Insulin Therapy to Improve BMI in Cystic Fibrosis Related Diabetes Without Fasting Hyperglycemia: Results of the CFRDT Trial

doi:10.2337/dc09-0585

Insulin Therapy to Improve BMI in Cystic Fibrosis Related Diabetes Without Fasting Hyperglycemia: Results of the CFRDT Trial

Antoinette Moran, MD (moran001{at}umn.edu),
Penelope Pekow, PhD,
Patricia Grover, RN,
Martha Zorn, MS,
Bonnie Slovis, MD,
Joseph Pilewski, MD,
Elizabeth Tullis, MD,
Theodore G. Liou, MD,
Holley Allen, MD and
the CFRDT Study Group

From the University of Minnesota, Minneapolis (AM, TG); University of Massachusetts, Amherst (PP, MZ); Vanderbilt University, Nashville, Tennessee (BS); University of Pittsburgh, Philadelphia (JP); St. Michael's Hospital, Toronto, Canada (ET); University of Utah, Salt Lake City (TL); and Baystate Medical Center, Springfield, Massachusetts (HA)

Abstract

Objective: Cystic fibrosis related diabetes (CFRD) without fasting hyperglycemia (FH-) is not associated with microvascular or macrovascular complications, leading to controversy about the need for treatment. The CFRD Therapy Trial (CFRDT) sought to determine whether diabetes therapy improves body mass index (BMI) in these patients.

Research Design and Methods: A 3-arm multi-center randomized trial compared 1 year of therapy with pre-meal insulin aspart, repaglinide, or oral placebo in CF subjects with abnormal glucose tolerance.

Results: One hundred adult patients were enrolled. Eighty-one completed the study including 61 with CFRD FH- and 20 with severely impaired glucose tolerance (IGT). During the year before therapy, BMI declined in all groups. Amongst CFRD FH-, insulin-treated patients lost 0.30±0.21 BMI units the year before therapy; after one year of insulin therapy, this pattern reversed and they gained 0.39±21 BMI units (p=0.02). No significant change in the rate of BMI decline was seen in placebo-treated patients (p=0.45). Repaglinide-treated patients had an initial significant BMI gain (0.53±0.19 BMI units, p=0.01) but this effect was not sustained. After 6 months of therapy they lost weight so that by 12 months there was no difference in the rate of BMI change during the study year compared to the year before (p=0.33). Amongst IGT patients, neither insulin nor repaglinide affected the rate of BMI decline. No significant differences were seen in the rate of lung function decline or the number of hospitalizations in any group.

Conclusions: Insulin therapy safely reversed chronic weight loss in patients with CFRD FH-.