A propensity-matched study of hypertension and increased stroke-related hospitalization in chronic heart failure

Hypertension is a risk factor for heart failure and stroke. However, the effect of hypertension on stroke in patients with heart failure has not been well studied. In the Digitalis Investigation Group trial, 3,674 (47%) of the 7,788 patients had a history of hypertension. Probability or propensity scores for a history of hypertension were calculated for each patient through use of a multivariable logistic regression model and were then used to match 2,386 pairs of patients with and without a history of hypertension. Kaplan-Meier and matched Cox regression analyses were used to estimate associations of a history of hypertension hospitalization for stroke during 37 months of median follow-up. After matching, patients without and with a history of hypertension had a mean systolic blood pressure of 127 mm Hg. Hospitalization for stroke occurred in 90 patients (rate, 129/10,000 person-years of follow-up) without a history of hypertension and 121 patients (rate, 178/10,000 person-years of follow-up) with a history of hypertension (hazard ratio when hypertension was compared with no hypertension=1.52; 95% confidence interval=1.11 to 2.08; p=0.010). This association was also observed among patients with baseline systolic blood pressure <140 mm Hg (hazard ratio=1.35; 95% confidence interval=1.01 to 1.81; p=0.044). In conclusion, a history of hypertension was associated with increased risk of hospitalization for stroke among patients with heart failure who were balanced in all measured baseline covariates, including blood pressure.