The economic burden of progressive chronic kidney disease among patients with type 2 diabetes.

Aims: To estimate the rate of progression of chronic kidney disease (CKD) among patients with type 2 diabetes (T2D) and calculate medical costs associated with progression.

Methods: We conducted a retrospective cohort study of 25,576 members at Kaiser Permanente who had T2D and at least one serum creatinine measurement in 2005. Using estimated glomerular filtration rate (eGFR), we assigned patients to baseline stages of kidney function (stage 0-2, >60ml/min/1.73m(2), n=21,008; stage 3, 30-59, n=3,885; stage 4, 15-29, n=683). We examined all subsequent eGFRs through 2010 to assess progression of kidney disease. Medical costs at baseline and incremental costs during follow-up were assessed.

Results: Mean age of patients was 60.6years, 51% were men, and mean diabetes duration was 5.3years. At baseline, 17.9% of patients with T2D also had stage 3 or 4 CKD. Incremental adjusted costs that occurred over follow-up (from baseline) was on average $4569, $12,617, and $33,162 per patient per year higher among patients who progressed from baseline stage 0-2, stage 3, and stage 4 CKD, respectively, compared to those who did not progress. Across all stages of CKD, those who progressed to a higher stage of CKD from baseline had follow-up costs that ranged from 2 to 4 times higher than those who did not progress.

Conclusions: Progression of CKD in T2D drives substantial medical care costs. Interventions designed to minimize decline in progressive kidney function, particularly among patients with stage 3 or 4 CKD, may reduce the economic burden of CKD in T2D.