Severe weight loss in early RA linked to increased mortality risk
medwireNews: Women with rheumatoid arthritis (RA) who experience severe weight loss early in the disease course have a higher risk for subsequent mortality than those who maintain a stable weight, researchers report.
Jeffrey Sparks (Brigham and Women’s Hospital, Boston, Massachusetts, USA) and study co-authors analyzed data from 902 women with RA and 7884 matched controls in the Nurses’ Health Study, finding that 41.1% of the RA patients and 29.2% of controls died over a mean follow-up of 17.0 years and 18.4 years, respectively.
They categorized participants, based on weight change between the period 2–4 years before and 2–4 years after disease diagnosis, into stable weight (change of ≤10 lb), and mild (loss or gain of >10–20 lb), moderate (loss or gain of >20–30 lb), or severe (loss or gain of >30 lb) weight change. Controls were grouped based on weight change over a comparable timeframe.
“We studied weight change during the period around the time of the RA diagnosis, because weight change during this period is more likely to be related to intrinsic disease processes rather than general aging processes,” explain Sparks and colleagues.
They found that RA patients who experienced severe weight loss had more than double the risk for mortality than those who maintained a stable weight around the time of diagnosis, with a hazard ratio (HR) of 2.78 after adjustment for factors including smoking, physical activity, and comorbidities, and a HR of 2.71 after additional adjustment for markers of disease severity.
These findings suggest that RA severity factors of serologic status, rheumatoid nodules, and radiographic erosions, “did not explain the increased risk,” say the researchers.
Severe weight loss versus stable weight was also associated with an attenuated, but still statistically significant, increased risk for mortality among the women without RA (adjusted HR=2.16).
In contrast to the results of some previous studies, there was no significant attenuation in mortality risk among RA patients and controls who experienced severe weight gain compared with those who maintained a stable weight (adjusted HR=1.45 and 1.19, respectively), which provides “evidence against an RA-specific obesity paradox for mortality,” report the researchers in Arthritis & Rheumatology.
They note that although the HR of 1.45 for severe weight gain “may suggest a modestly increased mortality risk in the RA cohort, the confidence interval was wide and was not statistically significant.”
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