All-cause mortality and competing risks of fatal and nonfatal vascular events in the Italian longitudinal study on aging: impact of lipoprotein(a)

Abstract

Among possible determinants of vascular events, the role of high lipoprotein(a) (Lp[a]) serum levels represents a still uncertain independent risk factor in elderly populations. Moreover, the cumulative incidence of nonfatal vascular events due to high Lp(a) serum levels is conditioned by the competing risk of death from any causes that are a function of age. After a 6.3-year median follow up, we tested the competing risks of all-cause mortality, cumulative fatal-nonfatal stroke events, cumulative fatal-nonfatal coronary artery disease (CAD) events, and nonfatal stroke or CAD events due to high Lp(a) serum levels in a population-based, prospective study conducted in one of the eight centers of the Italian Longitudinal Study on Aging (ILSA), Casamassima, Bari, Italy. Of 704 elderly individuals (65-84 years), 372 (169 women and 203 men) agreed to participate in the study. As compared with those in the lowest Lp(a) tertile serum levels, subjects in the highest tertile (>20 mg/dL) had a higher partially adjusted risk of nonfatal CAD (hazard ratio, 4.19; 95% confidence interval [CI], 1.36-12.94) and nonfatal stroke (hazard ratio, 3.38; 95% CI, 1.00-11.56). Compared with those in the lowest tertile, subjects in the highest tertile had a higher fully adjusted risk of nonfatal CAD (hazard ratio, 3.41; 95% CI, 1.08-10.78). Finally, overall no statistically significant association was found between Lp(a) and the risk of all-cause mortality, cumulative fatal-nonfatal stroke, and cumulative fatal-nonfatal CAD events. In our population, Lp(a) was not a significant independent predictor of stroke and death from all causes, but it was an independent predictor of nonfatal CAD. Finally competing risk, conditioning the timing and occurrence of vascular events in our study population, could be a correct approach for evaluating the role of Lp(a) lipoprotein in vascular disease among elderly people.