Predictors of substitution to generic drugs and physicians’ perceived exclusivity of substitution: A cross sectional survey among physicians

Abstract

The use of generic medicines facilitate access to treatment and reduce the overall health cost. Policies promoting generic substitution take into account many components such as quality and efficacy considering health stakeholders including physicians and pharmacists and identifying factors impacting generics prescription. The current study aimed to assess the association between the perception of physicians towards generics with their sex and age and their willingness to switch to generics after initial treatment. Furthermore, it aimed to evaluate the predictors for switching brands to generics after initial treatment and perceiving the exclusivity to perform this substitution. Prescription of generics to lower medical cost was more common among younger physicians compared to those 50 years and older. Interestingly, physicians aged 40 and above were more prone to prescribe generics to patients without medical coverage, while compared to physicians younger than 30 years of age. Age was significantly associated with switching initial treatment to generics, which was 2.46 times higher for physicians older than 50 years compared to those younger than 30 years. In addition, physicians practicing more than 20 years were about 1,5 times more accepting the substitution by pharmacists after initial treatment by brand while compared to physicians practicing for less than 10 years. Strategies to increase generic substitution and promoting its acceptance among physicians should take into consideration the different significant predictors. However, Further research is required to explore more factors, predicting prescription of generics in Lebanon, such as visits by medical representatives, regulations of the hospital that the physician is practicing, which are also proven to have high influence on the prescription practice of generics.

Keywords

Generic substitution predictors physicians prescription

Introduction

In the aim of facilitating access to treatment, governments adopted several measures and policies such as providing and promoting generics at a lower cost.^1,2 The use of cheaper generic medicines allow more savings and can achieve an average of 60% of cost savings for both patients and health insurance.^2–4 Generics are medicines that have the same quality, strength, purity, and stability as brand-name drugs, and are required to be equal in terms of dosage, safety and efficacy.⁵ Several studies showed that the physicians have doubts about the effectiveness and safety of generic medicines, while others consider generics as equally effective as the brand medicine.^6–8

Substitution from a brand to a generic medicine can be challenging, especially for patients with chronic diseases. For example, substituting to generic may confuse elderly and poly-medicated patients given that generics can differ in shape, taste and color.^9,10 In addition, pharmacological variations may arise, even between brand and generic formulations or between different generic formulations of the same drug. Furthermore, differences in excipients could affect the clinical efficacy and the occurrence of side effects.^11,12 Substitution policies mainly intend to increase adherence to therapies with maximized health outcomes and low adverse events, and to inform patients about the treatment, alternatives and the corresponding risks.¹³ Some barriers to generic medication use have been identified. For physicians, such barriers may be the lower safety and efficacy about them and the mistrust in the healthcare system, lack of organized generic medicine policy, distrust of physicians in pharmacists’ choice of alternatives, fear of patient confusion after substitution.^9,10,14 Pharmacists on the other hand, considered physicians as a barrier when the patients require a doctors’ advice before accepting the generic substitution and consider the education of patients as a professional challenge. Nonetheless, the availability of several generic alternatives made the choice for substitution to generics more challenging for both patients and healthcare professionals.^12,13

Promoting generic substitution requires taking into account many aspects such as quality and efficacy of generics, interests of health stakeholders including physicians, pharmacists and patients, and identifying factors impacting generics prescription.^15,16 Therefore, many surveys evaluated the knowledge of the stakeholders, particularly physicians, and their attitudes towards generic substitution.^17–19 Consequently, it has been noted that physicians’ knowledge, attitude, practice and perception towards generic substitutions were influencing the substitution of generic medicine after initial treatment with brands.^9,20 A systematic review of 52 studies from 11 countries found that 30% of the physicians have negative views of generics and considered them as lower quality, less effective and less safe than the brands.²¹ Furthermore, the socio-economic status of patients played a key role in the willingness of physicians to prescribe generic drugs.²²

