[Patterns of nephrology referral and predialysis management of patients with chronic kidney disease].

Introduction: Numerous studies showed that late referral (LR) to a nephrologist of patients with chronic kidney disease stated by a simple quantitative criterium (initiation of renal replacement therapy (RRT) within 3 or 4 months of referral to a nephrologist, independantly from the quality of care) is associated with worse survival rate, limited to the first 3 months following the initiation of RRT. We wanted to test a criterium of LR definition supposing a more important "dose of nephrological care", to try to understand the reasons of this early death.

Methods: One hundred and thirty-eight patients receiving their first RRT in 1999 and 2000 in Valenciennes (France) were enrolled in this study. Two LR definitions were used: a qualitative criterium C1 (whether the patient was under an uninterrumpted nephrological pre-dialysis care - independantly from the date of the nephrological referral - or not) and a more simple quantitative criterium C2 (initiation of RRT within 3 months of referral to a nephrologist). Comorbidity was assessed by Charlson's score. The analysis concerned the respective influence of C1 and C2 on the clinical and biological effects of chronical azotemia, on the circumstances at first RRT (emergency first dialysis, pulmonary edema, type of vascular access), and on survival rates (Kaplan-Meier's analysis).

Results: LR rates are 23% according to C1 and 20% according to C2. Comorbidity is similar in the different groups. Whatever the definition criterium, LR is associated to a lower hemoglobin and albumin, a more severe acidosis, a longer duration of first hospitalization, and higher rate of emergency first dialysis and use of central temporary catheter. The survival rates at 2 years following the first RRT of lately referred patients are 53% according to C1 (vs 86% for early referred patients, P<0,001) and 56% according to C2 (vs 84%, P<0,05). For both, early death (within the first 3 months) explained the observed differences of survival rates.

Conclusion: In this study, early death of lately referred patients seems to be independant from the criterium of definition of LR. Elements of explanation are suggested, and can lead to further prospective studies.