Prevalence and factors associated with adherence to anti-hypertensives among adults with hypertension in a developed Asian community: A cross-sectional study

Introduction: Poor adherence to anti-hypertensive medications (AHM) results in hypertension treatment failure. Understanding and addressing the factors associated with adherence to AHM may potentially improve health outcomes. This study aimed to assess the prevalence and factors associated with patients’ adherence to AHM in a developed Asian community. Methods: An assistant-administered questionnaire survey was conducted on multi-ethnic Asian adults aged 31–80 years with essential hypertension based on their electronic health records (EHR) at a public primary-care clinic. Data on their demographic characteristics, clinical measurements of blood pressure and body mass index, co-morbidities and prescriptions from the EHR, along with the Medication Adherence Report Scale-5 scores were collated, audited and analysed. A MARS-5 score of <25 indicated poor adherence. Logistic regression was used to identify factors associated with adherence to AHM. Results: Data of 395 patients were analysed. Of these, 179 (45.3%) had poor adherence to at least one AHM. Bivariate analysis showed that poor adherence was significantly associated with lower mean age (59 years old vs. 63 years old), higher mean clinic diastolic blood pressure (76 mmHg vs. 73 mmHg) and higher mean weight (70.4 kg vs. 67.4 kg). Logistic regression showed that patients with no co-morbidities (such as diabetes mellitus, dyslipidaemia, stroke and ischaemic heart disease) had better medication adherence (MA; odds ratio=1.98; 95% confidence interval 1.14–3.45; p=0.02). There was no significant MA difference between the classes, dose frequency and number of AHM. Conclusion: Almost half of the patients had poor adherence to at least one AHM. Co-morbidity significantly influenced their MA. Attention should be directed to patients with co-morbidities to assess their AHM adherence.