Inactivity among patients with systemic lupus erythematosus (SLE) was associated with a more than threefold increased risk for development of depression, researchers reported.
Among patients who described themselves as inactive at baseline, incident depression was diagnosed during the subsequent 2 years in 38% of SLE patients, compared with 14% of those who were active, according to Sarah L. Patterson, MD, and colleagues from the University of California San Francisco.
In a multivariate analysis that adjusted for sex, race, comorbidities, and disease activity and damage, the hazard ratio for incident depression among inactive SLE patients was 3.88 (95% CI 1.67-9.03), the researchers reported online in Arthritis Care & Research.
Depression is very common among SLE patients, being diagnosed in 40-50% at some point during their lifetimes compared with 17% of the general population, and can have serious deleterious impact on numerous disease-related outcomes including quality of life and disability.
“Though the higher prevalence of depression in lupus relative to the general population is well demonstrated, the psychological, biological, and lifestyle factors responsible — and measures that can be taken to mitigate them — are not yet well defined,” Patterson and colleagues wrote.
Among the factors contributing to depression in the general public is physical inactivity. To examine the possible role of this factor in patients with SLE, who often face barriers to exercise including pain, fatigue, and medication adverse effects, the researchers conducted annual interviews of individuals enrolled in the California Lupus Epidemiology Study during the years 2007 to 2009.
Depression was evaluated on the eight-item Patient Health Questionnaire depression scale, with scores of 10 or higher representing clinical depression. Inactivity was determined by the Rapid Assessment of Physical Activity instrument, in which patients who reported that they “rarely or never do any physical activities” were considered inactive.
The analysis included 225 patients who were not considered as having depression at baseline, although a history of depression was permitted, and was present in 26.1% of the cohort.
Participants’ mean age was 45, and almost 90% were women. The sample was diverse, with 35% Asian, 30% white, 22% Hispanic, 10% African-American, and the remainder classified as unspecified or other.
Disease duration was almost 17 years, and the mean Lupus Severity Index was 6.9.
A total of 18% of participants reported being sedentary, and these patients more often were Hispanic or African-American, had poverty-level incomes, and were less educated.
Over a mean of 26 months of follow-up, there were 37 new cases of depression. In a bivariate analysis, factors that were significantly associated with incident depression were:
- Inactivity, HR 2.89 (95% CI 1.46-5.71)
- Poverty-level income, HR 2.27 (95% CI 1.08-4.77)
- Disease damage, 1.23 (95% CI 1.08-1.40)
- Cardiovascular disease, HR 3.46 (95% CI 1.70-7.04)
But in the multivariate analysis, inactivity showed the strongest association — “even more than poverty-level income, racial/ethnic minority status, SLE disease activity, coexisting cardiovascular disease, or other comorbidities,” the researchers noted.
This was the first study to confirm an elevated risk for depression among sedentary lupus patients. “Given the high burden of depression experienced by lupus patients relative to the general population — even among those with low disease activity and less severe disease — this finding is an important step toward understanding the contribution of lifestyle factors to mood symptoms in a uniquely vulnerable patient group,” they wrote.
They recommended that clinicians implement routine screening for physical inactivity during follow-up visits, and provide education and referrals for exercise for sedentary patients.
Even light activities were beneficial, according to the authors, with benefits being seen for patients who did not necessarily meet recommended guidelines for physical activity.
The U.S. Office of Disease Prevention and Health Promotion 2018 Physical Activity Guidelines Update emphasized that even small increases in activity can provide health benefits, stating: “Individuals performing the least physical activity benefit most by even modest increases in moderate-to-vigorous physical activity.”
“In addition to reducing the risk of important physical comorbidities such as cardiovascular disease, our data suggest that a small increase in physical activity may also reduce the risk of major mental health challenges experienced disproportionally in SLE,” Patterson and colleagues concluded.
A limitation of the study, they said, was the reliance on patient reports of disease activity and other related factors.
The study was supported by the CDC, the Rheumatology Research Foundation, the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases, the Robert L. Kroc Chair in Rheumatic and Connective Tissue Diseases, and the Russell/Engleman Medical Research Center for Arthritis.
The authors reported no financial conflicts.