Evaluation of a Fixed-Dose Combination Antihypertensive Therapy versus Monotherapy on Medication Adherence and Blood Pressure Control: A Prospective Cohort Study

Background: Suboptimal medication adherence represents a critical obstacle to achieving target blood pressure levels in hypertensive patients globally. Fixed-dose combination (FDC) formulations have demonstrated potential for enhancing therapeutic compliance through streamlined dosing protocols and reduced medication complexity. To evaluate comparative effectiveness of fixed-dose combination antihypertensive regimens versus conventional monotherapy and free-combination approaches regarding medication adherence patterns and blood pressure management outcomes. Methods: This 6-month prospective observational cohort study recruited 1,248 treatment-naïve adults (ages 35-75) with newly diagnosed essential hypertension from three metropolitan primary care centers in Hyderabad, Pakistan between January and July 2025. Primary endpoint assessed medication adherence via proportion of days covered (PDC) methodology. Secondary endpoints included blood pressure target achievement rates, time-to-control intervals, and major adverse cardiovascular events. Results: FDC recipients (n=624) exhibited substantially superior medication adherence versus control participants (n=624), with mean PDC values of 82.4% compared to 64.7% (p