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Health Literacy and Risk Factors for Coronary Artery Disease (From the CONCARDPCI Study)

Open AccessPublished:July 16, 2022DOI:https://doi.org/10.1016/j.amjcard.2022.06.016
      In the setting of established coronary artery disease (CAD), lower health literacy is associated with poor outcomes. The aim of this study was to determine whether health literacy at the index admission was associated with established CAD risk factors and with changes in CAD risk factors from baseline until 6 months after percutaneous coronary intervention (PCI). A multicenter cohort study recruited 3,417 patients aged ≥18 years who were treated with PCI. Assessments were made at the index admission for PCI and at 6-month follow-up, including 4 of the 9 scales from the Health Literacy Questionnaire, an assessment of behavioral risk factors and psychologic risk factors for CAD. In this large study, key aspects of health literacy were associated with behavioral and psychologic risk factors for CAD. For each 1-unit higher score on the health literacy scales, weekly physical activity was 12 to 20 intensity-adjusted minutes higher, and the odds of being a nonsmoker were 24% to 72% higher. The risk factors for CAD improved from baseline to 6-month follow-up, although most were not significantly associated with health literacy. Still, patients with lower health literacy scores were more likely to report a greater reduction in depression symptoms from baseline to 6-month follow-up. In conclusion, the study provides evidence that several aspects of health literacy are associated with risk factors for CAD. These results serve as a reminder to healthcare teams to consider health literacy challenges in connection with secondary prevention care.

      Graphical abstract

      Introduction

      The health literacy of an individual represents the knowledge, confidence, and comfort to access, understand, appraise, remember, and use information about health.
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      Because low health literacy has been shown to be common among patients with coronary artery disease (CAD),
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      In addition to clinical conditions affecting cardiovascular risk, CAD is predominantly the result of behavioral risk factors.
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      There has also been a growing consensus that depression and anxiety should be considered as modifiable prognostic risk factors for CAD.
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      • Binno S
      2016 European Guidelines on cardiovascular disease prevention in clinical practice: The Sixth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of 10 societies and by invited experts)Developed with the special contribution of the European Association for Cardiovascular Prevention and Rehabilitation (EACPR).
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      Low health literacy has been associated with various social determinants of health,
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      affecting patients’ ability to take health-related decisions.
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      • Williams Sr., KA
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      2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.
      A lower level of health literacy has been associated with physical inactivity,
      • Aaby A
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      • Maindal HT.
      Health literacy is associated with health behaviour and self-reported health: a large population-based study in individuals with cardiovascular disease.
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      • Walters R
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      Health literacy for cardiac rehabilitation: an examination of associated illness perceptions, self-efficacy, motivation and physical activity.
      a higher body mass index (BMI),
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      Health literacy is associated with health behaviour and self-reported health: a large population-based study in individuals with cardiovascular disease.
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      and higher anxiety level.
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      However, none of the previous studies determined the associations between broader contemporary aspects of health literacy and risk factors for CAD before and after percutaneous coronary intervention (PCI). To fill this knowledge gap, this study aimed to determine whether health literacy at the index admission was associated with established CAD risk factors and with changes in CAD risk factors from baseline until 6 months after PCI.

