew’s Set of Brief Health Literacy Question. A reference population in Northern Taiwan (n=928) via the HLS-EU-Q in 2013–2014 was used as a reference to compare the health literacy between that of the general public and the patients. Data was analyzed by confirmatory factor analysis (CFA), internal consistency analysis, correlation analysis, and linear regression models.

      Results

      Patients’ health literacy assessed with the HL-SF12 was shown with high internal consistency (Cronbach α=.87), and moderately correlated with the single-item from Chew's Set of Brief Health Literacy Question, with satisfactory item-scale convergent validity (item-scale correlation ≥ .40), without floor/ceiling effect, and with satisfactory goodness of fit indices of the three-factor construct model for most of the patients. Their health literacy was significantly positively associated with female gender, higher income, and more often watching health-related TV programs. On the other hands, patients were reported with significantly higher healthcare health literacy than the general public, but not in general health literacy, disease prevention health literacy, or health promotion health literacy.

      Conclusion

      The comprehensive HL-SF12 was a valid and easy to use tool for assessing patients’ health literacy in the hospitals to facilitate healthcare providers in enhancing patients’ health literacy and healthcare qualities.

      Keywords

      Introduction

      Health literacy has been increasingly recognized as an important determinant of health [
      • Watson R.
      Europeans with poor “health literacy” are heavy users of health services.
      ]. Approximated one third of adults in the United States, Taiwan, as well as many other countries around the world, were noted to have low health literacy [
      • Lee S.-Y.D.
      • Tsai T.-I.
      • Tsai Y.-W.
      • Kuo K.N.
      Health literacy, health status, and healthcare utilization of Taiwanese adults: results from a national survey.
      ]. Low health literacy has been shown to be a potential health risk factor [
      • Nutbeam D.
      The evolving concept of health literacy.
      ] associated with poor health outcomes [
      • Lee S.-Y.D.
      • Tsai T.-I.
      • Tsai Y.-W.
      • Kuo K.N.
      Health literacy, health status, and healthcare utilization of Taiwanese adults: results from a national survey.
      ], and becomes an enormous challenge for almost all of the healthcare systems [
      • Paasche-Orlow M.K.
      • Schillinger D.
      • Greene S.M.
      • Wagner E.H.
      How health care systems can begin to address the challenge of limited literacy.
      ]. In contrast, adequate health literacy has been shown to enable better self-care with fewer health risks, better health outcomes, and lower health costs [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ].
      Health literacy has been defined by Sorensen and others to entail the knowledge, motivation and competences to access, understand, appraise, and apply information, to make judgments and decisions in terms of healthcare, disease prevention and healthy behaviors, to maintain and promote quality of life throughout the life course [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ]. The main differences between the general public and outpatients in regard to their health literacy were that patients experienced simultaneously existing health issues when they visited the hospital, sought assistance from the healthcare system, and contacted healthcare services. On the other hand, people with limited health literacy probably had difficulty accessing, understanding, evaluating and applying health information to manage their own health [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ]. Therefore, those who accessed the hospital may already have higher levels of health literacy than the others who did not. However, if the patients who visited the hospital in different departments and found it difficult to learn how to access the hospital, doctors, and follow-up on prescriptions and instructions for healthcare, limited health literacy could became barriers that prevent them from adhering to treatment [
      • Zhang N.J.
      • Terry A.
      • McHorney C.A.
      Impact of health literacy on medication adherence: a systematic review and meta-analysis.
      ]. Patients who visited different departments carried with them different healthcare experiences, which might incur various reflections on their health literacy. Therefore, patients’ health literacy might have modified and deviated from those of the general public, including their general health literacy, healthcare health literacy, disease prevention health literacy, or health promotion health literacy. It is important for healthcare providers to evaluate and understand patients’ health literacy before delivering their education and instruction.
