Analyses for the selection of the risk score model were based on the 467 patients allocated to the conventional therapy group in MADIT-II not falling in the VHR group. Of the 17 variables that were pre-specified as potential risk-stratifiers, 5 (female gender, a history of treated hypertension, previous documented ventricular tachyarrhythmias, systolic blood pressure <100 mm Hg, and smoking at any time) had hazard ratios <1.30 and p values exceeding 0.20 for all-cause mortality and were therefore dropped from further consideration as candidates for risk stratification. The remaining 12 variables were considered extensively for the development of the risk score (Table 3). When considered alone, the first 7 (atrial fibrillation [defined as the baseline rhythm at enrollment], BUN >26 mg/dl, NYHA functional class >II [defined as the highest functional class recorded in the 3-month period before enrollment], age >70 years, the presence of left bundle branch block [LBBB], a QRS duration >0.12 s, and serum creatinine >1.3 mg/dl) had hazard ratios for mortality in conventionally treated patients of 1.85 or greater and with p values <0.005 (except for LBBB, having smaller numbers because of missing data). The remaining 5 (EF <20%, heart rate ≥80 beats/min, number of hospitalizations in the year before enrollment >1, body mass index <25 kg/m2, and a history of treated diabetes mellitus) had hazard ratios ranging from 1.58 down to 1.48, with p values ranging from 0.04 to 0.06. The best-subset proportional-hazards regression, using these 12 binary covariates, led to a model with the 5 risk factors: age, NYHA functional class, BUN, atrial fibrillation, and QRS duration (Table 4). Although high levels of creatinine and the presence of LBBB were found to be powerful univariate predictors of outcome, these 2 risk factors did not provide incremental prognostic information when elevated BUN and a wide QRS duration (>0.12 s), respectively, were allowed in the multivariate model.