Oral Antidiabetics for Type 2 Diabetes and Chronic Kidney Disease

San Diego—An examination of electronic health record data from an integrated health system found that patients with type 2 diabetes and chronic kidney disease who had an oral antidiabetic drug regimen concordant with National Kidney Foundation (NKF) guidelines had better clinical and economic outcomes compared with those who did not follow NKF guidelines. The results were presented at the ADA meeting in a late-breaking poster titled Clinical and Economic Outcomes of Appropriate Oral Antidiabetic Drug Treatment among Type 2 Diabetes Mellitus Patients with Chronic Kidney Disease. According to the study’s authors, an estimated 23.6 million people in the United States have type 2 diabetes, and approximately 44% also have chronic kidney disease. They cited a report from the NKF recommending patients with type 2 diabetes and chronic kidney disease avoid many oral antidiabetic drugs or have their dosage adjusted. Between 2005 and 2010, the authors analyzed information from the database, which contains >3 million patients’ records. Patients were included in the study if they were diagnosed with diabetes between 2005 and 2010; were ≥18 years of age at the index date; were in the system for ≥12 months after the index date; had stage 3-5 chronic kidney disease; had no evidence of malignant tumor; and had an order following the index date for ≥1 of the following oral antidiabetic drugs: glyburide, glipizide, glimepiride, acarbose, miglitol, metformin, repaglinide, nateglinide, rosiglitazone, pioglitazone, sitagliptin, or saxagliptin. The index date was defined as the first occurrence of chronic kidney disease. The authors said patients were not concordant with NKF guidelines if they were prescribed an oral antidiabetic drug within 3 months of the index date that required a dosage adjustment but was not adjusted or should have been avoided based on NKF guidelines. After applying inclusion and exclusion criteria, there were 6058 patients in the study group. Of those, 3361 (55%) patients were NKF concordant and 2697 (45%) patients were non-NKF concordant. The groups were well balanced. The mean age was approximately 70 years, approximately 97% were white, approximately 90% had stage 3 chronic kidney disease, and the approximate mean score on the Charlson Comorbidity Index was 4.5. The NKF-concordant group consisted of 48.3% males compared with 37.6% males in the non–NKF-concordant group. At 12 months, 46.1% of patients in the NKF-concordant group had hemoglobin A1c levels <7% compared with 36.1% of patients in the non–NKF-concordant group (P<.05). In addition, 23.9% of patients in the NKF-concordant group were hospitalized during the 12 months compared with 27.9% in the non–NKF-concordant group (P<.05). It was also significantly more expensive to treat patients who did not adhere to NKF guidelines. The overall mean encounter cost for the NKF-concordant group was $9865 per patient compared with $11,357 for the non–NKF-concordant group (P<.05), while the mean diabetes-related encounter cost was $6694 for the NKF-concordant group and $8142 for the non–NKF-concordant group (P<.05). The mean hypoglycemia-related encounter cost for NKF-concordant patients was $239 compared with $525 for the non–NKF-concordant patients (P<.05). A subgroup analysis of patients who required dosage adjustment found similar trends, although most of the differences were not statistically significant. The authors hypothesized that the small sample used in the subgroup analysis may have contributed to the lack of statistical significance. The study had some limitations. The authors used oral antidiabetic drug order records to determine concordance with guidelines, but they could not determine if the patients took the drugs as prescribed. They also did not know the chronic kidney disease progression after the index date or the duration patients were on the oral antidiabetic drugs. Also, because of the retrospective cohort design, the study could only be used to determine inferences and not causation. This study was supported by Boehringer Ingelheim Pharmaceuticals, Inc.