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Gaps in the evidence for treatment decisions in cystic fibrosis: a systematic review
  1. Nicola Jane Rowbotham1,
  2. Sherie Smith1,
  3. Andrew P Prayle1,
  4. Karen A Robinson2,
  5. Alan Robert Smyth1
  1. 1 Evidence Based Child Health Group, Division of Child Health, Obstetrics and Gynaecology, University of Nottingham, Nottingham, UK
  2. 2 Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
  1. Correspondence to Professor Alan Robert Smyth, Division of Child Health, Obstetrics and Gynaecology, Nottingham NG7 2UH, UK; alan.smyth{at}


Introduction Cystic fibrosis (CF) is a multisystem disorder. Treatment is complex and evidence for treatment decisions may be absent. Characterising gaps in the research evidence will highlight treatment uncertainties and help prioritise research questions. We systematically identified the evidence gaps for treatment decisions in CF.

Methods We searched for systematic reviews and guidelines on treatment interventions in CF. Two researchers identified eligible reviews with arbitration from a third. Using a structured framework, we extracted and characterised evidence gaps.

Results There were 73 reviews and 21 guidelines that met our inclusion criteria. From these, we identified 148 evidence gaps across a range of treatment areas. We found 111 evidence gaps through systematic reviews and a further 37 from guidelines. The reason for an evidence gap could only be reliably characterised for systematic reviews. In most cases, there was more than one explanation—most commonly few or no trials (97/111 evidence gaps). Other important factors leading to evidence gaps were small sample size (49/111), inadequate duration of follow-up (38/111) or intervention (37/111) and factors relating to outcomes (35/111). Evidence gaps from both systematic reviews and guidelines fell into the following categories: Respiratory (91); Gastrointestinal (20); PhysiotherapyandExercise (16); Musculoskeletal (6); Endocrine (4); Basic defect of CF (8); Psychosocial (2); Ears, Nose and Throat (1).

Conclusions We have compiled an up-to-date list of treatment uncertainties in CF and the reasons for these uncertainties. These can be used as a resource to aid researchers and funders when planning future trials.

PROSPERO registration number Pre-results; CRD42015030111.

  • cystic fibrosis

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  • Contributors NJR, SS, ARS and KAR contributed to the study design. Data extraction and analysis were carried out by NJR and SS with advice from ARS. APP provided the source code and produced the interactive Prayle plot. All authors were involved in the preparation of the manuscript.

  • Funding This work was supported by a CF Trust Venture and Innovation Award (VIA025). NJR is an NIHR academic Clinical Fellow. SS is a Cochrane Systematic Reviewer. APP is an NIHR Academic Clinical Lecturer.

  • Competing interests Outside the submitted work: NJR reports non-financial support from Teva. ARS reports personal fees from Vertex, PTC, Roche, TEVA and Gilead. In addition, ARS has a patent Application No. 14737297.3 (in Europe) Biomarkers for Pseudomonas aeruginosa for The University of Nottingham pending and has taken part in clinical trials sponsored by Vertex, Raptor, Insmed, Pharmaxis and Boehringer Ingelheim.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Authors plan to make data available within 1 year of publishing this article via an online repository or on reasonable application.

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