Australians with systemic lupus erythematosus have a high rate of premature mortality compared to the general population, according to a WA study that has shown the life expectancy gap has persisted over three decades.
The increased risk of mortality was particularly high for younger people (under 40), Aboriginal Australians and those from lower socioeconomic groups, according to findings from a population-level cohort study of 2112 patients with SLE covering the period 1980-2014.
The study found that a hospitalisation for SLE was associated with multivariate-adjusted hazard ratio (aHR) for mortality of 2.03 compared to a control group of more 21,000 people from the general population.
Researchers at the University of WA found that people with SLE had higher rates of comorbidities (42% vs 20.5%), especially cardiovascular disease (44.7% vs 21.0%) and nephritis (16.4% vs 0.5%), compared to the general population. During 13 years of follow-up 26% of patients with SLE died compared to 11.6% of matched comparators in the general population.
Risk of death was highest for Aboriginal Australians (aHR 3.32), socioeconomically disadvantaged people (aHR 2.49), and people under <40 years old (aHR 7.46).
Writing in the journal Lupus Science and Medicine, the study investigators, led by Warren Raymond and Professor Johannes Nossent, noted that the risk of premature mortality in people with SLE was highest within five years of hospitalisation.
In younger patients, mortality was related to active (‘flaring’) disease and the higher incidence of infection, whereas deaths in older SLE patients were related to increased atherosclerotic cardiovascular disease and side effects of long-term treatment and comorbidity.
“Prevalent thromboembolic disease, harmful alcohol use, smoking, hypothyroidism, hypertension, dyslipidaemia and requirement of IV/IM corticosteroids were found to be effect modifiers of the association between a hospitalisation for SLE and premature mortality, and warrant further investigation,” they wrote.
As expected the risk of mortality was higher with in patients with lupus nephritis, but there was no additional mortality risk with factors such as the presence of antiphospholipid syndrome or other rheumatic disease conditions, including rheumatoid arthritis.
The researchers said the estimates for mortality for Australian patients with moderate-to-severe SLE were comparable to other studies, and the findings confirmed the high burden of comorbidities which may contribute to premature mortality.
“Beyond the attempt to manage the increased risk of premature mortality after a hospitalisation for SLE, clinicians should be particularly mindful about managing comorbidity and modifiable risk factors, such as smoking, alcohol consumption and obesity, to improve survival in this patient population,” they suggested.
“Special attention should be given to patients with SLE under 40 years of age, the socioeconomically disadvantaged, and Aboriginal Australians,” they concluded.