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Validation of a Predictive Score for HAST

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ClinicalTrials.gov Identifier: NCT03728595
Recruitment Status : Unknown
Verified March 2019 by The Leeds Teaching Hospitals NHS Trust.
Recruitment status was:  Recruiting
First Posted : November 2, 2018
Last Update Posted : April 1, 2019
Sponsor:
Information provided by (Responsible Party):
The Leeds Teaching Hospitals NHS Trust

Brief Summary:

Patients with chronic lung diseases travelling by plane often suffer with symptoms related to lower oxygen levels they are exposed to while flying.

Therefore, patients with respiratory conditions are routinely assessed to establish if they need supplemental oxygen in flight. A hypoxic altitude simulation test (HAST) is often part of this assessment and consists in having patients breathe a oxygen/nitrogen blend with a lower oxygen concentration compared to normal room air, simulating in-flight conditions. Oxygen levels are measured before and after the test through a blood sample (from the earlobe or an artery in the wrist) and with a finger probe. In-flight oxygen is required if the oxygen level in the blood is lower than 6.6 kPa. HASTs are time consuming, costly, and require a dedicated hospital appointment.

Using historical data, the Investigators developed scores based on capillary blood gas (blood sample from the earlobe), diagnosis and sex to predict the outcome of the HASTs. The Investigators validated the proposed scores in a separate historic cohort of patients and showed it had good concordance with the HASTs results.

In this study, the Investigators want to confirm prospectively if the score, based on blood results (venous and/or earlobe), can predict the outcome of the HASTs and therefore reduce the number of tests performed, travel time for patients, and costs for the NHS.

All patients, aged 18 or older, who are having a HAST for clinical purposes at the cardio-respiratory lab at Leeds Teaching Hospital NHS Trust will be invited to take part in the study. The Investigators will record diagnosis, results of HAST and previous spirometry from the medical notes, perform a spirometry if not done in the previous 12 months and collect a blood sample (one tube, 4 mls). With these data, the Investigators will calculate the score and assess its agreement with the outcome of the HAST.

Each participant's involvement in the study will last for approximately 90-120 minutes, which is the normal duration of a HAST.

The Investigators aim to include up to 280 subjects in the study.


Condition or disease Intervention/treatment
Chronic Respiratory Disease Hypoxia, Altitude COPD ILD Cystic Fibrosis Diagnostic Test: Venepuncture Diagnostic Test: Spirometry Diagnostic Test: Hypoxic altitude simulation test (HAST)

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Study Type : Observational
Estimated Enrollment : 280 participants
Observational Model: Case-Only
Time Perspective: Cross-Sectional
Official Title: A Predictive Score to Reduce the Use of Hypoxic-altitude Simulation Test (HAST) in Patients With Chronic Respiratory Disease Planning Air Travel - an External Validation Prospective Study
Actual Study Start Date : October 29, 2018
Estimated Primary Completion Date : July 2021
Estimated Study Completion Date : July 2021

Resource links provided by the National Library of Medicine


Group/Cohort Intervention/treatment
Patients with lung disease having HAST

Patients with chronic respiratory diseases who had a hypoxic altitude simulation test (HAST) for clinical purposes will have for research purposes:

  • venepuncture
  • spirometry.
Diagnostic Test: Venepuncture
A blood sample will be taken for serum bicarbonate

Diagnostic Test: Spirometry
All patients who have not had a spirometry in the 12 months prior to the HAST will undergo one on the day of the HAST.

Diagnostic Test: Hypoxic altitude simulation test (HAST)
HAST will be performed as per clinical team request. No changes to this intervention will be made for research purposes.




Primary Outcome Measures :
  1. ROC AUC for Model 1 (3*SaO2 - HCO3 - 4 if ILD - 4 if F -3 if COPD), and the relative sensitivity, specificity, positive and negative predictive value of the threshold identified for negative and positive HAST [ Time Frame: Up to 36 months ]
    The score based on Model 1 will be computed for all subjects and ROC curve analyses will be used to assess predictive value. Sensitivity, specificity, PPV and NPV for criteria previously identified in a historic cohort will be assessed.


