Early initiation of dialysis may modestly reduce the risks for death and major adverse cardiovascular events (MACE), an observational study finds. But the tradeoff may be in quality of life.
Among 10,290 patients with advanced chronic kidney disease (median age 73 years; 36% women) in the National Swedish Renal Registry, 3822 started dialysis, 4160 died, and 2446 had a MACE (a composite of cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke). Investigators examined dialysis initiation in this cohort at estimated glomerular filtration rates (eGFR; in mL/min/1.73 m2) from 4 to 19 in increments of 1.
Mortality displayed a U-shaped curved with eGFR, with the lowest death risk at eGFR 15-16. Compared with dialysis initiation at eGFR 6-7, initiation at eGFR 15-16 was significantly associated with a 5.1% lower absolute risk for death within 5 years, Edouard L. Fu, MD, PhD, of Leiden University Medical Center, Leiden, The Netherlands, and colleagues reported in BMJ.
“This 5.1% absolute risk difference corresponded to a mean postponement of death of 1.6 months over five years of follow-up,” Dr Fu’s team explained. “However, dialysis would need to be started four years earlier.” For most patients, this purported survival benefit would not outweigh the burden of more years spent on dialysis, according to the investigators.
The lowest absolute risk for MACE was 3.3% observed when dialysis was initiated at an eGFR of 13-14, using an eGFR of 6-7 as the reference.
The investigators adjusted analyses for multiple relevant factors, such as laboratory values and comorbidities. However, the study lacked information on nutritional status or muscle mass, uremic symptoms, volume status, and quality of life or physical activity. The team also noted that optimal eGFR to start dialysis may differ between hemodialysis and peritoneal dialysis; up to 39% of patients in Sweden start with peritoneal dialysis.
“Our results further suggest that in the absence of symptoms or strong indications, initiation of dialysis may be postponed until lower eGFR values are reached (intent to defer), without a large increase in mortality or cardiovascular events,” according to Dr Fu’s team.
The new findings differ from those of some previous reports, including a study published in Hemodialysis International in 2021. Dr Fu and colleagues suggested that some of these studies may have been subject to immortal time bias or selection/survivor bias.
Fu EL, Evans M, Carrero JJ, et al. Timing of dialysis initiation to reduce mortality and cardiovascular events in advanced chronic kidney disease: nationwide cohort study. BMJ 2021 Nov 29;375. doi:10.1136/bmj-2021-066306