      Methods

      The CONCARDPCI study is an interdisciplinary, multicenter, prospective cohort study. It uses a combination of data from hospital medical records and patient self-reports to identify novel pathways for follow-up care that contribute to improved outcomes in patients with CAD.
      • Norekvål TM
      • Allore HG
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      • Bjorvatn C
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      • Brørs G
      • Deaton C
      • Fålun N
      • Hadjistavropoulos H
      • Hansen TB
      • Igland S
      • Larsen AI
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      • Pettersen TR
      • Rasmussen TB
      • Schjøtt J
      • Søgaard R
      • Valaker I
      • Zwisler AD
      • Rotevatn S
      • Investigators CONCARD
      Rethinking rehabilitation after percutaneous coronary intervention: a protocol of a multicentre cohort study on continuity of care, health literacy, adherence and costs at all care levels (the CONCARDPCI).
      All adult patients undergoing PCI at 7 large referral PCI centers in Norway and Denmark were prospectively screened for eligibility from June 2017 to May 2019. Inclusion criteria were age ≥18 years and living at home at the time of inclusion. Exclusion criteria were inability to speak Norwegian/Danish or to complete the questionnaires, PCI without stent implantation, and PCI-related to transcatheter aortic or mitral valve implantation. The CONCARDPCI-study was approved by the Norwegian Regional Committee for Ethics in Medical Research (REK 2015/57) and by the Data Protection Agency in the Zealand region for the Danish centers (REG-145-2017). The study complied with the ethical principles outlined in the Declaration of Helsinki.
      Self-reported health literacy, risk factors for CAD, and sociodemographic data were collected at baseline during index hospitalization. Details about clinical characteristics were collected from patient medical records. All patients were followed up with postal or electronic self-report questionnaires assessing changes in risk factors for CAD (physical activity, smoking, anxiety, and depression) at the 6-month follow-up.
      Sociodemographic data included age, gender, cohabitation, education level, and work status. Clinical data included medical history.
      Elements of health literacy were measured using 4 of the 9 scales of the Health Literacy Questionnaire (HLQ).
      • Osborne RH
      • Batterham RW
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      • Buchbinder R.
      The grounded psychometric development and initial validation of the Health literacy questionnaire (HLQ).
      The scales chosen assessed the perspective of patients’ knowledge and confidence to access (“ability to find good information”), understand (“understanding health information well enough to know what to do”), and appraise information (“appraisal of health information”). Additionally, the scale “social support for health” reflected extrinsic dimensions of health literacy (e.g., patients’ social interactions related to the health care system), important for overcoming challenges associated with accessing, understanding, and using health information. A low HLQ score indicates that the respondent has difficulties within the scale.
      Behavioral risk factors for CAD included smoking status (current smoker or nonsmoker), BMI, and physical activity during leisure time. To assess engagement in regular physical activity (walking, skiing, swimming, and working out/sports) the physical activity frequency, intensity, and duration questionnaire was used.
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      Symptoms of anxiety and depression were measured using the hospital anxiety and depression Scale (HADS).
      • Zigmond AS
      • Snaith RP.
      The hospital anxiety and depression scale.
      For all instruments, details on computation of scores are stated in Supplementary material.
      Descriptive analyses were presented as percentages or counts for categorical variables, and as means and standard deviations for continuous variables. BMI, intensity-adjusted weekly physical activity, and HADS were analyzed descriptively as both continuous and categoric variables. To compare the differences in HLQ scales between subgroups, t-tests and one-way analysis of variance were used. Changes in the intensity-adjusted weekly physical activity score, smoking status, anxiety, and depression (HADS-anxiety[A] and HADS-depression[D]) from baseline to 6 months were analyzed using Kappa statistics or paired-samples t-tests, as appropriate.
      To estimate the associations of health literacy with BMI, the intensity-adjusted weekly physical activity score, HADS-A, and HADS-D at the index admission for PCI, respectively, unadjusted and adjusted linear regression models were used. To estimate whether health literacy was associated with the dichotomous outcome of smoking status, unadjusted and adjusted logistic regression models were used. Because sociodemographic factors, such as age, education, and gender, have been shown to be associated with management and control of modifiable risk factors for CAD,
      • De Smedt D
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      • Dallongeville J
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      • Kotseva K
      • Ž Reiner
      • Tokgözoğlu L
      • Clays E
      The gender gap in risk factor control: effects of age and education on the control of cardiovascular risk factors in male and female coronary patients. The EUROASPIRE IV study by the European Society of Cardiology.
      the regression analyses were performed with increasing covariate adjustments. The models used were: model 1: unadjusted; model 2: adjusted for age, education, and gender; model 3: model 2 plus previous diagnosis of CAD, peripheral artery disease, atrial fibrillation, chronic renal disease, diabetes, hypercholesterolemia, and hypertension. Additionally, for analyses, including HADS-A and HADS-D, model 3 was adjusted for a medical history of anxiety and depression.
      Mixed effects models were used to estimate the changes in the calculated intensity-adjusted weekly physical activity score, HADS-A, and HADS-D from baseline to 6-month follow-up. Mixed effects models were used to estimate whether baseline health literacy levels were associated with changes in risk factors for CAD over time. Time was included as a categoric variable (baseline vs 6 months) and a random effect was included for patient variations. Relations with changes over time are shown as interactions with time. The mixed effects models adjust for dependency of observations within participants and allow for imbalance between baseline and 6-month follow-up, for instance by allowing different regression coefficients over time within 1 subject. Thus, participants who only answered the questions at baseline and not at 6-month follow-up still contributed information to the model.
      • Twisk JWR.
      Continuous outcome variables - relationship with other variables.
      Changes in smoking status from baseline to the 6-month follow-up and whether changes were associated with baseline health literacy levels were investigated by logistic regression using generalized estimation equations, with an exchangeable correlation structure to account for within-person clustering. Each of these models was adjusted for age, gender, and education level.
      SPSS (IBM SPSS Statistics for Windows, Version 24.0. Armonk, New York) was used for descriptive statistics and linear regression, whereas the R (The R Foundation for Statistical Computing, Vienna, Austria) packages nlme and gee were used for mixed effects models and logistic regression with generalized estimation equations, respectively.

