The study, “Obesity Independently Associates with Worse Patient-Reported Outcomes in Women with Systemic Lupus Erythematosus,” was published in the journal Arthritis Care & Research.
Lupus patients experience poorer health-related quality of life and patient-reported outcomes than healthy individuals or those with other chronic conditions, such as rheumatoid arthritis. But the cause for these worse outcomes is not fully understood.
While obesity has been linked to worse patient-reported outcomes in other inflammatory conditions, research investigating if obesity could partly explain the poorer outcomes in lupus is still controversial.
To address this, researchers studied this link in 142 women with lupus included in the University of California at San Francisco Lupus Outcomes Study.
Among the participants, 47, or 33.1%, were considered obese, which was defined as having a fat mass index (FMI) above 13 kg/m² or body mass index (BMI) equal to or above 30 kg/m².
The impact of obesity was assessed in regards to disease activity, depressive symptoms, pain, and fatigue.
Disease activity across nine organs was measured using the Systemic Lupus Activity Questionnaire (SLAQ), which ranges from zero to 44, where higher scores indicate greater disease activity.
The Center for Epidemiologic Studies Depression Scale (CES-D), a 20-item scale with scores ranging from zero to 60, was used to measure depression.
Pain and fatigue were examined through the Short Form 36 (SF-36) Health Survey, a survey with scores ranging from zero to 36, where higher scores reflect less pain and fatigue.
The analysis showed that fat content, measured according to the fat mass index, was significantly associated with higher disease activity, higher burden of pain, and fatigue.
Compared with those who were not obese, obese patients had worse disease activity (15 versus 10 in SLAQ), twice as high depression scores (20 versus 10 in CES-D), and increased pain and fatigue (37 versus 46 in SF-36), the investigators found.
After adjusting for multiple sociodemographic parameters, including age, race, education, poverty status, and smoking, as well as disease duration and clinical features — disease damage and glucocorticoid use — obesity was still associated with significantly worse scores on all patient-reported outcomes.
“These findings highlight the need for lifestyle interventions targeting lupus patients who are overweight given the potential to reduce both cardiovascular risk and debilitating symptoms common in this disease,” the researchers wrote.