The influence of body composition on renal function in patients with coronary artery disease and its prognostic significance: a retrospective cohort study

Objective: We try to analyse the effect of renal functions on death in CAD patients with different body compositions. Methods: A retrospective analysis was conducted in 2989 consecutive patients with CAD confirmed by coronary angiography were enrolled and were grouped into two categories: basically preserved renal function (PRF) (eGFR >= 60 ml/min) and obviously reduced renal function (RRF) (eGFR < 60 ml/min). The influence of renal insufficiency on mortality of CAD was detected in every tertile of body composition, including body mass index (BMI), body fat (BF) and lean mass index (LMI). The end points were all-cause mortality. Results: The mean follow-up time was 29.1 +/- 12.5 months and death events occurred in 271 cases. The percentage of patients with RRF was positively correlated with BF and inversely correlated with the LMI, but no relationship to BMI. The survival curves showed that the risk of death was significantly higher in the RRF patients in all subgroups stratified using BMI, BF, or LMI (log rank test, all p < 0.001). The COX multivariate regression analysis showed that the risk of death was significantly higher in the RRF patients with high BF (HR 1.95, CI 1.25-3.05) and low LMI (HR 1.82, CI 1.19-2.79). Meanwhile, risk of death was significantly higher in RRF patients with a high BMI (HR 2.08, CI 1.22-3.55) or low BMI (HR 1.98, CI 1.28-3.08) but this risk was not significant in patients with a medium BMI (HR 1.12, 0.65-1.94). The subgroup analysis of patients with acute coronary syndrome (ACS) showed similar results. Conclusions: For patients with CAD, renal insufficiency was positively correlated with BF, inversely correlated with LMI, and unrelated to BMI. The effect of renal insufficiency on the risk of death of CAD was related to body composition.