Medication adherence among people living with hypertension and diabetes in Puno, Peru: A secondary analysis of formative data of the ANDES trial

Background: Hypertension is the leading modifiable risk factor for premature death globally despite the existence of evidence-based and cost-effective treatments. Medication nonadherence is cited as the main cause of treatment failure for hypertension. In Peru, adherence to anti-hypertensive medications of individuals with both hypertension and type 2 diabetes (T2D) is not well studied. The few studies that have investigated differences in anti-hypertensive medication adherence among patients with and without T2D have demonstrated both positive and negative effects. Methods: In a cross-sectional study in Puno, Peru, we compared anti-hypertensive medication adherence in individuals with hypertension between those with and without comorbid T2D. The primary outcome was adherence to anti-hypertensive medications as assessed by the Hill-Bone Compliance scale. The primary exposure variable was comorbidity status (i.e., having hypertension and diabetes vs. hypertension alone). Results: Of the 204 participants with hypertension (mean age 67 +/- 11 years, 60% female), 42 (21%) had comorbid diabetes. Participants with comorbid disease had higher overall anti-hypertensive adherence scores (49.5 +/- 2.8 vs. 48.0 +/- 4.1 points; p<0.001) and higher medication adherence scores (32.8 +/- 2.2 vs. 31.3 +/- 3.7 points; p<0.01) when compared to those with hypertension alone. In multivariable regression, comorbid diabetes and monthly income above 250 soles (68 USD) were associated with higher Hill-Bone Compliance scale scores by 1.5 +/- 0.7 points (p=0.025) and 2.0 +/- 0.7 points (p<0.01), respectively. Conclusions: Participants with comorbid hypertension and diabetes exhibited higher adherence to anti-hypertensive medications when compared to those with hypertension alone, suggesting that individuals with comorbid disease are more likely to adhere to anti-hypertensive medications.