Úsuga et al. investigated 312 Colombian Pso patients, reporting that 23% had not received physician guidance. Moreover, 30% of them did not have access to the Immunobiologicals (IMB) they were prescribed.14

DiBonaventura et al. analyzed data from Brazil’s 2012 National Health and Wellness Survey (NHWS) (n=12,000) and found that individuals with reported Pso were more likely to have a university degree, higher annual household income, higher employment rate, private insurance, be overweight/obese and have a smoking history. Pso was moderate in 20% and severe in 5.24% of this study’s population.15

Similarly, a Brazilian multicenter study (n=188) found that 34.8% of the patients reported difficulties in obtaining prescribed medications, with 12.8% resorting to judicialization to acquire treatment. The primary reasons were drug unavailability (43.1%) and financial issues (38.5%). The various means by which Pso patients obtained medications were through the Brazilian National Health System (Sistema Único de Saúde, SUS) and out-of-pocket (38.5%); exclusively out-of-pocket (35.8%); exclusively through SUS (19.8%) and exclusively through private health insurance (1.1%). Among the study participants, 30.5 were taking IMB.6 Lopes et al. suggested that psoriasis undertreatment might be a reality due to limited access to IMB.16

Lopes et al. studied 203 Pso patients receiving IMB through court orders in São Paulo, Brazil, from 2004 to 2010, finding that 59.5% of patients obtained the medication through the writ of mandamus, with 86.2% never attempting to obtain it from a public or private health organization before taking legal action. Most patients (69.5%) acquired IMB via SUS with a private prescription and 70.3% did not undergo follow-up examinations.17

Kivelevitch et al. studied adherence to treatment among Argentinian Pso patients (n=176) and reported that 33% of patients self-medicated, while 77% were non-adherent to treatment. The patients assessed in this sample were using topical drugs (97%) and systemic drugs 29%.28 The most common causes of non-adherence were lack of response to treatment (63%), clinical improvement (26%), economic factors (16%) and adverse effects (10%). When combined, the self-medication and non-adherence groups comprised 82% of the sample. Notably, 24% of patients believed Pso could be cured, and 86% stated they had not been informed about the risks of suspending or modifying treatment without supervision.

Queiroz-Vergara et al. investigated the factors contributing to delayed Pso diagnosis in Mexico (n=100).29 Their findings revealed that a mere 42% of patients received a diagnosis within one year of presenting symptoms and, among those, 89% were diagnosed by a dermatologist, even though the first medical appointment had been with a General Practitioner (GP) in 61% of cases. Of these patients, 31% had initiated treatment within the first year of diagnosis.

Lopes et al. assessed the impact of Pso on work productivity and daily activities among 188 Brazilian patients.30 Presenteeism was more frequent than absenteeism, with a mean (Standard Deviation, SD) of 14.4% (5.5%) compared to 6.3% (13.8%). Presenteeism is defined as the act of attending work while ill or experiencing a medical condition that impedes full capacity on the job. They estimated that patients would need to increase working hours by approximately 5% to compensate for productivity losses due to Pso, with a mean of 4.7hours (SD=5.4). In contrast, Ferreira et al. found no significant differences in absenteeism, presenteeism, overall work impairment, and activity impairment across varying levels of Pso severity.31

DiBonaventura et al. estimated that, in Brazil, between 28% and 40% of working hours were either missed or rendered ineffective due to Pso (n=210).15 Presenteeism was more frequent among Pso patients compared to patients without Pso (22.08% vs. 16.95%; p<0.05). They estimated that this difference equates to an additional 10 days per employee per year. Activity impairment (26.52% vs. 20.97%) and the number of physician visits (5.18 vs. 4.27) were also significantly more common among Pso patients (p<0.05). However, no differences were observed across severity levels.

Mazzuoccoloa et al. conducted a survey on the use of MTX for Pso treatment among Argentinian dermatologists (n=221).32 They found that two-thirds of dermatologists included the PPD test and/or a chest X-Ray in their pretreatment work-up. Half of them expected a clinically significant response between weeks 4 and 6 of MTX treatment, 44% between weeks 8 and 12, and 6% after 12 weeks. Approximately 76% stated that they would consider treatment failure if no significant response was observed after 12 weeks. Concerning efficacy, 30% of Argentinian dermatologists deemed MTX ineffective. The only variable associated with suboptimal MTX use was the prescriber’s perception of its ineffectiveness (OR=2.29; 95% CI 1.05–5.00, p=0.037).32

Silveira et al. examined guideline adherence for the prescription of IMB among 203 patients suing the state of São Paulo, Brazil, from 2004 to 2011.33 They discovered that over 20% of patients had not used any conventional interventions prior to launching their lawsuit. Topical agents were used by 16% of patients and phototherapy by 36.9%. About 71% of patients had previously used non-immunosuppressive systemic treatment. Since Brazilian guidelines mandate the use of topical and systemic therapy before starting IMB, only 34 (16.7%) patients met the guideline requirements. All patients had visited a physician at least once a year, but 25.2% did not undergo any laboratory tests. Overall, complete adherence to guidelines was observed in 14.2% of cases. 33

