Are Financial Payments From the Pharmaceutical Industry Associated With Physician Prescribing? : A Systematic Review

Abstract

Background: Financial payments from the drug industry to U.S. physicians are common. Payments may influence physicians' clinical decision making and drug prescribing.

Purpose: To evaluate whether receipt of payments from the drug industry is associated with physician prescribing practices.

Data sources: MEDLINE (Ovid), Embase, the Cochrane Library, Web of Science, and EconLit were searched without language restrictions. The search had no limiting start date and concluded on 16 September 2020.

Study selection: Studies that estimated the association between receipt of industry payments (exposure) and prescribing (outcome).

Data extraction: Pairs of reviewers extracted the primary analysis or analyses from each study and evaluated risk of bias (ROB).

Data synthesis: Thirty-six studies comprising 101 analyses were included. Most studies (n = 30) identified a positive association between payments and prescribing in all analyses; the remainder (n = 6) had a mix of positive and null findings. No study had only null findings. Of 101 individual analyses, 89 identified a positive association. Payments were associated with increased prescribing of the paying company's drug, increased prescribing costs, and increased prescribing of branded drugs. Nine studies assessed and found evidence of a temporal association; 25 assessed and found evidence of a dose-response relationship.

Limitation: The design was observational, 21 of 36 studies had serious ROB, and publication bias was possible.

Conclusion: The association between industry payments and physician prescribing was consistent across all studies that have evaluated this association. Findings regarding a temporal association and dose-response suggest a causal relationship.

Primary funding source: National Cancer Institute.

Figure 1.

Study Selection.

Figure 2:

Study results regarding the presence of a positive association between industry payments and prescribing. Results are shown on the level of the overall study (2A) and the individual analyses (2B). For studies, results were characterized as “all positive” (all analyses within that study had a positive association) or “mixed” (some analyses within that study had a positive association and some were null). For individual analyses, results were characterized as “positive” (increased industry payments associated with increased prescribing), “inverse” (increased industry payments associated with reduced prescribing), or “null” (no statistically significant association). Individual outcomes were also characterized as having assessed for a temporal association (+Temp/−Dose), a dose-response association (−Temp/+Dose), neither (−Temp/−Dose), or both (+Temp/+Dose).