Weekly Standard Kt/V_urea and Clinical Outcomes in Home and In-Center Hemodialysis

Background and objectives Patients undergoing hemodialysis with a frequency other than thrice weekly are not included in current clinical performance metrics for dialysis adequacy. The weekly standard Kt/V_urea incorporates treatment frequency, but there are limited data on its association with clinical outcomes.

Design, setting, participants, & measurements We used multivariable regression to examine the association of dialysis standard Kt/V_urea with BP and metabolic control (serum potassium, calcium, bicarbonate, and phosphorus) in patients incidental to dialysis treated with home (n=2373) or in-center hemodialysis (n=109,273). We further used Cox survival models to examine the association of dialysis standard Kt/V_urea with mortality, hospitalization, and among patients on home hemodialysis, transfer to in-center hemodialysis.

Results After adjustment for potential confounders, patients with dialysis standard Kt/V_urea <2.1 had higher BPs compared with patients with standard Kt/V_urea 2.1 to <2.3 (3.4 mm Hg higher [P<0.001] for home hemodialysis and 0.9 mm Hg higher [P<0.001] for in-center hemodialysis). There were no clinically meaningful associations between dialysis standard Kt/V_urea and markers of metabolic control, irrespective of dialysis modality. There was no association between dialysis standard Kt/V_urea and risk for mortality, hospitalization, or transfer to in-center hemodialysis among patients undergoing home hemodialysis. Among patients on in-center hemodialysis, dialysis standard Kt/V_urea <2.1 was associated with higher risk (adjusted hazard ratio, 1.11; 95% confidence interval, 1.07 to 1.14) and standard Kt/V_urea ≥2.3 was associated with lower risk (adjusted hazard ratio, 0.97; 95% confidence interval, 0.94 to 0.99) for death compared with standard Kt/V_urea 2.1 to <2.3. Additional analyses limited to patients with available data on residual kidney function showed similar relationships of dialysis and total (dialysis plus kidney) standard Kt/V_urea with outcomes.

Conclusions Current targets for standard Kt/V_urea have limited utility in identifying individuals at increased risk for adverse clinical outcomes for those undergoing home hemodialysis but may enhance risk stratification for in-center hemodialysis.