The association between multimorbidity and poor adherence with cardiovascular medications

Multimorbidity, defined as the presence of two or more chronic conditions, leads to a substantial public health burden. This study evaluated its association with adherence with cardiovascular medications in a Chinese population. A proportional stratified sampling was adopted to draw a representative sample of residents living in Henan Province, China. Interviewer-administered surveys were conducted by trained researchers. The outcomes included the number of chronic medical conditions, adherence with long-term medications (MMAS-8), and depressive symptoms (CESD-20). Binary logistic regression analysis was conducted to evaluate if medication adherence was associated with the presence of multimorbidity. From a total of 3866 completed surveys, the proportion of subjects having 0, 1 and ≥2 chronic conditions was 62.6%, 23.8% and 13.5%, respectively. Among 27.6% who were taking chronic medications, 66.6% had poor medication adherence (MMAS-8 score≤6). From binary logistic regression analysis, subjects with poor medication adherence were significantly associated with multimorbidity (adjusted odds ratio [AOR]: 1.35, 95% C.I. 1.02-1.78, p=0.037). Other associated factors included older age (AOR=1.04, 95% C.I. 1.03-1.05, p<0.001), smoking (AOR=1.63, 95% C.I. 1.16-2.30, p=0.005), family history of hypertension (AOR=1.51, 95% C.I. 1.19-1.93, p=0.001), and fair to poor self-perceived health status (AOR=2.15, 95% C.I. 1.69-2.74, p<0.001). Using medication adherence as the outcome variable, multimorbidity was significantly associated with poor drug adherence (AOR=1.34, 95% C.I. 1.02-1.77, p=0.037). Multimorbidity was associated with poorer medication adherence. This implies the need for closer monitoring of the medication taking behavior among those with multiple chronic conditions.