Comparing electrophysiological biomarkers and circulating cardiac biomarkers in predicting cardiovascular mortality and all-cause mortality in the akershus sleep apnea (ASAP) epidemiological cohort

Abstract

Abstract Background Major cardiovascular events (MACE) and mortality in obstructive sleep apnea (OSA) patients have been frequently reported. However, there is an ongoing debate regarding biomarkers predicting MACE and mortality in OSA. The Apnoea Hypopnea Index (AHI) has been used to assess the severity of Obstructive Sleep Apnea (OSA) despite poor association with adverse outcomes in OSA patients. Novel electrophysiological biomarkers (EPBs) such as desaturation parameters have been suggested as an alternative, and have been reported to be stronger predictors of cardiovascular mortality and heart failure. However, circulating cardiac biomarkers (CCBs) remain strong predictors of mortality and cardiovascular disease in the general population. Purpose To detect the incidence of MACE and all-cause mortality after a median of 13.8 years follow-up in individuals with OSA, and to assess the ability of CCBs and EPBs to predict MACE and all-cause mortality. Methods Polysomnography and CCB analyses (cardiac troponin I (cTnI) and T (cTnT)) were conducted in 459 participants in the Akershus Sleep APnea study (ASAP) between 2006-2008. EPBs evaluated were the AHI, oxygen desaturation index (ODI), desaturation duration (DesDur) and desaturation severity (DesSev). Cox regression and cumulative incidence Kaplan-Meier curves were used for survival analysis. Comparison of EPBs and CCBs in predicting MACE and all-cause mortality was assessed by the area under the curve (AUC). Results 77 and 35 participants reached the endpoint of MACE and all-cause mortality, respectively. In the adjusted cox regression model, cTnI and cTnT were significantly associated with MACE with a hazard ratios of 1.84 [95% Confidence interval [CI], 1.43, 2.37] and 1.52 [1.05, 2.20], respectively. Association of these CCBs with all-cause mortality was with a hazard ratios of 2.02 [1.38, 2.96] and 1.75 [1.05, 2.92], respectively. Moreover, cTnI had the highest AUC of 0.77 and 0.75 in predicting MACE and all-cause mortality. Notably, high AHI, ODI, DesDur and DesSev (upper quartile) increased the cumulative incidence of MACE and all-cause mortality in the subgroup of patients with high CCBs (upper quartile) compared to the subgroup of patients with high CCBs and low EPBs (lower quartile). Conclusion CCBs were more associated with all-cause mortality and MACE than EPBs in ASAP epidemiological cohort. However, the tested EPBs are important biomarkers that increase CCBs prediction of both MACE and all-cause mortality.