Incidence of Systemic Lupus Erythematosus Greater Among Younger Women vs Men in Sweden

Over a span of 14 years, the frequency and occurrence of systemic lupus erythematosus (SLE) remained consistent among patients in central Sweden, with similar disease characteristics observed during onset, according to study results published in ACR Open Rheumatology.

Investigators assessed longitudinal variations in the prevalence and incidence of SLE among adult patients in Sweden.

A single-center population-based cohort study was conducted, including patients diagnosed with SLE from 2008 to 2021. Diagnoses were confirmed via medical records and laboratory data. Prevalence rates were predicted using the entire population of Östergötland County, Sweden, while incidence rates were estimated per 100,000 inhabitants, stratified by both age and sex.

A total of 266 patients with prevalent lupus were included in the analysis. The overall mean patient age was 56.5 years; mean age among women vs men with SLE was 55.9 and 59.9 years, respectively.

The overall prevalence of SLE at the end of the study period was 71.5 per 100,000 inhabitants, with 86.1% of SLE diagnoses occurring among women.

The prevalence of SLE was higher among women (121.9 per 100,000 inhabitants) vs men (17.4 per 100,000 inhabitants).

During the study period, there were a total of 126 newly identified cases of SLE, resulting in an average annual incidence rate of 3.0 per 100,000 inhabitants.

The incidence rate was higher among women (4.8 per 100,000 inhabitants) vs men (1.2 per 100,000 inhabitants). Mean age at SLE diagnosis was 43.7 years.

Among patients aged at least 55 years at the time of diagnosis, the ratio of women to men diagnosed with SLE was significantly reduced, compared with patients diagnosed at younger ages.

Both age at diagnosis and disease activity measures increased throughout the year patients received their diagnoses (P < .05), while disease manifestations, such as lupus nephritis, did not show significant variation.

Within the first 5 years following SLE diagnosis 41.8% of patients experienced development of any organ damage.

The study was limited by the small sample size of patients diagnosed with SLE. 

The study authors concluded, “Despite public and tax-funded health care with universal access, accrual of [organ] damage appears to be a persisting problem because more than 40% had acquired damage within 5 years.”