A Review on The Impact of Pharmaceutical Promotions on Prescribing Behaviour

 

Clement V. L. Lim

National Institute of Education, Nanyang Technological University, Singapore

Department of Medical Affairs, Roche Pharma Singapore Pte Ltd, Singapore

*Corresponding Author E-mail: clement_lvl@hotmail.com

 

ABSTRACT:

Doctors may not be aware of how much promotion they are exposed to. This is both the most difficult area to research and the most important.  Therefore, as much as possible, research on the effect of promotion on behaviour should avoid relying on self‐report data to show causal relationships. Self‐report data are appropriate for finding out what people think is happening, or how they want to present themselves to others, but in this area, that may be far from the reality. This review looks at the evidence for several different possible effects of promotion on behaviour. These are the impact of promotion on individual prescribing behaviour, on overall drug sales, and on requests for formulary additions; the effect of DTCA on consumers’ decisions, the effect of promotion on the content of continuing medical education courses, and the impact of industry funding on research outcomes.

 

KEYWORDS: Management, Marketing, Healthcare.

 

 


1.  INTRODUCTION AND OBJECTIVE:

In this paper, various approaches utilised to study how promotions affect physician prescribing is examined (Darekar et al., 2016; Rejikumar et al., 2018). One approach uses self-reported reasons that account for changes in prescribing and investigate whether or not promotions is mentioned to be one of these reasons (Yaqub Khan et al., 2013; Pestun et al., 2019). It is inherent in such approaches that the exposure to and relative influence of promotions is self-assessed by the physicians (Madhusudan et al., 2020).

 

Consequently, such approaches often do little more than allow the physician to present researchers with their self-image of being people who are, or are not, influenced by promotion. Stronger evidence which elucidates some form of association between promotion and physician prescribing decision can be obtained from studies which examine the associations between variations in prescribing decisions and variations in reliance on promotion (Ashish et al., 2011). Physicians are typically asked general questions in these studies, such as how reliable or useful promotional information is as well as whether or not such information is important in their prescribing decision. Comparison is then made between those who have a positive assessment of promotion and those are more skeptical. Real prescribing data may be used, or can also be self-assessed or elicited in response to hypothetical situations (Tamil Selvan, 2013).

 

2. SELF‐REPORTED REASONS FOR PRESCRIBING CHANGES:

A study done in Scotland by Taylor and Bond (1991) used real prescribing data, whereby they asked 201 doctors to fill out duplicate prescriptions that included details about perceived influences on prescribing. Of the prescriptions, most were either repeat prescriptions or drugs that the prescribers had prescribed in the past. New drugs formed a median of 3.5% of the prescription items per doctor. Sales representatives were mentioned as influences for 20% of new drugs added to doctors’ prescribing repertoires during the research period. Sales representatives were more likely to be listed as an influence on the prescribing of drugs used short‐term (Gupta and Gupta, 2014). It is difficult to know how generalizable these findings might be. They may depend on the type of drugs that are being heavily marketed at the time, and other influences on prescribing at the time (Taylor and Bond, 1991).

 

Dasta et al. (1995) also obtained objective prescribing evidence through their study which received partial support from Abbott Laboratories.  Conducted in one inpatient and several outpatient medical care facilities, they examined physicians’ sources of information about Clarithromycin. Physicians in the hospitals who ordered for clarithromycin were contacted via phone while a questionnaire was sent to physicians in outpatient facilities when a prescription written by them was sent to the pharmacy. At the first interview, 65% of the doctors in the hospital reported that they have not had any contact with sales representatives nor used any samples. 18% of the outpatient prescribers reported hearing about clarithromycin first from a commercial source.  

 

Peay and Peay (1990) examined the role of different information sources in the specialists’ decision making when adopting new drugs. The specialists were asked about their general drug adoption practices as well as one of one of eight target drugs. Their findings suggest that commercial information sources are relatively unimportant to specialists whereby only 4.7% named commercial information sources as being the most influential in their decision making when prescribing the target drug.

 

These studies are better at identifying the influence of promotion than those that ask for a general self‐assessment of the influence of promotion, because they isolate particular prescribing decisions. But they cannot be taken at face value because they rely on doctors’ own assessments of what has influenced their decisions.

 

Two studies, by Curry & Putnam (1981) and Lurie et al. (1990) relied entirely on self‐ assessments of reasons for prescribing changes. The former found that only 0.3% of their respondents (practicing doctors in Maritime Canada) reported changing their practice in the last year because of discussions with sales representatives. The latter surveyed faculty at seven university teaching hospitals in the USA and house staff in two of the teaching programmes, about their interactions with pharmaceutical representatives. Twenty‐five per cent of the faculty and 32% of the residents reported that they had changed their practice at least once in the last year as a result of a discussion with a sales representative. 

