Table 1

Physician characteristics according to whether they received opioid-related industry payments in 2016

Cohort before propensity-matching*Cohort after propensity-matching*
Physicians who received opioid-related paymentsPhysicians who did not receive opioid-related paymentsStandardised difference %Physicians who received opioid-related paymentsPhysicians who did not receive opioid-related paymentsStandardised difference %
Number of physicians 25 923517 57621 88921 889
Sex, N (%)
 Female22.232.4−23.124.023.80.4
 Male77.867.623.176.076.2−0.4
Years in practice, mean 24.722.615.924.724.51.3
Medical school attended,%
 Top 20 schools in US6.811.4−15.87.27.00.1
 US schools ranked 21–5014.517.7−8.515.014.90.2
 Other schools78.671.017.777.878.1−0.7
Specialty,‡ %
Primary care
 Internal medicine18.018.4−0.920.819.34.0
 Family medicine26.314.330.228.530.0−3.0
 Other primary care§0.71.5−7.30.80.9−0.4
Surgery
 Neurosurgery0.40.9−5.60.50.41.2
 General2.83.6−4.83.33.6−2.1
 Obstetrics/gynecology2.05.5−18.52.42.7−2.2
 Orthopedic4.23.91.24.94.32.8
 Urology0.51.5−10.90.50.7−2.4
 Other surgery¶0.93.2−16.71.01.2−1.5
Specialists
 Pain medicine2.70.122.00.81.1−2.5
 Rehabilitation6.51.128.23.03.7−3.6
 Anesthesiology19.86.042.315.816.6−2.2
 Radiation oncology1.80.610.32.02.0−0.4
 Psychiatry0.64.1−23.70.70.43.5
 Hematology/oncology3.51.611.74.04.4−1.8
 Neurology2.22.10.62.52.40.7
 Other specialists**7.231.4−64.48.56.28.6
Amount of any general payments received in 2016 ($), mean††418.219.6108.3355.5325.74.0
Number of opioid prescriptions in 2016, mean††42.53.0118.027.026.90.3
Received opioid-related payments in 2015, % 52.53.2131.844.244.10.2
  • *One-to-one pair matching was performed by nearest-neighbor matching without replacement, with the use of a caliper width equal to 0.2 of the SD of the logit of the propensity score. A standardised difference of less than 10.0% was considered to indicate a negligible imbalance between the two groups.

  • †Top 20 schools and top 21 to 50 schools in the US were defined based on the U.S. News & World Report ranking (research ranking) in 2017. Other schools include foreign medical schools.

  • ‡Physicians with specialty in addiction medicine were also balanced in the cohort after propensity matching (14.1% vs 13.9%; standardised difference, 0.6%), These physicians were included in internal medicine, family medicine, anesthesiology or psychiatry.

  • §Other primary care includes preventive medicine, hospitalists and paediatrics.

  • ¶Other surgery includes plastic, otolaryngology, colorectal and thoracic/vascular surgery.

  • **Other specialists include allergy/immunology, cardiology, dermatology, endocrinology, gastroenterology, infectious disease, nephrology, nuclear medicine, ophthalmology, pathology, pulmonology, radiology and rheumatology.

  • ††Geometric mean was described because this variable was included in the propensity-score model after log-transformation.