Characterization of the patterns of care, access, and direct cost of systemic lupus erythematosus in Brazil: findings from the Macunaíma study
Authors: de Abreu Mirhelen Mendes , Monticielo Odirlei Andre , Fernandes Vander , Rodrigues Dalianna Luise Andrade Souto , da Silva Cristhiane Almeida Leite , Maiorano Alexandre Cristovão , Beserra Fernando dos Santos , Lamarão Flavia Rachel Moreira , de Veras Bruna Medeiros Gonçalves , David Nathalie , Araújo Magda , Alves Marcelly Cristinny Ribeiro , Stocco Matheus Amaral , Lima Fernando Mello , Borret Emilly , Gasparin Andrese Aline , Chapacais Gustavo Flores , Bulbol Guilherme Andrade , da Silva Lima Diogo , da Silva Natália Jardim Martins , Freitas Marta Maria Costa , Bica Blanca Elena Rios Gomes , de Lima Domingos Sávio Nunes , das Chagas Medeiros Marta Maria 
Published: April 2024

Abstract
Background
A cost of illness (COI) study aims to evaluate the socioeconomic burden that an illness imposes on society as a whole. This study aimed to describe the resources used, patterns of care, direct cost, and loss of productivity due to systemic lupus erythematosus (SLE) in Brazil.

Methods
This 12-month, cross-sectional, COI study of patients with SLE (ACR 1997 Classification Criteria) collected data using patient interviews (questionnaires) and medical records, covering: SLE profile, resources used, morbidities, quality of life (12-Item Short Form Survey, SF-12), and loss of productivity. Patients were excluded if they were retired or on sick leave for another illness. Direct resources included health-related (consultations, tests, medications, hospitalization) or non-health-related (transportation, home adaptation, expenditure on caregivers) hospital resources.Costs were calculated using the unit value of each resource and the quantity consumed. A gamma regression model explored cost predictors for patients with SLE.

Results
Overall, 300 patients with SLE were included (92.3% female,mean [standard deviation (SD)] disease duration 11.8 [7.9] years), of which 100 patients (33.3%) were on SLE-related sick leave and 46 patients (15.3%) had stopped schooling. Mean (SD) travel time from home to a care facility was 4.4 (12.6) hours. Antimalarials were the most commonly used drugs (222 [74.0%]). A negative correlation was observed between SF-12 physical component and SLE Disease Activity Index (− 0.117, p = 0.042), Systemic Lupus International CollaboratingClinics/AmericanCollegeofRheumatology Damage Index (− 0.115, p = 0.046), medications/day for multiple co-morbidities (− 0.272, p < 0.001), SLE-specific drugs/day (− 0.113, p = 0.051), and lost productivity (− 0.570, p < 0.001). For the mental component, a negative correlation was observed with medications/day for multiple co-morbidities (− 0.272, p < 0.001), SLE-specific medications/day (− 0.113, p = 0.051), and missed appointments (− 0.232, p < 0.001). Mean total SLE cost was US$3,123.53/patient/year (median [interquartile range (IQR)] US$1,618.51 [$678.66, $4,601.29]). Main expenditure was medication, with a median (IQR) cost of US$910.62 ($460, $4,033.51). Mycophenolate increased costs by 3.664 times (p < 0.001), and inflammatory monitoring (erythrocyte sedimentation rate or C-reactive protein) reduced expenditure by 0.381 times (p < 0.001).

Conclusion
These results allowed access to care patterns, the median cost for patients with SLE in Brazil, and the differences across regions driven by biological, social, and behavioral factors. The cost of SLE provides an updated setting to support the decision-making process across the country.