Echocardiography for the detection of valvulopathy associated with the use of ergot-derived dopamine agonists in patients with Parkinson's disease

Objective The ergot-derived dopamine agonists, cabergoline and pergolide, are associated with valvulopathy risk. In Japan, product labels were revised in April 2007 to recommend periodic echocardiography for patients taking these dopamine agonists, however, the compliance of physicians to follow through with this recommendation is unknown. This study assessed changes in echocardiography evaluation of patients with Parkinson's disease (PD) taking cabergoline or pergolide before and after the label revision and examined the factors related with echocardiography performance. Methods and Patients Medical claim data from January 2005 to December 2008 were used. Patients were divided into a C-P group (prescribed either cabergoline or pergolide) or reference group (prescribed other anti-PD drugs), and further classified based on whether they were prescribed these drugs "pre-revision" or "post-revision." The Cochran-Armitage trend test was used to compare the proportion of echocardiograms obtained amongst these groups before and after the revision. The frequencies of echocardiograms performed among the treatment groups for each period were compared by Fisher's exact test. Results A total of 222 subjects (C-P, 73; reference, 149) were assessed. The proportion of C-P patients undergoing echocardiography increased from 4.8% to 27.9% after revision of product labels (p=0.001), which was higher than those in the reference group following label revisions (11.0%) (p=0.014). Prescription duration of C-P after the revision was longer in the patients with echocardiography than without echocardiography (p=0.026). Conclusion Although echocardiography evaluations increased, more than 70% of PD patients prescribed cabergoline or pergolide did not undergo such assessment despite the product label recommendation. Adherence to drug safety recommendations should be facilitated with more feasible and effective measures.