Methods
Utilizing the publicly available payment database,10this analysis examined all personal payments to cardiologists from JPMA-affiliated pharmaceutical companies from 2016 to 2019. We included all cardiologists board-certified by the Japanese Circulation Society (JCS) as of September 2021. The JCS, established in 1935, is the sole professional body board-certifying cardiologists since 1989. As of the specified date, we identified 15,048 board-certified cardiologists from the JCS webpage. The JPMA only requires its member companies to disclose personal payments to individual physicians for lecturing, consulting, and writing services at individual physician level. More common payment categories such as meals, travel, accommodations, and other gifts are reported in aggregate, precluding individual-level analysis.19Therefore, we searched for the names of cardiologists and collected from the payment database only payments to cardiologists for lectures, consulting, and writing for this study. As payments in 2019 were the latest analyzable data at the time of data collection, we collected payments from 2016 to 2019.
We conducted descriptive analyses including mean and median payments per cardiologist and the proportion of cardiologists receiving payments. The concentration of payments among cardiologists was assessed using the Gini index, as in previous studies.20-22 Furthermore, we examined trends in the number of cardiologists receiving payments and the payment amounts from 2016 to 2019 using generalized estimating equation (GEE) models. To adjust for highly skewed distribution of payments, we used a log-linked GEE model with a Poisson distribution for the number of cardiologists receiving payments and a negative binomial GEE model for payments per cardiologist, as conducted in previous studies.11,13,16,19,23 For trend analysis, we adjusted for inflation, converting all payment values to 2019 Japanese yen value. Given that all data used in this study were publicly available and met the definition of non-human subjects research, institutional review board approval was not required in Japan.