      Results

      In total, 3,417 patients were included in the study (Figure 1). The characteristics and the health literacy level of the patients at the index admission for PCI are presented in Figure 2 and Table 1. Overall, patients with a higher health literacy score were younger, had a higher level of education, and more often cohabitating. Men had higher scores than women on 3 of the 4 scales (Supplementary Table 1). Behavioral and psychologic risk factors for CAD are shown in Table 2.
      Figure 1
      Figure 1The flow chart describing the participant enrollment and selection procedure of the CONCARDPCI study with detailed information about the exclusions and discontinuations during the 6-month follow-up of the study.
      Figure 2
      Figure 2Distribution of the 4 HLQ scales for the overall sample (n = 3,417). Social support for health score range: 1 to 4, Appraisal of health information score range: 1 to 4, Ability to find good health information score range: 1 to 5, Understand health information score range: 1 to 5.
      Table 1Demographic and clinical risk factors of patients at the index admission for percutaneous coronary intervention
      VariableTotal (n=3417)
      Age (year) (mean±SD)65.6 (0.9)
      Male2671 (78%)
      Female746 (22%)
      Danish/ Norwegian2824 (92%)
      Born in Denmark/Norway114 (5%)
      Immigrant135 (4%)
      Cohabitating2326 (76%)
      Living alone747 (24%)
      Education level
      Primary school639 (20%)
      Vocational school1374 (43%)
      High School298 (9%)
      College/University less than 4 years485 (15%)
      College/University 4 years or more380 (12%)
      Employment status
      Working1246 (39%)
      Retired1615 (51%)
      Other338 (11%)
      Medical history
      Anxiety and/or depression382 (11%)
      Atrial fibrillation408 (12%)
      Chronic renal disease156 (5%)
      Coronary artery disease1223 (36%)
      Diabetes598 (18%)
      Hypercholesterolemia1568 (46%)
      Hypertension1773 (52%)
      Percutaneous coronary intervention indication
      Elective percutaneous coronary intervention1317 (39%)
      Non-ST-segment elevation myocardial infarction/Unstable angina pectoris1351 (40%)
      ST-segment elevation myocardial infarction740 (22%)
      Health literacy
      Social support for health (mean±SD)3.0 (0.5)
      Appraisal of health information (mean±SD)2.5 (0.7)
      Ability to find good health information (mean±SD)3.5 (0.8)
      Understanding health information (mean±SD)3.7 (0.7)
      Table 2Behavioral and psychological risk factors for coronary artery disease at the index admission for percutaneous coronary intervention, and adjusted estimated changes in physical activity, smoking status, anxiety and depression from baseline to 6 months follow-up
      VariableBaseline6 monthsEstimate (95% CI)
      The models are adjusted for age, gender, and education level.
      OR (95% CI)
      The models are adjusted for age, gender, and education level.
      p-valueCohen's Kappa (95% CI)
      BMI (kg/m2) (mean±SD)27.7 (4.5)
       <18.522 (1%)
       18.5-24.9937 (28%)
       25- 29.91534 (45%)
       ≥30884 (26%)
      Physical activity (mean±SD)
      Calculated intensity-adjusted weekly physical activity score (Scale 0 to 750).
      103 (114)133 (124)28 (23; 32)<0.001
      Adherence to physical activity recommendation
      Adherent or nonadherent to physical activity recommendations according to a cutoff of 150 min/wk of moderate physical activity or alternatively 75 minutes of high intensity exercise.
       Yes742 (24%)803 (32.5%)1.48 (1.34;1.63)<0.0010.426 (0.387;0.465)
       No2330 (76%)1664 (67.5%)
      Smoking status
