Receiving industry payments is associated with prescribing habits of tadalafil

Introduction: We evaluated whether industry payments for tadalafil are associated with prescribing habits among urologists and primary care physicians. Methods: The Medicare Part D Public Use File and Open Payments Program database were linked to identify urologists and primary care physicians who prescribed and received a payment for tadalafil in 2015. We determined whether the presence and extent of payment were associated with tadalafil prescription habits. Statistical tests included the chi-squared test, Mann-Whitney U test, logistic regression and Pearson correlation coefficient. Results: Within 2015 Medicare Part D 2,602 urologists and 3,095 primary care physicians prescribed tadalafil. In the 2015 Open Payments/General Payments database 2,304 urologists and 12,465 primary care physicians received a payment from Eli Lilly and Company pertaining to tadalafil. The range of individual payments was $10.21 to $15,478.88 (median $25.16) for urologists and $1.39 to $21,681 (median $20.11) for primary care physicians. The presence of payment was associated with prescription of tadalafil for primary care physicians (OR 4.48, 95% CI 3.67-5.50, p <0.001) but not for urologists (p=0.922). Urologist prescription was not associated with increasing payment amount or greater number of payments. For primary care physicians there was an association of prescribing tadalafil with increasing payment amount (OR 1.01, 95% CI 1.00-1.02, p=0.02) and increasing number of payments (OR 1.15, 95% CI 1.03-1.28, p=0.01). There were weak but statistically significant correlations between claim count and payment amount for urologists and primary care physicians (r=0.063 and r=0.1, respectively, p <0.05). Conclusions: There is a significant relationship between payments and tadalafil prescribing habits. Scrutiny of these relationships has value in improving transparency and reflects the importance of the Open Payments system.