kjhp Korean Journal of Health Promotion Korean J Health Promot 2234-2141 2093-5676 The Korean Society of Health Promotion and Disease Prevention 10.15384/kjhp.2015.15.3.121 kjhp-15-121 Original Article Medication Adherence and its Predictors in Community Elderly Patients with Hypertension BaeSang Geun 1 JeonHye Ji 2 YangHyeon Su 2 KimBo Kyoung 2 ParkKi Soo 2 3 Department of Preventive Medicine, Kyungpook National University School of Medicine, Daegu, Korea Department of Preventive Medicine and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea Regional Cardiocerebrovascular Disease Center, Gyeongsang National University Hospital, Jinju, Korea Corresponding author：Ki Soo Park, MD, PhD Department of Preventive Medicine and Institute of Health Sciences, Gyeongsang National University School of Medicine, 15 Jinju-daero 816beon-gil, Jinju 52727, Korea Tel: +82-55-772-8095, Fax: +82-55-772-8099 E-mail: parkks@gnu.ac.kr 122015 19122015 153 121128 30052015 09092015 Copyright © 2015 The Korean Society of Health Promotion and Disease Prevention 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Background

Medication adherence is important for hypertension management but still stay low level. It is reasonable method to classify medication nonadherence into intentional nonadherence and unintentional nonadherence and manage it according to this categories. This study aimed to explore medication adherence and its predictors in community patients with hypertension, especially dividing into intentional nonadherence and unintentional nonadherence.

 Methods

Study subjects included 1,988 patients who were prescribed hypertension drugs among 2012 community health survey subjects of 10 cities in Gyeongsangnamdo and we analyzed medication adherence with hypertension and its predictors. We conducted chi-square test for nominal variable and ANOVA test for continuous variable and use multinominal regression to analyze independent predictors of intentional nonadherence and unintentional nonadherence in contrast to medication adherence.

 Results

Of the 1,988 patients, 49.7% were adherent, 26.1% were unintentionally nonadherent and 24.2% intentionally nonadherent. Independent predictors of unintentional nonadherence were depressive symptoms (odds ratio [OR]=1.696, P=0.047) and arthritis (OR=1.319, P=0.030) and independent predictors of intentional nonadherence were cardiocerebrovascular disease (OR=1.464, P=0.044), self-efficacy (OR=0.984, P=0.007), beliefs about medications questionnaire (necessity [OR=0.834, P<0.001] and concern [OR=1.236, P<0.001]).

 Conclusions

In order to manage hypertension in community, improvement in medication adherence is needed. Depressive symptom and self-efficacy need to be managed, but especially patients’beliefs about their medication need to be considered to improve intentional nonadherence.

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General characteristics and medication adherencea

Total Medication adherence Pb
Adherent Non-adherent
Unintentional Intentional
Age, y 68.8±10.4 69.3±9.9 (A) 69.3±10.2 (B) 67.1±11.3 (C) <0.001 (A=B≠C)
Sex 0.659
Male 675 (34.0) 344 (51.0) 168 (24.9) 163 (24.1)
Female 1,313 (66.0) 645 (49.1) 350 (26.7) 318 (24.2)
Educational level 0.119
≤Primary school 786 (39.5) 401 (51.0) 195 (24.8) 190 (24.2)
Middle school 658 (33.1) 333 (50.6) 184 (28.0) 141 (21.4)
≥High school 544 (27.4) 255 (46.9) 139 (25.6) 150 (27.6)
Monthly incomec, million (Korean won) 0.218
<100 1,245 (65.3) 621 (49.9) 324 (26.0) 300 (24.1)
100-200 313 (16.4) 160 (51.1) 88 (28.1) 65 (20.8)
200-300 174 (9.1) 86 (49.4) 37 (21.3) 51 (29.3)
≥400 175 (9.2) 76 (43.4) 51 (29.1) 48 (27.4)
Spouse 0.312
Yes 1,236 (62.2) 609 (49.3) 336 (27.2) 291 (23.5)
No 752 (37.8) 380 (50.5) 182 (24.2) 190 (25.3)
Depressive symptoms 0.015
Yes 98 (4.9) 35 (35.7) 33 (33.7) 30 (30.6)
No 1,890 (95.1) 954 (50.5) 485 (25.7) 451 (23.9)
Self-rated health status 0.417
Good or normal 912 (45.9) 466 (51.1) 237 (26.0) 209 (22.9)
Bad 1,076 (54.1) 523 (48.6) 281 (26.1) 272 (25.3)
Good sleep 0.167
Yes 923 (46.4) 458 (49.6) 256 (27.7) 209 (22.6)
No 1,065 (53.6) 531 (49.9) 262 (24.6) 272 (25.5)
CVD 0.604
Yes 229 (11.5) 108 (47.2) 60 (26.2) 61 (26.6)
No 1,759 (88.5) 881 (50.1) 458 (26.0) 420 (23.9)
Arthritis 0.064
Yes 823 (41.4) 387 (47.0) 235 (28.6) 201 (24.4)
No 1,165 (58.6) 602 (51.7) 283 (24.3) 280 (24.0)
Stressc 0.071
High 484 (24.4) 226 (46.7) 122 (25.2) 136 (28.1)
Low 1,502 (75.6) 762 (50.7) 395 (26.3) 345 (23.0)
Health education 0.087
Yes 587 (29.5) 287 (48.9) 140 (23.9) 160 (27.3)
No 1,401 (70.5) 702 (50.1) 378 (27.0) 321 (22.9)
Social support 17.1±3.4 17.2±3.4 (A) 17.2±3.4 (B) 16.6±3.5 (C) 0.002 (A=B≠C)
Self efficacy 34.6±11.8 35.2±12.0 (A) 34.3±11.7 (B) 33.4±11.5 (C) 0.017 (A=B≠C)

