Association of single measurement of estimated glomerular filtration rate and non-quantitative dipstick proteinuria with all-cause and cardiovascular mortality in the elderly. Results from the Progetto Veneto Anziani (Pro.V.A.) Study

Abstract

Objective: To explore the independent and combined clinical validity of estimated glomerular filtration rate (eGFR) and proteinuria on predicting all-cause and cardiovascular mortality in an Italian elderly population.

Methods: Baseline eGFR and proteinuria, all-cause and cardiovascular mortality during a mean follow-up time of 4.4 years were evaluated in 3063 subjects aged 65 years and older of the Progetto Veneto Anziani (Pro.V.A.) Study.

Results: Subjects with eGFR<60ml/min/1.73m(2) (n=956) presented a higher prevalence of proteinuria in comparison with those with eGFR≥60ml/min/1.73m(2) (33.8% vs 25.1%, p<0.01). After multivariable adjustment including proteinuria and major diseases, eGFR<60ml/min/1.73m(2) was not associated with increased all-cause mortality. After multivariable adjustment including eGFR and major diseases, proteinuria was associated with all-cause mortality in overall subjects (HR=1.43, 95% CI 1.15-1.78, p<0.01), and in both sexes. After multivariable adjustment both eGFR<60ml/min/1.73m(2) (HR=1.68, 95% CI 1.02-2.78, p=0.04), and proteinuria (HR=2.07, 95% CI 1.31-3.27, p<0.01) were associated with increased cardiovascular mortality. Subjects with both impaired eGFR and presence of proteinuria showed a higher risk for both all-cause and cardiovascular mortality compared to those with normal eGFR and absence of proteinuria.

Conclusion: In this general Italian elderly population proteinuria is an independent predictor of all-cause and cardiovascular mortality, while eGFR is not an independent predictor of all-cause mortality, and it is nominally significantly associated with cardiovascular mortality. However, mortality risk is higher in individuals with combined reduced eGFR and proteinuria.