      The European Health Literacy Assessment tool (HLS-EU-Q) with 47 items has been developed and validated in Europe [
      • HLS-EU Consortium
      Comparative report of health literacy in eight EU member states. The European Health Literacy Project 2009–2012 [internet].
      ,
      • Sørensen K.
      • Pelikan J.M.
      • Röthlin F.
      • Ganahl K.
      • Slonska Z.
      • Doyle G.
      • et al.
      Health literacy in Europe: comparative results of the European health literacy survey (HLS-EU).
      ], Japan [
      • Nakayama K.
      • Osaka W.
      • Togari T.
      • Ishikawa H.
      • Yonekura Y.
      • Sekido A.
      • et al.
      Comprehensive health literacy in Japan is lower than in Europe: a validated Japanese-language assessment of health literacy.
      ], and Taiwan [
      • Duong T.V.
      • Lin I.-F.
      • Sørensen K.
      • Pelikan J.M.
      • Van den Broucke S.
      • Lin Y.-C.
      • et al.
      Health literacy in Taiwan: a population-based study.
      ]. However, the questionnaire is relatively long and could cause potential measurement bias. Several short-form questionnaires have been developed to provide easy assessment of health literacy in the individuals, including the Short Test of Functional Health Literacy in Adults [
      • Baker D.W.
      • Williams M.V.
      • Parker R.M.
      • Gazmararian J.A.
      • Nurss J.
      Development of a brief test to measure functional health literacy.
      ], the Rapid Estimate of Adult Literacy in Medicine-Revised [
      • Bass P.F.
      • Wilson J.F.
      • Griffith C.H.
      A shortened instrument for literacy screening.
      ], short-form Mandarin Health Literacy Scale for clinical and research settings [
      • Lee S.-Y.D.
      • Tsai T.-I.
      • Tsai Y.-W.
      • Kuo K.N.
      Development and validation of the short-form Mandarin Health Literacy Scale.
      ], and the 3-item Chew’s Set of Brief Screening Questions (SBSQ) [
      • Chew L.D.
      • Bradley K.A.
      • Boyko E.J.
      Brief questions to identify patients with inadequate health literacy.
      ]. On the other hand, these questionnaires have been designed for certain clinical illnesses, but not on comprehensive general health literacy regarding the patient’s ability to manage their health [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ], which would provide effective interventions and education .
      The comprehensive short-form health literacy questionnaire (HL-SF12) has been developed from a population survey in Taiwan in 2015 [
      • Duong T.V.
      • Aringazina A.
      • Baisunova G.
      • Nurjanah N.
      • Pham T.V.
      • Pham K.M.
      • et al.
      Validation of HLS-EU-Qs for health literacy survey in Asia. The 3rd International Conference on Health Literacy and Healthcare Efficiency; 9th−11th November, 2015.
      ]. It was based on the conceptual model that considered four competences of an individual when dealing with health-relevant information (access/obtain, understand, appraise/judge/evaluate, and apply/use health information) to form judgment and make health-related decisions [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ], with a framework matrix of 12 subdimensions [
      • HLS-EU Consortium
      Comparative report of health literacy in eight EU member states. The European Health Literacy Project 2009–2012 [internet].
      ].
      There were a few health literacy survey tools validated and tested in clinical setting [
      • Baker D.W.
      • Williams M.V.
      • Parker R.M.
      • Gazmararian J.A.
      • Nurss J.
      Development of a brief test to measure functional health literacy.
      ,
      • Bass P.F.
      • Wilson J.F.
      • Griffith C.H.
      A shortened instrument for literacy screening.
      ,
      • Lee S.-Y.D.
      • Tsai T.-I.
      • Tsai Y.-W.
      • Kuo K.N.
      Development and validation of the short-form Mandarin Health Literacy Scale.
      ,
      • Chew L.D.
      • Bradley K.A.
      • Boyko E.J.
      Brief questions to identify patients with inadequate health literacy.
      ]. However, they mostly focused on functional health literacy, and were short of comprehensiveness and broadness of health literacy [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ]. The HL-SF12 was developed from the HLS-EU-Q47 using nation-wide data on the general public in Taiwan; it has not been used in clinical settings for healthcare providers. In addition, the difference between patients and the general public regarding health literacy has not been examined in Taiwan.
      This study aimed to evaluate the HL-SF12 on patients in a general hospital, and to identify the differences in health literacy between patients and the general public. The HL-SF12 was expected to serve more in the healthcare services as a fast and practical tool for health professionals to evaluate and understand patients’ health literacy when they deliver education or instruction.

