Interactions between pharmaceutical companies and healthcare providers (HCPs) are a routine part of medicine, from sponsored educational events to consulting arrangements and meals. But how much do those relationships influence prescribing decisions?
A new Cochrane systematic review found that clinicians who received gifts or payments from pharmaceutical companies were more likely to prescribe greater quantities of medications, make less appropriate prescribing decisions, and generate higher prescription costs than those with fewer or no such interactions.
The findings raise questions about how industry relationships may influence treatment decisions—even when those interactions are intended to provide information or professional education.
First, some background on industry relationships.
Pharmaceutical companies often engage with clinicians through several channels: sales representative visits, sponsored educational programs, conference activities, consulting arrangements, and payments for advisory board participation.
And while these interactions can introduce clinicians to new medications and emerging treatment options, the commercial objective of increasing product sales does not always align with choosing the most appropriate or cost-effective therapy for an individual patient.
Previous research has also raised similar concerns.
For example?
A systematic review published in Annals of Internal Medicine examined 36 studies and found that 89 of 101 analyses identified a positive association between pharmaceutical industry payments and prescribing.
And the federal Open Payments program also makes financial relationships between drug and medical device manufacturers and HCPs publicly accessible.
With this in mind: The new Cochrane review brought together a broader body of evidence to assess whether industry interactions are associated with measurable changes in prescribing behavior.
So what did researchers examine?
Their focus: the relationship between pharmaceutical industry promotional activities and four prescribing outcomes: medication appropriateness, prescription quantity, prescribing costs, and requests to add medications to hospital formularies.
Industry interactions were then grouped into four categories:
- Advertising and educational activities (such as pharmaceutical sales representative visits)
- Gifts, payments, and other financial transfers
- Free medication samples
- Institutional conflict-of-interest policies designed to restrict or manage promotional interactions
Go on …
The team searched multiple research databases and trial registries for studies published through January 2025.
To note: Rather than combining results into a single statistical estimate, the researchers summarized findings by exposure type and outcome.
- The reasoning: Each study differed substantially in their methods and measurements.
Who was included in the study?
The analysis included 93 studies, with most (88%) conducted in the United States and the remaining from the United Kingdom or European Union.
The review included 60 cross-sectional studies, 23 controlled cohort studies, four controlled before-and-after studies, four interrupted time series studies, one nested case-control study, and one randomized controlled trial.
- Among the focused topics: financial relationships, examining gifts and payments; advertising or educational activities; free medication samples; and conflict-of-interest policies.
Worth noting: Because individual studies addressed different outcomes and populations, the review did not report a single combined participant total.
And what did the researchers find?
The clearest pattern involved gifts and payments from pharmaceutical companies.
Compared with clinicians receiving no or fewer financial transfers, those receiving gifts or payments demonstrated:
- Less appropriate prescribing
- Higher prescription quantities
- Higher prescribing costs
The available evidence established associations with prescribing appropriateness and quantity, while the association with higher costs was considered probable.
So how did this compare with prior research?
Fairly consistent. A 2016 study published in JAMA Internal Medicine found that pharmaceutical industry payments were associated with higher rates of brand-name statin prescribing among Massachusetts physicians.
- Advertising and industry-sponsored education showed a similar direction of association.
Other studies involving a combined total of +150K prescribers found that the greater exposure to these activities was probably associated with increased prescribing volume—while additional research suggests that advertising and education may be associated with less appropriate prescribing and higher medication costs.
Importantly: These takeaways establish associations rather than proving that a particular payment or promotional interaction caused an individual prescribing decision.
Tell me more.
One notable finding (based on 3k prescribers) involved institutional policies intended to limit industry influence.
- Compared with institutions without such restrictions or with more lenient policies, stronger conflict-of-interest policies were associated with more appropriate prescribing.
Another one (based on evaluations of a combined +111k prescribers): suggested that these policies may also reduce prescription volume.
However: Whether restrictions consistently lower medication costs was less clear.
Go on …
The evidence surrounding free drug samples was similarly uncertain.
- Although samples can provide patients with access to medications, the review could not establish whether receiving them meaningfully changes prescribing appropriateness, quantity, or costs.
Researchers also found limited evidence concerning requests to add pharmaceutical products to hospital formularies. Only one study involving 105 prescribers examined that outcome, making conclusions particularly uncertain.
Speaking of limitations …
The review's biggest: predominance of observational research.
Only one of the 93 included studies was a randomized controlled trial (RCT), and that trial was judged to have a high risk of bias for the two outcomes assessed.
Several observational studies also had limitations in how they accounted for potential confounding factors.
- For example: Clinicians who receive industry payments may differ from those who do not in specialty, prescribing responsibilities, patient populations, or other characteristics.
These differences complicate efforts to establish causation. See here for more.
So what does this all mean for clinicians?
The findings suggest that financial relationships with pharmaceutical companies deserve consideration when evaluating prescribing practices.
For ophthalmologists and optometrists with prescribing authority, the implications extend to decisions involving branded medications, treatment alternatives, and the costs patients face when filling prescriptions.
This review wasn’t specific to eyecare though, was it?
No, it wasn’t. As such, the findings shouldn’t be interpreted as evidence that a particular ophthalmic medication, manufacturer, or prescribing arrangement produces the same effects.
The evidence does, however, support examining whether financial relationships and promotional exposure may influence prescribing patterns, alongside the clinical rationale for treatment decisions.
Anything else worth noting?
The review identified a recurring pattern across studies: greater exposure to pharmaceutical company interactions was associated with less appropriate prescribing and higher prescription quantities.
And moving forward?
The researchers highlighted the need for additional studies examining patient health outcomes, as changes in prescribing quantity or cost do not, by themselves, establish whether patients experienced better or worse clinical results.