#2576 Effect of dialysis versus conservative care on all-cause mortality in older patients with advanced CKD: nationwide Swedish cohort study

Abstract

Abstract Background and Aims Conservative care is emerging as an alternative to dialysis in older patients with advanced chronic kidney disease (CKD). However, high-quality evidence comparing the effect of dialysis versus conservative care on patient survival is lacking. Previous observational studies suffered from avoidable biases, such as immortal time bias and lead time bias, and adjusted for limited confounders. This study aimed to assess the effects of dialysis versus conservative care on mortality in older patients with advanced CKD. Method The target trial emulation framework was used to design and analyze this observational study. We conducted a nationwide observational cohort study using data from the Swedish Renal Registry between 2007-2021. We included all nephrologist-referred patients with eGFR < 20 ml/min/1.73 m2 who had a registered decision for dialysis or conservative care. Eligible patients were required to be ≥ 65 years with a Davies Comorbidity Score ≥ 2 or ≥ 80 years. The primary endpoint was 5-year all-cause mortality. Inverse probability of treatment weighting was used to adjust for 50 baseline confounders, including demographics, comorbidities, medication use, blood pressure, laboratory measurements, hospitalizations, and calendar year. Patients in the non-overlapping region of the propensity score distribution were excluded since they had an absolute indication for dialysis or conservative care. Cox proportional hazards regression was used to estimate intention-to-treat hazard ratios (HRs) with 95% confidence intervals (CIs), and the Kaplan-Meier estimator was used to estimate absolute risks. Additionally, we calculated the 5-year restricted mean survival times (RMST) and the 5-year RMST difference between dialysis and conservative care arms. To test the robustness and consistency of our main results, we performed a subgroup analysis in patients aged ≥80. Results Of 2834 eligible patients, 1903 had a registered choice for dialysis and 931 for conservative care. The median age was 81 years, 36.1% were female and median eGFR was 13.1 ml/min/1.73 m2. During the 5-year follow-up period, 29 conservative care patients started dialysis and 430 patients died before starting dialysis. After weighting, all confounders were balanced (standardized mean difference < 0.10). Compared to dialysis, conservative care was associated with a higher absolute 5-year risk of death (91.8% vs. 74.1%), corresponding with an absolute risk difference of 17.6% (95% CI 13.3%-21.9%) (Fig. 1). The adjusted hazard ratio for conservative care vs. dialysis was 2.3 (95% CI 2.0-2.6). The 5-year restricted mean survival times were 34.8 (95% CI 33.2-37.3) months for dialysis and 21.5 (95% CI 19.4-23.6) months for conservative care groups. The 5-year RMST difference was 13.3 months (95% CI 10.8-16.6), meaning that dialysis patients would live on average 13.3 months longer over a 5-year follow-up period than conservative care patients (Table 1). The results were consistent among people ≥ 80 years (adjusted HR 2.2, 95% CI 1.9-2.5; 5-year RMST difference 9.4 months, 95% CI 7.2-13.9). Conclusion In older patients with advanced CKD under nephrologist care, conservative care was associated with a higher risk of mortality than dialysis. These findings could improve the shared decision-making process with patients on the choice of kidney failure treatment.