A Multicenter Propensity Score Matching Study of Homologous Convective Volume (HCV): A New Comprehensive Parameter for Dialysis Dose That Improves Survival.

INTRODUCTION: The evaluation of hemodiafiltration (HDF) effectiveness concerning patient survival has primarily centered on convection volume. A limitation of this approach is that it overlooks two parameters: Kt/V and extracorporeal blood flow (Qb). This study aims to use the homologous convective volume (HCV) to compare mortality rates between patients undergoing hemodialysis and hemodiafiltration, with the hypothesis that higher HCV leads to lower mortality. METHODS: This observational study was conducted across 14 hemodialysis clinics within the Davita-Ecuador group. Patients who had undergone conventional hemodialysis or HDF were included in the study. HCV was calculated as: convective volume * Kt/V * Qb, expressed in liters per minute. Group A included patients with 0 to 9.9 liters of HCV, Group B included patients with 10 to 17.9 liters of HCV, and Group C included patients with approximately 18 or more liters of HCV. The variables analyzed included epidemiological, clinical, laboratory, impedance, medication use, and mortality. To adjust for potential confounders, propensity score matching (PSM) was performed. For group comparisons, ANOVA and Kaplan-Meier survival analysis were used. RESULTS: Using propensity score matching, 2537 patients were assigned to Group A, 213 to Group B, and 476 to Group C. The three groups were matched based on age, Charlson comorbidity index, sex, and presence of type 2 diabetes mellitus, ensuring equal distribution across the groups. There were no differences in weight distribution, body mass index, or comorbidities among the groups. Survival was 46.9 ± 0.7 months in Group A, 57.8 ± 2.0 months in Group B, and 61.9 ± 1.3 months in Group C (Log Rank (Mantel-Cox) Chi Square 67.65, P<0.001). CONCLUSION: HCV is a new and comprehensive parameter for measuring total dialysis dose because it combines the removal of small solutes (Kt/V), the removal of medium-sized solutes (convective volume), and Qb. A higher dialysis dose, as indicated by HCV, is directly linked to increased patient survival. The group receiving the highest dose (HCV of 18 liters or more) showed the greatest longevity (61.9 months) compared to groups with lower doses.