The protective effects of pioglitazone against diabetes continue for up to a year after patients with impaired glucose tolerance stop taking it, new research shows.
"It's quite impressive that we stopped the drug and still for upwards of a year patients got protection from the development of diabetes," Dr. Ralph DeFronzo, of the University of Texas Health Science Center in San Antonio, told Reuters Health by telephone. "It really took an entire year before the beneficial effects of the pioglitazone treatment wore off."
Thiazolidinediones (TZDs) are known to help prevent people at high risk for diabetes from developing the disease, but it is not clear whether their effects persist after a person stops taking them, Dr. DeFronzo and his team note in the Journal of Clinical Endocrinology and Metabolism, March 16.
To investigate, they looked at follow-up data from the ACT NOW trial on 293 patients, including 138 taking placebo and 152 taking pioglitazone (PIO). During the three-year trial, PIO reduced type 2 diabetes prevalence by 72%, and 48% of patients reverted to normal glucose tolerance.
During follow-up, which lasted a median 11.7 months, 12.3% of the placebo group and 11.2% of the PIO group developed diabetes, not a significant difference. But cumulative diabetes incidence from the beginning of study medication to washout was 10.7% for the PIO group, versus 22.3% for the placebo group (p<0.005). Twenty-three percent of the PIO group maintained normal glucose tolerance after the end of therapy, versus 13.8% of the patients on placebo.
The investigators also found that patients who converted to diabetes after stopping medication had lower insulin secretion/insulin resistance, on average, than those who did not.
Treating patients with prediabetes early with low doses of TZDs, possibly for life, is preferable to waiting until a person needs insulin treatment for many reasons, Dr. DeFronzo said, including cost and the difficulty of controlling glucose levels with insulin treatment.
There's also some evidence that the drug may also reduce the risk of recurrent heart attack, stroke, and death, according to Dr. DeFronzo. Based on data from the ACT NOW trial, he added, the number needed to treat to prevent one person from developing diabetes for one year is 18. "Now that pioglitazone is really quite inexpensive, this would be cost effective."
Pioglitazone's Diabetes-Preventing Effects Persist Up to a Year. Medscape. Mar 30, 2016.