       Current smoker529 (17%)247 (10%)1.66 (1.49;1.86)<0.0010.585 (0.536;0.634)
       Nonsmoker2655 (83)2291 (90%)
      HADS-T score (mean±SD)8.43 (6.6)6.26 (6.2)-1.91 (-2.13;-1.70)<0.001
      HADS-A score (mean±SD)4.97 (3.9)3.49 (3.5)-1.35 (-1.48;1.22)<0.001
       <82423 (76%)2167 (86%)<0.0010.323 (0.283;0.362)
       8 - <11447 (14%)245 (10%)
       ≥11323 (10%)122 (5%)
      HADS-D score (mean±SD)3.46 (3.3)2.78 (3.1)-0.57 (-0.69;-0.46)<0.001
       <82753 (86%)2280 (90%)<0.0010.315 (0.266; 0.364)
       8 - <11310 (10%)180 (7%)
       ≥11128 (4%)77 (3%)
      BMI = body mass index; CI = Confidence interval; HADS-A = hospital anxiety and depression scale anxiety; HADS-D = hospital anxiety and depression scale depression; HADS-T = Hospital anxiety and depression scale total; OR = Odds ratio; SD = standard deviation.
      low asterisk The models are adjusted for age, gender, and education level.
      Calculated intensity-adjusted weekly physical activity score (Scale 0 to 750).
      Adherent or nonadherent to physical activity recommendations according to a cutoff of 150 min/wk of moderate physical activity or alternatively 75 minutes of high intensity exercise.
      The associations between the health literacy scales and behavioral and psychologic risk factors for CAD at the index admission for PCI are presented in Table 3. The health literacy scales “ability to find good health information” and “understanding health information well enough to know what to do” were significantly negatively associated with BMI. All the health literacy scales were significantly associated with the intensity-adjusted physical activity score, so that, for a 1-unit higher score on each health literacy scale, the estimated weekly physical activity was 12 to 20 intensity-adjusted minutes higher. Furthermore, the fully adjusted model indicated that the 4 aspects of health literacy were associated with being a nonsmoker: for each 1-unit higher score on the health literacy scales, the odds of being a nonsmoker were 24% (“appraisal of health information”) to 72% higher (“social support for health”). Furthermore, for each 1-unit higher score for “social support for health”, “ability to find health information”, and “understand health information well enough to know what to do”, the HADS-D score was from 1 to 1.6 point lower. Similarly, 3 aspects of health literacy were significantly associated with the HADS-A scale, meaning that for each 1-unit higher score on the health literacy scales, the HADS-A score was 0.85 (“ability to find health information”) to 1.24 (“social support for health”) points lower. Conversely, for each 1-unit higher score for “appraisal of health information”, the HADS-A score was 0.23 points higher (Table 3).
      Table 3Unadjusted and adjusted association between health literacy, BMI, physical activity, HADS and nonsmoking status at baseline
      BMIPhysical activity
      Calculated intensity-adjusted weekly physical activity score (Scale 0 to 750).
      HADS-AHADS-DNonsmoking status
      Logistic regression.
      Coef.(95% CI)p-valueCoef. (95% CI)p-valueCoef.(95% CI)p-valueCoef.(95% CI)p-valueOR (95% CI)p-value
      Social support for health
      Model 1-0.41 (-0.70;-0.12)0.00622.81 (15.24;30.39)<0.001-1.32 (-1.57;-1.06)<0.001-1.78 (-1.99;-1.58)<0.0011.61 (1.36;1.91)<0.001
      Model 2-0.27 (-0.56;0.012)0.06020.55 (12.90;28.19)<0.001-1.34 (-1.59;-1.10)<0.001-1.77 (-1.98;-1.56)<0.0011.63 (1.36;1.95)<0.001
      Model 3-0.17 (-0.45;0.12)0.25219.68 (11.85;27.50)<0.001-1.24 (-1.49;-0.99)<0.001-1.64 (-1.84;-1.43)<0.0011.72 (1.43;2.07)<0.001
      Appraisal of health information
      Model 1-0.01 (-0.25;0.22)0.90514.22 (8.03;20.40)<0.0010.20 (-0.01;0.40)0.063-0.19 (-.036;-0.01)0.0381.28 (1.12;1.47)<0.001