      Methods

      Study design and sampling

      A cross-sectional survey was conducted by using the HL-SF12 developed by Asian Health Literacy research consortium [
      • Duong T.V.
      • Aringazina A.
      • Baisunova G.
      • Nurjanah N.
      • Pham T.V.
      • Pham K.M.
      • et al.
      Validation of HLS-EU-Qs for health literacy survey in Asia. The 3rd International Conference on Health Literacy and Healthcare Efficiency; 9th−11th November, 2015.
      ]. Convenient sampling method was used to recruit patients who visited the general outpatient department, orthopedics department, and traditional Chinese medicine (TCM) department in the National Taipei Hospital within 1 randomly selected week in each department from June 2015 to July 2015. These three departments represented three main groups of patients in this community general hospital, with patients in the general outpatient department representing those for nonsurgical treatment, the orthopedics department representing surgical patients, and in the TCM department representing those who sought traditional medicinal treatment.
      Patients who visited the above-mentioned departments, aged 18 years and more, were without psychiatric disorder, were able to read and understand the local language, and were willing to participate in the survey, were included during the study period.
      A total of 453 patients during the above-mentioned period were invited to the survey. Among them, 403 patients (response rate 89.0%) completed the interviews and were included in the final analysis. The sample size required for structural equation model and CFA was recommended as 5–10 times the number of items [
      • Kline R.B.
      Principles and practices of structural equation modeling.
      ]. The HL-SF12 consisted of 12 items. As such, the number of patients was 190 in the outpatient department, 130 in the orthopedics department, and 83 in the TCM department, which satisfied the requirement. The total sample size of 403 patients was also satisfactory.

      Measurements

      The HL-SF12 contained 12 items, the perceived difficulty of each health related task was rated on 4-point Likert scales (1=very difficult, 2=difficult, 3=easy, and 4=very easy), with a possible lowest mean score of 1, and a possible highest mean score of 4.
      In order to examine the convergent validity, a single-item from the SBSQ, “How confident are you in filling out medical forms by yourself?” was included [
      • Chew L.D.
      • Bradley K.A.
      • Boyko E.J.
      Brief questions to identify patients with inadequate health literacy.
      ].
      Sociodemographics and personal characteristics including age, gender, education (junior high school and below, senior high school, university and above), net income per month (< 667 USD, 667 > 1,667 USD, > 1,667 USD), self-perceived social status (low, middle, high), watching health-related TV (never, rarely, sometimes, often) were also measured.

      Data collection

      All the patients who visited the outpatient department, the orthopedics department, or the TCM department during the study period were invited to join the HL-SF12 survey anonymously, assisted by trained interviewers with standard protocol. The informed consent forms were signed before patients responded to the questionnaire. Each survey took about 15 minutes.

      Statistical analysis

      The general indices for health literacy (general, healthcare, disease prevention and health promotion) were standardized to unified metrics from 0 to 50 using the formula Index=(M – 1) × (50/3), where Index was the specific index calculated, M was the mean of all participating items for each individual, 1 was the minimal possible value of the mean (leading to a minimum value of the index of 0), 3 was the range of the mean, and 50 was the chosen maximum value of the new metric. Thus, an index value was obtained where 0 represented the lowest health literacy and 50 the highest [
      • HLS-EU Consortium
      Comparative report of health literacy in eight EU member states. The European Health Literacy Project 2009–2012 [internet].
