Practice Patterns and Outcomes of Online Hemodiafiltration: A Real-World Evidence Study in a Russian Dialysis Network

Abstract

<b><i>Background:</i></b> Evidence suggests that online hemodiafiltration (OL-HDF) is associated with improved survival. Whether the dose-response relationship between convective volume and mortality may be confounded by selection bias or descends from practice patterns is not clear. We sought to evaluate the role of patients’ characteristics and practice patterns on OL-HDF dose and mortality in a large private dialysis network in the Republic of Russia. <b><i>Methods:</i></b> In this multicenter, historical cohort study, we included adult incident patients on OL-HDF with at least 90 days of survival on renal replacement therapy in centers belonging to the Russian Federation Fresenius Medical Care network (January 1, 2011, to December 31, 2016). We evaluated predictors and outcomes (survival) of substitution volume target achievement (<i>Q</i>_sub &#x3e; 21 L/session). <b><i>Results:</i></b> Among 1,081 enrolled patients, the average <i>Q</i>_sub was 22.9 (±3.2) L/session; the mean ultrafiltration volume was 1.6 (±0.8) L/session. The mean age was 55.8 ± 13.2; 42% were woman. Most common comorbidities were congestive heart failure (39.7%) and peripheral vascular disease (21.7%). The average hemoglobin was 9.3 ± 1.3. The case-mix adjusted center effect accounted for 20% of variance in <i>Q</i>_sub. The top 10 most important variables associated with higher <i>Q</i>_sub were effective <i>Q</i>_b, serum protein, Charlson’s comorbidity index, hemoglobin, year of dialysis initiation (proxy of high <i>Q</i>_sub treatment policy in the clinic network), predialysis heart rate, serum bicarbonate, serum phosphate, age, serum sodium, and dry body weight. In addition, we found that the association of <i>Q</i>_b with <i>Q</i>_sub is moderated by year of enrollment, intradialytic weight gain, and coronary artery disease, whereas higher hemoglobin concentration moderated the relationship between treatment time and <i>Q</i>_sub. Finally, <i>Q</i>_sub between 21 and 25 L/session was associated with longer 5-year survival. <b><i>Conclusions:</i></b> Both center-dependent clinical practice standards and patient clinical conditions substantially contributed to the risk of low <i>Q</i>_sub. We confirmed previous evidence indicating better survival among patients with <i>Q</i>_sub ≥ 21 L/session.