(HealthDay)—Weight loss is a strong predictor of mortality in patients with rheumatoid arthritis (RA), according to a study published online June 26 in Arthritis & Rheumatology.

Joshua F. Baker, M.D., from the Philadelphia Veterans Affairs (VA) Medical Center, and colleagues identified 1,674 RA patients from the VA RA Registry and analyzed their medical records to identify body mass index (BMI) at each study visit, as well as date of death, if applicable.

The researchers noted 312 deaths over 9,183 person-years. After adjusting for demographics, comorbidities, BMI, smoking, and RA therapies, a loss in BMI of ≥1 kg/m² was associated with a greater risk of death (hazard ratio [HR], 1.99; P < 0.001). After adjusting for C-reactive protein and physical function, this association remained significant (HR 1.81; P < 0.001). The greatest risk of death was seen in patients with weight loss at an annualized rate of ≥3 kg/m² (HR, 2.49; P < 0.001). Low BMI (<20 kg/m²) in patients with a history of obesity (>30 kg/m²) was also associated with a greater risk of death (HR, 8.52; P < 0.001).

"These observations may explain the observed obesity paradox and do not support a biologically protective role of obesity," the authors write.

More information: Abstract
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