Systemic lupus erythematosus in general practice

Abstract

Systemic lupus erythematosus (SLE) is a rare multi-system autoimmune condition that presents symptomatically to general practice. Longer diagnostic intervals are generally associated with poorer health outcomes. The study aims to investigate the prevalence, presentation and time intervals from symptom onset to diagnosis in patients with SLE enrolled in general practice. Using computerised records from 14 general practices in Hamilton between 1 January 2000 to 20 March 2024, potential SLE cases were identified. All records were manually reviewed to identify the diagnosis based on the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria. The World Health Organization (WHO) age-standardised prevalence was calculated on definite and probable cases. Records were reviewed prior to diagnosis to understand the interval time from first presentation of symptoms to referral and diagnosis. From a total practice population of 96,348, 68 (0.1%) SLE cases were identified (55 definite, 6 probable, 7 possible). The average prevalence of SLE in 2024 was 90 per 100,000 for women and 13.5 per 100,000 for men. Pacific people were 1.6 times higher than non-Pacific people to have SLE (RR 1.57, SE 0.17, 95% CI 1.12-2.20). Most patients presented with musculoskeletal symptoms (42%) and attended to a health care professional (HCP) within one month of symptom onset (44%). The HCPs were primarily general practitioners (69.1%). The total median time from symptom onset to diagnosis was 150.5 days (4.9 months). Majority of the patients’ journey to diagnosis was primarily spent with the initial HCP (median 11.5, range 0-694, average 79.9 days) and on the wait list to see the first hospital specialist (median 34.5, range 0-276, average 53.4 days). The prevalence of SLE from these 14 practices is higher than previously reported. The total median time from symptom onset to diagnosis is within target; due to a wide range of outliers with whom it takes considerably longer to reach a diagnosis, on average patients with SLE have a delayed diagnosis. This study reveals areas to reduce delays: the time with the initial HCP, primarily general practitioners, and the wait time before seeing the first hospital specialists