title: Effectiveness of neuromuscular electrical stimulation for the rehabilitation of moderate-to-severe COPD: a meta-analysis.
abstract: OBJECTIVE
  Patients with COPD often experience skeletal muscle dysfunction. For those who are unable or unwilling to undertake physical training, neuromuscular electrical stimulation (NMES) may provide an alternative method of rehabilitation. The purpose of this meta-analysis was to investigate the controversial topic of whether this therapy is effective in patients with moderate-to-severe COPD.
  
  
  METHODS
  We pooled data from nine trials published between January 9, 2002 and January 4, 2016 across PubMed, Embase, Cochrane Central Register of Controlled Trials, Google Scholar, and relevant websites for randomized controlled trials. In these trials, patients with moderate-to-severe COPD were randomly allocated to receive NMES. Primary outcomes were quadricep strength and exercise capacity. The secondary outcome was health-related quality of life.
  
  
  RESULTS
  We extracted data from 276 patients. NMES contributed to statistically improved quadricep strength (standardized mean difference 1.12, 95% confidence interval [CI] 0.64-1.59,I2=54%;P<0.00001) and exercise capacity, including longer exercise distance (weighted mean difference 51.53, 95% CI 20.13-82.93,I2=90%;P=0.001), and longer exercise endurance (standardized mean difference 1.11, 95% CI 0.14-2.08,I2=85%;P=0.02). There was no significant difference in St George's Respiratory Questionnaire scores (weighted mean difference -0.07, 95% CI -2.44 to 2.30,I2=56%;P=0.95).
  
  
  CONCLUSIONS
  NMES appears an effectual means of enhancing quadricep strength and exercise capacity in moderate-to-severe COPD patients. Further research is demanded to clarify its effect on other outcomes and determine the optimal parameters for an NMES program.
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Rong-Chang
authors.initials: RC
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Li
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Bing-Peng
authors.initials: BP
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Wei-Liang
authors.initials: WL
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Zi-Qing
authors.initials: ZQ
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Ya-Ting
authors.initials: YT
authors.lastname: Huo
authors.affiliation: Zhujiang Hospital of Southern Medical University, Guangzhou, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University.
authors.forename: Lu-Qian
authors.initials: LQ
authors.lastname: Zhou
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D053580:Muscle Strength; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology / Q000534:rehabilitation*; D052097:Quadriceps Muscle / Q000294:innervation*; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D020127:Recovery of Function; D016896:Treatment Outcome
keywords: chronic obstructive pulmonary disease; exercise capacity; neuromuscular electrical stimulation; quadriceps muscle strength