Most articles were published in Brazil before 2019 when a new Clinical Protocol and Therapeutic Guideline (PCDT) for Pso made available adalimumab, etanercept, ustekinumab and secukinumab without the need for legal action.34 Following this development, the number of lawsuits declined in the country.10 Subsequently, risankizumab was added to the PCDT.35

In the last decade in Brazil, most IMBs for Pso were acquired through lawsuits, leading to inadequate patient monitoring6,33 and treatment interruption due to adverse effects. The lack of clear prescription requirements also contributes to physicians disregarding guidelines.6,33 According to Silveira et al., over 20% of patients had not used any conventional therapy before resorting to legal action.33 Delays in the inclusion of drugs in the PCDT and their purchase by the healthcare system led many pharmaceutical companies to provide medication for the start of treatment, which might have contributed to an increase in legal claims for medications. Lopes et al. stated that pharmaceutical industries maintained frequent communication with the majority of the patients.17

Brazilian Pso patients tend to have greater education, income, and private insurance rates than controls, suggesting that they are more likely to be diagnosed due to better access to medical care. French and Italian studies suggest that lower education and income levels are associated with more severe disease, fewer medical appointments, and fewer systemic treatment prescriptions.36,37 In the USA, younger age, lower income, and lack of insurance were associated with difficulties in acquiring IMB.38,39 Therefore, it is reasonable to assume that Pso prevalence and treatment access in Latin America might be grossly underestimated due to socioeconomic reasons.

Lopes et al. found that 34.8% of patients reported difficulties in obtaining prescribed medications. Most prescriptions for topical drugs in Brazil, such as high-potency Topical Corticosteroids (TCS), despite being included in the PCDT, require special requisition and excessive bureaucracy, making their acquisition process time-consuming.6 In our practice at a tertiary public hospital in Southern Brazil, the authors often see patients purchasing TCS with their own resources or using readily available low-potency TCS, which is not adequate for Pso treatment.40

Studies from Venezuela18 and Argentina19 have reported similar rates of LTBI among Pso patients (10.4% and 16%, respectively). In Colombia,20 the prevalence was significantly higher at 99%. When analyzing this study’s data, however, it is crucial to consider the potential influence of selection bias. Globally, there is a wide range of regional differences, with LTBI estimates ranging from 8.3% to 86.1%.41–47 The data becomes even more contrasting when comparing developed and developing countries.

A Latin American meta-analysis7 examining Pso patients undergoing anti-TNF treatment found an incidence rate of 636 cases per 100,000 patients-year for TB, which is considerably higher than the prevalence expected for the general population during the same period. Moreover, a Colombian study20 reported TB diagnoses even after a nine-month chemoprophylaxis with isoniazid. Similar findings were reported in publications from Turkey,48 France49 and the USA.45 Consequently, it is suggested that prophylactic measures may not fully prevent TB and that periodic screening should be conducted, especially in endemic regions.

Anti-TNF agents are generally considered first-line IMB for Pso treatment due to their cost-effectiveness.35 However, their usage may be limited owing to the potential risk of LTBI reactivation in Pso patients, leading physicians to prefer more expensive IMB options, which subsequently increases the economic burden.50 Furthermore, the PPD test has been shown to have limitations, most notably its low specificity in high BCG vaccine coverage scenarios and its reliance on patient immunocompetence for reliable results. Alternative tests, such as Interferon-Gamma Release Assays (IGRA), have been reported to be more specific, but their availability remains limited due to their high cost.51

Regarding other neglected diseases, scientific research in the context of Pso is scarce. Studies have suggested that the use of anti-TNF may be a risk factor for leprosy or reactivation of subclinical infections, which could possibly be explained by an interference with granuloma formation.52–54 Literature also cites leishmaniasis, especially visceral cases, as a potential infectious complication of anti-TNF immunosuppression.55,56 In the absence of specific guidelines, determining appropriate screening and therapeutic strategies can be challenging.

An Argentinian study highlighted self-medication and non-adherence as significant barriers to Pso treatment in Latin America, estimating them at 82% of patients.28 Similarly, Zhang et al. reported that 82.4% of Chinese patients discontinued doctor-prescribed medications or resorted to self-medication.57 Conversely, a British review found that up to 40% of patients do not use medications as directed,58 while a Turkish study observed a significantly lower non-adherence rate of 44.8%.59

In Argentina, 86% of patients stated that they had not been informed about the risks of unsupervised treatment changes28; Furthermore, 24% believed Pso could be cured. A lack of disease knowledge was also reported in China,57 where a higher percentage of patients in the self-medication group expected a complete cure (68.9 vs. 57.9%; p<0.001), and the consultation length related to adherence rates.

