Prevalence and associated factors of adherence to antihypertensive medication: a nationwide cross-sectional study

Abstract

Background: Hypertension is the leading modifiable risk factor for cardiovascular diseases, contributing significantly to global morbidity and mortality. Despite advancements in antihypertensive therapies, adherence to medication remains alarmingly low, particularly in low- and middle-income countries. There is limited representative research in Pakistan on adherence rates and associated factors, necessitating a comprehensive investigation. Objective: To determine the prevalence of adherence to antihypertensive medication and identify factors influencing adherence among hypertensive patients across Pakistan. Methods: A nationwide cross-sectional study was conducted between September 2021 and January 2023 across 225 healthcare facilities in Pakistan. A multistage random sampling strategy recruited 32,197 hypertensive patients. Adherence was assessed using the Self-Efficacy for Appropriate Medication Scale (SEAMS) and pill count methods. Multivariable binary regression analysis identified sociodemographic and clinical predictors of adherence. Results: Adherence to antihypertensive medication was observed in only 36.6% of hypertensive patients, with significant regional and demographic variations. Factors positively associated with adherence to antihypertensive medications include male gender (AOR = 4.64, 95% CI [1.53–14.11]), graduate education compared to postgraduate education (AOR = 1.23, 95% CI [1.08–1.39]), higher daily medication (> 9) compared to less (< 5) medications (AOR = 2.00; 95% CI [1.84–2.19]), higher daily dose frequency compared to single dose, and higher monthly income compared to less than 25,000/month. Conversely, negative associations include primary/secondary education to postgraduate (AOR = 0.16, 95% CI [0.14–0.18]), single marital status compared to married (AOR = 0.02 95% CI [0.01–0.04]), more than one comorbid condition (AOR = 0.81, 95% CI [0.74–0.89], smoking (AOR = 0.09, 95% CI[0.08–0.10]), uncontrolled hypertension (AOR = 0.74, 95% CI [0.69–0.78), and the rest of the regions compared to Islamabad. Conclusion: These findings highlight the complex interplay of demographics, medication patterns, and economic factors in medication adherence with very low adherence rates in Pakistan. Targeted, context-specific interventions—addressing affordability, education, and better awareness could potentially improve the adherence rates.