Industry payments to US neurologists related to multiple sclerosis drugs and prescribing (2015-2019): a retrospective cohort study.

Objectives: To measure the prevalence and magnitude of industry payments to neurologists prescribing multiple sclerosis (MS) drugs and determine whether payments are associated with prescribing.

Design: Retrospective observational study.

Setting: Data on neurologists prescribing MS drugs from 2015 to 2019 in the Medicare Part D database linked to the Centers for Medicare & Medicaid Services Open Payments database.

Participants: 7401 neurologists prescribing MS drugs from 2015 to 2019 to Medicare beneficiaries.

Main Outcome Measures: The primary outcome was the proportion of physicians' annual prescriptions manufactured by a given company. Generalised linear mixed models were used to evaluate associations between the presence and magnitude of payments and prescribing. The association between prescription volume and the likelihood of receiving payments as well as the value of payments was also assessed.

Results: Among 7401 neurologists, 5809 (78.5%) received payments totalling US$163.6 million between 2015 and 2019. While the median amount per physician was US$779 (IQR, US$188-US$2587), US$155.7 million (95.2%) accrued to the top 10% of payment recipients. Higher prescription volumes were associated with a higher likelihood of receiving any payment type, particularly for consulting services, non-consulting services and travel/lodging (p<0.001). Among payment recipients, the amount received was positively associated with prescription volume (p<0.001). Receipt of payments was associated with greater likelihood of prescribing the company's drugs compared with those who received no payments from that company (OR 1.13 (95% CI 1.11 to 1.15)), with the largest association for non-consulting services, such as being a speaker at an event (OR 1.53 (95% CI 1.44 to 1.62)). Larger payments were associated with a greater likelihood of prescribing (OR 1.10, 1.26, 1.29 and 1.50 for US$50, US$500, US$1000 and US$5000, respectively), as were longer durations of payments (OR 1.12 for single year to 1.78 for 5 consecutive years) and more recent payments (OR 1.03 for payments made 4 years prior to 1.34 for payments made in the same year).

Conclusions: Nearly 80% of neurologists prescribing MS drugs received at least one industry payment, with higher volume prescribers being more likely to receive payments. Physicians receiving payments were more likely to prescribe the company's drugs, with a stronger association for payments that were larger, sustained and recent.