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Observational cohort study to investigate the unmet need and time waiting for referral for specialist opinion in adult asthma in England (UNTWIST asthma)
  1. John D Blakey1,2,
  2. Alicia Gayle3,
  3. Mariel G Slater4,
  4. Gareth H Jones5,
  5. Michael Baldwin6
  1. 1 Respiratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
  2. 2 University of Liverpool Department of Health Services Research, Liverpool, UK
  3. 3 Market Access, Boehringer Ingelheim Ltd, Bracknell, UK
  4. 4 Medical Affairs, Boehringer Ingelheim Ltd, Bracknell, UK
  5. 5 Department of Respiratory Medicine, Royal Liverpool and Broadgreen Hospitals NHS Trust, Liverpool, UK
  6. 6 TA Respiratory/Biosimilars, Boehringer Ingelheim International GmbH, Ingelheim am Rhein, Germany
  1. Correspondence to Dr Mariel G Slater; mariel.slater{at}


Objectives This study aimed to estimate how many patients with asthma in England met the referral eligibility criteria using national asthma guidelines, identify what proportion were referred and determine the average waiting time to referral.

Design This is an observational cohort study.

Setting/Data sources Routinely collected healthcare data were provided by Clinical Practice Research Datalink records and Hospital Episode Statistics records from January 2007 to December 2015.

Participants Patients with asthma aged 18–80 years participated in this study.

Main outcome measures Eligibility for referral by the British Thoracic Society/Scottish Intercollegiate Guidelines Network (BTS/SIGN) 2016 guidelines, determined after a 3-month pharmacological therapy exposure assessment, was classed by either ‘high-dose therapies’, ‘continuous or frequent use of oral steroids’ or ‘incident eligibility’ during follow-up (continuous oral corticosteroids for more than 3 months, or ≥800 µg/day inhaled corticosteroids/long-acting β2-agonist (or three controllers) and ≥2 asthma attacks/year).

Results From the final cohort (n=23293), 19837 patients were eligible for specialist referral during follow-up based on the BTS/SIGN guideline recommendations. Among eligible patients without any previously recorded referral, 4% were referred during follow-up, with a median waiting time of 880 days (IQR=1428 days) between eligibility and referral.

Conclusions A large number of patients with asthma were eligible for specialist referral, of which a small proportion were referred, and many experienced a long waiting time before referral. The results indicate a major unmet need in asthma referral, which is a potential source of preventable harm and are likely to have implications regarding how services are organised to address this unmet need.

  • asthma
  • referral
  • specialist
  • observational
  • wait time

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  • Contributors AG, MGS, MB, JDB and GHJ planned/conducted the study. AG carried out the statistical analysis. All authors had full access to all the data in the study and contributed to the interpretation of results, revisions of the manuscript and approved the final manuscript. JB is the guarantor. Ishmam Nawar at MediTech Media provided editorial assistance in the development of the manuscript, funded by Boehringer Ingelheim.

  • Funding This study was funded by Boehringer Ingelheim. No restrictions have been placed on the choice of analyses or the interpretation of the results. All authors contributed to the study design and interpretation of data and were involved in the decision to submit the paper for publication. AG conducted data collection and analysis. The manuscript was written by Ishmam Nawar at MediTech Media under the conceptual direction of authors, funded by Boehringer Ingelheim.

  • Disclaimer JDB (lead author) affirms that the manuscript is an honest, accurate and transparent account of the study and no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

  • Competing interests In the last three years, JDB has received personal fees and non-financial support from Napp, AstraZeneca and Boehringer Ingelheim, and personal fees from Novartis and Teva, outside the submitted work. GHJ has received personal fees from Pfizer, AstraZeneca, Chiesi and GlaxoSmithKline, and non-financial support from Napp, outside the submitted work. AG was an employee of Boehringer Ingelheim at the time the study was carried out. MGS and MB are employees of Boehringer Ingelheim.

  • Patient consent for publication Not required.

  • Ethics approval These analyses were performed in accordance with relevant regulations/guidelines. This study was reviewed and approved by the Independent Scientific Advisory Committee for Medicines and Healthcare products Regulatory Agency database research (Ref: 17_026R) and an internal scientific committee of the study sponsor. As this was a non-interventional study using anonymised data, no patient consent was necessary.

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

  • Data availability statement Data are available on request from the CPRD. Their provision requires the purchase of a licence, and our licence does not permit us to make them publicly available to all. We used data from the version collected in April 2017 and have clearly specified the data selected in our Methods section. To allow identical data to be obtained by others, via the purchase of a license, we will provide the code lists on request. Licences are available from the CPRD ( The Clinical Practice Research Datalink Group, The Medicines and Healthcare products Regulatory Agency, 5th Floor, 151 Buckingham Palace Road, Victoria, London SW1 W 9SZ.

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