      ].
      Reliability analysis included the following: Internal consistency was tested with Cronbach α value set to greater than or equal to .70 for satisfactory reliability [
      • Cronbach L.J.
      • Shavelson R.J.
      My current thoughts on coefficient alpha and successor procedures.
      ]. The split-half reliability was also examined [
      • Hays R.D.
      • Anderson R.T.
      • Revicki D.
      Assessing reliability and validity of measurement in clinical trials. Quality of life assessment in clinical trials: methods and practice.
      ,
      • Tsai T.-I.
      • Lee S.-Y.D.
      • Tsai Y.-W.
      • Kuo K.N.
      Methodology and validation of Health Literacy Scale development in Taiwan.
      ].
      Convergent validity included the folloiwing: The correlation between health literacy as measured by HL-SF12 and by SBSQ (1 item) indicated the convergent validity of HL-SF12 of these patients [
      • Andresen E.M.
      Criteria for assessing the tools of disability outcomes research.
      ]. Item-scale convergent validity was examined by correlation between the item and its own theoretical scale [
      • Hays R.D.
      • Hayashi T.
      Beyond internal consistency reliability: rationale and user’s guide for multitrait analysis program on the microcomputer.
      ], which was determined by the Pearson correlation coefficient. When rho was between .36 to .67, it was considered moderately correlated, between .68 to 1.0, highly correlated [
      • Taylor R.
      Interpretation of the correlation coefficient: a basic review.
      ].
      Floor and ceiling effects analyses included the following: Floor/ceiling effects referred to a high percentage of participants scoring possibly the lowest score or achieving possibly the highest score, respectively. Therefore, minimal floor and ceiling effects were recommended and, for the HL-SF12 scale, a percentage of 15.0% at floor or at ceiling was considered a significant effect [
      • Terwee C.B.
      • Bot S.D.M.
      • de Boer M.R.
      • van der Windt D.A.W.M.
      • Knol D.L.
      • Dekker J.
      • et al.
      Quality criteria were proposed for measurement properties of health status questionnaires.
      ].
      Construct validity analyses included the following: To establish construct validity, CFA was conducted for health literacy consisting of three dimensions of health: healthcare, disease prevention, and health promotion. Twelve items from 12 hypothetical components of health literacy [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ], which were loaded onto the three factors (healthcare, disease prevention, and health promotion). The fit of the data to the model was examined by goodness of fit indices including (a) Absolute model fit: root mean square error of approximation, goodness-of-fit index (GFI); (b) Incremental fit: adjusted goodness of fit index (AGFI), comparative fit index (CFI), incremental fit index (IFI), and normal fit index (NFI); (c) Parsimonious fit, or the chi-square goodness of fit test: chi-square/degrees of freedom ratio (χ2/df ratio). More satisfied indices would indicate better construct validity of the questionnaire [
      • Floyd F.J.
      • Widaman K.F.
      Factor analysis in the development and refinement of clinical assessment instruments.
      ].
      Finally, the associations between sociodemographic, personal characteristics and health literacy measured by HL-SF12 were examined by linear regression models. A population in Northern Taiwan (n=928) via the HLS-EU-Q in 2013–2014 was used as a reference for comparison between the general public and the patients. The health literacy index score of general public in the Northern Taiwan was calculated by using the same 12 selected items as 12 items of HL-SF12 scale in measuring patient’s health literacy. The multivariate analysis controlled for age, gender, and education.
      All statistical analyses were performed using SPSS version 20.0 and AMOS version 22.0 (IBM Corp; Armonk, NY, USA). The significance level was set at p<.05.

