Obesity in rheumatic diseases: A modifiable target for improving outcomes?
medwireNews: Research presented at the 2017 ACR/ARHP Annual Meeting in San Diego, California, USA, highlighted the adverse effects of obesity on clinical and patient-reported outcomes in various rheumatic disorders, including axial spondyloarthropathy (axSpA), systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA). In this report, we outline the main findings of four studies addressing this issue.
Disease outcomes and QoL in axSpA patients
On behalf of her co-authors, Gillian Fitzgerald, from St James’s Hospital in Dublin, Ireland, presented their research into the impact of obesity on outcomes in 683 patients with axSpA drawn from the Ankylosing Spondylitis Registry of Ireland.
Of these, 38.9% were categorized as overweight and 28.4% as obese, based on BMI values of 25.0–29.9 kg/m2 and at least 30.0 kg/m2, respectively, while 31.6% were considered normal weight, with a BMI below 25 kg/m2.
Patients who were obese had significantly higher scores than either overweight or normal-weight participants on the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and BAS Metrology Index (BASMI), indicating worse disease activity and spinal mobility, respectively.
Obese patients also had significantly poorer functional status, as shown by the BAS Functional Index (BASFI) and Health Assessment Questionnaire (HAQ), and worse scores on the AS Quality of Life Scale (ASQoL) as well.
And in multivariable analysis obesity remained significantly associated with all these measures.
The researchers conclude in their poster that “[r]heumatologists need to be aware of the negative effects of being obese with axSpA,” and include weight-reduction strategies as part of the treatment plan.
Speaking to medwireNews, Fitzgerald pointed out that the findings were similar regardless of whether patients were receiving biologic treatment or not.
And she highlighted the importance of not only a daily exercise program for all axSpA patients, but also diet control. Fitzgerald said that although they had not specifically looked at diet in their study, in the general population diet has been shown to be “nearly more important” than exercise for weight control.
“A multidisciplinary strategy that includes the clinician and a physiotherapist who can put in place a safe and monitored exercise program would be very beneficial for these patients, as would having access to good nutritional advice,” she commented.
Obese SLE patients report worse outcomes
The analysis included 148 participants of the Arthritis Body Composition and Disability study, all women with SLE, for whom the researchers calculated not only BMI but also the fat mass index (FMI). This determines total fat – as measured by whole dual X-ray absorptiometry – adjusted for height.
Thirty-two percent of the sample were classed as obese according to an FMI of at least 13 kg/m2, and 30% due to a BMI of 30 kg/m2 or higher.
Sarah Patterson (University of California San Francisco, USA) and co-investigators found that obesity as defined by FMI was independently and significantly associated with higher levels of disease activity and depressive symptoms, as assessed by the patient-reported Systemic Lupus Activity Questionnaire (SLAQ) and Center for Epidemiologic Studies Depression Scale (CES-D), respectively.
There was also a significant association with more pain and fatigue, both reported using the Short Form 36 Health Survey (SF-36) via the Pain and Vitality subscales, respectively.
As outlined in the presented poster, the findings were similar when obesity was defined by BMI.
“Our findings underscore the need for lifestyle interventions targeting lupus patients who are overweight given the potential to reduce both cardiovascular risk and the severity of debilitating symptoms common in this disease,” the study authors conclude.
Obesity negatively impacts treatment response, synovitis in RA patients
In the first of two studies in patients with RA, lead author Elena Nikiphorou (King's College London, UK) and colleagues used data from 2420 participants of the Early RA Study (ERAS) and the Early RA Network (ERAN) cohorts, of whom 21.3% were obese (BMI≥30 kg/m2).
After accounting for demographic, disease, and clinical factors, obesity was associated with a significantly reduced likelihood of achieving remission or low disease activity, but with an increased probability of higher disability (HAQ, ≥1 vs <1), at corresponding odds ratios of 0.71, 0.69, and 1.63, the study authors reported in a poster session.
Nikiphorou emphasized in a press release: “Based on our data, there is a strong argument to include obesity screening and management as a central part of all treatment plans for RA patients.”
The second study – presented by Stefano Alivernini (Catholic University of the Sacred Heart, Rome, Italy) in an oral session – included 125 RA patients, 57 of whom were DMARD-naïve at inclusion, while 43 had an inadequate respond to methotrexate and 25 were in stable clinical remission, defined as a disease activity score below 1.6. Just under two-thirds of patients in each group were overweight or obese according to their BMI.
In the subgroup of treatment-naïve participants, follicular synovitis was observed in a significantly higher proportion of those with a BMI of at least 30 kg/m2 than normal-weight patients (BMI<25 kg/m2), at rates of 78.6% versus 39.1%.
And once these patients initiated RA therapy, those who were overweight or obese had a significantly worse clinical response to a treat-to-target approach relative to patients with a normal BMI at the 6 and 12 months follow-ups. Alivernini noted that the findings were the same regardless of the type of synovial inflammation (follicular or diffuse).
The effects of obesity were also evident among patients in stable remission. On the whole they had lower disease activity and lower levels of inflammatory markers than treatment-naïve participants, but overweight and obese participants in remission showed a higher degree of residual synovitis than their normal-weight counterparts.
“Body weight is one of the few modifiable risk factors for [RA] and should be controlled in RA patients in every phase of the disease course from disease onset to stable clinical remission achievement,” Alivernini concluded.
Speaking to medwireNews, Nikiphorou highlighted the “vicious circle” faced by obese RA patients – “you are obese, you walk less, which leads to more inflammation and higher disability, which in turn leads to a more sedentary lifestyle, and more obesity.”
She said that one of the key challenges is identifying the best strategy for these patients, and in line with Fitzgerald’s comments, postulated that “the best approach would revolve around a combination of dietary and lifestyle interventions as well as an exercise regime that was suited to the individual and education.”
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