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Sarcopenia after LSG

SS2 score is a reliable predictor of sarcopenia after LSG

Patients with a high risk of developing sarcopenia should “probably be identified early to intensify the nutritional and dietetic follow up.”

Researchers from France have reported that SS2 score - combining gender and skeletal muscle index (SMI) calculated from skeletal muscle cross-sectional area at the third lumbar vertebrae (SMA, cm2) - is a reliable tool for predicting the presence of sarcopenia one year after sleeve gastrectomy. The investigators concluded that SS2 can be used to can be used to target early intensification of nutritional and dietetic follow-up in this predicted high-risk population.

The paper, ‘Predictive score of sarcopenia occurrence one year after bariatric surgery in severely obese patients’, published in SOARD, sought to create a predictive score of sarcopenia from an observational prospective cohort of severely obese patients one year after sleeve gastrectomy.

The study included 184 severely obese patients who underwent sleeve gastrectomy between January 2013 and January 2014. The majority of patients were female (79%), the mean age was 42±0.9 years and the mean BMI was 43.2±0.5. Skeletal muscle cross-sectional area at the third lumbar vertebrae (SMA, cm2) was measured from the routinely performed computed tomography. The SMI was calculated as follows: SMA/height2 (cm2/m2). Sarcopenia was defined as an SMI<38.5 cm2/m2 for women and < 52.4 cm2/m2 for men. Measurements were performed at surgery and one year later and the interval between the two CT scan evaluations was 384±5 days. The researchers also compared the baseline clinico-biological parameters of sarcopenic and non-sarcopenic patients at one-year post-surgery.

Outcomes

The researcher found that the SS2 score was significantly higher than that of the SS1 score for the prediction of sarcopenia one year after sleeve gastrectomy (0.95±0.02 versus 0.90±0.02; p<0.01, Figure 1). The optimal cut-off for the SS2 score was 0.533 and predicted the presence of sarcopenia one year after sleeve gastrectomy with a sensitivity of 90% and a specificity of 91%, with a negative predictive value (NPV) of 95% and a good positive predictive value (PPV) of 83%.

Figure 1: ROC curves of SS2 and SS1 scores for the prediction of sarcopenia one year after sleeve gastrectomy. The diagonal line represents the detection achieved by chance alone (AUROC = 0.50); the ideal AUROC is 1.00. The SS1 score takes into account SMA [skeletal muscle cross-sectional area at the third lumbar vertebrae (cm2)] and gender. The SS2 score takes into account SMI [skeletal muscle index: SMA/height2 (cm2/m2)] and gender.

The authors noted that the prevalence of sarcopenia was 8% at surgery and increased to one third of patients one year after sleeve gastrectomy. Interestingly, more male patients presented with sarcopenia, had a lower initial BMI, a lower SMI at surgery, and a higher rate of initial sarcopenia than patients without sarcopenia. Unsurprisingly, all patients with sarcopenia at baseline presented sarcopenia after one year.

They reported that male gender independently and positively correlated with sarcopenia development (p<0.0001), and SMI independently and negatively correlated with sarcopenia development (p<0.0001).

Furthermore, the decrease of muscle mass significantly correlated with weight loss as the percentage of initial weight (<0.0001). However, the age of the patient was not an independent predictive factor of sarcopenia occurrence one year after surgery, although he authors state that this discrepancy is probably due to the young age of the patients in this study.

The researchers also noted that the impact of sarcopenia on long-term prognosis in patients with bariatric surgery is unknown, however they stressed that patients with a high risk of developing sarcopenia should “probably be identified early to intensify the nutritional and dietetic follow up.”

“The SS2 score should be used to select patients at risk of developing sarcopenia after bariatric surgery to intensify nutritional intervention,” the researchers conclude. “Further studies are necessary to validate this predictive score in an independent prospective external cohort and evaluate its long-term prognostic value.”

To access this paper, please click here

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