Effect of antihypertensive medication adherence on hospitalization for cardiovascular disease and mortality in hypertensive patients

Abstract

Antihypertensive medication treatment is one effective management strategy to prevent cardiovascular disease (CVD) and mortality. However, little research has been conducted on the rates of antihypertensive medication adherence and the effect of antihypertensive medication adherence on health outcomes in South Korea. We searched the Korean National Health Insurance Claims Database for records from 2003 to 2007. Patients in this study were 18 years of age or older and they were diagnosed with hypertension and newly prescribed antihypertensive medication in 2003. Adherence to antihypertensive medication was estimated as the medication possession ratio (MPR). Multivariate Cox regression was used to evaluate the association between medication adherence and adverse health outcomes after adjusting for patient demographics and clinical characteristics. Our study population consisted of 40,408 patients with a mean age of 51 years. Among the patients, 50.3% were men, 4.0% had Medicaid health insurance, 17.8% had diabetes, 20.9% had dyslipidemia and 42.4% were adherent (MPR ≥ 80%). Nonadherent patients (MPR<80%) were younger and more likely to have Medicaid health insurance; they had lower rates of diabetes and dyslipidemia compared with adherent patients. In the Cox multivariate analysis, nonadherence increased the risk of all adverse health outcomes, including all-cause mortality and hospitalization for CVD (hazard ratio: 1.57, confidence interval: 1.40-1.76). In conclusion, our study indicates that medication adherence is important for reducing hospitalization due to CVD and mortality.

Medication Adherence and the Risk of Cardiovascular Mortality and Hospitalization Among Patients With Newly Prescribed Antihypertensive Medications

“…Our study provides further support for previous findings 12,13,31 about the association of adherence to antihypertensive medication on hospitalization for CVD. Compared with those patients with good medication adherence, patients with poor adherence were 1.42× more likely to require hospitalization for AMI.…”

“…32,33 Whereas many previous findings were restricted to patients with diabetes mellitus or with previous CVD, [34][35][36] few studies have reported the importance of hypertensive medication adherence in primary prevention. Most research into primary prevention found a relationship between adherence to antihypertensive medication and CVD events 12,31,32 or all-cause mortality.…”

“…10,18,19 In a cohort study using the Korean National Health Insurance Claims Database (KNHICD), nonadherence to antihypertensive therapy increased all-cause mortality and the risk of hospitalization for CVD (HR, 1.57; 95% CI, 1.40-1.76). 12 However, this study did not include the patients' cause of death and hence was not able to evaluate specific CVD mortality among the Korean population.…”

“…A meta-analysis reported that patients adherent to antihypertensive medications showed better blood pressure control, compared with those who were nonadherent (odds ratio, 3.44; 95% confidence interval [CI], 1.60-7.37). 11 Evidence is mounting that patients who show poor adherence to antihypertensive medication have a higher risk of adverse outcomes, including allcause hospitalization and CVD hospitalization, 12,13 and they have higher healthcare costs 14 compared with patients with good adherence. 12,13,15 A recent cohort study 15 reported that a good-adherence group had a significantly lower incidence of acute cardiovascular events, compared with a group with poor adherence to antihypertension medication (hazard ratio [HR], 0.62; 95% CI, 0.40-0.96).…”

“…11 Evidence is mounting that patients who show poor adherence to antihypertensive medication have a higher risk of adverse outcomes, including allcause hospitalization and CVD hospitalization, 12,13 and they have higher healthcare costs 14 compared with patients with good adherence. 12,13,15 A recent cohort study 15 reported that a good-adherence group had a significantly lower incidence of acute cardiovascular events, compared with a group with poor adherence to antihypertension medication (hazard ratio [HR], 0.62; 95% CI, 0.40-0.96). Pittman et al 16 also reported that patients with a medication adherence of ≥80% decreased their risk of CVD-related hospitalization by 33% (odds ratio, 1.33; 95% CI, 1.25-1.41) and emergency department visits by 45% (odds ratio, 1.45; 95% CI, 1.33-1.58).…”