Results
Of the 6,107 board-certified neurologists, 3,615 (59.2%) received personal payments from the pharmaceutical companies over the five years between 2016 and 2020 (Table 1). The total amounts of personal payments were in $45,726,920 entailing 37,337 payments. For neurologists who received at least one payment, the median amount per neurologist was $2,423 (interquartile range [IQR]: $765–$9,076), in contrast to a mean of $12,649 (standard deviation [SD]: $35,012) over the five-year span. The Gini index, used to measure payment distribution among neurologists, was 0.871, suggesting that a small proportion of neurologists received the majority of personal payments over the five years. Specifically, the top 1% (61 neurologists), 5% (305 neurologists), and 10% (611 neurologists) of these neurologists received 30.3%, 52.8%, and 78.8% of all personal payments, respectively. Of the three payment categories, lecturing payments occupied 84.4% of overall payments to the neurologists ($38,612,931). Additionally, 58.1% of all neurologists received at least one lecturing payments from the pharmaceutical companies between 2016 and 2020. Mean value per payment was $1,243 for lecturing payments, $1,236 for consulting payments, and $915 for writing payments.
Of 78 pharmaceutical companies making payments to the neurologists, Daichi Sankyo made the largest amounts of personal payments totaling $6.3 million, followed by Eisai ($5.0 million), Takeda Pharmaceutical ($4.5 million), Otsuka Pharmaceutical ($3.8 million), and Kyowa Kirin ($3.2 million). The top 5 and 10 companies with the largest payment amounts were responsible for 50.2% ($22.9 million) and 74.5% ($34.1 million) of all payments over the five years.
The total annual amounts of personal payments to neurologists showed an increasing trend from $8.8 million in 2016 to $10.0 million in 2019 (Table 2), but decreased to $8.1 million in 2020. There was a similar trend in the number of payments over the five years. Of all neurologists, 33.0% to 36.8% received at least one personal payment each year. The number of neurologists receiving payments significantly increased by 1.5% (95% confidence interval [95% CI]: 0.4%–2.6%, p<0.001) each year from 2179 in 2016 to 2292 in 2019. Among neurologists receiving payments, median annual payments per neurologist were from $1,077 to $1,356 in monetary value and 2.0 in the number of payments. Payments per neurologist annually increased by 3.2% (95% CI: 0.9%–5.5%, p=0.006) in monetary value and by 3.5% (95% CI: 2.4%–4.7%, p<0.001) in the number of payments between 2016 and 2019. Contrarily, there was significant decreases of 14.3% (95% CI: -16.4% to -10.1%, p<0.001) in the number of neurologists receiving payments and 21.1% (95% CI: -25.3% to -16.7%, p<0.001) in payments per neurologist in 2020 when compared to those in the previous years.