Populations and outcome measures used in ongoing research in sarcopenia

Sarcopenia research may be hampered by the heterogeneity of populations and outcome measures used in clinical studies.

The aim of this study was to describe the inclusion/exclusion criteria and outcome measures used in ongoing research in sarcopenia.

All active intervention studies registered in the World Health Organization with the keyword sarcopenia were included. Study design, type of intervention, inclusion/exclusion criteria and outcome measures were registered and classified.

In April 2014, 151 studies on sarcopenia were registered in the WHO database. One hundred twenty-three were intervention studies. Most trials (94.3 %) were single centre and randomized (93.5 %), 51.2 % were double blind. Nutritional interventions (36.6 %), physical exercise (12.2 %) or both (19.5 %) were the most common interventions tested. Only 54.4 % included subjects of both genders, and 46.3 % had an upper age limit. Definition of the target populations was heterogeneous, with 57.7 % including healthy subjects and none using recent definitions of sarcopenia. Lifestyle and the degree of physical activity of subjects were not described or considered in most cases (79.7 %). Subjects with cardiovascular, neuropsychiatric or metabolic disorders and those with physical disability were usually excluded. Muscle mass and muscle strength were the primary outcome variables in 28.5 and 29.5 % of studies and physical performance in 19.5 %, but only 4.1 % used the three variables used the three of them. An additional 26.8 % used biological outcome variables. Little information and agreement existed in the way muscle and physical performance parameters were measured.

We found a large heterogeneity in trial design, definition of populations and outcome measures in present research.