      Ethical considerations

      The study was approved by the Institutional Review Board of the National Taipei Hospital, Ministry of Health and Welfare, Taiwan (TH-IRB-0014-0019).

      Results

      The mean age of participants was 44.9 years±15.8 years, with 61.1% women, 46.9% with senior high school education and below, and 53.1% with university education and above. A total of 32.2% claimed they were unemployed or with student status; 11.9% claimed their monthly income was less than 667 USD per month; 49.2% claimed between 667 > 1,667 USD, and 38.8% claimed more than 1,667 USD. In total, 33.3% of the participants self-reported low social status, and 66.7% with middle or high social status; 35.4% reported never or rarely watching health-related TV, 46.4% reported sometimes watching, and 18.2% reported watching often (Table 1).
      Table 1Bivariate and Multivariate Linear Regression Analyses for Health Literacy and Sociodemographics (N=403).
      Variablesn%Model 1Model 2
      Model R2=0.099.
      B (95%CI)βpB (95%CI)βp
      Age (yr), Mean±SD44.9±15.8–0.06 (–0.11, –0.01)–.12.013–0.04 (–0.10, 0.02)–.07.232
      Gender
       Women (=n)24561.1
       Men15638.9–2.83 (–4.32, –1.33)–.18< .001–2.40 (–3.93, –0.87)–.15.002
      Education
       Junior high school and below (=n)7919.7
       Senior high school10927.22.99 (0.83, 5.15).18.0070.85 (–1.59, 3.28).05.495
       ≥ College/university21353.13.40 (1.47, 5.33).23.0011.37 (–1.16, 3.90).09.289
      Employment status
       Unemployed (=n)12832.2
       Employed27067.81.03 (–0.56, 2.62).06.203
      Net income per month (USD)
       < 667 (=n)4711.9
       667 > 1,66719449.23.62 (1.22, 6.02).24.0032.84 (0.28, 5.41).19.030
       > 1,66715338.84.12 (1.66, 6.58).27.0012.90 (0.13, 5.67).19.040
      Self-perceived social status
       Low (=n)13333.25
       Middle & high26766.752.86 (1.30, 4.42).18< .0011.57 (–0.16, 3.29).097.075
      Departments
       General OPD (=n)19047.1
       Orthopedics13032.3–0.58 (–2.27, 1.11)–.04.5020.60 (–1.11, 2.31).04.490
       TCM8320.6–2.08 (–4.03, –0.13)–.11.037–1.50 (–3.53, 0.53)–.08.147
      Watched health-related TV
       Never & rarely (=n)14235.4
       Sometimes18646.42.73 (1.09, 4.37).18.0011.94 (0.27 to 3.61).13.023
       Often7318.23.00 (0.89, 5.12).15.0063.22 (0.97 to 5.48).16.005
      Note. BMI=body mass index; CI=confident interval; OPD=out-patient department; TCM=traditional Chinese medicine.
      a Model R2=0.099.
      The reliability of the HL-SF12 was very high, with Cronbach α of .87 for all the study populations, and it was acceptable for patients from the outpatient department, orthopedics department, and TCM department, at .88, .87, .88, respectively [
      • Cronbach L.J.
      • Shavelson R.J.
      My current thoughts on coefficient alpha and successor procedures.
      ]. In addition, its split-half Spearman-Brown coefficient of .80–.86 was satisfactory for all the patients and those in different departments (Table 2) [
      • Hays R.D.
      • Anderson R.T.
      • Revicki D.
      Assessing reliability and validity of measurement in clinical trials. Quality of life assessment in clinical trials: methods and practice.
      ,
      • Tsai T.-I.
      • Lee S.-Y.D.
      • Tsai Y.-W.
      • Kuo K.N.
      Methodology and validation of Health Literacy Scale development in Taiwan.
      ].
      Table 2Convergent Validity, Item-scale Convergent Validity, Internal Consistency Reliability, and Floor/ceiling Effects of HL-SF12 in Patients (N=403).
      Patient groupsValidityReliabilityFloor effects (%)Ceiling effect (%)
      Spearman’s correlation with “confident with forms” (SBSQ)Item-scale convergent validity (Range of correlations)Cronbach αSplit-half Spearman–Brown coefficient
      General OPD.34.55–.73.88.860.503.60
      Orthopedics.50.48–.74.87.830.005.30
      TCM.31.51–.70.88.850.004.80
      Overall.42.51–.71.87.840.203.60
      Note. HL-SF12=short-form health literacy 12 items questionnaire; OPD=out-patient department; SBSQ=Chew's Set of brief health literacy screening questions; TCM=traditional Chinese medicine.
      The correlation between HL-SF12 and single-item SBSQ was with Spearman’s rho at .31–.50, a moderate level for patients of different departments (Table 2). This provided evidence of convergent validity for the survey tool used in diverse patient populations [
      • Andresen E.M.
      Criteria for assessing the tools of disability outcomes research.
      ]. No significant floor/ceiling effect was detected, as the percentages of patients with the lowest scores or the highest scores in health literacy at floor or ceiling were less than 15.0%. This indicated that the responsiveness of HL-SF12 scale was satisfactory for use in different patient groups (Table 2).
