U-shaped association between serum albumin and development of chronic kidney disease in general hypertensive patients.

BACKGROUND & AIMS We aimed to examine the association between serum albumin (SAlb) and the development of chronic kidney disease (CKD), and examine any possible effect modifiers in general hypertensive patients with normal renal function and with no previous cardiovascular diseases (CVD). METHODS This is a post-hoc analysis (performed at May, 2018) of 12,621 hypertensive adults with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 and SAlb ≥35.0 g/L from the renal sub-study of the China Stroke Primary Prevention Trial (CSPPT), conducted from May 2008 to August 2013. The primary outcome was development of CKD, defined as a decrease in eGFR of ≥30% and to a level of <60 mL/min/1.73 m2; or end stage renal disease. RESULTS The median follow-up duration was 4.4 years. Overall, the association between SAlb levels and risk of the primary outcome followed a U-shape. The risk of CKD development significantly decreased with the increment of SAlb (per g/L: OR = 0.92; 95% CI: 0.88-0.96) in participants with SAlb <51.4 g/L, and increased with the increment of SAlb (per g/L: OR = 1.06; 95%CI: 1.01-1.11) in participants with SAlb ≥51.4 g/L. Moreover, in participants with SAlb <51.4 g/L, the association between SAlb and CKD development remained significant in participants without proteinuria (per g/L: OR = 0.93; 95% CI: 0.88-0.99). The association between SAlb and CKD development was not significantly modified by age, sex, folic acid treatment, proteinuria, systolic blood pressure (SBP) at baseline and time-averaged SBP during the treatment period (all P-interactions>0.05). CONCLUSIONS There was a U-shaped association between SAlb levels and risk of CKD development among general hypertensive patients with normal renal function and without CVD, with a turning point at about 51.4 g/L.