The findings add further doubt to the validity of BMI as an accurate reflection of body fat (BF).
For the study, BMI and BF of 174 RA patients, 43 osteoarthritis (OA) patients and 82 healthy controls were compared.
Analysis showed that for a given BF, patients with RA had BMI levels 1.83kg/m2 lower than healthy controls. No significant differences were noted between patients with OA and healthy controls. The findings suggest that in patients with RA, a BMI cut-off point of 23kg/m2 should be considered for overweight and 28kg/m2 for obesity.
Reduction of these thresholds could lead to a further 10–15 per cent of people with RA being considered as overweight or obese, triggering closer scrutiny of cardiovascular risk factors in these patients.