Systematic review on the use of bioelectrical impedance analysis in chronic obstructive pulmonary disease

Abstract

Background: Bioelectrical impedance analysis (BIA) is a widely used method for evaluating body composition in patients with COPD, by means of specific BIA predictive equations. Alternatively, raw BIA variables are receiving increasing interest in clinical practice, due to their ability to identify malnutrition. Aims and objectives: To investigate the use of BIA in COPD, according to the Transparent Reporting of Systematic Reviews and Meta-Analysis (PRISMA) criteria. Methods: Original studies published between 1985 to 2016 were retrieved using two different databases (PubMed and SCOPUS). Results: Eighty-seven original papers were finally included. Four COPD-specific BIA equations to predict fat-free mass (FFM) were found. These were used in 35 papers, while non-specific BIA equations in 9 and those provided by the manufacturers in 13. Twenty-three papers did not specify which equation was used (figure). FFM was evaluated by BIA in 73 papers, FFMI in 61 and appendicular skeletal muscle mass (ASMM) in 5. Only eight papers provided data on raw BIA variables (in particular, 3 papers on phase angle and 1 paper on multi-frequency impedance ratio). Finally, according to different diagnostic criteria, BIA derived FFM, FFMI or ASMM were used for identifying the occurrence of reduced skeletal muscle mass (6 papers), cachexia (7 papers) or sarcopenia (4 papers). Conclusions: Most studies did not used COPD-specific BIA equations to predict FFM in COPD patients. In spite of the increasing interest in the clinical setting, few data are available on raw BIA variables in COPD. BIA may be useful for diagnosing nutritional phenotypes such as cachexia or sarcopenia in COPD patients.