Drug Use and Increased HbA1c Levels in Non-diabetic Very Elderly Persons: the Kungsholmen Project

Objective: To examine the association between the use of drugs with potential hyperglycemic effects and increased HbA1c levels in a very elderly population.

Methods: This was a cross-sectional study of older subjects age 81 years and over from the second follow-up (1994-1996) of the Kungsholmen project, a population-based study of elderly in an urban area of Stockholm, Sweden. The study population consisted of 578 subjects, with a mean age of 86.7 years, without known diabetes mellitus. Glucose levels were assessed using HbA1c. Information on drug use was based on personal interviews. Diagnoses of diabetes mellitus, hypertension, and congestive heart failure were obtained from personal or relative interviews, assessment by the examining physician, and from the computerized inpatient register. Measures of other factors that may influence glucose homeostasis included body mass index, s-K(+), s-Ca(2+), thyroid stimulating hormone, and sedimentation rate.

Results: High HbA1c levels (>5.3%) indicating hyperglycemia were seen in 11% of the women and 12% of the men. Use of loop diuretics was significantly associated with high levels of HbA1c in both women and men, even after adjusting for hypertension and congestive heart failure. Eighteen percent of users of loop diuretics had high levels compared with 8% among non-users.

Conclusion: Our results indicate that loop diuretics may have hyperglycemic effects in the very elderly. This finding can be of clinical importance as loop diuretics are among the most commonly taken drugs in this population.