title: Factors Associated With Attrition in Randomized Controlled Trials of Vocal Rehabilitation: Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  This study aimed to determine the dropout rates and the reasons for dropout in randomized clinical trials of vocal rehabilitation.
  
  
  METHODS
  This study used systematic review and meta-analysis (CRD42013003807).
  
  
  METHODS
  We included randomized controlled trials for voice disorders. In June 2015, we searched the following databases: MEDLINE, EMBASE, Cochrane, Clinical Trials, and AJSLP. The titles and abstracts or full texts of articles were independently analyzed by two reviewers. Study quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) scale. Our initial research base included more than 8491 articles.
  
  
  RESULTS
  A total of 51 articles were obtained using our eligibility criteria. The low-quality studies evaluated had higher dropout rates (odds ratio: 3.3, 95% confidence interval: 1.04-12.9). Studies with healthy patients (45%) or vocal training versus no training (25%) also had higher dropout rates. Methodological issues seemed to have a greater influence on the dropout rates of the studies included in the co-occurrence matrix.
  
  
  CONCLUSIONS
  Dropout rates of approximately 15% occur in randomized clinical trials of speech therapy when assessed by the Grading of Recommendations Assessment, Development and Evaluation. Studies with lower methodological quality had higher patient loss rates. Methodological and clinical reasons accounted for the highest dropout rates in the studies included in this meta-analysis.
authors.affiliation: UCSF/USA, UFCSPA/Brazil, Porto Alegre, Rio Grande do Sul, Brazil. Electronic address: taiscmoreira@gmail.com.
authors.forename: Tais
authors.initials: T
authors.lastname: de Campos Moreira
authors.affiliation: UFCSPA/Brazil, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Camila Dalbosco
authors.initials: CD
authors.lastname: Gadenz
authors.affiliation: UNIFESP/Brazil, São Paulo/São Paulo, Brazil.
authors.forename: Dirce Maria
authors.initials: DM
authors.lastname: Capobianco
authors.affiliation: Duke University, Durham, North Carolina.
authors.forename: Luciana Rizzieri
authors.initials: LR
authors.lastname: Figueiró
authors.affiliation: UFCSPA/Brazil, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Maristela
authors.initials: M
authors.lastname: Ferigolo
authors.affiliation: Duke University, Durham, North Carolina.
authors.forename: Joao Ricardo N
authors.initials: JR
authors.lastname: Vissoci
authors.affiliation: UFCSPA/Brazil, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Helena M T
authors.initials: HM
authors.lastname: Barros
authors.affiliation: UFCSPA/Brazil, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Mauriceia
authors.initials: M
authors.lastname: Cassol
authors.affiliation: Duke University, Durham, North Carolina.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pietrobon
mesh_terms: D006801:Humans; D010352:Patient Dropouts; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012107:Research Design; D013070:Speech Therapy / Q000379:methods*; D016896:Treatment Outcome; D014832:Voice Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000534:rehabilitation*; D014833:Voice Quality; D014834:Voice Training
keywords: Attrition rate; Dropout; Rehabilitation; Voice; Voice disorders