Association Between Serum Albumin Level and All-Cause Mortality in Patients With Chronic Kidney Disease: A Retrospective Cohort Study

Abstract

Background: The association between serum albumin and all-cause mortality (ACM) in patients with chronic kidney disease (CKD) is presently unclear.

Methods: The study subjects included 201 patients diagnosed with CKD, eliminating those with end-stage renal disease, who were admitted to our hospital from January 2014 to January 2015. The patients were divided into 4 groups according to serum albumin level (Q1: 1.60-3.88 g/dL; Q2: 3.89-4.13 g/dL; Q3: 4.14-4.43 g/dL, and Q4: 4.44-5.51 g/dL). The clinical outcome was ACM, and the difference was compared using odds ratio (OR) and 95% confidence interval (CI).

Results: After a median follow-up of 1480 days, 32 patients died (15.92%). The ACM was found to be 28.00%, 20.00%, 8.00%, and 7.84% in the 4 groups (P = 0.012). Pearson correlation analysis revealed a positive association between the serum albumin level and glomerular filtration rate (GFR) (r = 0.22, P = 0.001). Once the potential confounding factors were adjusted, the results indicated that decreased serum albumin was a risk factor for ACM (Q2 vs Q1: OR = 0.50, 95% CI: 0.17-1.47; Q3 vs Q1: OR = 0.12, 95% CI: 0.03-0.48; Q4 vs Q1: OR = 0.26, 95% CI: 0.07-0.98). The receiver operating characteristic curve indicated that the optimum threshold of serum albumin to predict ACM was 4 g/dL, and the area under the curve was 0.69 (95% CI: 0.60-0.79).

Conclusions: Decreased serum albumin is a risk factor for ACM in patients with CKD, with the optimal threshold being 4 g/dL.

Keywords: All-cause mortality; Chronic kidney disease; Cohort study; Serum albumin.