Death risk stratification in patients aged 60 years and older with stage 5 chronic kidney disease using frailty assessment and comorbidity evaluation

   Aim. To assess the impact of frailty and comorbidity on treatment outcomes in patients aged 60 years and older starting chronic dialysis.

   Methods. A single-center trial included 245 patients aged 60 years and older with chronic kidney disease stage 5 (CKD 5). All the patients were examined for hyperhydration and residual renal function and pre-dialysis blood parameters (creatinine, urea, potassium, albumin, lymphocytes, hemoglobin) were evaluated. The Cumulative Frailty Index (CFI) and Charlson Comorbidity Index (CCI) were used to assess frailty and comorbid disease burden, respectively. Survival analysis was performed using the Kaplan–Meier estimator, Cox proportional hazard regression model was used to assess the impact of individual parameters on patient survival.

   Results. As a result of the univariate statistical analysis, variables independently associated with worse survival were: age > 65 years, residual renal function (glomerular filtration rate (GFR) according to the CKD-EPI formula ≤ 3 ml/min/1.73 m², diuresis < 400 ml/day), hyperhydration, uremia indicators (creatinine ≤ 520 µmol/l, urea > 44 mmol/l), protein-energy undernutrition (PEU) laboratory signs (albumin ≤ 30 g/l, lymphocytes ≤ 0.6 × 10⁹/l ), as well as CFI ≥ 0.5 (3.5 (2.4–5.1), p < 0.001), CCI > 5 points (1.6 (1.2–2.3), p = 0.005). All the patients were divided into group 1 (patients with CFI ≥ 0.5), group 2 subgroup 1 (CFI < 0.5 and CCI > 5 points), group 2 subgroup 2 (CFI < 0.5 and CCI ≤ 5 points).There were differences in median survival (44 vs 279 vs 672 days), one- and two-year survival in the selected groups and subgroups. It was revealed that the greatest influence on life expectancy in ≥ 60 year-old patients with CKD 5 on chronic dialysis was not exerted by the classic criteria of age, renal nitrogen excretion function and PEU, but by the presence of severe frailty and high comorbidity, which made it possible to identify groups at risk of death: the high-risk group included patients with CFI ≥ 0.5, the intermediate-risk group – patients with CFI < 0.5 and CCI > 5 points, the standard-risk group – patients with CFI < 0.5 and CCI ≤ 5 points.

   Conclusion. CFI and CCI are superior to azotemia, PEU, and GFR in predicting and stratifying risk of death in ≥ 60 year-old patients with CKD 5. We, therefore, propose that CFI and CCI be used to determine treatment modality for CKD 5 in this cohort of patients.

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