 

Hence, to conclude, doctors rarely acknowledge that promotion has influenced them to make specific prescribing changes. Specialists tend to report that promotion has less effect on them.

 

Prescribing by those who rely on commercial information

A study by Hemminki (1974) observed no link between physicians’ prescribing characteristics and self-reported reliance on promotion. Specifically, Hemminki (1974) noted that the observed frequency of prescribing psychotropic drugs did not differ between doctors who chose journals, textbooks or commercial sources as their primary source of information.

 

However, most other studies found links. A study by Mapes (1977) noted that doctors who reported relying on pharmaceutical industry literature had a greater likelihood of prescribing three or more drugs which frequently caused side effects. Using prescribing data collected by the Department of Health in the UK, it was found that doctors who did not endorse industry as a source of post-graduate knowledge tend to prescribe medicines that were newer, safer and more effective. Family physicians who reported having a lesser reliance on sales representatives (Bower and Burkett, 1987) tend to prescribe more generic medicines. Similar behaviour was also observed in residency trained doctors as well as regular readers of the New England Journal of Medicine. The self-assessed ability to recognise generic medicine names were also noted to be highest amongst doctors that had the least reliance on journal advertising and were regular readers of the Medical Letter. In Kentucky USA, a study by Caudill et al. (1996) found that primary care doctors and those who rated information from sales representatives highly (as credible, available, and applicable) and reported using it more tend to select more expensive prescribing options. However, the study had a low response rate. Becker et al. (1972) and Stolley et al. utilised self-reported data on the attitudes to and re. They noted that doctors who were reliant on journal articles who demonstrated disdain towards journal advertisements, sales representatives as well as retail pharmacists as sources of information received higher from the experts and also prescribed less chloramphenicol.

 

The study reported in Becker et al. and Stolley et al. (1972) used self‐report data on attitudes to and reliance on promotion; expert ratings of responses to questions about prescribing for certain conditions, and knowledge about certain drugs; and analysis of actual prescribing of chloramphenicol (an antibiotic that should not be widely used). They found that doctors who relied on journal articles and tended to be disdainful of journal advertisements, sales representatives and retail pharmacists as sources of information received higher ratings from the experts and prescribed less chloramphenicol. Better prescribers were more positive about generics, and gave other indications of a less positive attitude towards the industry and promotion than other doctors. A single question, about whether sales representatives were good sources of prescribing information about new medicines, produced the highest correlation with prescribing appropriateness. Berings et al. (1994) found that Belgian doctors in their study who felt that commercial sources of information were more important, prescribed more benzodiazepines than those who rated these sources as less important. Their prescribing was observed through the use of special prescription forms provided by the researchers.

 

In the Netherlands, Haayer (1982) presented eight case studies of hypothetical patients to GPs and asked them if they would prescribe medication for this patient, and if so, what they would prescribe. An expert panel assessed the rationality of their prescriptions. The GPs were later interviewed and asked about their use of different sources of information about medicines. Less than half (48%) of the prescribing decisions made were rated as ‘entirely rational’.

 

Differences between doctors accounted for more variance than differences between cases: that is, doctors seem to be more or less rational prescribers, over a range of different conditions. Haayer (1982) found that reliance on information provided by the pharmaceutical industry was negatively associated with prescribing rationality. That is, doctors who relied on promotional information wrote less rational prescriptions for the case studies than those who reported relying less on promotion.

 

Cormack and Howells (1992) did a survey on UK GPs before and after attending a course on benzodiazepine prescribing. Their prescribing habit was analysed using Prescription Pricing Authority data and adjusted by their number of patients and the number over 65 years old. A very wide range of scores were produced and doctors were classified as high or low benzodiazepines prescribers. Through interviews, it was found that low prescribers viewed information from pharmaceutical companies with greater scepticism than high prescribers.

 

In Ontario, Williams and Cockerill (1990) found who reported writing higher weekly numbers of prescription had greater contact with the industry (i.e. interaction with sales representatives, accepting benefits such as meals or conference fees) and had a greater likelihood than others of rating sales representatives and industry-sponsored seminars as important sources of information. It was suggested that the higher prescribers may be likely to have spent more time in their medical practice per week compared to the lower prescribers. However, Williams et al. noted that the higher prescribers reported prescribing more medicines per patient, which reinforced the idea that these doctors are those who prescribed heavily. One other possible explanation of these findings is the notion that sales representatives selectively targeted doctors known to be heavier prescribers. These findings are shared by Williams, Cockerill and Lowry (1990).

 

Evidence also suggest that those who have a greater reliance on promotion tend to be older, and are usually earlier adopters of new medicines. Stross (1987) investigated the reasons of changing the management of chronic airway obstruction in small community hospitals between 1978 and 1983. Through chart audits, he noted significant changes in the management of the condition during this period. Through the study years, he also interviewed the doctors who managed patients at these hospitals and found that older doctors reported having a greater reliance on sales representatives as a source of information for changing patient management. Stross (1987) examined the decisions to adopt three types of medicines-single‐agent bronchodilators, beta‐sympathomimetic agents and corticosteroid aerosols, with approximately 35% of doctors mentioning sales representatives to be their most important source of information for the last two medicines when deciding to adopt them. Early adopters of the change had a greater likelihood than late adopters to regard sales representatives as a major source of information. Findings from this study is useful as it reports significant observed changes in prescribing that were identified by the researcher.

 

In an area in the UK, Strickland-Hodge and Jepson (1982) compared the characteristics of the first and last 100 doctors prescribing cimetidine. Despite having a response rate of only 50%, they observed that earlier prescribers tend to rate commercial sources of information significantly higher than that of the late prescribers. Examples of commercial information sources included sales representatives, advertisements in medical journals, direct mail, MIMs as well as controlled circulation journals (Dhara et al., 2016; Lad et al., 2017). Early prescribers were also found to read more of their direct mail than late prescribers and tend to read fewer journals. 

 

These studies collectively suggest that doctors who regard promotions more highly and report having a greater reliance on it as a source of information tend to prescribe more medicines and adopt newer medicines earlier than other doctors and also prescribe in a less rational manner. However, only circumstantial evidence exist for a causal link between promotion and individual prescribing. These results may partly be due to other doctor characteristics such as attitudes to risk, beliefs about clinical experience and evidence, views of new technologies as well as academic inclination or ability. For example, doctors who place a greater emphasis on their clinical experience over scientific evidence is less likely to respond to evidence presented in journals and hence may not prescribe as rationally i.e. according to the evidence. Doctors who are less academically inclined also may not read journals and have a greater reliance on advertising due to its accessibility, leading to less optimal prescribing habits. The main limitation of these studies is that they cannot demonstrate that doctors who report reliance on promotional information would prescribe differently or more rationally had they not rely on promotions.

 

3. PRESCRIBING AND EXPOSURE TO PROMOTION:

A relationship between seeing sales representatives and prescribing new drugs was showed by Peay and Peay (1988) whereby they interviewed 124 private practice physicians with regards to their perception and use of temazepam (a benzodiazepine hypnotic) as well as their information sources about the drug. Conducted in 1981 (about a year after introduction of temazepam in Australia), they found that contact with a sales representative about temazepam consistently led to a favourable reception of the drug at various points of the adoption process. Physicians who had seen a sales representative reported earlier awareness and prescription of the drug. They also had a greater tendency to rate the drug as a moderate (rather than minor) advancement over other drugs, and were more likely to prescribe it routinely over other alternatives. Amongst the physicians who saw sale representatives, those who see them more than once a week were aware of the drug earlier and prescribed it earlier, with a greater tendency to prescribe it over other alternatives. Apart from contact with sales representative, Peay and Peay (1988) did not find any relationship between the physicians’ professional involvement or involvement in the medical community and their beliefs about temazepam.

 

Advantages of this study include that it does not rely on physicians’ self-assessment on whether or not promotions affected their prescribing decisions as well as their level of reliance on commercial information. Questions such as “have you seen a sales representative regarding temazepam?” requests for a simple fact that will be significantly easier for physicians to recall as opposed to questions such as the number of journal advertisements seen, etc. The group of GPs who had seen sales representatives about temazepam may have included more of the commercial information oriented doctors described above, but this is unlikely to account completely for Peay and Peay’s (1988) results.

 

Another important study was conducted by Orlowski and Wateska (1992), who analysed the effects of drug company sponsored educational symposia in resort locations (all expenses paid trips) on physicians’ prescribing. Utilising the pharmacy inventory, the use of two drugs were tracked within one institution 22 months before and 17 months after each symposium about them. Data on the national usage of these drugs were also collected, with informal interviews conducted with doctors who had attended the symposia. Majority of the physicians mentioned that their prescribing decision would not be influenced by the symposia, although some indicated that it may trigger them to think of the drug more and may also convince them on the benefits of using the drug. The authors noted a highly significant and dramatic increase in the usage of these drugs after the relevant symposia. However, these increases were not reflected in national data, nor do they seem to affect the hospital’s use of alternative drugs. From this study, it indicates that promotions does have the potential to increase prescribing regardless of whether or not those exposed to it consider themselves prone to such influences.     