A recent study in China reported significant differences in knowledge levels between physicians of different ages, working experience and position.²³ Another study conducted in 2010 in Malaysia showed that the majority of general physician’s (GP) indicated a high generic prescribing rate which was significantly associated with age, years of practice and country of graduation.⁷ A cross-sectional survey conducted in Slovenia found that 96.3% of GP were willing to substitute to cheaper generics if the price was lower by 25–35%.²⁴ On the other side, a survey conducted in Iraq emphasized the impact of promotional marketing on generic prescription.²⁵ Furthermore, older physicians are three times more likely to have a negative attitude towards generics compared to young physicians.²⁶

Generics’ use in Lebanon is still in its early stage and previous studies highlighted a large potential for increasing its use among healthcare professionals given that only 39.5% of Lebanese physicians reported that governmental policies encouraged generic prescription.^25,26 Due to the pandemic, economic crisis and political unrest, the health system is experiencing shortage in medical supply with an increased demand in medicines. To date, no studies assessed the predictors for switching to generics in Lebanon. Accordingly, the objectives of this study were to (i) assess the association between the perception of physicians towards generics with their sex and age, and (ii) to evaluate the predictors for switching brands to generics after initial treatment and perceiving the exclusivity to perform this substitution.

Methods

Study design

An observational cross-sectional study was conducted in 2020 targeting physicians through face-to-face interview using a survey provided in their private clinics or in different hospitals across Lebanon.

Settings and participants

The study sample consisted of a convenience sample of 270 physicians, which was frequency-matched between general practitioners versus specialists. The eligibility criteria were: Lebanese physicians practicing medicine at the time of the study regardless of their sociodemographic characteristics. Exclusion criteria were: being retired, holding a non-clinical position (public health, teaching, and epidemiology). Physicians were visited at any time of the day taking into consideration their availability and acceptance to take part in the study. After getting a list of available physicians during the day the interviewers were in the hospital, physicians were approached and asked if they accept to participate in the study. The average time to fill the survey was 5–10 min.

Study instrument

A survey was used to collect data from participants. This survey was based on the one used in a previous study in Lebanon.¹⁹ After some alterations based on two experts’ opinions, it was piloted on 10 physicians working in different hospitals (public and private). Accordingly, questions with lack of clarity and comprehensiveness were adjusted or deleted.

The survey consisted of two parts. The first part collected the general characteristics of the participants (sex, age, governorate of work, type and source of certificate together with years of experience). The second part included six questions exploring physicians’ perception towards generics, drivers to prescribe them and acceptance to substitute to generics after initial treatment. All questions were close-ended, either by yes/no, or other options. Data were collected by two pharmacists who were trained together to minimize interviewer bias.

Ethical considerations

Before filling the survey, the respondents were informed about the purpose of the study. A written statement for informed consent was signed from each participant. They were explained that their participation is anonymous since no name or contacts were provided and they could withdraw their participation at any point. No economic incentives were provided.

Statistical analysis

Statistical analysis was performed using Statistical Package for Social Sciences (SPSS Inc, Chicago, Illinois) Version 26. Categorical data were described using frequencies and percentages whilst age was described using mean and standard deviation. Bivariate analyses, using Chi-square test and Fisher exact test, were performed to test the association between physicians’ perception toward generics and their sex and age categories on one side and willingness to switch to generics and perception of exclusivity to substitute medicines with the general demographics on the other side. In addition, two multivariable analyses using logistic regression models were performed to test the predictors of switching and exclusivity of performing it. Variables with a p-value < .2 in the bivariate analyses were potential candidates for the multivariate model. A p-value < .05 was considered statistically significant in the multivariate model.

Results

In total 287 physicians were approached from which 270 were included based on the previously defined criteria (94.1%). Table 1 represents the general characteristics of the participants. The sample included more males (N = 184, 68.4%) than females (N = 85, 31.6%) with a mean age of 32.4 ± 6.2 years. Most of the physicians were located in Beirut and Mount Lebanon (47.2% and 33.1% respectively). The sample was distributed almost equally between general practitioners (N = 138, 51.9%) and specialists (N = 128, 48.1%) with a majority of private universities’ graduates (N = 165, 61.6%). Physicians with less than 5 years of experience constituted 34.3% of the sample and those with more than 20 constituted 18.3%.

Table 1.

Distribution of the general characteristics of the physicians.

