Impact of serum albumin level and variability on short-term cardiovascular-related and all-cause mortality in patients on maintenance hemodialysis

Studies have shown that low serum albumin (Salb) levels are associated with a high risk of mortality among patients on maintenance hemodialysis (MHD); however, the impact of Salb variability on short-term cardiovascular mortality remains unclear. Herein, we investigated the association between Salb levels and Salb variability on short-term all-cause and cardiovascular-related mortality in patients on MHD. Eligible patients on MHD at Chongqing General Hospital between June 2017 and June 2020 were recruited in this study. Patients were grouped by Salb levels (normal Salb, ≥3.8 g/dL; low Salb, 3.4–3.8 g/dL; and lower Salb, 2–3.4 g/dL) and Salb variability (decreased, >5% loss; increased, >5% gain; and steady, 5% loss to 5% gain). Associations between Salb levels, Salb variability, and all-cause and cardiovascular-related mortality were analyzed using Cox regression models. A survival analysis was performed using the Kaplan–Meier analysis. We enrolled a total of 181 patients on MHD with an average age of 65 years (interquartile range [IQR], 53–75 years). The mean Salb level was 3.8 ± 0.6 g/dL (IQR 2.9–4.4 g/dL), and the median Salb variability was 2.6% per year (IQR, −4.1 to 6.5). Fifty-two (29%) patients died, including 31 (17%) patients who died due to cardiovascular-related causes. Compared with the other groups, the lower Salb group had higher all-cause mortality (P < .01). Cox regression analyses revealed that lower Salb levels and decreased Salb variability were independently associated with all-cause mortality (hazard ratio [HR] = 1.95, 95% confidence interval [CI] 1.103–3.452; HR = 2.245, 95% CI 1.084–4.650), whereas increased Salb variability was independently associated with cardiovascular-related mortality (HR = 2.919, 95% CI 1.178–7.234; P < .05). Lower Salb levels were an independent predictor of all-cause mortality in patients on MHD. Increased Salb variability was strongly associated with cardiovascular-related mortality in the same population, especially in the short-term and in patients with normal Salb levels. Significantly elevated Salb variability should be evaluated to reduce cardiovascular-related mortality.