This work was the first nationwide survey evaluating the use and perception of GDs among the Brazilian population. Given that cost and reliance on drugs have been suggested in previous studies as key factors influencing adherence to medication, it is important to reduce individual healthcare costs in order to increase patients’ adherence to drug therapy [14].
Rural area residents were excluded from the sample, because of its minor proportion comparing to total of Brazilian population (15.6%) and the difficulty of access this scattered population [12]. It is worth emphasizing that, on the last Census, the quotas of gender and age in rural areas are similar to the urban population: (i) Urban – Male 48.3% and Female 51.7%; Rural – Male: 52.6% and Female: 47.4%; (ii) Urban - 15 to 34 years: 46.2%, 35 to 64 years: 44.2%, ≥65 years: 9.6%, and Rural - 15 to 34 years: 46.8%, 35 to 64 years: 42.8%, ≥65 years: 10.5% [12].
In this study, GDs have or had been used by 44.6% of the population within the past three months. This figure is higher than the frequency found in 2006/2007 in an area covered by a family health unit in a city in southern Brazil (9.9%). It is also higher than that found in another southern Brazilian city in 2002 (3.6%) [8,15]. These differences can be explained by the three month period used in the present study, as compared with the 7 and 15 days, respectively, used in the previous studies. Moreover, it can be explained by the ease of access to these drugs, since the market share of GDs has increased almost three-fold in Brazilian healthcare centers throughout the past five years [5].
Higher use of GDs was observed in the female and elderly populations, which can be explained by the higher use of medicines in general, by these two groups [16,17]. The higher use of GDs among the elderly population may also be related to their lower spending power, which may cause a preference for cheaper products like GDs. In August 2013, GDs were, on average, 56.63% cheaper than their respective brand name drugs (BDs) in Brazil [18].
Regarding the participants’ perceptions of the attributes of GDs, it was observed that almost a third (30.4%) believed GDs were less effective than BDs, and the most negative opinions were observed in the lower income, elderly and nonwhite populations. These results are consistent with previous studies, which found unfavorable opinions on the effectiveness, safety, tolerability and acceptance of GDs associated with low income, nonwhite race and advanced age of the respondents [11,19-22]. This raises a concern as to the acceptance of GDs and the adherence to drug therapy in these groups.
Additionally, participants who was taking or had taken GD in the past three months disagreed more with the statement that GDs were less effective than BDs. It is possible to assume that experience with GDs could possibly influence attitudes in a positive way.
In 2001 the National Health Surveillance Agency (ANVISA) surveyed 2,220 customers in 236 different cities, and observed that 80% of the participants were confident that GDs had the same effect as BDs [23]. A study conducted in the state of Rio Grande do Sul in 2002 found that 70% of the 3,182 participants believed GDs had similar quality compared to BDs, and a study conducted in Paraná in 2011 showed that 64.3% of the 374 participants were of the same opinion [8,15]. In this study, the majority of 58.8% of the 5,000 participants disagreed that GDs are less effective than BDs. This may represent a decline in the credibility of GD over the years. On the other hand, there were several differences between the surveys which may explain the variation: this study covered a greater population and more regions than previous studies and used a different survey approach concerning questions and methodology.
Although most of participants had a positive perception regarding the effectiveness of GDs, 59% said that if there were no price difference, they would prefer BDs. This finding reinforces the idea that price has a strong influence on the decision to purchase a GD, which was observed in a study conducted in the North of Brazil that evaluated the social representations of GDs by consumers and demonstrated price as a fundamental element in building product value and guiding market choice [24].
The findings indicate an underuse of GDs, with 41% of the participants agreeing with the statement “Generic drugs are more suitable or appropriate than brand name drugs for mild, banal or less serious diseases”. This result is in line with previous findings that participants would be more willing to use generics for less serious diseases, and it suggests that they may be more reluctant to use them for more serious diseases [21,25,26].
Another important finding is that a significant portion of the population agreed that BDs cause more side effects than GDs (28.1%). This proportion increased to almost a third when we evaluated only nonwhite and low-income populations. One possible explanation for this result is that some participants may see generics as products with reduced effectiveness, compared with brand name drugs, because they consider GDs to be less effective. Thus, BDs are perceived as stronger medications, and would cause more side effects than generics. The work, conducted by Sewell (2012), also indicated a perception regarding GDs as a weaker product. However, Sewell observed that GDs were perceived as having to be stronger to produce the same effect as BDs, leading to more side effects, contrary to what we found in the present study [26]. However, the expectation for more adverse events with BDs may be due to the perceived higher strength. More studies, and a better understanding regarding the population’s perceptions, are needed to confirm this finding and the underlying reasons.
Given the importance of physicians’ views as opinion leaders in the use of GDs, we also evaluated the population’s perceptions regarding the preference of these professionals. Less than half of the participants agreed with the statement that physicians prefer to prescribe generic drugs (45.8%). Moreover, it was observed that the low-income participants were more of the opinion that physicians prefer to prescribe GDs than the higher income population. We consider this difference by income to be positive, since this result indicates that physicians take socioeconomic criteria into account when making prescriptions. Another explanation is the greater use of the public health system by people with low incomes. According the National Sample Survey of Households (PNAD) conducted in 2008 by the IBGE, and a study by Zilda Pereira da Silva (2006), the population belonging to the first quintile (poorest 20%) is the main user of the public health system in Brazil [27,28]. Physicians from the public health system are obliged to prescribe drugs by their Brazilian Common Denomination (Denominação Comum Brasileira - DCB) or, in its absence, by the International Nonproprietary Name (INN) [29]. In these cases, users of public health system received more prescriptions for GDs than users of private health systems.
Evaluating perceptions on the attributes of generic drugs by gender, we found no statistically significant differences between the responses of women and men, except that women agreed more with the statement that physicians prefer to prescribe GDs. This finding differs from the study conducted by Shank (2009), which observed that women were more likely than men to report that generics offer better value than brand name drugs [11]. A potential explanation for the perceived higher prescribing of GDs among the women could be that a higher percentage of women tends to be in the lower income class and thus, more women may depend on the public system [30]. This effect would be even more pronounced for the differences between races [31].
The present work investigated the population’s perception regarding GDs, but did not investigate the reasons for the perceptions. It is necessary to explore the underlying reasons, for instance, if the negative perception that part of population has regarding GD is caused by lack of knowledge between the two types of drugs. Moreover, it is necessary to investigate whether the regulation and health surveillance concerning GDs in Brazil are appropriate to ensure effectiveness and interchangeable products with assured quality.
It is also necessary to educate the general public with regard to correct and conscious use of the different types of drugs. As suggested by a study conducted by Joan-Antoni Vallès (2002) in Spain, verbal information and the distribution of explanatory material about GDs for patients will increase their use [32]. However, further studies are needed to confirm the importance of patient education in the choice of drugs in Brazil.