		Frequency (%)
Sex (N = 269)	Male	184 (68.4%)
Sex (N = 269)	Female	85 (31.6%)
Age (years) (N = 265)	Mean ± SD.	32.4 ± 6.2
	22–29	101 (38.1%)
	30–39	55 (20.8%)
	40–49	52 (19.6%)
	>50	57 (21.5%)
Governorate of work (N = 269)	Beirut	127 (47.2%)
	Mount Lebanon	89 (33.1%)
	North	26 (9.7%)
	Bekaa	22 (8.2%)
	Other	5 (1.8%)
Type of certificate (N = 266)	General practitioner	138 (51.9%)
Type of certificate (N = 266)	Specialist	128 (48.1%)
Source of certificate (N = 268)	Public universities	49 (18.3%)
	Private universities	165 (61.6%)
	Outside the country	54 (20.1%)
Years of practice (N = 268)	<5	92 (34.3%)
	5–9	49 (18.3%)
	10–14	49 (18.3%)
	15–20	29 (10.8%)
	>20	49 (18.3%)

Results given in term of frequency (percentage).

Bivariate analysis associating physicians’ perception toward generics with sex and age is described in Table 2. The sex of the participants was significantly associated with accepting the substitution of prescribed brands to generics by pharmacists (p = .003) where 82.1% of males did not accept it compared to 65.9% of females. Age was significantly associated with the motif for prescribing generics where 88.1% of doctors aged between 22–29 prescribed generic to lower the medical cost for the patients versus 55.8% of those aged between 40–49 and 73.7% of those more than fifty (p < .001). The majority of physicians older than 40 years prescribed generics for patients with no medical coverage compared to almost 45% of younger physicians (p = .004).

Table 2.

Association between the perception of the participants toward generics with age and sex.

Questions		Sex
Questions		Male N (%)	Female N (%)	p-value
Do you prefer prescribing generics over brands?(N = 269)
	Yes	58 (31.5%)	25 (29.4%)	.726
	No	126 (68.5%)	60 (70.6%)
Do you prescribe generics to lower the cost for the patients?(N = 269)
	Yes	140(76.1%)	68(80%)	.476
	No	44(23.9%)	17(20%)
Do you prescribe generics to patients with no medical coverage?(N = 269)
	Yes	98(53.3%)	46(54.1%)	.896
	No	86(46.7%)	39(45.9%)
Do you think that generics have compared to brands: (N = 265)
	Same efficacy	126(70%)	52(61.9%)	.191
	Less efficacy	54(30%)	32(38.1%)
Do you encourage generic prescription? (N = 265)
	Yes	73(39.7%)	26(30.6%)	.151
	No	111(60.3%)	59(69.4%)
Do you accept the substitution to generics by the pharmacists? (N = 265)
	Yes	33 (17.9%)	29 (34.1%)	.003
	No	151 (82.1%)	56 (65.9%)

Questions		Age
Questions					22–29 N (%)	30–39 N (%)	40–49 N (%)	>50 N (%)	p-value
Do you prefer prescribing generics over brands? (N = 265)
	Yes	32 (31.7%)	16 (29.1%)	12 (23.1%)	20 (35.1%)	.565
	No	69 (68.3%)	39 (70.9%)	40 (76.9%)	37 (64.9%)
Do you prescribe generics to lower the cost for the patients?(N = 265)
	Yes	89 (88.1%)	45 (81.8%)	29 (55.8%)	42 (73.7%)	<.001
	No	12 (11.9%)	10 (18.2%)	23 (44.2%)	15 (26.3%)
Do you prescribe generics to patients for not having medical coverage?(N = 265)
	Yes	44 (43.6%)	25 (45.5%)	32 (61.5%)	40 (70.2%)	.004
	No	57 (56.4%)	30 (54.4%)	20 (38.5%)	17 (29.8%)
Do you think that generics have compared to brands: (N = 260)
	Same efficacy	64 (63.4%)	33 (62.3%)	34 (65.4%)	43 (79.6%)	.165
	Less efficacy	37 (36.6%)	20 (37.7%)	18 (34.6%)	11 (20.4%)
Do you encourage generic prescription? (N = 265)
	Yes	32 (31.7%)	17 (30.9%)	21 (40.4%)	27 (47.4%)	.173
	No	69 (68.3%)	38 (69.1%)	31 (59.6%)	30 (52.6%)
Do you accept the substitution to generics by the pharmacists? (N = 265)
	Yes	25 (24.8%)	14 (25.5%)	11 (21.2%)	11 (19.3%)	.825
	No	76 (75.2%)	41 (74.5%)	41 (78.8%)	46 (80.7%)

