Hyperglycemia and incidence of frailty and lower extremity mobility limitations in older women

Abstract

Objectives: To determine the degree to which hyperglycemia predicts the development of frailty and lower extremity mobility limitations.

Design: Secondary data analysis of longitudinal data collected in a prospective cohort study.

Setting: Baltimore, Maryland.

Participants: Three hundred twenty-nine women from the Women's Health and Aging Study II aged 70 to 79 at baseline who had all variables needed for analysis.

Measurements: Glycosylated hemoglobin (HbA1c) at baseline, categorized as less than 5.5%, 5.5% to 5.9%, 6.0% to 6.4%, 6.5% to 7.9%, and 8.0% and greater, was the independent variable. The incidence of frailty and lower extremity mobility limitations (based on self-reported walking difficulty, walking speed, and Short Performance Physical Battery score) was determined (follow-up ≈ 9 years). Frailty was assessed using the Cardiovascular Health Study criteria. Covariates included demographic characteristics, body mass index, interleukin-6 level, and clinical history of comorbidities. Statistical analyses included Kaplan-Meier survival curves and Cox regression models adjusted for important covariates.

Results: In time-to-event analyses, HbA1c category was associated with incidence of walking difficulty (P = .049) and low physical performance (P = .001); association with incidence of frailty and low walking speed had a trend toward significance (both P = .10). In regression models adjusted for demographic characteristics, HbA1c of 8.0% or greater (vs < 5.5%) was associated with an approximately three-times greater risk of incident frailty and three to five times greater risk of lower extremity mobility limitations (all P < .05). In fully adjusted models, HbA1c of 8.0% or greater (vs < 5.5%) was associated with incident frailty (hazard ratio (HR) = 3.33, 95% confidence interval (CI) = 1.24-8.93), walking difficulty (HR = 3.47, 95% CI = 1.26-9.55), low walking speed (HR = 2.82, 95% CI = 1.19-6.71), and low physical performance (HR = 3.60, 95% CI = 1.52-8.53).

Conclusion: Hyperglycemia is associated with the development of frailty and lower extremity mobility limitations in older women. Future studies should identify mediators of these relationships.