Having systemic lupus erythematosus (SLE) can considerably increase the likelihood of developing angioedema, a new study suggests. Women, African-Americans, and younger patients may be particularly susceptible, its findings show.
The research, “Systemic Lupus Erythematosus and Angioedema: A Cross-Sectional Study From the National Inpatient Sample,” was published in the journal Archives of Rheumatology.
Previous reports into individual patients and small groups of patients identified an association between two types of angioedema — hereditary angioedema and acquired angioedema with C1-inhibitor deficiency — and SLE, an autoimmune disorder typically affecting multiple systems in the body. However, epidemiological studies — that look into disease in populations and typically involve large numbers of patients — are lacking.
To address this gap, researchers from the U.S. and China analyzed data from the National Inpatient Sample (NIS), the largest publicly available inpatient database in the U.S., representing 20% of all U.S. non-federal hospitals.
Between 2012 and 2014, the database registered a total of 90,485 hospitalizations in people diagnosed with angioedema. Of these, 1,505 also had SLE.
Depending on whether the statistical model accounted for angioedema-related comorbidities, SLE patients showed 1.71 to 2.54 higher odds of developing angioedema than people without SLE.
Consistent with previous data in SLE patients, the group with both angioedema and SLE was younger (mean age 44 vs. 58 years), and included more females (89% vs. 57%) and more African-Americans (57% vs. 38%) than the group without SLE. People with both disorders were also more likely to be on Medicaid, a U.S. government-run health insurance program, than private insurance (25% vs. 16%) and to have a low income (45% vs. 36%).
As for angioedema-related comorbidities, having SLE was associated with a higher risk of atopic disorders (18% vs. 13%) like allergic rhinitis, atopic dermatitis, and asthma, a type of small blood vessel inflammation (0.33% vs. 0.04%), infections (40% vs. 24%), and higher numbers of a type of white blood cell called eosinophils (1% vs. 0.24%) than did people without SLE.
In contrast, having SLE did not increase the likelihood of medication adverse effects, anaphylaxis (a serious allergic reaction), or C1-inhibitor deficiency.
Urinary tract infections had the only significant infection-rate difference between these groups, with a higher risk in people with SLE and angioedema than in those with angioedema only (12% vs. 7%).
In terms of systemic comorbidities, angioedema patients with SLE were more likely to have chronic kidney disease (37% vs. 15%), but less likely to have high blood pressure (44% vs. 60%), diabetes mellitus (17% vs. 32%), coronary artery disease (12% vs. 18%), and chronic obstructive pulmonary disease (1% vs. 3.3%).
“Our study demonstrates that SLE is associated with higher odds of having [angioedema], including severe [angioedema] as the principal reason for inpatient admission,” the researchers wrote.
As it is “possibly an independent risk factor” for angioedema, clinicians “should be vigilant” for this disorder when managing people with SLE in the hospital, they added.