Rate of Decline of Kidney Function, Modality Choice, and Survival in Elderly Patients with Advanced Kidney Disease

In elderly, dependent patients with advanced chronic kidney disease, dialysis may confer only a small survival advantage over conservative kidney management (CKM). We investigated the role of rate of decline of kidney function on treatment choices and survival.

We identified a retrospective (1995-2010) cohort of patients aged over 75 years, with progressive kidney impairment and an estimated glomerular filtration rate (eGFR) between 10 and 15 ml/min/1.73 m2. All subsequently chose to be treated by either dialysis or CKM. Patients were followed for a minimum of 3 years.

Of 250 patients identified, 92 (37%) opted for dialysis and 158 (63%) for CKM. Mean age was 80.9 ± 4.0 years. eGFR was 13.3 ± 1.4 initially and 8.7 ± 3.0 ml/min/1.73 m2 at follow-up. Both were similar in those on dialysis and CKM pathways. Rate of decline of eGFR was more rapid in those choosing dialysis (0.45 (interquartile range, IQR 0.64) vs. 0.21 (IQR 0.28) ml/min/1.73 m2/month, p < 0.001), and independently predicted choice of CKM. In patients with high comorbidity, choice of dialysis was associated with a non-significant adjusted survival advantage of 5 months. Inclusion in models of time dependent eGFR during follow-up (eGFRtd) - a reflection of the rate of decline of kidney function - showed it to be independently associated with mortality risk in those on the CKM (p < 0.001) but not on the dialysis pathway. CKM pathway patients at the 25th centile of eGFRtd had an adjusted survival of 7 months compared to 63 months for those at the 75th centile.

Rate of decline of kidney function is a determinant of CKM choice in elderly patients and is associated with mortality risk in patients of the CKM pathway. These findings should inform counselling.