Age was significantly associated with accepting to switch to generics after initial treatment with a brand medicine where only 38.6% of physicians aged less than 30 accepted it compared to 55.6% of those aged 30–39 and almost 61% of physicians aged more than 50 years (p = .037). Furthermore, the years of practice were significantly associated with this acceptance given that 43% of physicians with less than 10 years of experience accepted to switch to generics after initial treatment with brands compared to a higher percentage for those with 10–20 years (50%) of practice and more than 20 years (64.4%) respectively (p = .033) (Table 3A). Table 3B shows that both age and sex were significantly associated with perceiving an exclusive right of switching medicines with a higher perception for males (62%) compared to females (48.2%) (p = .034). Moreover, physicians aged more than 50 had higher perception (70.2%) for exclusivity of switching medicines when compared to the other groups (p = .017).

Table 3.

Bivariate analysis associating (A) switching to generics after initial treatment and (B) perceiving the exclusive right to prescribe medicines with the general characteristics of the physicians.

(A)	Switching to generics after initial treatment
Questions	Yes N (%)	No N (%)	p-value
Sex (N = 267)
Male	89 (48.9%)	93 (51.1%)	.919
Female	41 (48.2%)	44 (51.8%)
Age (N = 263)
22–29	39 (38.6%)	62 (61.4%)	.037
30–39	30 (55.6%)	24 (44.4%)
40–49	24 (46.2%)	28 (53.8%)
>50	34 (60.7%)	22 (39.3%)
Type of certificate (N = 264)
General practitioner	69 (50.4%)	68 (49.6%)	.445
Specialist	58 (45.7%)	69 (54.3%)
Source of certificate (N = 268)
Public universities	24 (50%)	24 (50%)	.288
Private universities	75 (45.2%)	91 (54.8%)
Outside the country	31 (57.4%)	23 (42.6%)
Years of practice (N = 266)
<10 years	60 (42.9%)	80 (57.1%)	.033
10–20 years	39 (50%)	39 (50%)
>20 years	31 (64.4%)	17 (35.4%)

(B)	Exclusivity of switching medicines
Questions	Yes N (%)	No N (%)	p-value
Sex (N = 269)
Male	114 (62%)	70 (38%)	.034
Female	41 (48.2%)	44 (51.8%)
Age (N = 265)
22–29	60 (59.4%)	41 (40.6%)	.017
30–39	32 (58.2%)	23 (41.8%)
40–49	21 (40.4%)	31 (59.6%)
>50	40 (70.2%)	17 (29.8%)
Type of certificate (N = 266)
General practitioner	86 (62.3%)	52 (37.7%)	.077
Specialist	66 (51.6%)	62 (48.4%)
Source of certificate (N = 270)
Public universities	28 (57.1%)	21 (42.9%)	.823
Private universities	94 (56.3%)	73 (43.7%)
Outside the country	33 (61.1%)	21 (38.9%)
Years of practice (N = 268)
<10 years	84 (59.6%)	57 (40.4%)	.317
10–20 years	39 (50%)	39 (50%)
>20 years	30 (61.2%)	19 (38.8%)

After adjusting for age, the odds of acceptance to switch to generics after initial treatment with a brand medicines is 1.99 times higher for physicians aged 30–39 compared to those aged less than 30 years (OR 1.99; CI 1.02–3.89; p-value .044). In addition, the odds of switching to generics is 2.46 times higher for physicians older than 50 compared to those younger than 30 years (OR 2.46; CI 1.26–4.79; p-value .008). Nevertheless, after adjusting for age and sex, the odds of perceiving the exclusive right of switching medicines to patients is 55% lower among physicians aged 40–49 versus those less than 30 (OR 0.45; CI 0.23–0.90; p-value .024). Moreover, females had 42% lower odds to perceive an exclusive right to substitute medicines compared to men (OR 0.58; CI 0.34–0.99; p-value .050) (Table 4).

