Potential overtreatment of diabetes mellitus in older adults with tight glycemic control

Abstract

Importance: In older adults with multiple serious comorbidities and functional limitations, the harms of intensive glycemic control likely exceed the benefits.

Objectives: To examine glycemic control levels among older adults with diabetes mellitus by health status and to estimate the prevalence of potential overtreatment of diabetes.

Design, setting, and participants: Cross-sectional analysis of the data on 1288 older adults (≥65 years) with diabetes from the National Health and Nutrition Examination Survey (NHANES) from 2001 through 2010 who had a hemoglobin A1c (HbA1c) measurement. All analyses incorporated complex survey design to produce nationally representative estimates.

Exposures: Health status categories: very complex/poor, based on difficulty with 2 or more activities of daily living or dialysis dependence; complex/intermediate, based on difficulty with 2 or more instrumental activities of daily living or presence of 3 or more chronic conditions; and relatively healthy if none of these were present.

Main outcomes and measures: Tight glycemic control (HbA1c level, <7%) and use of diabetes medications likely to result in hypoglycemia (insulin or sulfonylureas).

Results: Of 1288 older adults with diabetes, 50.7% (95% CI, 46.6%-54.8%), representing 3.1 million (95% CI, 2.7-3.5), were relatively healthy, 28.1% (95% CI, 24.8%-31.5%), representing 1.7 million (95% CI, 1.4-2.0), had complex/intermediate health, and 21.2% (95% CI, 18.3%-24.4%), representing 1.3 million (95% CI, 1.1-1.5), had very complex/poor health. Overall, 61.5% (95% CI, 57.5%-65.3%), representing 3.8 million (95% CI, 3.4-4.2), had an HbA1c level of less than 7%; this proportion did not differ across health status categories (62.8% [95% CI, 56.9%-68.3%]) were relatively healthy, 63.0% (95% CI, 57.0%-68.6%) had complex/intermediate health, and 56.4% (95% CI, 49.7%-62.9%) had very complex/poor health (P = .26). Of the older adults with an HbA1c level of less than 7%, 54.9% (95% CI, 50.4%-59.3%) were treated with either insulin or sulfonylureas; this proportion was similar across health status categories (50.8% [95% CI, 45.1%-56.5%] were relatively healthy, 58.7% [95% CI, 49.4%-67.5%] had complex/intermediate health, and 60.0% [95% CI, 51.4%-68.1%] had very complex/poor health; P = .14). During the 10 study years, there were no significant changes in the proportion of older adults with an HbA1c level of less than 7% (P = .34), the proportion with an HbA1c level of less than 7% who had complex/intermediate or very complex/poor health (P = .27), or the proportion with an HbA1c level of less than 7% who were treated with insulin or sulfonylureas despite having complex/intermediate or very complex/poor health (P = .65).

Conclusions and relevance: Although the harms of intensive treatment likely exceed the benefits for older patients with complex/intermediate or very complex/poor health status, most of these adults reached tight glycemic targets between 2001 and 2010. Most of them were treated with insulin or sulfonylureas, which may lead to severe hypoglycemia. Our findings suggest that a substantial proportion of older adults with diabetes were potentially overtreated.

Figure 1

Achieved Glycemic Control Among Older US Adults With Diabetes Mellitus Across 3 Health Status Categories Health status categories are relatively healthy, complex/intermediate health, and very complex/poor health, as described in the Methods section. There was no statistical difference in achieved glycemic control across health status (P = .43). The number of older US adults with diabetes corresponding to each health status category is indicated in millions of persons. HbA_1c indicates hemoglobin A_1c.

Figure 2

Treatment of Older US Adults With Diabetes Mellitus With an HbA_1c Level of Less Than 7% Across Health Status Categories There was no statistical difference in type of treatment across health status categories among these adults (P = .43). The number of US adults corresponding to older adults with diabetes with a hemoglobin A_1c (HbA_1c) level of less than 7% in each health status category is indicated in millions of persons.