Vitamin D deficiency may increase the risk of acute kidney injury in patients with diabetes and predict a poorer outcome in patients with acute kidney injury.

Backgound: People with diabetes are much more likely to develop acute kidney injury (AKI) than people without diabetes. Low 25-hydroxy-vitamin D [25(OH)D] concentrations increased the risk of AKI in specific populations. Few studies have explored the relationship between the 25(OH)D level and AKI in patients with diabetes. We conducted this study to investigate the relationship between the plasma level of 25(OH)D and the risk of AKI in patients with diabetes, and to evaluate whether the 25(OH)D level could be a good prognostic marker for AKI progression.

Methods: A total of 347 patients with diabetes were retrospectively reviewed. The primary endpoint was the first event of AKI. The secondary endpoint is need-of-dialysis. AKI patients were further followed up for 6 months with the composite endpoint of end-stage renal disease (ESRD) or all-cause death. Kaplan-Meier survival analysis and Cox proportional hazards models were used.

Results: During a median follow-up of 12 weeks (12.3 ± 6.7), 105 incident AKI were identified. The middle and high tertiles of baseline 25(OH)D levels were associated with a significantly decreased risk of AKI and dialysis compared to the low tertile group (HR = 0.25, 95% CI 0.14-0.46; HR = 0.24, 95% CI 0.13-0.44, respectively, for AKI; HR = 0.15; 95% CI 0.05-0.46; HR = 0.12; 95% CI 0.03-0.42, respectively, for dialysis). Sensitivity analysis revealed similar trends after excluding participants without history of CKD. Furthermore, AKI patients with 25(OH)D deficiency were associated with a higher risk for ESRD or all-cause death (HR, 4.24; 95% CI, 1.80 to 9.97, P < 0.001).

Conclusion: A low 25 (OH) vitamin D is associated with a higher risk of AKI and dialysis in patients with diabetes. AKI patients with 25(OH)D deficiency were associated with a higher risk for ESRD or all-cause death.