People with systemic lupus erythematosus (SLE) have a threefold greater likelihood of having up to five or more comorbidities in comparison with people in the general population, according to the results of two separate U.S. population-based studies.
The higher rate of comorbidities seen included many of those commonly reported before, such as cardiovascular and renal disease, but also some that may be less frequently associated with SLE, notably chronic obstructive pulmonary disease (COPD) and cardiac arrhythmias.
“In the past, the characterization of SLE comorbidities has relied on individual comorbidity assessment,” Alí Duarte García, MD, said at the 14th International Congress on Systemic Lupus Erythematosus, held together will the 6th International Congress on Controversies in Rheumatology and Autoimmunity.
“However, a patient-centric approach where a patient as a whole is seen and how many comorbidities they accrue has not been performed.” added Duarte García, who is a rheumatologist at the Mayo Clinic in Rochester, Minn.
Multiple conditions “overrepresented” in SLE patients
Dr. Duarte García reported the findings of one of the studies, both of which used data from the Rochester Epidemiology Project, a record-linkage system that collates clinical and hospital data from individuals who live in 19 counties in southeast Minnesota and eight counties in western Wisconsin; these patients have agreed to share their medical records for research.
The study population included 479 individuals diagnosed with SLE according to joint 2019 European Alliance of Associations for Rheumatology and American College of Rheumatology criteria. These were matched by age, sex, race, and county to 479 individuals without SLE.
The mean age of the study population was 53 years, 82% were women, and 86% were White.
“We defined multimorbidity as those patients who have two or more comorbidities and substantial multimorbidity as those patients who have five or more comorbidities,” Dr. Duarte García explained.
A previously published list of 44 categories of comorbidities was used to classify the multimorbidity seen, and 27 of these were “overrepresented” in patients with SLE.
Patients with SLE averaged 5.3 comorbidities, whereas control study subjects had 2.9. Comparing SLE with non-SLE individuals, the odds ratio for having two or more comorbid conditions was 2.96, and for five or more comorbidities it was 3.06.
The highest odds ratio comparing SLE with non-SLE individuals was seen for pulmonary disorders (39.0).
Dr. Duarte García highlighted four comorbidities that occurred in SLE patients that were perhaps more unusual: congestive heart failure (OR, 13.3), valvular heart disease (OR, 4.2), cardiac arrhythmias (OR, 2.85), and COPD (OR, 2.7).
“Given the association of multimorbidity with poor outcomes, care delivery strategies to manage multimorbidity are needed in SLE,” Dr. Duarte García concluded.
Similar findings seen in cutaneous lupus
There is also an excess of comorbid conditions in people with cutaneous lupus erythematosus (CLE), Mehmet Hocaoglu, MD, said in reporting the findings of the second study.
Dr. Hocaoglu, an internal medicine resident at the University of Maryland Medical Center in Baltimore, and part of the same team of researchers as Dr. Duarte García, noted that in skin-related lupus the risk of multimorbidity was about doubled.
For this separate analysis, a total of 303 patients with cutaneous lupus had been matched to 303 controls from the general population. Odds ratios for having two or more or five or more comorbidities were a respective 2.27 and 1.65.
Among the comorbidities seen that were higher in those with cutaneous lupus than in the general population subjects were fibromyalgia, liver disease, hypertension, anemia, hypothyroidism, and COPD.
“Further research is definitely needed to identify if the driver of this multimorbidity in CLE patients is the disease itself or the treatments CLE patients are receiving or a multifactorial cause that is driving the disease association,” Dr. Hocaoglu said.