      The root mean square error of approximation was less than .08, and other goodness of fit indices (GFI, AGFI, CFI, IFI, NFI) were .90 or higher, demonstrating good model–data fit [
      • Floyd F.J.
      • Widaman K.F.
      Factor analysis in the development and refinement of clinical assessment instruments.
      ]. The GFI was .89 for patients in the TCM department, while the AGFI was .88 for patients in the outpatient department and orthopedics department, and .82 for patients in TCM department. The NFI value was .89 for patients in orthopedics department, .87 for patients in TCM department; both were considered a tolerable fit [
      • Kline R.B.
      Principles and practices of structural equation modeling.
      ]. The overall results supported the fitness of the three-factor structure within the HL-SF12 in different patients (Table 3, Figure 1).
      Table 3Construct Validity of HL-SF12 in Different Patient Populations with Goodness of Fit Indices (N=403).
      Model
      Three-factor model of health literacy included health literacy in healthcare, disease prevention and health promotion.
      Absolute model fitIncremental fitParsimonious fit
      RMSEAGFIAGFICFIIFINFIχ2/df
      General OPD.07.93.88.96.96.911.87
      Orthopedics.06.93.88.97.97.891.41
      TCM.06.89.82.97.97.871.25
      Overall.07.94.91.94.94.923.27
      Note. AGFI=adjusted goodness-of-fit index; CFI=comparative fit index; GFI=goodness-of-fit index; HL-SF12=short-form health literacy 12 items questionnaire; IFI=incremental fit index; NFI=normal fit index; OPD=out-patient department; RMSEA=root mean square error of approximation; TCM=traditional Chinese medicine.
      a Three-factor model of health literacy included health literacy in healthcare, disease prevention and health promotion.
      Figure thumbnail gr1
      Figure 1Structure equation model of health literacy with 12 selected items from 12 components loading into three domains of health (health care, disease prevention, and health promotion) of short-form health literacy 12 items questionnaire (HL-SF12). Note. A2.1, A2.2, A2.3, A2.4, A2.5,A2.6, A2.7, A2.8, A2.9, A2.10, A2.11, A2.12 are items of HL-SF12 questions. On a scale from very easy to very difficult, how easy would you say it is to: A2.1 …find information on treatments of illnesses that concern you? A2.2 …understand the leaflets that come with your medicine? A2.3 …judge the advantages and disadvantages of different treatment options? A2.4 …call an ambulance in an emergency? A2.5 …find information on how to manage mental health problems like stress or depression? A2.6 …understand why you need health screenings (such as breast exam, blood sugar test, blood pressure)? A2.7 …judge which vaccinations you may need? A2.8 …decide how you can protect yourself from illness based on advice from family and friends? A2.9 …find out about activities (such as meditation, exercise, walking, Pilates) that are good for your mental well-being? A2.10 …understand information in the media (such as Internet, newspaper, magazines) on how to get healthier? A2.11 …judge which everyday behavior (such as drinking and eating habits, exercise) is related to your health? A2.12 … join a sports club or exercise class if you want to?
      The associations between health literacy and its contributory determinants were analyzed by simple linear regression (model 1) including one independent variable and general health literacy index as dependent variable; multiple linear regression model (model 2) included age, gender, education, employment status, net income per month self-perceived social status, department visited, frequency of watching health-related TV as independent variables. The general health literacy index was a dependent variable in the models. The results demonstrated that health literacy was significantly negatively associated with male gender (unstandardized regression coefficient, B=–2.40, p<.001), positively associated both with their incomes (B=2.84–2.90, p<.05) and watching health-related TV program (B=1.94–3.22, p<.05; Table 1). However, no association was found between health literacy and education (B=0.85–1.37, p>.05) or different departments visited (B=–1.50 to 0.60, p>.05; Table 1).
      In addition, the difference in health literacy between the general public and the patients was analyzed by multiple linear regression model adjusted for age, gender, and education. The result showed that these patients reported significantly higher than their reference general public with regard to healthcare health literacy (B=1.65, p=.001), but did not significantly differ in general health literacy (B=0.81, p=.058), disease prevention health literacy (B=0.84, p=.095), or health promotion health literacy (B=–0.05, p=.922; Table 4).
      Table 4Difference(s) between General Public (as reference group) and Out Patients Regarding HL via Multiple Linear Regression Analysis.
      Health LiteracyOut patients

