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Abstract: FR-OR106

Associations Between Body Mass Index, Kt/V, and Outcomes Among Patients Treated with Peritoneal Dialysis

Session Information

Category: Dialysis

  • 703 Dialysis: Peritoneal Dialysis

Authors

  • Sibbel, Scott, DaVita Clinical Research, Minneapolis, Minnesota, United States
  • Cohen, Dena E., DaVita Clinical Research, Minneapolis, Minnesota, United States
  • Colson, Carey, DaVita Clinical Research, Minneapolis, Minnesota, United States
  • Tentori, Francesca, DaVita Clinical Research, Minneapolis, Minnesota, United States
  • Brunelli, Steven M., DaVita Clinical Research, Minneapolis, Minnesota, United States
  • Schreiber, Martin J., DaVita, Inc, Denver, Colorado, United States
Background

Among patients treated with peritoneal dialysis (PD), achievement of Kt/V ≥ 1.7 indicates adequate dialysis. The volume of urea distribution (V) is based on bodyweight. Because the water content and metabolic activity of fat mass differ from that of lean,V may be over-estimated in obese patients, such that Kt/V under-estimates adequacy. Recalculation of V based on lean body mass might enable more accurate estimation of dialysis adequacy in such patients.

Methods

Data were derived from deidentified records of adults (body mass index [BMI] 15-45 kg/m2) who initiated PD with a large dialysis organization Jan 2016 – June 2018. Patients were followed from PD start until death, censoring, or study end (Dec 2018). Kt/V was calculated on the basis of bodyweight or estimated lean body mass. Associations between time-updated values of BMI, Kt/V, and outcomes were estimated using Poisson models that included an interaction term for BMI and Kt/V.

Results

At baseline, among 16,443 patients, mean BMI was 28.1 ± 5.8 kg/m2, Kt/V was 2.4 ± 0.7, and 16.1% of patients had Kt/V < 1.7. Across BMI categories, lower Kt/V was associated with higher hospitalization rate; no interaction between Kt/V and BMI was observed (p>0.05). Similar results were obtained when Kt/V was recalculated on the basis of estimated lean body mass. Among patients with BMI≥30 and recalculated Kt/V ≥ 1.7 but standard Kt/V < 1.7, hospitalization rates were 1.98-fold (95% confidence interval 1.80 – 2.17) higher than among patients with Kt/V ≥ 1.7 by both measures.

Conclusion

Associations between Kt/V and outcomes do not differ on the basis of BMI. Calculation of Kt/V on the basis of estimated lean body mass may over-estimate dialysis adequacy, with potential negative consequences for patient outcomes.