# Mapping the spatial and temporal frequency of systemic lupus erythematosus in Brazil

## TL;DR

This study maps the spread of lupus in Brazil over 14 years, showing rising cases and regional differences.

## Contribution

The study provides the first comprehensive spatial and temporal analysis of SLE in Brazil using national health data.

## Key findings

- SLE prevalence increased by 15.5% annually from 2008 to 2022.
- Southeast and South regions had the highest SLE rates, with clustering in São Paulo and Paraná.
- More rheumatologists correlated with higher SLE case reporting (R=0.567).

## Abstract

The aim of this study was to analyze the spatial and temporal distribution of systemic lupus erythematosus (SLE) cases in Brazil from 2008 to 2022.

We conducted an ecological study based on data from patients treated in the Unified Health System. SLE cases were identified using International Classification of Diseases-10 codes and analyzed by geographic region, age, and color/race. Spatial distribution was assessed to identify high and low prevalence, while temporal trends were evaluated through annual percentage change (APC).

In 2022, the national prevalence was 52.3/100,000 inhabitants, with marked geographical disparities. Southeast (68.14/100,000) and South (66.37/100,000) regions showed the highest reporting rates. Spatial analysis identified significant clustering, particularly in São Paulo and Paraná, accounting for 95.4% of the high-prevalence municipalities. Temporal analysis of the adult population revealed a consistent increase in SLE prevalence from 2008 to 2022 (APC=15.5%, p<0.001), which was most pronounced in the Northeast and South, while a slower increase was observed in the North. A correlation was observed between the number of rheumatologists and the number of cases/100,000 inhabitants (R=0.567, p=0.002).

This study reveals significant geographic disparities and a rising trend in SLE prevalence across Brazil. The clustering of cases in specific municipalities and the correlation between rheumatologist availability and prevalence underscore the need for targeted healthcare resources. These findings highlight the importance of investigating how healthcare access impacts regional disparities in SLE prevalence and advancing equitable care nationwide.