      Model 2-0.03 (-0.26;0.20)0.81411.80 (5.58;18.02)<0.0010.22 (0.01;0.42)0.036-0.15 (-0.32;0.03)0.1080.002
      Model 3-0.10 (-0.33;0.13)0.39211.96 (5.61;18.30)<0.0010.22 (0.01;0.42)0.038-0.17 (-0.35;0.01)0.0601.24 (1.06;1.44)0.007
      Ability to find good health information
      Model 1-0.10 (-0.31;0.10)0.33021.73 (16.42;27.04)<0.001-0.77 (-0.95;-0.59)<0.001-0.98 (-1.13;-0.83)<0.0011.32 (1.17;1.48)<0.001
      Model 2-0.22 (-0.44;-0.01)0.04017.10 (11.35;22.85)<0.001-0.87 (-1.06;-0.68)<0.001-1.03 (-1.19;-0.88)<0.0011.37 (1.20;1.57)<0.001
      Model 3-0.26 (-0.47;-0.05)0.01616.95 (11.08;22.83)<0.001-0.85 (-1.04;-0.66)<0.001-0.99 (-1.15;-0.83)<0.0011.38 (1.20;1.58)<0.001
      Understand health information
      Model 1-0.36 (-0.60;-0.12)0.00326.04 (19.80;32.28)<0.001-1.11 (-1.32;-0.90)<0.001-1.19 (-1.37;-1.02)<0.0011.49 (1.29;1.72)<0.001
      Model 2-0.40 (-0.64;-0.15)0.00120.51 (13.89;27.14)<0.001-1.12 (-1.34;-0.91)<0.001-1.22 (-1.40;-1.04)<0.0011.47 (1.25;1.72)<0.001
      Model 3-0.38 (-0.62;-0.14)0.00219.64 (12.89;26.40)<0.001-1.13 (-1.34;-0.91)<0.001-1.13 (-1.34;0.92)<0.0011.51 (1.28;1.77)<0.001
      BMI = body mass index; CI = Confidence interval; Coef = coefficient; HADS-A = hospital anxiety and depression scale anxiety; HADS-D = hospital anxiety and depression scale depression; OR = Odds ratio.
      Model 1. unadjusted. Model 2: adjusted for age, gender, education level. Model 3: Model 2 plus medical history of CAD, periphery artery disease, atrial fibrillation, chronic renal disease, diabetes, hypercholesterolemia, and hypertension. Additionally, for analysis including HADS; Model 3 was adjusted for medical history of anxiety and depression.
      low asterisk Calculated intensity-adjusted weekly physical activity score (Scale 0 to 750).
      Logistic regression.
      The estimated weekly physical activity score increased by 28 intensity-adjusted minutes from baseline to 6-month follow-up, and adherence to physical activity recommendations increased from 24% to 33%. Further, the proportion of nonsmokers increased during follow-up. Finally, anxiety and depression scores decreased from baseline to 6 months (Table 2).
      In the mixed effects model, none of the 4 health literacy scales were significantly associated with the change in the calculated intensity-adjusted physical activity score or smoking status from baseline to 6-month follow-up (Supplementary Tables 2 and 3). However, patients with lower scores for “social support for health”, “ability to find good health information”, and “understanding health information well enough to know what to do” were more likely to have a greater decrease in their HADS-D score from baseline to 6-month follow-up. However, this subpopulation had a higher score for depression symptoms at baseline, which was also sustained at 6-month follow-up (Figure 3 and Supplementary Table 2). Patients with a higher level for “appraisal of health information” were more likely to have a greater reduction in HADS-A (Figure 3and Supplementary Table 2). The aspects of health literacy were not significantly associated with changes in behavioral risk factors for CAD. Factors associated with missing data at 6 months are presented in Supplementary Table 4.
      Figure 3
      Figure 3Mixed effect models estimating the association of health literacy levels at the index admission on changes in HADS-anxiety and HADS-depression from baseline to 6 months follow-up. Reference: 66-year-old, male, education level primary school. AHI = Appraisal of health information; FHI = Ability to find good health information; SS = Social support for health; UHI = Understand health information well enough to know what to do.

