Ultrafiltration Rate and Mortality in Maintenance Hemodialysis Patients

Abstract

Background Observational data have demonstrated an association between higher ultrafiltration (UF) rates and greater mortality among hemodialysis (HD) patients. Prior studies were small and did not consider potential differences in the association across body sizes and other related subgroups. No study has investigated UF rates normalized to anthropometric measures beyond body weight. Also, potential methodological shortcomings in prior studies have led to questions about the veracity of the UF rate–mortality association. Study Design Retrospective cohort. Setting & Participants 118,394 HD patients dialyzing in a large dialysis organization, 2008–2012. Predictors Mean 30-day UF rates were dichotomized at 13 and 10 mL/h/kg, separately, and categorized using various cut-points. UF rates normalized to body weight, body mass index and body surface area were investigated. Outcomes All-cause mortality. Measurements Multivariable survival models were used to estimate the association between UF rate and all-cause mortality. Results At baseline, 21,735 (18.4%) individuals had UF rates >13 mL/h/kg and 48,529 (41.0%) had UF rates > 10 mL/h/kg. Median follow-up time was 2.3 years, and the mortality rate was 15.3 deaths per 100 patient-years. Compared to UF rates ≤13, UF rates >13 mL/h/kg were associated with greater mortality (adjusted HR, 1.31; 95% CI, 1.28–1.34). Compared to UF rates ≤10, UF rates >10 mL/h/kg were associated with greater mortality (adjusted HR, 1.22; 95% CI, 1.20–1.24). Findings were consistent across subgroups of sex, race, dialysis vintage, session duration, and body size. Higher UF rates were associated with greater mortality when normalized to body weight, body mass index, and body surface area. Limitations Residual confounding cannot be excluded given the observational study design. Conclusions Regardless of the threshold implemented, higher UF rate was associated with greater mortality in the overall study population and across key subgroups. Randomized controlled trials are needed to investigate whether UF rate reduction improves clinical outcomes. Index words hemodialysis, mortality, ultrafiltration rate (UFR), body size, body weight, body mass index (BMI), body surface area (BSA), anthropometric measures, metabolic mass, rapid fluid removal, end-stage renal disease (ESRD)

Association of Ultrafiltration Rate with Mortality in Incident Hemodialysis Patients

“…These results were consistent to those of prior studies [27]. Obese or higher weight patients may have greater underlying CV risk and thereby may be more vulnerable to complications associated with higher UFRs (i.e., intradialytic hypotension, myocardial stunning).…”

Ultrafiltration Rate Scaling in Hemodialysis Patients

“…1–4 These observational findings are supported by mechanistic studies showing that intradialytic end-organ ischemic injury may occur in response to aggressive fluid removal. 5–7 As a result of these studies and others, there has been heightened interest in improving clinic-level fluid management across the dialysis community, 8 ultimately leading to the approval of an UF rate reporting measure for the 2020 Centers for Medicare and Medicaid (CMS) End Stage Renal Disease (ESRD) Quality Incentive Program (QIP).…”

“…10 Then, citing data from an observational analysis of UF rates (considered scaled to body weight, body mass index and body surface area) and all-cause mortality by Assimon et al , they noted that: 1) the rapid UF rate—mortality association may be more pronounced in patients of greater body weight, and 2) the UF rate—mortality association may be more consistent when scaled to body surface area than when scaled to body weight. 4 Daugirdas and Schneditz appropriately pointed out that the Assimon et al . analyses were not stratified by sex, potentially obscuring important information that could shed light on the optimal approach to UF rate scaling.…”

Recovery Time after Hemodialysis Is Inversely Associated with the Ultrafiltration Rate

“…It remains to be investigated whether the reduction of recovery time may be obtained with the increase of the UFR in the routine clinical practice and whether this is appropriate. In fact, it is well known that a higher UFR has been associated with increased mortality [19][20][21] and with hemodynamic effects such as reduced myocardial blood and myocardial stunning [22][23][24]. Nevertheless, an ideal UFR has not yet been identified [25].…”