Enhanced fitness: a randomized controlled trial of the effects of home-based physical activity counseling on glycemic control in older adults with prediabetes mellitus

J Am Geriatr Soc. 2012 Sep;60(9):1655-62. doi: 10.1111/j.1532-5415.2012.04119.x.


Objectives: To determine whether a home-based multicomponent physical activity counseling (PAC) intervention is effective in reducing glycemic measures in older outpatients with prediabetes mellitus.

Design: Controlled clinical trial.

Setting: Primary care clinics of the Durham Veterans Affairs (VA) Medical Center between September 29, 2008, and March 25, 2010.

Participants: Three hundred two overweight (body mass index 25-45 kg/m(2) ), older (60-89) outpatients with impaired glucose tolerance (fasting blood glucose 100-125 mg/dL, glycosylated hemoglobin (HbA1c) <7%) randomly assigned to a PAC intervention group (n = 180) or a usual care control group (n = 122).

Intervention: A 12-month, home-based multicomponent PAC program including one in-person baseline counseling session, regular telephone counseling, physician endorsement in clinic with monthly automated encouragement, and customized mailed materials. All study participants, including controls, received a consultation in a VA weight management program.

Measurements: The primary outcome was a homeostasis model assessment of insulin resistance (HOMA-IR), calculated from fasting insulin and glucose levels at baseline and 3 and 12 months. HbA1c was the secondary indicator of glycemic control. Other secondary outcomes were anthropometric measures and self-reported physical activity, health-related quality of life, and physical function.

Results: There were no significant differences between the PAC and control groups over time for any of the glycemic indicators. Both groups had small declines over time of approximately 6% in fasting blood glucose (P < .001), and other glycemic indicators remained stable. The declines in glucose were not sufficient to affect the change in HOMA-IR scores due to fluctuations in insulin over time. Endurance physical activity increased significantly in the PAC group (P < .001) and not in the usual care group.

Conclusion: Home-based telephone counseling increased physical activity levels but was insufficient to improve glycemic indicators in older outpatients with prediabetes mellitus.

Trial registration: ClinicalTrials.gov NCT00594399.

Publication types

  • Controlled Clinical Trial
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging / physiology
  • Anthropometry
  • Blood Glucose / analysis*
  • Body Mass Index
  • Counseling*
  • Female
  • Glycated Hemoglobin / analysis
  • Homeostasis
  • Humans
  • Insulin Resistance
  • Male
  • Middle Aged
  • Motor Activity / physiology*
  • Physical Fitness / physiology*
  • Prediabetic State / physiopathology*
  • Prediabetic State / prevention & control*
  • Quality of Life
  • Time Factors
  • Treatment Outcome
  • Veterans*


  • Blood Glucose
  • Glycated Hemoglobin A

Associated data

  • ClinicalTrials.gov/NCT00594399