Weight fluctuation and incidence of end-stage renal disease in Korea: a nationwide cohort study

Background: The impact of weight or weight changes on kidney function remains a matter of debate. This study aimed to investigate the association between weight fluctuation and the incidence of end-stage renal disease (ESRD) using data from the Korean National Health Insurance Corporation health checkups (2009–2015).Methods: The study included 2,310,667 participants (1,546,749 men and 763,918 women), aged ≥40 years. Weight fluctuation was assessed using the average real variability (ARV) of weight and categorized into quartiles (Q1–Q4). Hazard ratios (HRs) and 95% confidence intervals for ESRD incidence were calculated using multivariable Cox proportional hazards models.Results: After adjustment for comorbidities, increased body mass index was associated with a decreased HR for ESRD. The highest quartile of weight variability (ARV Q4) demonstrated a higher probability and HR for ESRD compared to the lower variability quartiles (Q1–Q3). Among men, individuals with sustained weight, and those with weight gain, the ARV Q4 group showed significantly increased HRs for ESRD (HR of 1.372, 1.222, and 1.49, respectively). Furthermore, irrespective of changes in creatinine levels, all ARV Q4 groups exhibited increased HRs for ESRD (HR of 1.342, 1.472, and 1.299, respectively).Conclusions: High weight fluctuation (ARV Q4) was associated with an increased incidence of ESRD in the general Korean population, with notable significance in men and in groups with sustained or increased weight. Clinically, individuals in the ARV Q4 category should be considered at risk for ESRD, and early interventions should be pursued for this population.