 

The impact of visits by sales representatives and samples on prescribing was examined through a study by Gonul et al. (2001). The author used data from Scott-Levin Inc (a pharmaceutical consulting firm) derived from surveys administered to doctors, which included prescribing, minutes of detailing received for different drugs as well as the number of samples received in a typical week in each month from January 1989 to December 1994. A single condition was examined along with the seven drugs that are used to manage the condition. However, a major weakness of the study is that it is not clearly mentioned whether or not these were seven different drugs, or the probability of the medicine being prescribed (other things being equal). However, from the study, it was also shown that no further increment in sales of the same drug. Through a multinomial logit model, exposure to personal selling towards a particular medicine i.e. sales representative visit and sampling increases observed from excessive detailing or sampling. In addition, promotions also had lesser influence on physicians who manages a high proportion of Medicare or Health Maintenance Organization patients. The authors also suggested that there was no negative social consequences associated with personal selling. However, there is little evidence in the study to support this from the study. It is difficult to evaluate the study’s conclusion as it is unclear if the study examined seven brands of the same drug or seven different drugs. The health consequences in selecting different drugs in response to marketing are likely to be different from those of changes in different brands of the same drug.

 

Walton (1980) suggested that prescribing is also associated with the recall of print advertisements. A study in 1980 examined 1000 private practice doctors who were shown print advertisements whereby the drug and company names and logos were blacked out. The physicians were asked if they had seen the advertisement before. They were then read a list of the advertised products and asked if they had prescribed or recommended these in the last month. For 95% of the advertisements, the percentage of doctors who prescribed them were higher in those who were aware of the advertisements as compared to those who were not.

 

Research by Walton (1980), a pharmacist and advertising executive, suggests that recall of print advertisements is associated with prescribing. In one study published in 1980, results are presented from a study of 1000 doctors in private practice who were shown print advertisements with drug and company names and logos blacked out. They were asked whether they had seen each advertisement before, and were then read a list of the advertised products and asked if they had prescribed or recommended these in the last month. For 95% of the advertisements the percentage of doctors who prescribed them was greater for those aware of the advertisements than for those not aware of them. However, the effect of specialty was not controlled for. That is, doctors may be both more likely to notice and recall, and to prescribe, drugs relevant to their specialty. A similar study by Walton (1980) appears to be a smaller version or subset of this study. 

 

A range of advertising industry-related studies was reviewed by Matalia (1994). These studies claimed to show the effectiveness of print advertising. Advertisements were evaluated by family practitioners and internists in the first study.

 

Matalia (1994) reviews a range of advertising industry‐related studies that claim to show the effectiveness of print advertising. In the first, family practitioners and internists evaluated advertisements. ‘Prescribing data’ were also collected but it is unclear whether these are self‐assessments of willingness to prescribe, or actual prescription data. Matalia (1994) claims that as non‐prescribers became more familiar with the advertisements their willingness to write trial prescriptions increased. It seems from his earlier description that this study assessed correlations between attitudes and familiarity with advertisements, so he seems to be extrapolating from data collected at one point in time from a range of people, to trends over time. The account of the second study is somewhat more convincing, but again the methods and analysis are not described well enough for proper evaluation. The study was an experiment where different groups of doctors (who had prescribed similar numbers and value of prescriptions in the previous six months) were sent identical journals but with varying numbers of advertisements for a mature cardiovascular drug (i.e. one that had been on the market for some time). Those in the group who received the most advertising increasingly prescribed the drug. After 12 months the manufacturers market share was 4% higher in the high intensity and 2.3% higher in the medium intensity group, than in the lower group. The third study was also a kind of experiment. Companies stopped all promotion for four products from nine months before the study. Four advertisements were designed for the study and placed in half the copies of eight journals. Doctors were interviewed, and those who had received the advertisements were more likely to recall the products than those who had not. However, prescribing was not analysed: the outcome variable was simply recall of the products. To conclude, exposure to promotion influences prescribing more than some doctors realise. 

 

4. CONCLUSION:

In an ideal scenario, studies would utilise actual prescribing data before and after documented exposure to promotion while keeping other factors which influences prescribing constant. However, it is extremely challenging to create this in real life. Hence researchers often have to rely on self-assessments of exposure to or reliance on promotions and self-reported prescribing. A general consensus from these studies strongly suggest that doctors that rely on promotional information tend to heavier and less rational prescribers. They also tend to adopt new medicines earlier than those who are less reliant on promotion. However, a limitation of such studies is that it cannot demonstrate causal relationship between promotion and prescribing. Confounding of the results by other factors such as the method of payment as well as practice setting. In addition, these studies are also unable to establish a temporal relationship between promotions and inappropriate prescribing – are physicians who tend to rely more on promotion may already be poorer prescribers to begin with, or does a reliance on promotion lead to poorer prescribing habits? Therefore, research in this area does not prove that prescribing decisions would improve if doctors had a lesser reliance on promotion.

 

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Received on 10.01.2021            Modified on 16.02.2021

Accepted on 14.03.2021           ©AandV Publications All right reserved

Asian Journal of Management. 2021; 12(3):291-296.

DOI: 10.52711/2321-5763.2021.00044