Table 4.

Predictors of acceptance to switch to generics after initial treatment and perceiving the exclusivity to prescribe medicines.

Switching to generics after initial treatment	Unadjusted model		Adjusted model
Switching to generics after initial treatment	OR [95% CI]	p-value	OR [95% CI]	p-value
Age in years (20–29 as reference)
30–39	1.99 [1.02–3.89]	.044	1.99 [1.02–3.89]	.044
40–49	1.36 [0.69–2.68]	.370	1.36 [0.69–2.68]	.370
>50	2.46 [1.26–4.79]	.008	2.46 [1.26–4.79]	.008
Years of practice (<10 as reference)
10–20	1.33 [0.77–2.33]	.310	—	—
>20	2.43 [1.23–4.79]	.010	—	—
Exclusivity of switching to generics	Unadjusted model		Adjusted model
Exclusivity of switching to generics	OR [95% CI]	p-value	OR [95% CI]	p-value
Age in years (20–29 as reference)
30–39	0.95 [0.49–1.85]	.882	0.95 [0.48–1.86]	.873
40–49	0.46 [0.23–0.92]	.027	0.45 [0.23–0.90]	.024
>50	1.61 [0.80–3.21]	.179	1.37 [0.67–2.79]	.394
Female (male as reference)	0.57 [0.34–0.96]	.035	0.58 [0.34–0.99]	.050
Specialist (general practitioner as reference)	0.64 [0.39–1.05]	.077	—	—

OR: Odds ratio; CI: Confidence interval; Baseline answers for the questions ´´No´´

Discussion

Generics are proven to be effective alternatives for brand medicines, while lowering the cost of the treatment.²⁷ Physicians and community pharmacists have an essential role in the prescription and substitution of the generics. The main objective of this study was to assess the effect of sex and age on the perception of physicians towards generics, to analyze their willingness to switch to generics after initial treatment as well as their exclusivity of switching medicines and to evaluate the predictors for switching brands to generics after initial treatment and perceived physicians’ exclusivity to perform this substitution. In different countries, the use of generics differs based on patients and physicians’ perception of both their efficacy and effectiveness.^20,28 Many factors such as gender, sex, education level, specialty, years of experience can affect doctors’ prescription as well as substitution of brands to generics by pharmacists.^29,30

Results of this study have demonstrated that in Lebanon age of the physicians as well as sex and years of practice are significantly associated to their prescription behavior in different situations. The age of a physician was significantly associated with the prescription of the generics to lower the medical costs, as prescription of generics for this purpose was more common among younger physicians while compared to physicians 50 years and older. Interestingly, physicians aged 40 and above were more prone to prescribe generics to the patients without medical coverage, while compared to physicians younger than 30 years of age. Findings from a study carried out in the United States are in line with this study´s results in terms of the fact that physicians aged 55 years and above were 3 times less likely to prescribe brands compared to physicians younger than 35 years, while the generics for those products were available. Moreover, younger physicians were less likely to have negative opinion towards the quality of generics and were having personal preference for generics.²¹ This can be explained by the fact that young physicians have more knowledge and trust towards generic products than their senior colleagues. This can also be affected by willingness of young doctors to accept and listen to the medical representatives, who are the main source of getting information about generic medicines, as this was demonstrated by several studies.^31,32

This study results are in line with the study conducted in Northeastern Ethiopia where proportion of male physicians who prescribe generic drugs was higher while compared to the proportion of female physicians who prescribe generic drugs, but without any statistical significance.³³ While evaluating the effect of the sex on physicians’ acceptance of brand substitution to generics by pharmacists, females were about two times more prone to accept the change compared to males. Moreover, females had lower odds to perceive an exclusive right to substitute medicines while compared to males. However, in comparison to the study conducted in Italy, our results didn’t demonstrate any differences between females and males and their prescription behaviors. While study results from Italy showed slight gender-related differences whereas female physicians were less likely to prescribe generics while compared to males.²⁹ This can also explain the association found in this study where females have lower odds when it comes to exclusive right to substitute medicines. There is a need to explore underlying factors to explore more about this association in Lebanon.

