Prevalence of sarcopenic obesity: comparison of different diagnostic criteria and exploration of optimal screening methods.

Background And Aims: Despite concerns on the adverse health outcomes of sarcopenic obesity (SO), exploration regarding the applicability of different diagnostic criteria and the optimal screening methods is still lacking. This study aims to compare the prevalence and diagnostic agreement of SO under four diagnostic criteria in Chongming, Shanghai, China and assess the diagnostic value of nine screening methods for SO.

Methods: The study population included older people aged ≥ 65 years. The Asian Working Group for Sarcopenia-2019 (AWGS-2019) was used to diagnose sarcopenia. Obesity was defined using percentage of body fat (PBF), percent of body fat exceeding the 60th percentile (60% PBF), body mass index (BMI) and waist circumference (WC). The four diagnostic criteria for SO were AWGS + PBF, AWGS + 60% PBF, AWGS + BMI and AWGS + WC. Nine screening methods were the sarcopenia questionnaire [the questionnaire with five items to screen for sarcopenia (SARC-F), the addition of calf circumference to the SARC-F (SARC-CalF), and the addition of elderly age and BMI to the SARC-F (SARC-F + EBM)] combined with commonly used obesity indicators. Cohen's kappa compared agreement between diagnostic criteria, whilst sensitivity, specificity, receiver operating characteristics (ROC) and area under the ROC curve (AUC) compared the diagnostic value of nine screening methods.

Results: A total of 1407 older people were enrolled. The prevalence of SO ranged from 0.3 to 9.9%. The highest agreement between AWGS + 60% PBF and AWGS + PBF. When the AWGS + PBF was used as the 'gold standard' (due to its high agreement and high prevalence), SARC-CalF + PBF had the highest AUC value, and SARC-F + BMI had the highest sensitivity. The recommended cut-off values for SARC-F + BMI are SARC-F ≥ 1 score and BMI ≥ 19.845 kg/m², and the recommended cut-off values for SARC-CalF + PBF are SARC-CalF ≥ 5 score and PBF ≥ 34.55%.

Conclusion: The prevalence of SO varied greatly amongst the four diagnostic criteria. AWGS + PBF is recommended for diagnosing SO in older people. SARC-F + BMI and SARC-CalF + PBF can be used as screening methods for SO.