Age and comorbidity may explain the paradoxical association of an early dialysis start with poor survival

Abstract

Starting patients on dialysis early has been increasing in incidence in several countries. However, some studies have questioned its utility, finding a counter-intuitive effect of increased mortality when dialysis was started at a higher estimated glomerular filtration rate (eGFR). To examine this issue in more detail we measured mortality hazard ratios associated with Modification of Diet in Renal Disease eGFR at dialysis initiation for 11,685 patients from the French REIN Registry, with sequential adjustment for a number of covariates. The eGFR was analyzed both quantitatively by 5-ml/min per 1.73 m(2) increments and by demi-decile (i.e., 5 percentiles of the distribution); the 15th demi-decile, including values around 10 ml/min per 1.73 m(2), was our reference point. The patients more likely to begin dialysis at a higher eGFR were older male patients; had diabetes, cardiovascular diseases, or low body mass index and level of albuminemia; or were started with peritoneal dialysis. During a median follow-up of 21.9 months, 3945 patients died. The 2-year crude survival decreased from 79 to 46%, with increasing eGFR from less than 5 to over 20 ml/min per 1.73 m(2). Each 5-ml/min/1.73 m(2) increase in eGFR was associated with a 40% increase in crude mortality risk, which weakened to 9%, but remained statistically significant after adjusting for the above covariates. Analysis by demi-decile showed only the highest to be at significantly higher risk. Hence we found that age and patient condition strongly determine the decision to start dialysis and may explain most of the inverse association between eGFR and survival.

Factors Influencing the Decision to Start Renal Replacement Therapy: Results of a Survey Among European Nephrologists

“…4,[17][18][19] Consistent with our finding that only 7% indicated that the planned start was never delayed, a possible explanation for these differences may be that the actual start usually is later than the planned start.…”

“…Results from Lassalle et al 19 also showed higher percentages of older patients and diabetes and cardiovascular diseases in patients starting at eGFR Ͼ10 mL/min/1.73 m 2 . Similar results were found by Abbreviations: CI, confidence interval; eGFR, estimated glomerular filtration rate; RRT, renal replacement therapy.…”

“…Since the previous survey on this matter in 2000, several debates and cohort studies were published suggesting that starting RRT at higher eGFRs may be harmful. [2][3][4][5][6]8,12,14,18,19,28 Therefore, we needed an update regarding current opinions on this topic.…”

Estimated Glomerular Filtration Rate at Re-Initiation of Dialysis and Mortality in Failed Kidney Transplant Recipients

“…The main concern of observational studies including ours is the difference between the clinical characteristics and dialysis indications of the early and late initiation groups. Patients with early dialysis initiation were more likely to be men and diabetic, have severe heart failure or coronary heart disease, are less likely to have glomerulonephritis or polycystic kidney disease and have lower serum albumin level and more comorbidity and in summary, they are sicker patients [5,9,14,17]. In our DAGL patients, we found similar results.…”

“…Data from the US Renal Data System (USRDS) between 1996 and 2008 showed that the proportion of patients initiating hemodialysis (HD) with an estimated GFR (eGFR) >10 mL/min/ 1.73m 2 increased from 20 to 52% and those with a starting eGFR of ≥15 mL/min/1.73m 2 increased from 4 to 17% [5,6]. Interestingly, most of the recent observational trials and a landmark randomized controlled trial failed to show a survival benefit of early initiation of dialysis in CKD patients [5,[7][8][9][10][11][12][13][14][15][16][17][18].…”