This, and other studies, suggest an association between obesity and seronegative RA, but not with ACPA-positive RA. Could it be that fat poses difficulty to proper assessment of whether a tender joint is truly swollen/inflamed, resulting in more “benefit-of-doubt” positive diagnoses? Ultrasound would come in handy here to sharpen the clinician’s acumen.
Study finds increased CRP, ESR levels in obese women with RA is related to fat mass rather than disease activity
Not recognising this may lead to unnecessary and even harmful over-treatment of obese RA patients. It is important to assess the disease activity through various outcome measures (clinical and patient-reported), rather than blindly treating lab numbers.
Association of High Body Mass Index With Decreased Treatment Response to Combination Therapy in Recent‐Onset Rheumatoid Arthritis Patients
Obesity and reduction of the response rate to anti–tumor necrosis factor α in rheumatoid arthritis: An approach to a personalized medicine
Weight Loss, the Obesity Paradox, and the Risk of Death in Rheumatoid Arthritis
Things aren’t great at the other end of the spectrum for RA patients either. All cause mortality is higher in those who suffer weight loss and sarcopaenia, probably reflective of heightened chronic inflammation and inadequate disease control.