[Validation of cut points of skeletal muscle mass index for identifying sarcopenia in Chilean older people].
OBJECTIVE
To estimate and validate cut-off points of skeletal muscle mass index (SMI) in Chilean population, for using in an algorithm for a diagnosis of sarcopenia developed by European Working Group on Sarcopenia in Older People (EWGSOP).


METHODS
Secondary analysis of Cross-sectional data in 440 Chilean older subjects to estimate cut-off points of SMI determined by DEXA and predicted by an anthropometric equation. Afterward a cross-sectional validation in a sample of 164 older people was performed. Anthropometric measures, self-reported health status, physical performance tests and DEXA were carried out. Decreased muscle strength was defined as handgrip strength <15 kg in women and <27 kg in male. Cut-off points of SMI were defined as values under 20th percentile for DEXA measures and estimated through ROC curves for the anthropometric model. Biological validity of the algorithm was tested by contrasting the diagnosis with physical performance tests and functionality.


RESULTS
Cut-off points of SMI obtained by DEXA were 7.19 kg/m² in men and 5.77 kg/m² in women and 7.45 kg/ m² and 5.88 kg/m², respectively for the predicted by the model. Sensibility and specificity of estimations vs DEXA measures were 80% and 92% in men and 77% and 89% in women.


CONCLUSIONS
We obtained cut-off points of SMI for DEXA and for a prediction equation for older adults Chilean, with good sensibility and specificity for the measurement by DEXA. It will allow to apply the EWGSOP algorithm to the early diagnosis of sarcopenia and to develop programs for prevention, delay or reversion this syndrome.
Instituto de Nutrición y Tecnología de los Alimentos (INTA) de la Universidad de Chile.. llera@inta.uchile.cl.
Lydia
L
Lera
Instituto de Nutrición y Tecnología de los Alimentos (INTA) de la Universidad de Chile.. bangel@inta.uchile.cl.
Bárbara
B
Ángel
Instituto de Nutrición y Tecnología de los Alimentos (INTA) de la Universidad de Chile.. hsanchez@inta.uchile.cl.
Hugo
H
Sánchez
CISA.. picrin@yaisypicrin.cl.
Yaisy
Y
Picrin
Instituto de Nutrición y Tecnología de los Alimentos (INTA) de la Universidad de Chile.. mjhormazabal@inta.cl.
María José
MJ
Hormazabal
Servicio de Salud y Educación, Municipalidad Huechuraba. Chile.. andyquiero@yahoo.es.
Andrea
A
Quiero
Instituto de Nutrición y Tecnología de los Alimentos (INTA) de la Universidad de Chile..
Cecilia
C
Albala
D015502:Absorptiometry, Photon; D000203:Activities of Daily Living; D000368:Aged; D000465:Algorithms; D000886:Anthropometry; D001835:Body Weight; D002677:Chile; D003430:Cross-Sectional Studies; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009929:Organ Size; D010809:Physical Fitness; D012372:ROC Curve; D015203:Reproducibility of Results; D055948:Sarcopenia / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity