Pilot study of prescription-event monitoring in Japan comparing troglitazone with alternative oral hypoglycemics

Abstract

Objective: To examine adverse events reported in a pilot study of the prescription-event monitoring in Japan (J-PEM) scheme, comparing troglitazone with other oral hypoglycemics. Methods: We used a cohort study with a concurrent control in which information was gathered from both doctors and pharmacists. Crude event rates were calculated and compared between troglitazone (T) and alternative oral hypoglycemics (control drugs, C) using the likelihood ratio test. When the difference was statistically significant, possible confounding mechanisms were examined using Poisson regression analysis. Results: Of 3115 patient codes registered, pharmacists were sent 2078 questionnaires and returned 1814 (87%), while doctors were sent 1858 questionnaires and returned 671 (36%). The difference in crude rates was statistically significant in 11 events (seven where T>C and four where C>T) reported by pharmacists and ten events (three where T>C and seven where C>T) reported by doctors. Among those, in two events, "weight increased" (T>C) and "abnormal hepatic function" (T>C), significant differences were observed in data from both doctors and pharmacists. Regression analysis revealed that the difference in crude rates for "nausea" (T>C) was possibly due to an uneven distribution of genders and that for "weight increased" (T>C) was possibly due to an uneven distribution of compliance. Patients with hepatic function abnormalities associated with troglitazone could be divided into two subtypes: one with a slight increase in serum lactate dehydrogenase concentration only and the other with elevated serum alanine aminotransferase. Conclusions: Comparison of the event rates between troglitazone and control drugs, followed by regression analysis, revealed several features of adverse events associated with drugs, including possible confounding mechanisms. Troglitazone-induced hepatic function abnormalities may be divided into two subtypes.