Prevalence of sarcopenia with different DXA indices in a population with high-risk obesity

Arnaiz Elena Gonzalez; Roza Lucia Gonzalez; Bachiller Beatriz Ramos; de la Maza Begona Pintor; David Barajas-Galindo; Rodriguez Isidoro Cano; Maria Ballesteros-Pomar

doi:10.1530/endoabs.81.EP303

Background: Sarcopenic obesity(SO) is an entity characterized by excess fat mass(FM) and low muscle mass (LMM) and function. Excess FM itself can lead to loss of muscle mass and function at any age. The combination of obesity and sarcopenia is a proven risk factor for frailty, comorbidities and mortality. New diagnostic criteria have been developed for this entity.

Aims: To assess the prevalence and severity of SO with different indices by DXA, in a group of individuals with high-risk obesity(HRO).

Methods: Prospective observational study of individuals with HRO(BMI>35 kg/m²) under follow-up by the obesity unit of the Complejo Asistencial Universitario de León. We collected demographic and anthropometric variables, body composition by dual energy X-ray absorptiometry(DXA, A Lunar Idxa; GE Healthcare, USA), hand grip strength(HGS) (Dynex®, DynExgrip) and physical performance with the timed up and go test(TUG). For the diagnosis of LMM with DXA, the equations appendicular skeletal muscle mass (ASM;lean mass arms and legs–bone mass arms and legs), appendicular skeletal muscle mass index (ASMI;ASM/height²), total skeletal mass index (TSMI; TSM/height², TSM:ASMx1.33), lower extremity skeletal muscle mass index (LESMI;LESM/height², LESM: lean mass legs–bone mass legs), appendicular lean mass index (ALMI;ALM/height², ALM: lean mass arms+ lean mass legs), skeletal muscle mass index (SMI;(ASM/weight)×100) and appendicular lean mass/weight (ALM/W;(ALM/weight)×100) were used.

Results: 124 subjects were included, 71.8% women, mean age 42.6 (SD 9.0) years, mean BMI 46(SD 5.2 kg/m²). The cut-off points and percentage of patients diagnosed with low strength, muscle mass and low physical performance are shown in the table below.


Diagnosis	Variables	Cut-off point	Female(n = 89)	Male(n = 35)	Total(n = 124)
Low muscle function	HGS	Female<16 kg.Male<27 kg	13.5%(n = 12)	17.1%(n = 6)	14.5%(n = 18)
	ASM	Female<15 kg.Male<20 kg	6.7%(n = 6)	2.9%(n = 1)	5.6%(n = 7)
	ASMI	Female<5.5 kg/m².Male<7 kg/m²	0%	5.7%(n = 2)	1.6%(n = 2)
	TSMI	Female<6 kg/m².Male<9 kg/m²	0%	2.9%(n = 1)	0.8%(n = 1)
LLM	LESMI	Female<3.7 kg/m², Male<5.1 kg/m²	0%	5.7%(n = 2)	1.6%(n = 2)
	ALMI	Female<5.45 kg/m².Male<7.26 kg/m²	0%	2.9%(n = 1)	0.8%(n = 1)
	SMI	Female<23.5%.Male<29.9%	100%(n = 89)	100%(n = 35)	100%(n = 124)
	ALM/W	Female<19.4%.Male<25.7%	83.1(n = 74)	97.1%(n = 34)	87.1%(n = 108)
Low physical performance	TUG>10 seconds&unix2794;Falling risk	21.4%(n = 19)
	31.4%(n = 11)
	24.2%(n = 30)

Severity	Low hand grip strength+Low physical performance	4.5%(n = 4)	11.4%(n = 4)	6.5%(n = 8)

Conclusions: The prevalence of low muscle mass with DXA varies according to the parameter and setting used. The adjustment of DXA-derived parameters for muscle mass, should be made according to the investigated cohort in terms of ethnicity, BMI, sex and age range. In this population, if we take into account the two criteria; muscle mass (with SMI) and muscle function (HGS), 13% of women and 17% of men will have sarcopenia, 4.5% and 11.4% severe sarcopenia respectively.

Endocrine Abstracts

EP303