Risk factors for renal progression in patients with CKD and coexisting COPD

Chronic diseases rarely occur in isolation, and chronic kidney disease (CKD) is no exception. There has been considerable research on the interplay between the heart and kidneys, but studies on the relationship between the lungs and kidneys are less common. The interaction between pulmonary and renal functions in areas such as acid–base metabolism, chronic inflammation, and bone metabolism is increasingly gaining clinical attention.

In this cohort study, we examined 480 patients with stages 3–4 CKD and COPD (GOLD stages 1 and 2) to identify risk factors that contribute to the progression of renal function to a composite endpoint, which includes a 40% decline in estimated glomerular filtration rate (eGFR) and the onset of end-stage renal disease during follow-up periods. A Cox proportional hazards regression model was used to investigate the risk factors associated with the timing of renal event endpoints in the study population. Additionally, the restricted cubic spline method was used to explore the relationship between quantitative variables and survival risk.

Our study included 480 eligible patients with an average follow-up period of 21.41 ± 14.90 months, during which 224 individuals (46.7%) experienced the composite renal endpoints. Multivariable Cox regression analysis revealed that systolic blood pressure (SBP) [1.01 (1.00–1.02), p = 0.002], hemoglobin (Hb) [HR 0.89 (0.83–0.96), p = 0.002], albumin (Alb) [0.96 (0.93–0.99), p = 0.009], and edema [1.73 (1.29–2.33), p < 0.001] were independent risk factors for the renal endpoints.

The adjusted multivariable Cox regression analysis demonstrated that elevated SBP and edema were factors that promoted the occurrence of composite endpoints, while higher levels of Hb and Alb were protective factors.