Background Cachexia is a complex metabolic syndrome where unintentional weight loss is associated with chronic and malignant disease. Cachexia is associated with frailty, reduced quality of life and poor survival. Systematic identification of cachexia is lacking in practice though consensus definitions exist. The aim of the review is to describe the common tools and diagnostic criteria used to identify cachexia and to describe the healthcare settings in which screening and identification takes place.

Methods A systematic review of primary research studies published in English, 2008 to 2019, was conducted using MEDLINE, EMBASE, PsycINFO, and CINAHL.

Results Most studies were in cancer cachexia (84/98) and all were conducted in secondary care settings and five studies specifically in palliative care settings. Three studies assessed the risk of developing cachexia. All but one study used basic anthropometric measurements. Body composition was assessed in 68 studies where imaging techniques such as CT, MRI and BIA were used. Patients were also assessed for muscle strength, nutritional status, and inflammatory markers. Sixty-one studies used published diagnostic criteria and from 2011, under half of the cancer studies used the Fearon et al criteria (33/79 studies). In studies without a referenced criteria, a weight loss of 5% or more in the past 6 months was the most common inclusion criteria (13/37 studies).

Conclusions Cancer cachexia studies are increasingly adopting one consensus definition (Fearon et al) but not consistently. Few studies assessed cachexia risk, and none were conducted in primary care and few in palliative care settings. Most assessments were made in secondary care where active treatment for the associated disease is being undertaken. There is a need for detection of early markers of cachexia for those at risk coupled with the development of effective interventions for those with symptoms before the onset of refractory cachexia.