Table 3.
Results of sensitivity analyses of associations between amount of industry payments and annual generic drug prescribing rates
| Industry Payment Category | Mean Annual Generic Drug Prescribing Rate Rate Ratio (99% Confidence Interval)1 |
|---|---|
| Adjusted Model2 | |
| By type of industry payments | |
| General payments2 | |
| Exposure: No payment | ref |
| $100 and less | 0.98 (0.97, 0.98)* |
| $100-500 | 0.95 (0.95, 0.95)* |
| More than $500 | 0.95 (0.95, 0.95)* |
| Research payments3 | |
| Exposure: No payment | ref |
| $5,000 and less | 0.98 (0.96, 1.00) |
| $5,000-50,000 | 0.92 (0.90, 0.94)* |
| More than $50,000 | 0.89 (0.86, 0.91)* |
| Ownership payments4 | |
| Exposure: No payment | ref |
| $25,000 and less | 1.02 (1.00, 1.04) |
| $25,000-500,000 | 1.06 (1.05, 1.08)* |
| More than $500,000 | 1.06 (1.04, 1.09)* |
| By annual prescribing volume | |
| Limit to prescribers with annual claims ≥2,0005 | |
| Exposure: No payment | ref |
| $100 and less | 0.99 (0.98, 0.99)* |
| $100-500 | 0.97 (0.97, 0.97)* |
| More than $500 | 0.94 (0.93, 0.94)* |
| Limit to prescribers with annual claims ≥5,0006 | |
| Exposure: No payment | ref |
| $100 and less | 0.99 (0.99, 0.99)* |
| $100-500 | 0.98 (0.97, 0.98)* |
| More than $500 | 0.94 (0.93, 0.94)* |
| Limit to prescribers with annual claims ≥10,0007 | |
| Exposure: No payment | ref |
| $100 and less | 1.00 (0.99, 1.00) |
| $100-500 | 0.98 (0.98, 0.99)* |
| More than $500 | 0.95 (0.94, 0.95)* |
| By prescriber’s specialty | |
| Limit to physicians only8 | |
| Exposure: No payment | ref |
| $100 and less | 0.99 (0.98, 0.99)* |
| $100-500 | 0.96 (0.96, 0.97)* |
| More than $500 | 0.96 (0.96, 0.97)* |
| Limit to psychiatrists only9 | |
| Exposure: No payment | ref |
| $100 and less | 0.99 (0.99, 1.00)* |
| $100-500 | 0.98 (0.98, 0.99)* |
| More than $500 | 0.95 (0.94, 0.95)* |
| Limit to cardiologists only10 | |
| Exposure: No payment | ref |
| $100 and less | 1.00 (0.99, 1.00) |
| $100-500 | 0.98 (0.98, 0.99)* |
| More than $500 | 0.95 (0.95, 0.96)* |
| Limit to family medicine prescribers only11 | |
| Exposure: No payment | ref |
| $100 and less | 0.99 (0.99, 0.99)* |
| $100-500 | 0.97 (0.97, 0.97)* |
| More than $500 | 0.94 (0.94, 0.95)* |
| Limit to internal medicine prescribers only12 | |
| Exposure: No payment | ref |
| $100 and less | 0.98 (0.98, 0.99)* |
| $100-500 | 0.96 (0.96, 0.97)* |
| More than $500 | 0.92 (0.91, 0.92)* |
Generalized linear regression models with Poisson distribution, controlling for all covariates
Exposure variable is the sum of general payments calculated from the 2013 Open Payment data
Exposure variable is the sum of research payments calculated from the 2013 Open Payment data
Exposure variable is the sum of ownership payments calculated from the 2013 Open Payment data
Limiting to prescribers with annual Medicare Part D claims ≥2,000, n=174,700
Limiting to prescribers with annual Medicare Part D claims ≥5,000, n=78,131
Limiting to prescribers with annual Medicare Part D claims ≥10,000, n=26,567
Limiting to physicians only by removing non-physicians such as nurses and physician assistants, n=520,951
Limiting to psychiatrists only, n=34,034
Limiting to cardiologists only, n=21,903
Limiting to family medicine prescribers only, n=97,625
Limiting to internal medicine prescribers only, n=114,195
P<0.001