After controlling for sex, age was a predicting factor while evaluating the exclusive right of switching medicines which was higher among physicians 30 years and younger while compared to the group aged 40–49. Whereas assessing the predictors for switching brands to generics after initial treatment and taking the exclusivity to perform this substitution, age was significantly associated with switching initial treatment to generics, which was 2.46 times higher for physicians older than 50 years compared to those younger than 30 years. The study conducted in the United Arab Emirates showed that majority of physicians highlighted the importance of prescribing generics to reduce health cost though only less than half of the participants agreed that it would improve their patients’ compliance.³⁴ In the same study physicians with 30–40 years of experience disagreed more with that statement, stating that the cost of treatment is not the only factor to reach compliance. This can also explain the fact that physicians younger than 29 years in this study, assuming without having 30–40 years of experience, were more prone to prescribe generics to lower the medical cost for patients compared to their older colleagues.

Furthermore, physicians practicing more than 20 years were about 1.5 times more accepting the substitution by pharmacists after initial treatment by brand while compared to physicians practicing less than 10 years. Another study conducted in China found that physicians practicing more than 20 years were more confident in the safety of generics while compared to the physicians practicing less than 10 years.³⁵ This might imply our results that physicians practicing more than 20 years were more accepting generic substitution by pharmacists after initial treatment. Also, most probably they have more trust towards pharmacists, which might affect their acceptance of change. As was demonstrated in the study from France another factor that might affect the accepting the substitution pattern is patient’s opposition to the substitution, which is the most significant factor associated with higher use of the non-generic term among prescribers.³⁶ It can be hypothesized that less experienced doctors might feel safer to continue treatment with brand products, as they might have not used more generics yet and are not very confident in their substitution.

Interestingly, there were no differences among prescription patterns, substitution by generics and specialty of physician. Study carried out in two regions of France demonstrated that general practitioners have less knowledge regarding generic products, thus sometimes they are facing some challenges to find appropriate information related to generic products, which might have an effect of less prescription of generics by GPs.³⁷ Further information, such as hospital regulations on generic prescription in Lebanon, is required to adequately evaluate this data.

Continuous professional development of physicians and pharmacists through guided sessions endorsing their knowledge and clarifying misconceptions about generics is crucial in addition to strategies and regulations of the Ministry of Public Health.³⁸ It has been shown that these regulations are having a huge impact on prescription and substitution behaviors as in some countries, such as Sweden and Finland, its mandatory to change a brand prescription to generic medicine by pharmacists if there is no specific instruction note from the physician stating that only brand should be prescribed.³⁹ The Swedish Medical Products Agency (MPA) produces a list of therapeutically interchangeable products to guide the process of generic substitution in Sweden which greatly impacted the process and resulted in cost-effective solutions for patients.

This study had several limitations. The small sample size may affect the external validity of the findings and therefore cannot be generalized to all the physicians. Interviewer bias might arise but was reduced by providing a uniform training to the data collectors. Moreover, due to the limited interviewing time recall bias might occur and therefore may affect the precision of the results. However, this study provides an overall baseline to understand physicians’ acceptance to switch to generics after initial treatment and assessing their perception of whom can do so. Consequently, strategies promoting generic prescription can be tailored taking into consideration those predictors.

Conclusion

Age and years of practice were independently associated to the acceptance to substitute to generics after initial treatment. Age and sex were independently associated with the perception of exclusivity of physicians to perform this substitution. This suggests the need for targeted education programs and relevant guidelines to increase the awareness about generics among physicians. Further research is required to explore more factors that influence prescription of generics in Lebanon, such as visits by medical representatives, regulations of the hospital that the physician is practicing, which are also proven to have high influence on the prescription practice of generics.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Georges Hatem

Elsa Lahoud

Roula Ajrouche

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