      n=403

      M±SD
      General public

      n=928

      M±SD
      B (95%CI)
      The analysis was adjusted for age, gender, and education.
      βp
      General HL35.6±7.634.8±6.50.81 (–0.27, 1.66).06.058
      Healthcare HL35.9±8.334.4±7.61.65 (0.70, 2.61).10.001
      Disease prevention HL35.3±8.934.5±7.60.84 (–0.15, 1.82).05.095
      Health promotion HL35.5±8.635.7±7.9–0.05 (–1.05, 0.95)–.01.922
      Note. CI=confident interval; HL=Health Literacy.
      a The analysis was adjusted for age, gender, and education.

      Discussions

      Low health literacy was shown to be associated with poor health outcomes, higher mortality rates, and greater health disparity [
      • Lee S.-Y.D.
      • Tsai T.-I.
      • Tsai Y.-W.
      • Kuo K.N.
      Health literacy, health status, and healthcare utilization of Taiwanese adults: results from a national survey.
      ,
      • Husson O.
      • Mols F.
      • Fransen M.
      • Poll Franse L.
      • Ezendam N.
      Low subjective health literacy is associated with adverse health behaviors and worse health related quality of life among colorectal cancer survivors: results from the profiles registry.
      ]. Lee and colleague studied the link between health literacy, self-care activities, and quality of life among type 2 diabetes patients from out-patients clinics [
      • Lee E.-H.
      • Lee Y.W.
      • Moon S.H.
      A structural equation model linking health literacy to self-efficacy, self-care activities, and health-related quality of life in patients with type 2 diabetes.
      ]. Results suggested that health literacy was recommended in clinical practice for enhancing self-care activities and could improve health-related quality of life in patients. Therefore, it was important to identify patients at different levels of health literacy and provide adequate and effective interventions such as tailored counseling, improved provider–patient interactions, organizing information by patient preference using plain language and visual items [
      • Lee T.W.
      • Lee S.H.
      • Kim H.H.
      • Kang S.J.
      Effective intervention strategies to improve health outcomes for cardiovascular disease patients with low health literacy skills: a systematic review.
      ]. SBSQ was short and applicable in some busy clinical settings [
      • Wallston K.A.
      • Cawthon C.
      • McNaughton C.D.
      • Rothman R.L.
      • Osborn C.Y.
      • Kripalani S.
      Psychometric properties of the brief health literacy screen in clinical practice.
      ]. However, it was limited in assessing patients’ functional health literacy, and showed lack of comprehensiveness of health literacy which was related to the ability of patients to manage their own health [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ].
      The HLS-EU-Q with 47 items had been developed and validated based on the comprehensive conceptual framework of health literacy covering multicontexts of health in healthcare, disease prevention, and health promotion [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ,
      • HLS-EU Consortium
      Comparative report of health literacy in eight EU member states. The European Health Literacy Project 2009–2012 [internet].
      ,
      • Sørensen K.
      • Pelikan J.M.
      • Röthlin F.
      • Ganahl K.
      • Slonska Z.
      • Doyle G.
      • et al.
      Health literacy in Europe: comparative results of the European health literacy survey (HLS-EU).
      ]. The HL-SF12 was further developed and validated by using the data collected from 3,015 members of the general public in Taiwan in 2013–2014, which kept all 12 hypothetical dimensions of comprehensive health literacy [
      • Duong T.V.
      • Aringazina A.
      • Baisunova G.
      • Nurjanah N.
      • Pham T.V.
      • Pham K.M.
      • et al.
      Validation of HLS-EU-Qs for health literacy survey in Asia. The 3rd International Conference on Health Literacy and Healthcare Efficiency; 9th−11th November, 2015.
      ]. However, this new comprehensive tool was for the first time validated and used in a clinical setting to serve as a fast and effective tool for health professionals to evaluate patients’ health literacy before delivering the services. The results in current study in different groups of patients were shown with high level of internal consistency and split-half Spearman-Brown coefficient, suggesting satisfactory reliability of the tool [
      • Cronbach L.J.
      • Shavelson R.J.
      My current thoughts on coefficient alpha and successor procedures.
      ,
      • Tsai T.-I.
      • Lee S.-Y.D.
      • Tsai Y.-W.
      • Kuo K.N.
      Methodology and validation of Health Literacy Scale development in Taiwan.
      ]. The Cronbach α values of HL-SF12 in patient populations were similar to that using the HLS-EU-Q47 with the general public in Taiwan (Cronbach α=.96) [
      • Duong T.V.
      • Lin I.-F.
      • Sørensen K.
      • Pelikan J.M.
      • Van den Broucke S.
      • Lin Y.-C.
      • et al.
      Health literacy in Taiwan: a population-based study.
      ], and that of European countries (Cronbach α=.87–.97) [
      • HLS-EU Consortium
      Comparative report of health literacy in eight EU member states. The European Health Literacy Project 2009–2012 [internet].
      ].
      The results of CFA supported construct validity of the HL-SF12 in different patient groups with satisfactory goodness of fit indices, with 12 items loading highly on three hypothetical factors of comprehensive health literacy [
      • Kline R.B.
      Principles and practices of structural equation modeling.
      ,
      • Floyd F.J.
      • Widaman K.F.
      Factor analysis in the development and refinement of clinical assessment instruments.
      ]. At the item level, all 12 items were shown with satisfactory correlation with their own scale (item-scale correlation ≥ .40) [
      • Hays R.D.
      • Hayashi T.
      Beyond internal consistency reliability: rationale and user’s guide for multitrait analysis program on the microcomputer.
      ]. Furthermore, at the scale level, health literacy as measured by the HL-SF12 was fairly correlated with that as measured by the single-item “confident with forms” of the SBSQ, which provided adequate evidence of convergent validity [
