Therapeutic Inertia and Delays in Insulin Intensification in Type 2 Diabetes: A Literature Review

BACKGROUND: Therapeutic inertia leading to delays in insulin initiation or intensification is a major contributor to lack of optimal diabetes care. This report reviews the literature summarizing data on therapeutic inertia and delays in insulin intensification in the management of type 2 diabetes. METHODS: A literature search was conducted of the Allied & Complementary Medicine, BIOSIS Previews, Embase, EMCare, International Pharmaceutical Abstracts, MEDLINE, and ToxFile databases for clinical studies, observational research, and meta-analyses from 2012 to 2022 using search terms for type 2 diabetes and delay in initiating/intensifying insulin. Twenty-two studies met inclusion criteria. RESULTS: Time until insulin initiation among patients on two to three antihyperglycemic agents was at least 5 years, and mean A1C ranged from 8.7 to 9.8%. Early insulin intensification was linked with reduced A1C by 1.4%, reduction of severe hypoglycemic events from 4 to <1 per 100 person-years, and diminution in risk of heart failure (HF) by 18%, myocardial infarction (MI) by 23%, and stroke by 28%. In contrast, delayed insulin intensification was associated with increased risk of HF (64%), MI (67%), and stroke (51%) and a higher incidence of diabetic retinopathy. In the views of both patients and providers, hypoglycemia was identified as a primary driver of therapeutic inertia; 75.5% of physicians reported that they would treat more aggressively if not for concerns about hypoglycemia. CONCLUSION: Long delays before insulin initiation and intensification in clinically eligible patients are largely driven by concerns over hypoglycemia. New diabetes technology that provides continuous glucose monitoring may reduce occurrences of hypoglycemia and help overcome therapeutic inertia associated with insulin initiation and intensification.