ObjectivesTo determine the trends in incidence, prevalence and mortality of systemic lupus erythematosus (SLE) in a US population over four decades.MethodsWe identified all the patients with SLE in Olmsted County, Minnesota who fulfilled the European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) criteria for SLE during 1976–2018. Age-specific and sex-specific incidence and prevalence dates were adjusted to the standard 2000 projected US population. The EULAR/ACR score was used as a proxy for disease severity. Standardised mortality ratio (SMR) was estimated.ResultsThere were 188 incident SLE cases in 1976–2018 (mean age 46.3±SD 16.9; 83% women). Overall age-adjusted and sex-adjusted annual SLE incidence per 100 000 population was 4.77 (95% CI 4.09 to 5.46). Incidence was higher in women (7.58) than men (1.89). The incidence rate increased from 3.32 during 1976–1988 to 6.44 during 2009–2018. Incidence rates were higher among the racial and ethnic minority populations than non-Hispanic whites. The EULAR/ACR score did not change significantly over time. Overall prevalence increased from 30.6 in 1985 to 97.4 in 2015. During the study period, there was no improvement in SMR over time (p=0.31).ConclusionsThe incidence and prevalence of SLE are increasing in this US population. The increase in incidence may be at least partially explained by the rising ethnic/racial diversity of the population. There was no evidence that the severity of SLE has changed over time. The survival gap between SLE and the general population remains unchanged. As the US population grows more diverse, we might continue to see an increase in the incidence of SLE.

Objective To estimate the incidence and time-to-classification of systemic lupus erythematosus (SLE) by the 1997 American College of Rheumatology (ACR97) criteria, the Systemic Lupus International Collaborating Clinics (SLICC) criteria, and the European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) criteria. Methods We identified all incident SLE cases from 2000–2018 in the well-defined Olmsted County population. Clinical data included in the ACR97, SLICC and EULAR/ACR criteria were manually abstracted from medical records. All incident cases met at least one of the 3 classification criteria. Time-to-classification was estimated from the first documented lupus-attributable disease manifestation to the time of criteria fulfillment by each of the three definitions. Annual incidence rates were age or age/sex adjusted to the 2000 US population. Results Of 139 incident cases there were 126 cases by the EULAR/ACR criteria, corresponding to an age/sex-adjusted incidence of 4.5 per 100 000 population (95% CI, 3.7–5.2). The age/sex-incidence was higher than that of the SLICC criteria (113 cases; 4.0 per 100 000 [95%CI, 3.3 – 4.7], p= 0.020) and the ACR97 (92 cases; 3.3 per 100 000 [95%CI 2.6–3.9], p< 0.001). The median time from first disease manifestation to criteria fulfillment was shorter for the EULAR/ACR criteria (29.4 months) than the ACR97 criteria (47.0 months, p< 0.001) and similar to the SLICC criteria (30.6 months, p= 0.83). Conclusion The incidence of SLE was higher by the EULAR/ACR criteria compared with the ACR97 and the SLICC criteria, and the EULAR/ACR criteria classified patients earlier that the ACR97 criteria but similar to the SLICC criteria.

Objective There is a paucity of population‐based studies investigating the epidemiology of lupus nephritis (LN) in the US and long‐term secular trends of the disease and its outcomes. We aimed to examine the epidemiology of LN in a well‐defined 8‐county region in the US. Methods Patients with incident LN between 1976 and 2018 in Olmsted County, Minnesota (1976–2009) and an 8‐county region in southeast Minnesota (2010–2018) were identified. Age‐ and sex‐specific incidence rates and point prevalence over 4 decades, adjusted to the projected 2000 US population, were determined. Standardized mortality ratios (SMRs), survival rates, and time to end‐stage renal disease (ESRD) were estimated. Results There were 72 patients with incident LN between 1976 and 2018, of whom 76% were female and 69% were non‐Hispanic White. Mean ± SD age at diagnosis was 38.4 ± 16.24 years. Average annual LN incidence per 100,000 population between 1976 and 2018 was 1.0 (95% CI 0.8–1.3) and was highest in patients ages 30–39 years. Between the 1976–1989 and 2000–2018 time periods, overall incidence of LN increased from 0.7 to 1.3 per 100,000, but this was not statistically significant. Estimated LN prevalence increased from 16.8 per 100,000 in 1985 to 21.2 per 100,000 in 2015. Patients with LN had an SMR of 6.33 (95% CI 3.81–9.89), with no improvement in the mortality gap in the last 4 decades. At 10 years, survival was 70%, and 13% of LN patients had ESRD. Conclusion The incidence and prevalence of LN in this area increased in the last 4 decades. LN patients have poor outcomes, with high rates of ESRD and mortality rates 6 times that of the general population.