Changes in treatment of hyperglycemia in a hypertensive type 2 diabetes population as renal function declines

Cardiovascular complications associated with expensive noninsulin agents for type 2 diabetes are the focus of concern in light of the risk of kidney dysfunction with aging. Head-to-head comparisons are unavailable to guide the choice of new drugs for hyperglycemia in patients with type 2 diabetes, decreased estimated glomerular filtration rate (eGFR) and increased cardiovascular risk. A first approach would be to document current medication choices.

All prescriptions for 10 151 patients (5623 males/4528 females) with both type 2 diabetes and hypertension seen two or  more times during a 5-year period (2007-12) at Joslin Diabetes Center were evaluated. {mean age 64 years [interquartile range (IQR) 64-65)], body mass index 31 kg/m² (IQR 30-32) and mean eGFR 78 mL/min/1.73 m² (IQR 78, 78)}.

Insulin was used in >60% of patients, metformin in 50% and sulfonylurea derivatives in 25%. Dipeptidyl peptidase 4 (DPP4) and acarbose class drugs were prescribed in 10% of patients, GLP-1 in 8% and other classes [including thiazolidinediones (TZD)] in <5%. Patients were grouped into four drug Categories none, 447 (4%); insulin only, 3836 (38%); other than insulin, 2910 (29%) and insulin combinations, 2955 (29%). Common combinations included insulin/metformin [n = 2493 (25%)], insulin/sulfonylureas [706 (7%)], metformin/sulfonylureas [2017 (20%)], metformin/GLP1 [949 ( 9%)], metformin/DPP4 [895 (9%)] and metformin/TZD [500 (5%)]. Insulin use increased to 70% from 35% as eGFR dropped to <30 mL/min/1.73 m²; use of insulin combined with other drugs dropped to 12% from 31% and the use of other drugs alone without insulin dropped similarly to 12% from 30%.

Reduced renal function was associated with increased use of insulin and decreased use of other anti-diabetic agents in a statistically significant progression. BMI and gender did not influence medication choice.