Hospitalisation for systemic lupus erythematosus associates with an increased risk of mortality in Australian patients from 1980 to 2014: a longitudinal, population-level, data linkage, cohort study

Abstract

ObjectiveMortality rates for patients with SLE have not been reported in Australia. This study determined the association between a hospitalisation for SLE with mortality.MethodsPopulation-level cohort study of patients with SLE (n=2112; 25 710 person-years) and general population comparators (controls) (n=21, 120; 280 637 person-years) identified from hospital records contained within the WA Rheumatic Disease Epidemiological Registry from 1980 to 2013. SLE was identified by ICD-9-CM: 695.4, 710.0, ICD-10-AM: L93.0, M32.0. Controls were nearest matched (10:1) for age, sex, Aboriginality and temporality. Using longitudinal linked health data, we assessed the association between a hospitalisation for SLE mortality and mortality with univariate and multivariate Cox proportional hazards and competing risks regression models.ResultsAt timezero, patients with SLE were similar in age (43.96 years), with higher representation of females (85.1% vs 83.4%, p=0.038), Aboriginal Australians (7.8% vs 6.0%) and smokers (20.5% vs 13.2%). Before study entry, patients with SLE (mean lookback 9 years) had higher comorbidity accrual (Charlson Comorbidity Index ≥1 item (42.0% vs 20.5%)), especially cardiovascular disease (CVD) (44.7% vs 21.0%) and nephritis (16.4% vs 0.5%), all p<0.001. During follow-up (mean 12.5 years), 548 (26.0%) patients with SLE and 2450 (11.6%) comparators died. A hospitalisation for SLE increased the unadjusted (HR 2.42, 95% CI 2.20 to 2.65) and multivariate-adjusted risk of mortality (aHR 2.03, 95% CI 1.84 to 2.23), which reduced from 1980 to 1999 (aHR 1.42) to 2000–2014 (aHR 1.27). Females (aHR 2.11), Aboriginal Australians (aHR 3.32), socioeconomically disadvantaged (aHR 2.49), and those <40 years old (aHR 7.46) were most vulnerable. At death, patients with SLE had a higher burden of infection (aHR 4.38), CVD (aHR 2.09) and renal disease (aHR 3.43), all p<0.001.ConclusionsA hospitalisation for SLE associated with an increased risk of mortality over the 1980–2014 period compared with the general population. The risk was especially high in younger (<40 years old), socioeconomically disadvantaged and Aboriginal Australians.

Cancer development in patients hospitalized with systemic lupus erythematosus: A population‐level data linkage study

“…This whole‐of‐population cohort study used data linked by the Western Australian Data Linkage System (WADLS), which uses probabilistic matching (99.7% accuracy) to identify individuals across administrative health data sets 9 . The Western Australian Rheumatic Disease Epidemiological Registry (WARDER) includes all private and public hospital separations (emergency department presentations, inpatient episodes, including same‐day interventions and admissions, as well as, cancer notifications, and death notifications) statewide for over 200 000 patients with rheumatic disease conditions and another 200 000 non‐exposed general population comparators 1 . The WARDER comprises of information linked from the Hospital Morbidity Data Collection (HMDC, from 1970), WA Cancer Registry (from 1982) and the Death Register (from 1969) and the Emergency Department Data Collection (from 2002).…”

“…Within participants of the WARDER, hospitalizations for SLE were identified in the HMDC between 1 January 1980 and 31 December 2013 by ICD‐9‐CM: 695.4, and 710.0, and ICD‐10‐AM: M32.0, M32.1, M32.8, M32.9, L93.0, L93.1, and L93.2 1 . Administrative data have been validated for the identification of rare diseases, and suitable for producing epidemiological estimates 14 ; and, having at least one ICD‐9‐CM code of SLE (ICD‐9: 694.4 and 710) having a positive predictive value of 70%–96% in administrative or claims data, 15 which is even higher (≥97%) when patients are seen by a specialist 16 .…”

“…Other studies support an increased risk of cervical, 4 hematological, particularly non‐Hodgkin's lymphoma, and kidney cancers 5 ; with some showing a decreased risk of prostate cancer and bladder cancer, 6 or no association with breast, uterine, ovarian, colorectal, or brain cancers 7 . Australian data were not available for aggregation in the meta‐analyses, 2,3 including data on cancer development in Aboriginal Australians with SLE; an ethnic group with higher demand for hospitalizations, including SLE‐related hospitalizations 1 . Furthermore, Australia has unique environmental exposures, including very high levels of background ultraviolet radiation and high levels of silica dust particles, which makes data from this region important to include in future studies 8 .…”

Gastrointestinal Manifestations in Patients with Systemic Lupus Erythematosus

“… 4 Moreover, in an Australian population-based study, patients with SLE had an increased likelihood and risk of mortality associated with GI and hepatic diseases. 5 …”

“…4 Moreover, in an Australian population-based study, patients with SLE had an increased likelihood and risk of mortality associated with GI and hepatic diseases. 5 The potential severity of SLE-related GI manifestations is concerning, considering that more than 50% of SLE patients develop GI symptoms at some point during the course of illness. 6 The incidence and prevalence of GI involvement during the course of SLE disease vary widely.…”