Among patients initiating hemodialysis (HD), those with a greater proportion of sessions with an ultrafiltration rate (UFR) higher than 13 mL/kg/hr may have greater risks for all-cause and cardiovascular death, a new study finds.

“This data shows that even in the first three months of the dialysis tenure, the frequency of dialysis sessions with high UFR impact mortality and thus careful fluid management and consideration for longer dialysis times are important,” José E. Navarrete, MD, Emory University School of Medicine, Atlanta, Georgia, and colleagues wrote in Kidney 360.

The Centers for Medicare and Medicaid Services (CMS) monitor the number of patients per dialysis facility with an UFR greater than 13 mL/kg/hr based on a single session per month, but CMS does not determine the frequency of episodes of high UFR per patient. CMS recently included target weight achievement and ultrafiltration rate as part of the ESKD quality metrics.

Continue Reading

The investigators categorized 1050 patients initiating HD into quartiles based on their proportion of sessions with UFR greater than 13 mL/kg/hr. The median age of the cohort was 59 years and 92% were Black. Overall, a high UFR occurred in 5% of dialysis sessions. The first dialysis session of the week was more often associated with high UFR.

Compared with the bottom quartile (no episodes of high UFR), the top quartile (26% of sessions with high UFR) had a significant 54% higher risk for all-cause mortality, the investigators reported. The risk for cardiovascular mortality was a significant 54% and 74% higher for patients in the top 2 quartiles, respectively. The model adjusted for patient age, best vascular access (no catheter), diabetes, history of congestive heart failure, dialysis adequacy, mean arterial pressure after dialysis, and serum albumin. The study lacked data on residual renal function.

Median survival was significantly longer for patients in the bottom than top quartile: 8.8 vs 5.6 years.

The mean UFR for the top quartile was only 9.8 mL/kg/h, which means most patients would not have been flagged as high risk according to CMS guidelines, the investigators pointed out. Only 31% of patients never experienced high UFR.

Male gender, younger age, shorter duration of hemodialysis sessions, lower weight, diabetes, higher serum albumin, and history of heart failure were significantly associated with a greater proportion of sessions with high UFR.

“Future directions and applications of our findings are for clinical guidelines to take into account the number of HD sessions with high UFR and not just one session per month on laboratory day as it may not accurately reflect one’s absolute mortality risk,” Dr Navarrete’s team concluded.


Navarrete JE, Rajabalan A, Cobb J, Lea JP. Proportion of hemodialysis treatments with high ultrafiltration rate and the association with mortality. Kidney360. Published online May 5, 2022. doi:10.34067/KID.0001322022