Study Links Obesity to Worse Outcomes in Women with Lupus

Obese women with systemic lupus erythematosus (SLE) have a poorer quality of life and suffer more symptoms than women of normal weight, according to new research presented at the 2017 ACR/ARHP Annual Meeting in San Diego.

The study, “Obesity Independently Associates with Worse Patient Reported Outcomes in Women with Systemic Lupus Erythematosus,” shows these women have higher disease activity, worse depressive symptoms, more pain and more fatigue — suggesting that rheumatologists should make it a priority to get these patients to lose weight.

“We know from prior research that patients with lupus experience worse health-related quality of life and greater symptom burden compared to the general population, but we do not yet have a complete explanation for these worse experiences,” Dr. Sarah Patterson, a rheumatology fellow at the University of California, San Francisco (UCSF), said in a press release.

“For example, neither disease-specific factors such as disease activity nor sociodemographic factors such as poverty fully explain the observed severity of these symptoms,” she said. “And because we are interested in understanding how lifestyle factors such as exercise and weight management impact outcomes in lupus, we sought to determine if excess fat associates with worse PROs [patient-reported outcomes] in this disease.”

Obesity is known to worsen systemic inflammation in the general population and contribute to worse disease-related outcomes in rheumatoid arthritis patients. But its impact in lupus patients remains poorly characterized.

That led UCSF researchers to ask whether too much body fat was an independent risk factor for worse PROs in this population.

The team studied adult women diagnosed with lupus who had been recruited from the Arthritis Body Composition and Disability (ABCD) study. They then calculated a series of parameters, including body-mass index (BMI) and fat mass index (FMI) — a measure of total fat mass adjusted for height. Obesity was defined as FMI 13 kg/m² or higher, and BMI higher than or equal to 30 kg/m².

Researchers looked at how obesity affected four validated PROs: disease activity, measured according to the Systemic Lupus Activity Questionnaire (SLAQ); depressive symptoms, according to the Center for Epidemiologic Studies Depression Scale (CES-D); pain, using the Short Form 36 Health Survey (SF-36) Pain Subscale; and fatigue, using the SF-36 Vitality Subscale.

The study enrolled 148 women (65 percent of them white, 14 percent Asian and 13 percent black) with a mean age of 48 years. The mean disease duration in the group was 16 years, and 45 percent of the patients were on glucocorticoids.

Researchers found that 32 percent of women met the criteria for obesity as measured by FMI, and 30 percent as measured by BMI. For both definitions, obesity was associated with worse patient-reported outcomes: higher disease activity and higher levels of depressive symptoms, more pain, and more fatigue.

Overall, these findings support obesity as an independent risk factor for worse outcomes in lupus women.

“Our findings have important clinical implications because the PROs we measured, particularly pain and fatigue, are known to have profound effects on quality of life and remain a major area of unmet need for people with lupus,” said Patterson.

“The relationship we observed between excess fat and worse outcomes underscores the need for lifestyle interventions targeting lupus patients who are overweight. More research is needed in this area, but it is possible that such interventions will reduce both cardiovascular risk and the severity of debilitating symptoms common in this disease,” she concluded. “In the meantime, I hope this work sparks greater interest and motivation among rheumatologists to address weight management with their lupus patients.”