Secondary Outcome Measures :
  1. ROC AUC for the simplified score (3*SpO2 - sHCO3 - 4 if ILD - 4 if F - 3 if COPD) [ Time Frame: Up to 36 months ]
    The simplified score will be computed for all subjects. ROC analyses will be performed and criteria to identify negative and positive HAST at 95%, 97.5% and 99% will be chosen.

  2. ROC AUC for Model 2, and Model 3 and for baseline pO2 and relative sensitivity, specificity, positive and negative predictive value of the previously identified thresholds. [ Time Frame: Up to 36 months ]
    The scores based on Model 2 and 3 will be computed for all subjects and ROC curve analyses will be used to assess predictive value. Sensitivity, specificity, PPV and NPV for criteria previously identified in a historic cohort will be assessed.


Other Outcome Measures:
  1. Negative and positive predictive value for the criteria chosen for the simplified score. [ Time Frame: Up to 36 months ]
    Criteria to maximise specificity for negative and positive HAST, respectively, will be chosen for the simplified score (Outcome 2). NPV and PPV for these criteria will be assessed.

  2. Identification of a new predictive model for the outcome of the HAST [ Time Frame: Up to 36 months ]
    Exploratory outcome: in case the previously identified models will not be validated, a new score will be developed using binary logistic regression analysis.

  3. Identification of a model to predict the flow-rate of oxygen required by patients who have a positive HAST. [ Time Frame: Up to 36 months ]
    During the HAST flow-rate of oxygen is titrated for patients with a positive outcome. As exploratory outcome we aim to develop a model to predict the final flow-rate required for patients who need oxygen in flight.


Biospecimen Retention:   Samples Without DNA

The Investigator will collect a blood sample to be processed for serum bicarbonate.

As processing a sample for serum bicarbonate is very susceptible to pre-analytical sources of error, samples will be analysed immediately after collection and then discarded.



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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Outpatient attending for a HAST at Leeds Teaching Hospital NHS Trust.
Criteria

Inclusion Criteria:

  • Age ≥18 years old (at the time of HAST)
  • Clinically stable
  • Hypoxic altitude simulation test, scheduled as part of the clinical care

Exclusion Criteria:

  • Inability to provide informed consent
  • Being part of a clinical trial, which would exclude patients who are taking part in other studies including observational studies.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03728595


Contacts
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Contact: Giulia Spoletini +44 01132069106 giulia.spoletini@nhs.net

Locations
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United Kingdom
St James's University Hospital, LTHT Recruiting
Leeds, West Yorkshire, United Kingdom, LS9 7TF
Contact: Giulia Spoletini    +44 01132069106    giulia.spoletini@nhs.net   
Sponsors and Collaborators
The Leeds Teaching Hospitals NHS Trust
Investigators
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Principal Investigator: Giulia Spoletini Leeds Teaching Hospital NHS Trust
Publications:

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Responsible Party: The Leeds Teaching Hospitals NHS Trust
ClinicalTrials.gov Identifier: NCT03728595    
Other Study ID Numbers: RM18/109075
247902 ( Other Identifier: IRAS )
18/WS/0117 ( Other Identifier: HRA/REC4 West of Scotland )
First Posted: November 2, 2018    Key Record Dates
Last Update Posted: April 1, 2019
Last Verified: March 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by The Leeds Teaching Hospitals NHS Trust:
gas exchange
in-flight hypoxia
hypoxic altitude simulation test
blood gas response
Additional relevant MeSH terms:
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Cystic Fibrosis
Respiration Disorders
Respiratory Tract Diseases
Altitude Sickness
Hypoxia
Pancreatic Diseases
Digestive System Diseases
Lung Diseases
Genetic Diseases, Inborn
Infant, Newborn, Diseases
Signs and Symptoms, Respiratory