Use of rosiglitazone in physicians' office-based treatment of diabetes patients fell 60%, while pioglitazone use showed just a 9% drop during a 16-month period that included three Food and Drug Administration advisories in 2007 about the drugs' cardiovascular risks.
That gap “is noteworthy,” and “considerable evidence supports the greater safety” of pioglitazone over rosiglitazone, Andrew Cohen and his colleagues wrote in an investigation that was published online.
The investigators studied IMS Health's National Disease and Therapeutic Index monthly figures on oral diabetic therapies that were utilized during office treatment visits from January 2003 to June 2009.
Data on the use of the glitazone drug class for diabetic patients aged 35 years and older who did not have type 1 diabetes were analyzed in four time frames: January 2003–January 2005; February 2005–January 2007, a period when safety concerns were first revealed; February 2007–May 2008, when the FDA issued the advisories on cardiovascular risks and 6 months thereafter; and June 2008–June 2009, wrote Mr. Cohen of the University of Chicago, and his colleagues.
Following the publication of safety concerns that linked glitazone use to serious cardiovascular episodes, but prior to the FDA's advisories, overall glitazone use had begun declining from 34% of type 2 diabetes patients' office treatment visits to 29% (Diabetes Care 2010 Jan. 26 [doi:10.2337/dc09-1834]).
Rosiglitazone use showed a “sharp decline” following reports—scientific evidence, the FDA's advisories, and media coverage—of the cardiovascular risks of glitazone; however, pioglitazone use “did not similarly decline” in light of the FDA's class-wide advisory, the authors stated.
“Decreases in rosiglitazone and pioglitazone use occurred non-selectively, rather than among those at highest cardiovascular risk,” they said, adding that the changes “are important because glitazones were widely adopted into practice following their market debut despite questions regarding their potential safety.”
Although glitazone use showed “rapid increases” from the class's debut—growing at an annual rate of 22%, and peaking at 34% (11.2 million) of all treatment visits among patients with type 2 diabetes—it decreased at a 29% rate during the FDA advisory period before leveling off to a statistically nonsignificant decline of 2%, the investigators found.
In the latter period, rosiglitazone constituted 23% (1.8 million office visits) and pioglitazone 77% (5.8 million visits) of glitazone use.
The “continuing uncertainty” over the drugs' cardiovascular risks “suggests the importance of the routine inclusion of cardiovascular end points in studies that are used to seek FDA approval for diabetes therapies” and “their limited role as monotherapy for diabetes or use in patients at elevated risk of congestive heart failure or ischemic heart disease,” Mr. Cohen and his associates concluded.
The study was funded through a career development award from Robert Wood Johnson Physician Foundation and the Agency for Healthcare Research and Quality to Dr. G. Caleb Alexander, the principal investigator, also of the University of Chicago. No disclosures were reported.