The association between the serum uric acid to creatinine ratio and all-cause mortality in elderly hemodialysis patients

Abstract

Background: Elderly hemodialysis patients have a higher rate of mortality than nonelderly hemodialysis patients. Recent studies shown that the serum uric acid to creatinine ratio (SUA/Scr) was associated with all-cause mortality in general adults. The purpose of the present study was to investigate the association between the SUA/Scr and all-cause and cardiovascular disease mortality among elderly hemodialysis patients. Methods: A total of 222 patients (≥ 60 years) who received hemodialysis more than 8 h per week at Taizhou Second People’s Hospital for at least 3 months were enrolled in the present study from January 2015 to December 2019. Clinical characteristics including age, sex and height et. al, were obtained from the hemodialysis database. The laboratory data, including albumin (ALB), total cholesterol (TC), serum uric acid (SUA), serum creatinine (Scr) and so on, were collected before hemodialysis and analyzed by automatic biochemical analyzer. Survival information was recorded during the follow-up period. Multiple Cox regression was carried out to analyze the association between SUA/Scr and all-cause mortality. The survival rate of each group was calculated by the Kaplan–Meier method, and the ratio of survival curves was analyzed by the log-rank test. The contribution of SUA/Scr for predicting all-cause mortality risk was evaluated by net reclassification improvement (NRI). Results: During the 19-month observation period, 78 patients died. Individuals in the nonsurviving group had significantly older ages (P < 0.001), body mass index (BMI) (P = 0.004), serum creatinine (P = 0.005) and prealbumin (P = 0.006) than surviving patients. After adjusting for age, sex, BMI, prealbumin, dialysis vintage, dialysis frequency, single-pool Kt/V (spKt/V), DM, hypertension and comorbidities, a higher ratio of SUA/Scr was independently associated with a higher risk of all-cause mortality (HR: 1.292; 95% CI: 1.013–1.648; P = 0.039). The predict value on all-cause mortality of SUA/Scr was superior to SUA (additive NRI = 0.214, P = 0.015) and Scr (additive NRI = 0.476, P < 0.001) among elderly hemodialysis patients. Conclusion: The serum uric acid to creatinine ratio is strongly associated with all-cause mortality in elderly hemodialysis patients which is more predictive than SUA or Scr alone.