Analysis of patient's survival on renal replacement therapy in a large city: a multicenter prospective cohort observational study

A direct comparison of the long-term effectiveness of combined interventions in controlled studies is often challenging, if not infeasible due to ethical concerns, due to ethical concerns, including the reluctance to withhold potentially beneficial treatments. This gap can be addressed through pragmatic research or the analysis of large prospectively collected datasets, such as registers. In addition providing valuable outcome assessments, these datasets enable the formation of matched groups for comparison in interventional studies, which, under certain conditions, may serve as a form of quasi-randomization. This study analyzes data from the renal replacement therapy registry in a large city, covering the period from the transition of dialysis to the compulsory medical insurance system in 2009, ensuring accurate tracking of therapy initiation and outcomes untill the COVID-19 pandemic, which disrupted the stable organization and outcomes of dialysis. The analysis focuses on factors associated to patient survival, particularly those directly related to dialysis and chronic kidney disease syndromes during this period. The overall five-year survival rate was 60.4%±1.5%. Factors at dialysis initiation associated with adverse outcomes included: age (+1% risk increase per year of age), the underlying disease diagnosis, baseline residual GFR below 5.3 ml/min/1.73 m2 (+41%), or below 3.6 ml/ min/1.73 m2 (+55%), phosphatemia above 1.78 mmol/L (+58%) or below 1,13 mmol/ L (+38%); calcemia outside the target range (+57% risk for low levels, +120% risk for high levels); natremia (above 141 mmol/L (+62%); albuminemia (below 36 g/L (+22%); interdialytic weight gain (+23% for each 1% of body weight increase), and urgent of dialysis initiation. During maintenance dialysis (indicator period – 3th-15th months) adverse outcomes were associated with phosphatemia above 1.78 mmol/l (68% risk increase), calcemia above 2.5 mmol/L (+122% risk) and their interaction, as well as ultrafiltration rate above 8 ml/hour/kg (165% risk increase and higher for more fast ultrafiltration). Additional risk factors include worsening hyperphosphatemia (+72%), deviation in calcemia from target range (+16% risk for downward shifts, +43% risk for upwards shifts) and ultrafiltration rate exceeding 10 ml/hour/kg (+21%). Notably, anemia correction indicators and their trends, under current favorable treatment practice, were not identified as significant risk factors. Detailed patient data will facilitate the evaluation of intervention impacts on dialysis outcomes by enabling comparison matched historical cohorts.