Table 9. Relationship between exposure to information from drug companies and prescribing costs (by year of publication and then study design/size).
| Exposure to Information from Drug Company | Study (First Author Name) | Results | Change in Prescribing Costs |
| Effect of PSR visits | Watkins [66] | High cost prescribers were more likely to see PSRs at least once a week than low cost prescribers | OR 3.11 (95% CI 2.48–3.89); p<0.01a |
| Caamano [68] | There was no association between PSR visits and the cost of prescriptions | Adjusted regression coefficient: 21.0; p = 0.962 | |
| Gonul [69] | PSR visits were associated with increased physicians' price sensitivity | Maximum likelihood estimate, 0.0012; t statistic 3 (p<0.001) | |
| Rizzo [50] | PSR visits were associated with reduced price elasticity for the promoted drug | Sales estimate +0.14; t statistic 2.97 (p<0.01) | |
| Caudill [71] | Frequency of PSR visits was associated with higher prescribing costs | Multivariate regression beta +0.155; p = 0.01 | |
| Journal advertisements | Watkins [66] | High cost prescribers were less likely to “rarely or never” read journal advertisements than low cost prescribers | OR 0.79 (95% CI 0.64–0.98); p = 0.02a |
| Mailed information from pharmaceutical companies | High cost prescribers were less likely to “rarely or never” read mailed information than low cost prescribers | OR 0.49 (95% CI 0.38–0.64); p<0.01a | |
| Total promotional investment/summated scores of commercial information use/general use of commercial sources | Spurling [55] | Reduced n PSR visits and volume of promotional material were associated with an increased generic prescribing at 3 and 9 mo | 3 mo: OR 2.28 (95% CI 1.31–3.86); p = 0.0027a |
| 9 mo: OR 2.07 (95% CI 1.13–3.82); p = 0.016a | |||
| Windmeijer [41] | Promotional outlay (PSR visits, journal advertisements, direct mail) was associated with reduced price elasticity for promoted drugs | ln regression coefficient −0.0102 (se 0.0055) p<0.05 | |
| Information delivered without conventional promotion | Freemantle [35] | There was no significant difference in costs between the group that was detailed by PSRs instructed by a local health authority and the control group | Mean difference: £122.32 (95% CI −£94.91 to £342.91) |
a
Chi-squared statistic.