Total 1,988 (100.0) 989 (49.7) 518 (26.1) 481 (24.2) Abbreviation: CVD, cardiocerebrovascular disease.

Values are presented as N (%) or mean±SD.

Calculated by chi-squre-test or analysis of variance (Turkey multiple comparison).

Missing values are presented.

BMQ and medication adherencea

Total Medication adherence Pb
Adherent Non-adherent
Unintentional Intentional
BMQ (necessity) 17.6±3.9 17.9±3.9 (A) 17.7±3.8 (B) 16.6±3.8 (C) <0.001 (A=B≠C)
BMQ (concerns) 13.6±2.9 13.3±2.9 (A) 13.4±3.0 (B) 14.4±2.9 (C) <0.001 (A=B≠C)

Abbreviation: BMQ, beliefs about medicines questionnaire.

Values are presented as mean±SD.

Calculated by analysis of variance (Turkey multiple comparison).

Predictors of medication adherencea

Unintentional nonadherence versus adherence Intentional nonadherence versus adherence
OR 95% CI P OR 95% CI P
Lower Upper Lower Upper
Stress (high/low) 0.958 0.728 1.261 0.759 1.171 0.882 1.556 0.275
Depressive symptoms (yes/no) 1.696 1.008 2.854 0.047 1.376 0.782 2.423 0.268
Self-rated health status (good or normal/bad) 0.949 0.737 1.221 0.683 0.813 0.620 1.067 0.136
CVD (yes/no) 1.084 0.758 1.549 0.658 1.464 1.010 2.122 0.044
Arthritis (yes/no) 1.319 1.028 1.693 0.030 1.288 0.984 1.685 0.065
Health education (yes/no) 0.898 0.699 1.154 0.266 1.027 0.793 1.330 0.839
Social support 0.999 0.966 1.033 0.958 0.970 0.935 1.007 0.108
Self efficacy 0.993 0.983 1.004 0.208 0.984 0.973 0.996 0.007
BMQ (necessity) 0.971 0.938 1.005 0.096 0.834 0.802 0.868 <0.001
BMQ (concerns) 1.019 0.977 1.062 0.393 1.236 1.179 1.296 <0.001

Abbreviations: OR, odds ratio; CI, confidence interval; CVD, cardiocerebrovascular disease; BMQ, beliefs about medicines questionnaire.

Calculated by multinomial regression, adjusted for age, sex, education, monthly income and spouse.

Predictors of beliefs about medication questionnairea

Necessity Concerns
Unstandardized coefficients P Unstandardized coefficients P
B SE B SE
Stress (high/low) -0.311 0.197 0.116 -0.165 0.161 0.305
Depressive symptoms (yes/no) -0.509 0.384 0.185 -0.332 0.313 0.289
Self-rated health status(good or normal/bad) 1.516 0.180 <0.001 0.801 0.146 <0.001
CVD (yes/no) -1.374 0.256 <0.001 -0.592 0.208 0.005
Arthritis (yes/no) -0.628 0.182 0.001 -0.281 0.148 0.058
Health education (yes/no) 0.636 0.178 <0.001 -0.446 0.145 0.002
Social support 0.068 0.024 0.005 -0.028 0.020 0.162
Self efficacy -0.022 0.008 0.004 -0.019 0.006 0.003

Abbreviations: B, β SE, standard error; CVD, cardiocerebrovascular disease.

Calculated by multiple regression adjusted for age, sex, education, monthly income and spouse.