      Discussion

      In this large study of patients attending routine coronary care, lower scores for the 4 aspects of health literacy were significantly associated with being a smoker, having a lower physical activity level, and a higher burden of depression and anxiety. Furthermore, a higher BMI was significantly associated with lower “ability to find health information” and “understanding health information well enough to know what to do”. There was a significant improvement in physical activity and smoking cessation, but these changes were not significantly associated with health literacy. Patients with a lower health literacy score at baseline had a higher burden of depression symptoms but less depression symptoms from baseline to 6-month follow-up. This underpins the need for increased availability of secondary prevention programs, such as eHealth technologies, which can provide easier access to health information and educational materials, including support for physical activity, smoking cessation, and psychologic management.
      • Brørs G
      • Pettersen TR
      • Hansen TB
      • Fridlund B
      • Hølvold LB
      • Lund H
      • Norekvål TM.
      Modes of e-health delivery in secondary prevention programmes for patients with coronary artery disease: a systematic review.
      Lower health literacy was significantly associated with a higher burden of both anxiety and depression at the index admission for PCI. No other studies have determined an association between health literacy and anxiety and depression symptoms in patients with CAD. However, a study of patients with heart failure reported that patients with higher levels of depression had lower health literacy, which impacted their self-care behaviors.
      • Wang B
      • Xia L
      • Yu J
      • Feng Y
      • Hong J
      • Wang W.
      The multiple mediating effects of health literacy and self-care confidence between depression and self-care behaviors in patients with heart failure.
      Another study of patients with chronic kidney disease reported that having more depressive symptoms was negatively associated with health literacy.
      • Stømer UE
      • Gøransson LG
      • Wahl AK
      • Urstad KH.
      A cross-sectional study of health literacy in patients with chronic kidney disease: associations with demographic and clinical variables.
      Because it is well known that depression is associated with an increased risk of a poorer clinical outcome in patients after PCI,
      • Zhang WY
      • Nan N
      • Song XT
      • Tian JF
      • Yang XY
      Impact of depression on clinical outcomes following percutaneous coronary intervention: a systematic review and meta-analysis.
      these results suggest that it is prudent to focus on health literacy in secondary prevention care for patients with depression and anxiety symptoms after PCI. Additionally, there was a significant improvement in depression and anxiety symptoms from baseline to 6-month follow-up and a significant association between health literacy and the changes in depression symptoms over this period. These associations indicated that the health literacy scale “appraisal of health information” was weakly associated with the reduction in anxiety but not with depression symptoms after PCI. However, these associations were small and may be related to the higher burden of symptoms at baseline.
      Patients with lower health literacy were more likely to be less physically active at the index admission for PCI. A 1-unit higher mean scale score for “understand health information well enough to know what to do” has previously been shown to be associated with being physically inactive.
      • Aaby A
      • Friis K
      • Christensen B
      • Rowlands G
      • Maindal HT.
      Health literacy is associated with health behaviour and self-reported health: a large population-based study in individuals with cardiovascular disease.
      Similarly, a Scottish study that examined 5 distinct health literacy profiles in a cardiac rehabilitation setting reported that people with a range of lower health literacy profiles tended to be physically inactive.
      • Walters R
      • Leslie SJ
      • Sixsmith J
      • Gorely T.
      Health literacy for cardiac rehabilitation: an examination of associated illness perceptions, self-efficacy, motivation and physical activity.
      Moreover, although the degree of association between health literacy and BMI and smoking differ in previous studies, our study found that patients with lower health literacy were more likely to have a higher BMI and to be smokers. These results are in line with the AHA scientific statement, which states that health literacy is associated with a healthier lifestyle and favorable behaviors.
      • Magnani JW
      • Mujahid MS
      • Aronow HD
      • Cené CW
      • Dickson VV
      • Havranek E
      • Morgenstern LB
      • Paasche-Orlow MK
      • Pollak A
      • Willey JZ
      American Heart Association Council on Epidemiology and Prevention; Council on Cardiovascular Disease in the Young; Council on Cardiovascular and Stroke Nursing; Council on Peripheral Vascular Disease; Council on Quality of Care and Outcomes Research; and Stroke Council. Health literacy and cardiovascular disease: fundamental relevance to primary and secondary prevention: a scientific statement from the American Heart Association.
      However, the diverse questionnaires used in previous studies limit the opportunity to compare the results.
      There was a significant improvement in physical activity and smoking cessation at the 6-month follow-up, but these changes were not significantly associated with the aspects of health literacy. This result corresponds with another longitudinal study showing a nonsignificant association between health literacy and changes in lifestyle at 6-month follow-up.
