Prevalence of systemic lupus erythematosus in Peru and its association with environmental and healthcare factors: An ecological study

Objective
To estimate the prevalence of Systemic Lupus Erythematosus (SLE) in Peru in 2017 and its association with altitude, environmental temperature, and physician density.
Methods
This ecological study was performed using population data from the 2017 Peruvian census. The number of SLE cases for each department was obtained from the National Health Registries using the ICD-10 code M32. Altitude, environmental temperature and physician density were obtained for each department from the National Institute of Statistics and Informatic (Instituto Nacional de Estadística e Informática) registries. The prevalence for each department was calculated adjusting for age and sex. Then a negative binomial regression was performed to estimate the prevalence ratio (PR) and evaluate factors associated with the prevalence of SLE.
Results
The national prevalence of SLE was 40.2 per 100,000 people. Two age groups had the highest prevalence: 12–17 years and 30–59 years. Females exhibited a higher prevalence than males, particularly in the 30–59 age group (113.9 vs 16.1 per 100,000, respectively). An inverse relationship was observed between the age- and sex-adjusted prevalence in each department and altitude (PR 0.97; 95% CI: 0.94–0.99). On the other hand, there was a direct relationship with physician density (PR: 1.04; 95% CI: 1.01–1.07). No association was found between the adjusted prevalence and environmental temperature or latitude.
Conclusion
The prevalence of SLE in Peru aligns with global estimates. The inverse relationship with altitude and the direct association with physician density suggest that environmental and healthcare access factors may influence disease distribution. Further research is needed to explore the underlying mechanisms driving these associations.