How does late nephrological co-management impact chronic kidney disease? - An observational study

Aims: To assess the impact of late referral (LR) for nephrological co-management compared with early referral (ER) on morbidity and mortality in chronic kidney disease (CKD) and to identify individual factors associated with higher mortality in LR, correcting for lead-time and immortal time bias. Patients and methods: Retrospective observational study comparing 46 LR patients with 103 ER patients. The quality of CKD management was assessed by measures to prevent CKD progression and to modify CKD complications and cardiovascular risk factors according to current guidelines. One-year mortality of LR and ER was compared and factors associated with mortality were identified. Analysis was performed with equivalent GFR (glomerular filtration rate) of ER and LR at baseline to correct for lead-time and immortal time bias. Results: Late referral was associated with inferior control of most risk factors for CKD progression, CKD complications and cardiovascular risk factors. In particular, glycaemic control, the use of angiotensin converting enzyme inhibitors and angiotensin-2-receptor blockers in diabetic nephropathy or proteinuria, the control of nutritional and volume status were inferior in LR. One-year mortality was significantly higher in LR (RR 5.9 (95% CI 1.5-19.6); p < 0.01). Inadequate control of blood pressure, anaemia, volume status, malnutrition and emergency initial dialysis, but not LR itself were independently associated with mortality. Conclusions: Late referral was associated with a substantially lower survival after correction for lead-time and immortal time bias and with inferior control of most risk factors for CKD progression, complications and cardiovascular risk factors. CKD patients may particularly profit from adequate control of blood pressure, anaemia, nutritional and volume status, and avoidance of emergency initial dialysis as these factors may predominately contribute to survival.