# Cutaneous vasculitis in systemic lupus erythematosus: epidemiology and risk factors over a 20-year follow-up

## TL;DR

This study examines how often skin vasculitis occurs in lupus patients over 20 years and identifies factors linked to its development.

## Contribution

The study reveals a significant decline in skin vasculitis incidence over time and identifies specific risk and protective factors in SLE patients.

## Key findings

- The incidence of cutaneous vasculitis in SLE decreased from 34.4% to 2.1% over 18 years of follow-up.
- Cutaneous vasculitis was associated with multiple clinical features, serological markers, and inversely with AZA and antimalarial use.
- Patients with CV were more likely to experience organ damage.

## Abstract

Cutaneous vasculitis (CV) is common in SLE, but the epidemiology and risk factors remain unclear. We aimed to identify the trends and risk factors for CV in patients with SLE over a period of 20 years.

The Birmingham Lupus Cohort is an observational longitudinal cohort of SLE patients. Patients were enrolled within 3 years of meeting their fourth ACR criterion. Disease activity, laboratory test results and treatment records were collected. A multivariable shared frailty Cox proportional hazard model was used to identify clinical, laboratory and treatment-related variables associated with the development of CV.

We included 392 patients: 95.7% were female. The median (interquartile range) duration of follow-up was 9.2 (5.1–14.7) years. CV occurred in 27% of SLE patients, of whom 43.3% had two or more CV events. This study demonstrated a marked decline in the incidence rates of CV, decreasing from 34.4% (95% CI 29.7, 39.3) during the first 3 years after enrolment to 2.1% (95% CI 0.05, 11.5) after 18 years of follow-up. Development of CV was associated with RP, constitutional, mucocutaneous, musculoskeletal, haematological and cardiovascular involvement, anti-Sm antibodies, anti-dsDNA, and hypocomplementemia. However, the use of AZA and antimalarials was inversely associated with the development of CV. Patients with CV were more likely to develop at least one item of organ damage.

The incidence rates of CV in SLE decreased over the follow-up period and CV is associated with defined clinical, serological and treatment-related factors.