Relationship of Troponin T and Age- and Sex-Adjusted BNP Elevation Following Subarachnoid Hemorrhage with 30-Day Mortality

Background: Troponin and brain natriuretic peptide (BNP) levels are predictors of mortality following subarachnoid hemorrhage (SAH). Prior studies used strict cutoffs for BNP elevation; however, normal levels of BNP are increased in older persons and women. We explored the association of troponin elevation and BNP elevation adjusted for sex and age with 30-day mortality. Methods: In this retrospective cohort study of patients with SAH, collected data included peak troponin T and BNP levels. Mortality data were obtained from inpatient mortality data and available records. Troponin T elevation was defined as more than 0.10 ng/mL; BNP elevation was defined as greater than the 95th percentile reference limit by age and sex for patients without cardiovascular disease. Associations of elevated troponin T and BNP were estimated from a log-binomial regression model reporting relative risks (RRs), 95 % CIs, and P values; missing data were imputed with the sample median or most frequent category. Results: This study included 175 SAH patients. In single-variable analysis, peak troponin T level greater than 0.10 ng/mL was associated with increased risk in 30-day mortality (RR 4.38; 95 % CI 2.43–7.89; P < .001); there was no association with elevated peak BNP adjusted for age and sex (RR 1.13; 95 % CI 0.55–2.35; P = .74). There was no evidence suggesting that the combination of elevated peak BNP and elevated peak troponin increased the risk of 30-day mortality. Conclusions: Elevated troponin was an independent predictor of 30-day mortality following SAH; however, when adjusted for age and sex, elevations in BNP did not have this association.