Adequacy of blood pressure control and level of adherence with antihypertensive therapy

Objectives: To determine the adequacy of blood pressure (BP) control and level of adherence to pharmacotherapy in hypertensive out-patients.Design: Cross-sectional study.Setting: General medical outpatient clinics at a tertiary referral hospital, Kenyatta National Hospital.Subjects: Hypertensive with at least one documented renewal of prescription. Main outcome measure: Adequacy of BP control and level of adherence by the Hill- Bone score.Results: Of 783 patients screened over a six month period, 575 (73%) met the inclusion criteria and 264 were randomly recruited; 67% were female; mean age was 57.3 years; mean duration of hypertension was 6.75 years (range six months to 31 years);21.6% had normal BMI. Knowledge of lifestyle measures for BP control was weight loss 50%, exercise 54% and salt restriction 80%. Number of antihypertensives prescribed were 35.2% two drugs, 36.6% three drugs and 14.9% on four or more drugs; with drugs class being thiazide diuretics 64.1%, B-blockers 55.7%, calcium channel blockers 55.3% and angiotensin system inhibitors at 50.4%. Sixty eight (26%) had adequate BP control and 114 (58.5%) of those with inadequate BP control had BP of > 160/l00mmHg. Eightyfour (31.8%) of the patients were fully adherent to antihypertensive therapy. Non adherence was not significantly associated with any socio-demographic factors. Poor BP control was significantly associated with non adherence (p=0.006, r2=0.54 SBP, 0.63 DBP), obesity (p=0.03), and increasing number of medications (p=0.012 DBP and 0.038 SBP);other factors included obesity, suboptimal dosing and suboptimal therapeuticcombinations. Conclusion: We document poor BP control in 75% of our treated hypertensive patients and this is largely due to non adherence, with other associated factors being obesity, suboptimal drug combinations and doses.