Epidemiology and Damage Accrual of Systemic Lupus Erythematosus in Central Sweden: A Single‐Center Population‐Based Cohort Study Over 14 Years From Östergötland County

Abstract

ObjectiveVariations in prevalence and incidence of systemic lupus erythematosus (SLE) within a geographically defined area of central Sweden over a time period of 14 years were examined. Longitudinal differences in disease activity, laboratory test results, and damage accrual were investigated.MethodsAdults (aged ≥18 years) residing in Östergötland County between 2008 and 2021 (mean adult population: 357,000 citizens) with confirmed SLE were identified and followed prospectively until death, December 31, 2021, or emigration. We estimated annual incidence per 100,000 inhabitants stratified by sex and age. Linear regression with year of diagnosis as the outcome assessed whether each clinical measurement at diagnosis varied over time.ResultsPrevalence on December 31, 2021, was 71.5 of 100,000 (87% female). One hundred twenty‐six new cases were identified during the study period, yielding a mean annual incidence of 3.0 of 100,000 inhabitants; this was higher in females (4.8/100,000) than in males (1.2/100,000). Mean age at diagnosis was 43.7 years (SD 17.3). Age at diagnosis and disease activity measures increased over the calendar year of diagnosis (P < 0.05) whereas disease manifestations, including lupus nephritis, did not vary significantly. Accrual of organ damage was demonstrated over time since diagnosis and stratified by sex, lupus nephritis, and corticosteroid‐related damage. Approximately 40% developed damage within 5 years.ConclusionSLE prevalence and incidence estimates remained constant over 14 years, and disease phenotypes at SLE onset were similar. SLE was diagnosed also among older individuals with a smaller female‐to‐male ratio. Estimates of prevalence and incidence were comparable to previous Scandinavian reports but lower than observed in registry data from the US and the UK.

Declining Incidence of Systemic Lupus Erythematosus in Norway 1999–2017: Data From a Population Cohort Identified by International Classification of Diseases, 10th Revision Code and Verified by Classification

“…Using the 1997 ACR criteria, the estimated incidence rate for adult SLE (1.6 per 100,000 per year) was low compared to previous smaller-scaled studies from Scandinavia. [24][25][26][27][28] Our data also support a decreasing trend in incidence during the study period. Although effects of other factors, including methodologic, cannot be ruled out, this may reflect a de facto decrease in recent years, in line with previous European population-based studies from Sweden , 24 Italy (2012-2020), 29 and Spain (2002-2006), 30 and from South-Korea (2005-2015).…”

“…Although effects of other factors, including methodologic, cannot be ruled out, this may reflect a de facto decrease in recent years, in line with previous European population‐based studies from Sweden (1981–2006), 24 Italy (2012–2020), 29 and Spain (2002–2006), 30 and from South‐Korea (2005–2015) 31 . In a recently published Swedish study (2008–2021) and a Danish study (1995–2011), the incidence rates were more stable 28,32 33 .…”

“…Using this clinical assessment approach, we confirmed SLE diagnosis in 45% (1,558 per 3,488) of the study cohort, underscoring the challenge of diagnosing SLE in clinical practice. Using the 1997 ACR criteria, the estimated incidence rate for adult SLE (1.6 per 100,000 per year) was low compared to previous smaller‐scaled studies from Scandinavia 24–28 …”

“…31 In a recently published Swedish study (2008-2021) and a Danish study (1995-2011), the incidence rates were more stable. 28,32 data from Crete, Greece, showed a stable incidence from 2010 to 2013, after a prior increase from 1999 to 2010. 33 Only one other populationbased study, from Minnesota, has applied the 2019 EULAR/ ACR criteria.…”

Obesity and tobacco smoking are independently associated with poor patient-reported outcomes in SLE: a cross-sectional study

“…Patients diagnosed with SLE from the Linköping University Hospital meeting the 1982 American College of Rheumatology (ACR) [ 29 ] and/or the 2012 Systemic Lupus Erythematosus International Collaborating Clinics Group (SLICC) criteria [ 30 ] ( n = 325) were included in the present cross-sectional analysis of data captured at visits between January 2008 and September 2021. An extensive characterisation of this cohort was recently published [ 31 ]. Among consecutive visits, the first visit with complete demographic, clinical, and patient-reported data was selected for the present analysis.…”