Impact of blood pressure and medication adherence on clinical outcomes in patients with hypertension

Abstract

Background: Hypertension is a key risk factor for cardiovascular disease. Thus, effective blood pressure (BP) management and adherence to antihypertensive medications are crucial for reducing these risks in patients with hypertension. We evaluated the effect of BP and medication adherence on the clinical outcomes of patients with hypertension.

Methods: This is retrospective cohort study utilized data from the Korean National Health Insurance Database. We analyzed data from 238,950 patients with hypertension aged ≥20 who underwent at least two health checkups between 2009 and 2012. Patients were categorized according to their systolic BP (SBP) and medication adherence. The primary outcome was a composite of all-cause death, myocardial infarction, ischemic stroke, hemorrhagic stroke, and hospitalization for heart failure. Cox proportional hazard models were used to estimate hazard ratios (HR) for composite outcomes.

Results: Higher SBP groups were associated with increased risk of composite outcomes compared to the 120-129 mmHg group (<120 mmHg, HR 1.065; 130-139 mmHg, HR 1.056; 140-149 mmHg, HR 1.068; and ≥150 mmHg, HR 1.238). In addition, across all SBP categories, poor adherence significantly elevated the risk of composite outcomes, even after adjusting for confounding factors. Among all categories, patients with high SBP (≥150 mmHg) and poor adherence had the highest risk.

Conclusion: Higher SBP and poor medication adherence were independently associated with worse clinical outcomes in patients with hypertension. Strategies to enhance medication adherence and achieve optimal BP control are essential to reduce cardiovascular risk.

Keywords: adherence; blood pressure; cardiovascular disease; hypertension; medication; outcome.

Figure 1

Study population. *Examined variables: systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose, cholesterol, body mass index (BMI), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), triglycerides (TG), creatinine, hemoglobin, waist circumference, and high-density lipoprotein (HDL); questionnaire items: physical activity, smoking status, and alcohol consumption. ^†Prescription of antihypertensive medication along with diagnosis codes I10–I13, I15. Antihypertensive medications include diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors (ACEi), angiotensin II receptor blockers (ARB), and others (such as alpha-blockers and vasodilators).

Figure 2

Forest plot stratified by systolic blood pressure and medication adherence. (A) Forest plot of HRs for the composite primary outcome according to SBP categories and medication adherence levels. (B) Forest plot of HRs for the composite primary outcome according to medication adherence levels and SBP categories. HRs shown are adjusted using Model 3, including age, sex, body mass index, smoking status, alcohol consumption, physical activity, household income, Charlson comorbidity index, and use of glucose- and lipid-lowering drugs. The reference group had an SBP of 120–129 mmHg and good adherence. The plot illustrates the increased risk associated with higher SBP and poorer adherence to antihypertensive medication. CI, confidence interval; HR, hazard ratio; SBP, systolic blood pressure.