Glucose Control, Sulfonylureas, and Insulin Treatment in Elderly People With Type 2 Diabetes and Risk of Severe Hypoglycemia and Death: An Observational Study.

Objective

To estimate the relative and absolute risk of severe hypoglycemia and mortality associated with glucose control, sulfonylureas, and insulin treatment in elderly people with type 2 diabetes.

Research design and methods

We identified elderly subjects (≥70 years old) with type 2 diabetes between 2000 and 2017 in the U.K. Clinical Practice Research Datalink primary care database with linkage to hospitalization and death data. Subjects with three consecutive HbA_1c values <7% (53 mmol/mol) while on insulin and/or sulfonylureas within 60 days prior to the third HbA_1c value (exposed) were matched with subjects not exposed. Hazard ratios (HRs) and absolute risks were estimated for hospitalizations for severe hypoglycemia and cardiovascular and non-cardiovascular-related mortality.

Results

Among 22,857 included subjects (6,288 [27.5%] exposed, of whom 5,659 [90.0%] were on a sulfonylurea), 10,878 (47.6%) deaths and 1,392 (6.1%) severe hypoglycemic episodes occurred during the follow-up. In comparison with nonexposed subjects, the adjusted HR in exposed subjects was 2.52 (95% CI 2.23, 2.84) for severe hypoglycemia, 0.98 (0.91, 1.06) for cardiovascular mortality, and 1.05 (0.99, 1.11) for noncardiovascular mortality. In a 70-, 75-, 80-, and 85-year-old subject, the 10-year risk of severe hypoglycemia was 7.7%, 8.1%, 8.6%, and 8.4% higher than in nonexposed subjects, while differences for noncardiovascular mortality ranged from 1.2% (95% CI -0.1, 2.5) in a 70-year-old to 1.6% (-0.2, 3.4) in an 85-year-old subject. Sulfonylurea and insulin use were more relevant predictors of severe hypoglycemia and death than were glucose levels.

Conclusions

Elderly subjects with type 2 diabetes and low HbA_1c on sulfonylurea or insulin treatment experienced a substantially higher risk of hospitalization for severe hypoglycemia but had no clear evidence of increased risks of mortality.