MP335HYPERPHOSPHATEMIA: A MARKER OF RENAL INJURY AND OUTCOME IN PATIETS WITH EARLY STAGE DIABETIC NEPHROPATHY

Abstract

Introduction and Aims: Here, we investigated the association between hyperphosphatemia and renal outcome in patients with type 2 diabetes and DN, especially in patients with an eGFR>=60ml/min/1.73m 2. Methods: A total of 597 patients with DN were identified in our study. The median follow-up period for these patients was 36 months. Renal outcomes were defined by progression to end-stage renal disease (ESRD) and doubling of serum creatinine. Results: The prevalences of hyperphosphatemia (serum phosphate>1.45 mmil/L) in the enrolled DN patients with eGFR>90, between 60 and 90, and <60ml/min/1.73m 2 were 25/214 (11.7%), 25/150 (16.7%), and 71/233 (30.5%), respectively. Hyperphosphatemia was significantly associated with enhanced tubulointerstitial injury markers (P<0.01) as well as a high rate of tubulointerstitial injury (interstitial fibrosis tubular atrophy scores and interstitial inflammation scores, P<0.05) in DN patients with eGFR>=60ml/min/1.73m 2. The levels of the urinary tubulointerstitial injury markers including the NAG, RBP and NGAL were significantly difference among quintiles of serum phosphorus (P<0.01; Figure 1). Additionally, patients with baseline serum phosphate levels in higher quartiles had a higher cumulative incidence of ESRD (log-rank, P<0.01; Figure 2). Risk persisted after adjusting for age, sex, blood pressure, lipid level, body mass index, proteinuria, plasma calcium and eGFR (P<0.001, Table 1). The association between serum phosphorus and ESRD risk persisted and was stronger when the sample was restricted to those with a baseline eGFR equal to 60-90ml/min per 1.73m 2, but not when it was restricted to patients with a baseline eGFR of 30-60ml/min per 1.73m 2 (Table 2). Conclusions: These findings indicated that hyperphosphatemia is an independent risk factor of ESRD and significantly associated with tubulointerstitial injury in patients with DN, especially in patients with eGFR>=60ml/min/1.73m 2. (Table presented).