Androgen deprivation therapy (ADT) for prostate cancer hampers glycemic control in men with diabetes, report researchers.
"Men with diabetes who start ADT should be counseled about the potential need for intensification of diabetes therapy and should have their HbA1c [glycated hemoglobin] levels monitored during therapy, especially if they continue on long-term ADT," warn Nancy Keating (Brigham and Women's hospital, Boston, Massachusetts, USA) and colleagues.
The team conducted an observational study using US Department of Veterans Affairs registry data from 2001-2004 linked with 2000-2005 administrative data for 2237 men with prostate cancer who initiated ADT, each of whom was propensity-matched with prostate cancer patients who did not start the treatment.
A comparison of data at baseline (from time of prostate cancer diagnosis) and at 1 and 2 years showed that initiating ADT upon diagnosis was associated with increased HbA1c levels and the requirement of additional antidiabetic medications.
As reported in European Urology, the HbA1c value at baseline was 7.24% both in men who were treated with ADT and those who were not. During the first year of follow-up, HbA1c decreased in those who did not receive ADT to 7.14%, while in those treated with ADT the reverse occurred, with the mean HbA1c level rising by a significant 0.14% to 7.38%.
Similarly, after 2 years of follow-up, the mean HbA1c remained significantly increased in those on ADT, at 7.35%, while it was still decreased among those not treated with ADT, at 7.16%.
Overall, 18.2% of men on ADT had an HbA1c increase of more than 1% at 1 year versus 11.9% of those not treated with ADT.
The rates for initiating or increasing a new class of diabetes drug was 248.6 per 1000 person-years in the ADT patients, which was significantly higher than the 209.6 per 1000 person-years in their non-ADT counterparts.
A Cox proportional hazard model showed that starting ADT was associated with a significantly increased likelihood for the addition of diabetes medication, at a hazard ratio of 1.20.
Previous population-based studies have associated ADT use with the development of diabetes, note the researchers, but the effects of ADT on diabetes control for patients who already have diabetes are not known.
"We found that ADT was associated with worsening diabetes control despite the intensification of pharmacologic therapy for diabetes, further supporting a causal association between ADT and diabetes," write Keating et al.
"Physicians should continue to weigh potential benefits and risks of treatment when making decisions about the use of ADT, particularly when used in settings for which the benefits have not been clearly established," concludes the team.
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