Metformin prescribed to only half of patients with type 2 diabetes and CKD, newer medications less utilized
More health care providers prescribe metformin to patients with type 2 diabetes and chronic kidney disease than other diabetes medications, with most prescriptions coming from primary care physicians, according to findings published in the Journal of Diabetes and its Complications.
“We found a large variation by age, race and ethnicity, income, geographic region, and provider specialty in the way conventional and newer antidiabetic medications were prescribed in patients with type 2 diabetes and chronic kidney disease,” Jinnie J. Rhee, MS, ScD, faculty in the division of nephrology at Stanford University School of Medicine, told Endocrine Today. “Most medications were prescribed by primary care physicians, but endocrinologists were the ones that favored newer drugs the most — particularly GLP-1 agonists.”
Rhee and colleagues identified 38,577 adults (mean age, 72 years; 50.9% women) with type 2 diabetes and CKD from the Clinformatics Data Mart, OptumInsight Life Science data set who had at least one diabetes medication prescription from Jan. 1, 2014, to Jan. 1, 2015. The diabetes medications included in the analysis were GLP-1 receptor agonists, DPP-IV inhibitors, metformin, sulfonylureas, thiazolidinediones and insulin.
Nearly half of the cohort was prescribed metformin (49.2%), primarily among those with stage 1 CKD (65%), stage 2 CKD (65.5%) and stage 3a CKD (55.3%). Less than 40% of those with stage 3b (32.5%), stage 4 (10.6%) and stage 5 (2.1%) CKD were prescribed metformin. Primary care providers accounted for 81.7% of the metformin prescriptions while endocrinologists accounted for 6.1% of these prescriptions.
“Metformin is the first-line therapy for type 2 diabetes management as recommended by clinical practice guidelines,” Rhee said. “It was surprising to see that while metformin was the most commonly prescribed medication, only about half of the patients were treated with metformin, and fewer than two-thirds of patients with early stage CKD were prescribed metformin.”
Other drug classes
Sulfonylureas were prescribed to 38.8% of the study population, with the researchers noting that glipizide was the most popular of this drug class and prescribed to 60% of those receiving a sulfonylurea prescription. Patients with stage 3b CKD (45.3%) and stage 4 CKD (46.2%) were prescribed sulfonylureas most frequently, with less than 40% of those with other stages of the disease receiving a sulfonylurea prescription. PCPs were responsible for most prescriptions of this drug class (81%) while endocrinologist accounted for 6.4%.
Roughly one-quarter of the study population was prescribed insulin (24.8%), with 59.4% of those with stage 5 CKD and 42.3% of those with stage 4 CKD receiving an insulin prescription. The percentage of insulin prescriptions for those with less severe forms of CKD fell below 30%. Endocrinologists provided 17.9% of the insulin prescriptions and PCPs provided 69%.
TZDs were prescribed to 6.2% of the study population, including 7.2% of those with stage 3b CKD and 7.9% with stage 4 CKD, with less than 6% of those in each of the remaining stages receiving a TZD prescription. Endocrinologists were responsible for 9.5% of these prescriptions while PCPs were responsible for 78.2%.
DPP-IV inhibitors were prescribed to 12.3% of those in the study population with the highest percentages found in those with stage 3b CKD (15.7%) and stage 4 CKD (17.3%). In addition, GLP-1 receptor agonists were prescribed to 3.4% of the study population, including 6.1% of those with stage 1 CKD, with the percentages falling below 5% for those with more severe kidney disease. Endocrinologists accounted for 31.7% of the prescriptions for GLP-1 receptor agonists and 9.9% of the prescriptions for DPP-IV inhibitors. PCPs were responsible for 56.8% of the prescriptions for GLP-1 receptor agonists and 75.8% of the prescriptions for DPP-IV inhibitors.
A prescription for multiple medications or combination therapy was received by 5.9% of the study population, including 11.4% of those with stage 1 CKD, 8.3% of those with stage 2 CKD, 6% with stage 3a CKD, 3.2% with stage 3b CKD, 1.6% with stage 4 CKD and 0.2% with stage 5 CKD. Ten percent of the combination therapy prescriptions were from endocrinologists and 78.4% were from PCPs.
“This research highlights how antidiabetic medications are being prescribed and by whom, and shows that there may be knowledge or competency gaps among providers who do not specialize in diabetes care, especially when it comes to treatment with newer medications,” Rhee said. “Such prescribing patterns can point to the importance of evaluating various strategies that could potentially improve drug prescribing in this very clinically vulnerable population, whether through decision support systems, improved and updated medical education and training, etc.” – by Phil Neuffer
Disclosures: The authors report no relevant financial disclosures.