      • Andresen E.M.
      Criteria for assessing the tools of disability outcomes research.
      ]. Since there was no significant floor/ceiling effects, this assured that the HL-SF12 was valid in differentiating patients with low or high health literacy [
      • Lim C.R.
      • Harris K.
      • Dawson J.
      • Beard D.J.
      • Fitzpatrick R.
      • Price A.J.
      Floor and ceiling effects in the OHS: an analysis of the NHS PROMs data set.
      ].
      The validity of HL-SF12 was robust by results of linear regression analysis to predict the association between health literacy and its associated factors. The result showed that health literacy was found to be significantly different between male and female, between levels of incomes, and frequency of watching health-related TV program. The findings were similar with those in previous studies, that women’s health literacy was generally found to be higher than those of men [
      • Sørensen K.
      • Pelikan J.M.
      • Röthlin F.
      • Ganahl K.
      • Slonska Z.
      • Doyle G.
      • et al.
      Health literacy in Europe: comparative results of the European health literacy survey (HLS-EU).
      ,
      • Nakayama K.
      • Osaka W.
      • Togari T.
      • Ishikawa H.
      • Yonekura Y.
      • Sekido A.
      • et al.
      Comprehensive health literacy in Japan is lower than in Europe: a validated Japanese-language assessment of health literacy.
      ], positively associated with net income per month [
      • HLS-EU Consortium
      Comparative report of health literacy in eight EU member states. The European Health Literacy Project 2009–2012 [internet].
      ,
      • Sørensen K.
      • Pelikan J.M.
      • Röthlin F.
      • Ganahl K.
      • Slonska Z.
      • Doyle G.
      • et al.
      Health literacy in Europe: comparative results of the European health literacy survey (HLS-EU).
      ], and watching health promoting television or health-related series [
      • Do M.P.
      • Kincaid D.L.
      Impact of an entertainment-education television drama on health knowledge and behavior in Bangladesh: an application of propensity score matching.
      ].
      In the bivariate analysis, education was shown as a protective factor for health literacy. In multivariate analysis, however, the association between education and general health literacy index was not found in current study which was similar with another population-based study in Taiwan [
      • Duong T.V.
      • Lin I.-F.
      • Sørensen K.
      • Pelikan J.M.
      • Van den Broucke S.
      • Lin Y.-C.
      • et al.
      Health literacy in Taiwan: a population-based study.
      ]. It indicated that income (B=2.84–2.90), and watching health-related TV (B=1.94–3.22) were shown to contribute more in variances of general health literacy than education attainment did (B=0.85–1.37) in model 2 (Table 1). On the other hands, health literacy was suggested to be more likely influenced by income, life-long learning experiences (i.e., watching health related TV), or participating in the health promotion activities [
      • Do M.P.
      • Kincaid D.L.
      Impact of an entertainment-education television drama on health knowledge and behavior in Bangladesh: an application of propensity score matching.
      ]. This may indicate inadequate health-related contents in general education curriculum in Taiwan that education attainment was less important to health literacy in the study population.
      The HL-SF12, in this study, was able to identify the difference between the general public and patients, specifically on healthcare health literacy, but not on disease prevention health literacy or health promotion health literacy. The patients who experienced healthcare services in the hospital were expected to have higher health literacy in healthcare than those of the general public, while their health literacy in disease prevention and health promotion were similar to those of the general public.
      In addition, health literacy was not found to be different between patients from departments. This reflected that patients visited different departments based on their health needs or demands, while health literacy was an accumulated process where people needed to develop the knowledge and skills through their lifetime to manage their own health [
      • Sørensen K.
      • Van den Broucke S.
      • Brand H.
      • Fullam J.
      • Doyle G.
      • Pelikan J.
      • et al.
      Health literacy and public health: a systematic review and integration of definitions and models.
      ].
      Finally, this study suggested using this new comprehensive tool in different patient populations to evaluate and compare the association of disease-focused health literacy and associated factors in future research.

      Strength and limitations

      The study was conducted in patients in specific departments in one general community hospital. The results suggested its much wider application in the clinical settings.
      The study demonstrated that the comprehensive HL-SF12 was useful in different patient populations and the general public. However, the test-retest reliability was not examined due to the cross-sectional study design. In addition, the past experiences of the general public and these patients were not accessible. Further investigations of this tool in other clinical settings and in different countries with different study designs were recommended.

      Conclusion

      This was the first study to investigate the validity of the comprehensive HL-SF12 in different patient populations, and comparing it with the general public population. The results indicated that the HL-SF12 was a valid tool in the clinical settings to serve as a comprehensive health literacy survey for doctors and nurses to assess patients’ health literacy.

      Conflict of interest

      The authors reported no conflict of interest.

      Acknowledgments

      The authors would thank the Department of Orthopedics, the Department of Traditional Chinese Medicine, and the General Out-patient Department of the National Taipei Hospital for financial and administrative supports. This study was supported by the National Taipei Hospital.

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