To examine the published scientific literature regarding the prevalence of sarcopenia in ageing people, with different diagnostic criteria, using bioelectrical impedance analysis (BIA) to assess the muscle mass.

A systematic review was carried out following the PRISMA Statement. Three online databases were searched during May 2015 using pre-defined search terms. Prevalence studies of sarcopenia in well-defined populations of adults ≥50 years, using BIA to measure body composition, were selected.

Fifty-four articles were eligible for a full reading, and after a second round of exclusions a total of twelve studies met all the inclusion criteria. Eight were carried out in community-dwelling elderly people, two in nursing home residents, one in a convalescence and rehabilitation unit and one in hospitalized population. Five studies of sarcopenia's prevalence according to EWGSOP criteria were found, and in four of them the prevalence was higher in men. Prevalence of sarcopenia was higher in convalescence and rehabilitation units (77.6%), followed by elderly people living in nursing homes (32.8%).

Sarcopenia is highly prevalent in older individuals, especially in rehabilitation units. All the studies of prevalence carried out before the current sarcopenia consensus are studies to establish cutoff points of low muscle mass but they do not reflect sarcopenia's prevalence because they do not take into account muscle function.