Table 7. Relationship between exposure to information from drug companies and prescribing quality (by year of publication and then study design/size).
Exposure to Information from Drug Company | Study (First Author Name) | Result in Exposed Group Versus Controls (Where Applicable) | Change in Prescribing Quality Result |
Effect of PSR visits | de Bakker [61] | Wider prescribing range was associated with more visits from PSRs in the last 4 wk | Beta coefficient +0.18 (p<0.05)a |
Muijrers [64] | More frequent visits from PSRs was associated with less adherence to prescription guidelines | Multiple linear regression: | |
Beta −0.23 (95% CI −0.32 to −0.15) p<0.05 | |||
Mansfield [82] | Frequency of visits from PSRs was not associated with a difference in quality score | Pearson coefficient of 0.0363; p = 0.247 | |
Blondeel [81] | Based on responses to 8 case histories: | Multivariate regression analysis: | |
First contact with a drug from the pharmaceutical industry was not associated with quality index; | p>0.1 | ||
n PSRs received was associated with poorer quality index; | p>0.05 | ||
Based on prescriptions for actual patients: First contact with a drug from the pharmaceutical industry was associated with reduced quality of prescribing; | p<0.01 | ||
n PSRs received was not associated with poorer quality index | p>0.1 | ||
Becker [77] | Fewer visits from PSRs/month were not associated with a change in the appropriateness of prescribing | Gamma statistic; 0.04, not statistically significant | |
Attendance at pharmaceutical sponsored meeting | Mansfield [82] | Attendance at pharmaceutical sponsored meetings was associated with lower quality scores | Pearson correlation coefficient of 0.0635; p = 0.043 |
Spingarn [39] | Attendees at a sponsored talk about Lyme disease were less likely to choose appropriate oral antibiotics for mild Lyme disease than nonattendees | 0% of attendees (n = 22) chose appropriate antibiotics compared to 21% (n = 53) of nonattendees; Fisher exact test: p = 0.027 | |
For attendees and nonattendees of a sponsored talk about Lyme disease there was no difference in choice of acceptable treatment for Lyme disease with central nervous system signs | OR = 3.2 (95% CI 0.8–19.2) | ||
Attendees of a sponsored talk about Lyme disease were more likely to appropriately choose the sponsoring company's treatment for Lyme disease complicated by 2nd degree heart block | OR = 7.9 (95% CI 2.4–29.3) | ||
Journal advertisements | Becker [77] | Infrequent use of journal ads as a source of prescribing information by doctors was not associated with a change in the appropriateness of prescribing | Gamma statistic 0.373, not statistically significant |
Total promotional investment/summated scores of commercial information use/general use of commercial sources | de Bakker [61] | There was a positive correlation for how frequently doctors used the pharmaceutical industry as a source of information and the range of drugs they prescribed | Beta coefficient +0.15 (p<0.05)a |
Haayer [74] | Frequency of use of information from the pharmaceutical industry was associated with less rational prescribing | Beta coefficient +0.134 ; p<0.001 | |
Information delivered without conventional promotion | Andersen [37] | Participation in a randomized controlled trial was not associated with a change in guideline adherence at 2 y for trial sponsor's medication | OR 1.00 (95% CI 0.84–1.19) |
Kazmierczak [59] | Mailed warning letters regarding tramadol for those with a seizure risk were not associated with a change in prescription rates for tramadol | 9 (10%) prescriptions before and 7 (9%) after warning letters were sent out no association detected | |
Soumerai [58] | PSR visits: Propoxyphene use continued a preexisting decline of about 8% a year during the time when warnings from the manufacturing pharmaceutical company were conveyed by PSRs after which time this decline halted, however a statistical association was not shown. Refill rates and rates of overdose did not change following the warnings | No association detected | |
Mailed Information: Propoxyphene use continued a preexisting decline of about 8% a year during the time when warnings from the manufacturing pharmaceutical company were expressed by PSRs after which time this decline halted, however a statistical association was not shown. Refill rates and rates of overdose did not change following the warnings | No association detected |
Assumes a wide prescribing range is lower quality prescribing than a narrow prescribing range.