Adherence to Antihypertensives in Patients With Comorbid Condition

BACKGROUND: Comorbidity has been noted as a potential barrier to proper adherence to antihypertensive medications. OBJECTIVES: We decided to investigate whether comorbidity could significantly affect adherence of Iranian patients with hypertension to their medication regimen. PATIENTS AND METHODS: Two hundred and eighty consecutive hypertensive patients were interviewed in 4 cities of Iran. The 8-item Morisky medication adherence scale (MMAS-8) (validated in Persian) was used to assess medication adherence. This scale determines adherence by scores as lower than 6 (low adherence), 6 or 7 (moderate adherence), and 8 (high adherence). Comorbidity was considered as any concomitant medical condition, which necessitates the patient to take medicine for a minimum of 6 months prior to the interviews. RESULTS: The most common comorbid conditions were ischemic heart disease (65 patients, 23.2%), diabetes mellitus (55 patients, 19.6%), and dyslipidemia (51 patients, 18.2%). Mean (± SD) MMAS-8 score in comorbid group was 5.68 (± 1.85) and in non-comorbid hypertensive patients, it was 5.83 (± 1.91) (P = 0.631). Mean (± SD) number of comorbidities was 1.53 (± 0.75) in low adherence group compared to 1.54 (± 0.77) in moderate/high adherers (P = 0.98). With increasing the number of comorbid diseases, the proportion of patients with high adherence decreased successively from 20% in those with no comorbid disease to 14.1% in those with one or two comorbid conditions, and finally 11.1% in those with 3 to 5 comorbid conditions. CONCLUSIONS: With increasing the number of comorbid conditions, the proportion of patients with high adherence decreases. In our opinion, this finding is a useful clinical note for healthcare providers when managing patients with hypertension who have other medical problems at the same time.