New Pooled Cohort Risk equations: application to a recent stroke patient population

Recently, Pooled Cohort Risk (PCR) equations, which incorporate new sex- and race-specific estimates of the 10-year risk for atherosclerotic cardiovascular disease (ASCVD) including stroke, for ASCVD-free adults were introduced. Given the importance of secondary stroke prevention and benefit of a potential tool to readily identify stroke patients at high intermediate-term vascular risk for appropriate treatment, we evaluated the prediction and discrimination of the PCR and Framingham Cardiovascular Risk (FCR) equations after a recent stroke.

We conducted an analysis of Vitamin Intervention for Stroke Prevention dataset of 3555 recent non-cardioembolic stroke patients aged ≥ 35 years and followed for 2 years. Subjects were categorized as having low-PCR/low-FCR (<20%), high-PCR/high-FCR (≥ 20%), and known-ASCVD. Independent associations of high-PCR/high-FCR with recurrent stroke (primary outcome) and stroke/coronary heart disease (CHD)/vascular death (secondary outcomes) were assessed.

Both PCR and FCR were independently related to both outcomes: compared with low-PCR, high-PCR was associated with stroke (adjusted hazard ratio, 1.79; 95% CI, 1.25-2.57) and stroke/CHD/vascular death (2.05; 1.55-2.70). Compared with low-FCR, high-FCR was associated with stroke (2.06; 1.34-3.16) and stroke/CHD/vascular death (1.57; 1.12-2.20). The c-statistic of PCR/FCR as a continuous variable for stroke was 0.56 (95% CI, 0.54-0.58) and 0.56 (0.54-0.57), respectively and for stroke/CHD/vascular death was 0.62 (0.60-0.63) and 0.61 (0.59-0.63), respectively.

Both PCR and FCR are significant predictors of recurrent vascular events among patients after a recent non-cardioembolic stroke, but neither one of them is an optimal model for discriminating intermediate-term ASCVD prediction among stroke patients already receiving secondary stroke prevention.