Accelerated Loss of Residual Kidney Function in Incremental Hemodialysis

Background Incremental hemodialysis (iHD) involves gradually increasing dialysis dose as residual kidney function (RKF) declines. RKF has been identified as a strong predictor of patient survival. Given the importance of maintaining RKF in hemodialysis patients, our study aimed to analyze predictors of accelerated RKF loss in those undergoing iHD. Methods We retrospectively analyzed 37 incident patients who started twice-weekly iHD between March 2017 and May 2022. Inclusion criteria were age ≥18 years, Kru ≥3 ml/min/1.73 m², urinary output ≥500 ml/day, and ability to comply with monthly interdialytic urine collection. Accelerated RKF loss was defined as a ≥25% decrease in Kru from baseline within three months. Results Of 30 patients with complete data, 30% (n=9) experienced accelerated RKF loss. These patients were older, had a higher prevalence of diabetes, more comorbidities, and lower baseline glomerular filtration rate (GFR). They also had more intradialytic complications and were more likely to have prescribed dry weight exceeding normohydrated weight by >1 kg. Multivariate analysis showed only baseline GFR below 7 ml/min/1.73 m² independently predicted accelerated RKF loss. Conclusions Our study identifies baseline GFR below 7 ml/min/1.73 m² as a key independent predictor of accelerated RKF loss in iHD patients. While factors such as older age, diabetes, higher comorbidity burden, and intradialytic complications were associated with accelerated RKF loss in univariate analysis, they were not significant in the multivariate model. These findings highlight the importance of careful patient selection and management in iHD programs, with particular attention to baseline GFR. By identifying patients at higher risk of rapid RKF decline, clinicians can implement targeted strategies to preserve RKF and potentially improve long-term outcomes.