Relationship Between Peritoneal Protein Clearance and Hemoglobin in Peritoneal Dialysis Patients: A Prospective Cohort Study

Abstract

The relationship between higher peritoneal protein clearance (PPCl) and hemoglobin (Hb) levels in peritoneal dialysis (PD) patients is unknown. We explored this relationship and interaction on all-cause mortality in this prospective cohort study with a large number of PD patients. We enrolled prevalent PD patients in a single PD center. Demographic characteristics and clinical and biochemical data were collected. The total amount of protein loss in the dialysate and PPCl corrected for serum albumin were calculated. The primary study endpoint was all-cause mortality. We examined the relationship between PPCl, Hb, and all-cause mortality in the Cox regression model. We included a total of 487 PD patients (58.3% males, mean age 49.5±14.9years). The median PD duration at enrollment was 30.1 (15.8-48.3) months. Mean Hb level was 11.1±1.9g/dL, and 221 (45.3%) patients had Hb levels <11g/dL. Patients with Hb<11g/dL had lower serum albumin, lower residual renal creatinine clearance, and higher PPCl. In a multilinear regression model, PPCl (β=-0.12, P=.015) had an independent negative linear association with Hb levels. In the logistic regression model, higher PPCl was independently associated with lower Hb (<11g/dL) (odds ratio=1.02; 95% confidence interval [CI]: 1.01-1.03). In the overall cohort, after adjusting for confounders in the Cox regression model, decrease in Hb level was independently associated with increased risk (hazard ratio: 0.86, 95% CI: 0.77-0.95) of all-cause mortality. Interaction-effect test showed that PPCl influenced the relationship between Hb level and all-cause mortality (P=.011). After adjusting for confounders, lower Hb level was independently associated with a higher risk (hazard ratio: 0.85, 95% CI: 0.74-0.97) of all-cause mortality only in patients with PPCl ≥59.5mL/day and not in patients with lower PPCl. Higher PPCl was an independent predictive factor of lower Hb levels in PD patients. Therefore, PPCl influenced the relationship between Hb level and all-cause mortality in PD patients.