BACKGROUND: Rheumatoid arthritis (RA) has an indirect effect on body composition. Body mass index (BMI) is not a valid predictor of body fat in RA patients. OBJECTIVE: To evaluate the accuracy of BMI in identifying obesity diagnosed according to dual energy X-ray absorptiometry (DXA) in well-controlled RA patients. METHODS: An observational, cross-sectional, descriptive, analytical study. We used 3 different cutoffs for obesity as determined by DXA: >35% total fat, >40% total fat, and >35% central fat mass (central obesity). RESULTS: One hundred one patients were included. We found that 35% total fat corresponded to a BMI of 24kg/m2, with a sensitivity of 90% and specificity of 75% (area under the curve [AUC] 0.917); 40% total fat to a BMI of 25kg/m2, with a sensitivity of 86% and specificity of 39% (AUC 0.822); and 35% central fat mass to a BMI of 22kg/m2, with a sensitivity of 97% and specificity of 84% (AUC 0.951). CONCLUSION: Obesity according to DXA was underdiagnosed when the classic BMI cutoffs were used in well-controlled RA patients.
BACKGROUND:Rheumatoid arthritis (RA) has an indirect effect on body composition. Body mass index (BMI) is not a valid predictor of body fat in RApatients. OBJECTIVE: To evaluate the accuracy of BMI in identifying obesity diagnosed according to dual energy X-ray absorptiometry (DXA) in well-controlled RApatients. METHODS: An observational, cross-sectional, descriptive, analytical study. We used 3 different cutoffs for obesity as determined by DXA: >35% total fat, >40% total fat, and >35% central fat mass (central obesity). RESULTS: One hundred one patients were included. We found that 35% total fat corresponded to a BMI of 24kg/m2, with a sensitivity of 90% and specificity of 75% (area under the curve [AUC] 0.917); 40% total fat to a BMI of 25kg/m2, with a sensitivity of 86% and specificity of 39% (AUC 0.822); and 35% central fat mass to a BMI of 22kg/m2, with a sensitivity of 97% and specificity of 84% (AUC 0.951). CONCLUSION:Obesity according to DXA was underdiagnosed when the classic BMI cutoffs were used in well-controlled RApatients.
Keywords:
Absorciometría dual por rayos X; Artritis reumatoide; Body mass index; Diagnosis; Diagnóstico; Dual energy X-ray absorptiometry; Obesidad; Obesity; Rheumatoid arthritis; Índice de masa corporal
Authors: David Monasor-Ortolá; Jose Antonio Quesada-Rico; Ana Pilar Nso-Roca; Mercedes Rizo-Baeza; Ernesto Cortés-Castell; Asier Martínez-Segura; Francisco Sánchez-Ferrer Journal: Int J Environ Res Public Health Date: 2021-11-18 Impact factor: 3.390