Optimal threshold of urinary albumin-to-creatinine ratio (UACR) for predicting long-term cardiovascular and noncardiovascular mortality

Abstract

Purpose: Traditional cutoff values of urinary albumin-to-creatinine ratio (UACR) for predicting mortality have recently been challenged. In this study, we investigated the optimal threshold of UACR for predicting long-term cardiovascular and non-cardiovascular mortality in the general population.

Methods: Data for 25,302 adults were extracted from the National Health and Nutrition Examination Survey (2005-2014). Receiver operating characteristic (ROC) curve analysis was performed to assess the predictive value of UACR for cardiovascular and non-cardiovascular mortality. A Cox regression model was established to examine the association between UACR and cardiovascular and non-cardiovascular mortality. X-tile was used to estimate the optimal cutoff of UACR.

Results: The UACR had acceptable predictive value for both cardiovascular (AUC (95% CI) for 1-year, 3-year and 5-year mortality, respectively: 0.769 (0.711-0.828), 0.764 (0.722-0.805) and 0.763 (0.730-0.795)) and non-cardiovascular (AUC (95% CI) for 1-year, 3-year and 5-year mortality, respectively: 0.772 (0.681-0.764), 0.708 (0.686-0.731) and 0.708 (0.690-0.725)) mortality. The optimal cutoff values were 16 and 30 mg/g for predicting long-term cardiovascular and non-cardiovascular mortality, respectively. Both cutoffs of UACR had acceptable specificity (0.785-0.891) in predicting long-term mortality, while the new proposed cutoff (16 mg/g) had higher sensitivity. The adjusted hazard ratios of cardiovascular and non-cardiovascular mortality for the high-risk group were 2.50 (95% CI 1.96-3.18, P < 0.001) and 1.92 (95% CI 1.70-2.17, P < 0.001), respectively.

Conclusions: Compared to the traditional cutoff value (30 mg/g), a UACR cutoff of 16 mg/g may be more sensitive for identifying patients at high risk for cardiovascular mortality in the general population.

Keywords: Cardiovascular mortality; National health and nutrition examination survey; Non-cardiovascular mortality; Urinary albumin-to-creatinine ratio; X-tile.