Hierarchical linear and logistic modeling of outcomes of antihypertensive treatment in elderly patients: findings from the PREVIEW study

Achieving guideline-recommended blood pressure targets is difficult in older adults with hypertension. We completed a subgroup analysis of patients 65 years of age or older enrolled in PREVIEW, a prospective, multicenter, pharmacoepidemiological study of the determinants and outcomes of second-line antihypertensive treatment with valsartan in Belgium. Multilevel modeling was used to identify physician- and patient-level determinants of blood pressure values and practice guideline-derived definitions of blood pressure control. Data on 1560 patients and 504 physicians were used in this analysis. Blood pressure control rates for patients age 65 and over were lower for systolic (34.2% vs. 38.6%) and combined systolic/diastolic blood pressure (31.2% vs. 34.4%) compared to the entire PREVIEW sample. Twenty-seven percent of the variability in systolic, and 32% in diastolic pressure after 90 days of treatment were attributable to such variables as physicians' knowledge and adherence to evidence-based guidelines, practice patterns, and experience; with the remaining variance attributable to various demographic, behavioral, and clinical patient-related factors. Several independent predictors of uncontrolled blood pressure after 90 days of treatment were identified, largely confirming factors identified as determinants of blood pressure values. Recommendations for managing hypertension in the elderly are made in view of these findings.