High demand for medical care often results in shorter patient-physician interactions, particularly in low-resource settings. Physicians may not allocate sufficient time to educate patients about their condition, specifically the manageable but incurable nature of Pso, which leads to unmet treatment expectations and subsequently poor adherence. This is especially important since greater treatment satisfaction has been statistically associated with improved adherence in Pso.59

There appears to be a pressing need for enhancing dermatological training for GPs.29 In Mexico, 61% of patients initially consulted a GP, but 89% were ultimately diagnosed by a dermatologist. This contrasts with the situation in the UK, where 82% of Pso patients receive treatment exclusively within the primary healthcare setting.60

Griffiths et al. studied the impact of treatment guidelines on appropriate British referrals for specialist care.61 They found a significant improvement in adequate referrals in the intervention group (78%) compared to the control group (59%) (difference=19.1%; Odds Ratio [OR=2.47], 95% CI 1.31–4.68; ICC=0). In Australia, GPs encounter Pso cases approximately only 10 times during their three-year training period,62 which is not sufficient for them to become adequately acquainted with such a complex condition. A Portuguese study reported that GPs tend not to view Pso as a systemic condition.63

The implementation of Pso guidelines targeting primary healthcare in Latin America could potentially shorten the time to diagnosis and better equip GPs to manage the condition, as well as alleviate the workload on tertiary centers. A cost-effective alternative would be the diffusion of telemedicine. This way, primary care providers would have the option, when necessary, of consulting with a trained dermatologist regarding treatment options and the need for referral to a tertiary center. This approach may lead to more timely and effective treatment for Pso patients, thereby improving their overall quality of life.

Contrary to most studies published in other regions,64–68 Latin American literature did not find a statistically significant difference in work productivity across levels of Pso severity.15,31 This discrepancy, however, may be attributed to the small sample sizes of these studies.

Lopes et al. was the only study that utilized the Work Productivity and Activity Impairment Questionnaire to assess work productivity loss.30 Their finding of a predominance of presenteeism aligned with data from a multinational study conducted by Villacorta et al.64 It is noteworthy that the absenteeism and presenteeism rates discovered in both studies were similar, but the mean Dermatology Life-Quality Index (DLQI) score in Lopes et al. was higher than in Villacorta et al. (mean=7.2 [SD=6.8]; 5.1 [95% CI 4.8‒5.4]). This could be a positive indicator since DLQI scores have been associated with worse work impairment.64,69 Additionally, Lopes et al. included only patients with moderate or severe Pso, while Villacorta et al. had 32.6% of patients with mild Pso.30,64 Furthermore, the unemployment rate (12.2%) was comparable to the overall Brazilian population’s unemployment rate during the same period (12.7%).70

Bronckers et al., conversely, found higher rates of absenteeism compared to presenteeism [mean (SD) 50% (46%); 20% (60%), respectively].71 This might be partially explained by the high percentage of females in their sample (70.7%).71,72 Lopes et al. found a mean productivity loss index of 4.7% (SD=5.4%) in the Work Limitations Questionnaire, which was lower than the one reported by Schmitt et al. (mean 7.6% [SD=9.1%]).30,69 Overall, work impairment due to Pso in Latin America seems to be similar to that in other regions.

Mazzuoccoloa et al. reported suboptimal use of MTX by 76% of dermatologists in Argentina.32 Comparable results were found in Holland, where 11% of dermatologists were not well-informed about guidelines. Although 80% of Dutch dermatologists use MTX in clinical practice, only 52% adhere to treatment guidelines when prescribing it.73 In a global survey on MTX use across 63 countries (38% European; 22.7% South American), approximately 40% of dermatologists prescribed insufficient maintenance doses of MTX,74 and 32.4% reported never or rarely increasing MTX dosages in patients with initial inadequate response.74 This could explain why 30% of Argentinian dermatologists consider MTX to be ineffective.32

Regarding pretreatment screening, the relatively high frequency of chest X-ray, HIV and PPD testing observed in Africa is probably due to the region’s high prevalence of HIV and tuberculosis.74 This may also account for the high rates of positive pre-IMB tuberculosis screening tests reported in Argentina.32

The limitations of the current systematic review on Pso in Latin America primarily stem from the limited availability and low quality of studies on the subject, with most research focused on Brazil, potentially hindering the generalizability of findings to the entire region. Small sample sizes in some studies, methodological differences, and variability in adherence to treatment guidelines may further impact the reliability and consistency of the results. Additionally, the lack of data on specific aspects, such as the relationship with neglected diseases, limits the conclusions that can be drawn in those areas. Despite these limitations, this review offers valuable insights and highlights areas where further research and improvements are needed.