Association between hydration status and the risk and all-cause mortality of diabetic kidney disease

Background: This cohort study aimed to explore the relationship between hydration status and the risk of diabetic kidney disease (DKD) as well as all-cause death in DKD patients. Methods: Weighted univariable and multivariable logistic regression models were used to explore the association between hydration status and DKD risk in diabetic population while weighted univariable and multivariable Cox regression models were used to identify the association between hydration status and all-cause mortality in DKD patients. Kaplan-Meier curve was plotted to present the survival probability of patients with different hydration status. Estimates were presented as odds ratio (OR), and hazard ratio (HR) with 95% confidence interval (CI). Results: The mean follow-up time was 79.74 (+/- 1.89) months. There were 2041 participants with DKD, and 2889 participants without. At the end of the follow-up, 965 participants were alive. The risk of DKD was increased as the increase of osmolarity level (OR = 1.07, 95%CI: 1.05-1.08). The elevated risk of DKD was observed in patients with impending dehydration (OR = 1.49, 95%CI: 1.19-1.85) or current dehydration (OR = 2.69, 95%CI: 2.09-3.46). The association between increased osmolarty level and elevated risk of all-cause mortality in DKD patients was statistically different (HR = 1.02, 95%CI: 1.01-1.03). Current dehydration was correlated with increased all-cause mortality risk in DKD patients (HR = 1.27, 95%CI: 1.01-1.61). Compared to DKD patients with normal hydration, the survival probability of DKD patients with current dehydration was significant lower (p < 0.001). Conclusion: Increased osmolarity level was associated with increased risk of DKD and elevated risk of all-cause mortality in DKD patients.