      • Lu M
      • Hravnak M
      • Ma J
      • Lin Y
      • Zhang X
      • Shen Y
      • Xia H.
      Prediction of changes in adherence to secondary prevention among patients with coronary artery disease.
      This may relate to the short follow-up period or that, after PCI, patients were motivated and determined to increase physical activity and smoking cessation, irrespective of their health literacy.
      • Fålun N
      • Fridlund B
      • Schaufel MA
      • Schei E
      • Norekvål TM.
      Patients’ goals, resources, and barriers to future change: a qualitative study of patient reflections at hospital discharge after myocardial infarction.
      It is important to emphasize the low proportion adhering to the physical activity recommendations. Although the increase was 50% during follow-up, approximately 2 in every 3 participants were not following the recommendations. Further, only a minority of participants smoked at baseline, and the proportion of smokers decreased during follow-up. For many patients, there already is ample information and support to stop smoking, and it is possible that the specific health literacy scales were not the ones that are most relevant to patients in this setting regarding smoking cessation.
      This study has both strengths and limitations. First, the study is timely given that the AHA scientific statement on health literacy calls for studies determining the associations between health literacy and CAD.
      • Magnani JW
      • Mujahid MS
      • Aronow HD
      • Cené CW
      • Dickson VV
      • Havranek E
      • Morgenstern LB
      • Paasche-Orlow MK
      • Pollak A
      • Willey JZ
      American Heart Association Council on Epidemiology and Prevention; Council on Cardiovascular Disease in the Young; Council on Cardiovascular and Stroke Nursing; Council on Peripheral Vascular Disease; Council on Quality of Care and Outcomes Research; and Stroke Council. Health literacy and cardiovascular disease: fundamental relevance to primary and secondary prevention: a scientific statement from the American Heart Association.
      Second, the cohort design with patient involvement and the use of standardized patient-reported outcome measures, combined with data abstracted from medical records, are robust features of CONCARDPCI.
      • Norekvål TM
      • Allore HG
      • Bendz B
      • Bjorvatn C
      • Borregaard B
      • Brørs G
      • Deaton C
      • Fålun N
      • Hadjistavropoulos H
      • Hansen TB
      • Igland S
      • Larsen AI
      • Palm P
      • Pettersen TR
      • Rasmussen TB
      • Schjøtt J
      • Søgaard R
      • Valaker I
      • Zwisler AD
      • Rotevatn S
      • Investigators CONCARD
      Rethinking rehabilitation after percutaneous coronary intervention: a protocol of a multicentre cohort study on continuity of care, health literacy, adherence and costs at all care levels (the CONCARDPCI).
      Third, the large sample size provides adequate power for the analyses. The study had a high inclusion rate (82%). Although 25% of patients did not respond the outcome questionnaires at 6-month follow-up, there were no significant associations between health literacy, anxiety, or depression at baseline and whether the patients answered the questions or not (Supplementary Table 4). However, smoking status and intensity of physical activity were significantly associated with missingness, and there may be unmeasurable nonresponse bias for these outcomes. A strength of this study is that we used a measure of health literacy designed to detect change in outcomes (the HLQ). However, to reduce respondent burden only 4 of 9 HLQ scales were used. The other scales may have provided insights, such as skills related to actively managing health, relations with healthcare providers, or ability to navigate the healthcare system.
      • Osborne RH
      • Batterham RW
      • Elsworth GR
      • Hawkins M
      • Buchbinder R.
      The grounded psychometric development and initial validation of the Health literacy questionnaire (HLQ).
      Notwithstanding the complexity of health literacy, the scales we included cover pertinent aspects of health literacy, reflecting competencies for participation in the health care process. Health literacy was only measured at the index admission for PCI. Because health literacy is dynamic,
      • Morris NS
      • Maclean CD
      • Littenberg B.
      Change in health literacy over 2 years in older adults with diabetes.
      it is possible that it changed during follow-up, leading to further changes in CAD risk factors. Finally, the generalizability of the results may be limited to high-income countries and/or settings with universal health coverage; therefore, further work is needed across diverse health systems.
      In conclusion, in a population of patients treated with PCI, there was evidence that health literacy was associated with behavioral and psychologic risk factors at the index admission for PCI. Behavioral and psychologic risk factors for CAD control improved from baseline to 6-month follow-up, mostly without significant associations with health literacy. However, most patients did not follow the recommendations for physical activity. Lastly, there was evidence that health literacy was associated with changes in anxiety and depression symptoms at the 6-month follow-up. Strategies for secondary prevention that address barriers to improving modifiable risk factors due to limited health literacy are pivotal in reducing the risk of future CAD events.

      Acknowledgment

      The authors thank Marie Hayes for development of the graphical abstract.

      Disclosures

      The authors have no conflicts of interest to disclose.

      Appendix. Supplementary materials

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