Baseline Quality of Life and Risk of Stroke in the ALLHAT Study (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial)
AbstractBackground and Purpose—
The visual analogue scale is a self-reported, validated tool to measure quality of life (QoL). Our purpose was to determine whether baseline QoL predicted strokes in the ALLHAT study (Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial) and evaluate determinants of poststroke change in QoL. In the ALLHAT study, among the 33 357 patients randomized to treatment arms, 1525 experienced strokes; 1202 (79%) strokes were nonfatal. This study cohort includes 32 318 (97%) subjects who completed the baseline visual analogue scale QoL estimate.Methods—
QoL was measured on a visual analogue scale and adjusted using a Torrance transformation (transformed QoL [TQoL]). Kaplan–Meier curves and adjusted proportional hazards analyses were used to estimate the effect of TQoL on the risk of stroke, on a continuous scale (0–1) and by quartiles (≤0.81, >0.81≤0.89, >0.89≤0.95, >0.95). We analyzed the change from baseline to first poststroke TQoL using adjusted linear regression.Results—
After adjusting for multiple stroke risk factors, the hazard ratio for stroke events for baseline TQoL was 0.93 (95% confidence interval, 0.89–0.98) per 0.1 U increase. The lowest baseline TQoL quartile had a 20% increased stroke risk (hazard ratio=1.20 [95% confidence interval, 1.00–1.44]) compared with the reference highest quartile TQoL. Poststroke TQoL change was significant within all treatment groups (P≤0.001). Multivariate regression analysis revealed that baseline TQoL was the strongest predictor of poststroke TQoL with similar results for the untransformed QoL.Conclusions—
The lowest baseline TQoL quartile had a 20% higher stroke risk than the highest quartile. Baseline TQoL was the only factor that predicted poststroke change in TQoL.Clinical Trial Registration—
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000542.