Visit-to-visit variability in albuminuria predicts renal function deterioration in patients with type 2 diabetes

Aims/Introduction We aimed to study the predictive ability of visit-to-visit variability in albuminuria for changes in renal function in patients with type 2 diabetes mellitus. Materials and Methods The cohort study was carried out in a single medical center. In the model development cohort of 1008 subjects, we developed the albuminuria variability score (AVS) to evaluate the visit-to-visit variability in albuminuria, which was the percentage of the number of changes in the urine albumin : creatinine ratio >= 3.39 mg/mmol among all visit-to-visit urine albumin : creatinine ratio differences within an individual. Multivariate logistic regression was applied to predict the influence of AVS levels on the occurrence of study end-points. In another independent validation cohort of 310 participants, survival analysis was carried out to evaluate the ability of AVS in predicting the study end-point. Results In the model development cohort, a higher AVS was associated with higher adjusted odds of having a declined or rapidly declined estimated glomerular filtration rate (eGFR) trajectory (1.84, 95% confidence interval 1.23-2.76 and 5.70, 95% confidence interval 2.28-14.25, respectively), a resultant eGFR <60 mL/min/1.73 m(2) (2.61, 95% confidence interval 1.63-4.16) and a >40% decline in eGFR from baseline (6.44, 95% confidence interval 2.15-19.26). In the validation cohort, a higher AVS independently predicted a 5-year decrease of >40% in eGFR to <60 mL/min/1.73 m(2) (adjusted hazard ratio 3.33, 95% confidence interval 1.10-10.05). Integrated discrimination index and concordance statistics showed that AVS significantly improved the predictive ability of the models. Conclusions Visit-to-visit variability in albuminuria can independently predict long-term renal function deterioration in patients with type 2 diabetes mellitus. Further investigations are warranted to elucidate the potential clinical applications.