NIV outcomes study
Research type
Research Study
Full title
Validation of a novel scoring system to predict inpatient mortality in exacerbations of Chronic Obstructive Pulmonary Disease requiring assisted ventilation with supplementary longitudinal assessment of quality of life and other patient-centred outcomes over one year.
IRAS ID
206694
Contact name
Stephen Bourke
Contact email
Sponsor organisation
Northumbria Healthcare NHS Foundation Trust
Duration of Study in the UK
2 years, 6 months, 4 days
Research summary
Summary of Research
Exacerbations of Chronic Obstructive Pulmonary Disease (COPD) account for 12% of UK hospital admissions. During an exacerbation, the lungs may be unable to adequately clear carbon dioxide (“waste gas”), and the blood becomes more acidic as it accumulates (termed respiratory acidaemia). Respiratory acidaemia has a high mortality and non-invasive ventilation (NIV) can be lifesaving. Clinicians currently lack a simple method to accurately predict outcome and often overestimate the risk of death resulting in under-use of NIV. We aim to assist decision making by developing a simple prognostic tool, and in turn challenge nihilism by providing objective outcome data. Our results can inform discussions about treatment options with patients/families resulting in increased use of NIV in those who will benefit, and enhanced palliative care provision in those who will not. A simple prognostic tool will have been derived by the time the proposed study commences.
Patients who survive an episode of respiratory acidaemia have high rates of readmission and can experience a poor quality of life. When assessing suitability for NIV, the clinician and patient are required to consider the likelihood of the patient recovering to a quality of life acceptable to them. However, we lack robust data on quality of life recovery and predictors of poor quality of life. Consequently this discussion is often ill-informed.
The proposed study has 2 facets that should be considered separately.
1) To validate the prognostic tool prospectively in at least 425 consecutively admitted patients both in the trust where it was developed and in other trusts to ensure it retains predictive accuracy (internal and external validation).
2) Consenting patients surviving to discharge will be undergo a 12-month longitudinal assessment of life after NIV. This will examine functional status, anxiety and depression, quality of life and willingness to undergo NIV again using validated questionnaires.
Summary of Results
In the UK, over 141,000 people are admitted into hospital due to Exacerbations of Chronic Obstructive Pulmonary Disease (ECOPD) annually. Around one-quarter of these patients develop life-threatening respiratory failure, with a build-up of carbon dioxide (waste gas). Treatment with non-invasive ventilation (NIV) halves the risk of dying. It involves wearing a tightly-fitted mask connected to a ventilator to help patients breathe out more carbon dioxide. Despite this, there is evidence of poor practice and prognostic pessimism. A clinical prediction tool could improve decision making regarding ventilation, but hitherto none was routinely used.
We previously derived the proposed NIV outcomes (NIVO) score by identifying the strongest independent predictors of survival in consecutive patients admitted with AECOPD requiring assisted ventilation in two hospitals serving differing populations. The current study assessed the performance of the NIVO score in 733 patients with confirmed COPD, and 111 patients with a clinical diagnosis of COPD (without lung function tests to confirm the diagnosis) across 10 NHS Trusts.
In-hospital mortality was 20.1%. The NIVO score comprises six simple categorised variables that can be easily scored at the bedside (1. extended Medical Research Council Dyspnoea score 1–4/5a/5b; 2. time from admission to acidaemia >12 h; 3. pH <7.25; 4. presence of atrial fibrillation; 5. Glasgow coma scale ⩽14; and 6. chest radiograph consolidation). NIVO offers very good prediction of in-hospital mortality (c-statistic= 0.79) across all levels of risk, and outperforms alternative tools. It also performs well in patients with a clinical diagnosis of unconfirmed COPD.
Potential uses include ensuring discussions with patients and their families about ventilation are informed by an accurate estimate of likely outcome, challenging pessimism and comparing risk-adjusted outcomes across centres. The NIVO score will be used in the next UK national NIV audit.
Before patients were discharged from hospital we asked if they would be interested in a year-long quality of life study to assess how well they recovered and what living with COPD is like. 272 patients agreed. The questions assessed COPD symptoms, ability to perform everyday activities, their levels of anxiety and depression, and a feel for their general overall health.
On average it took patients around 2 months to recover to their best quality of life after leaving hospital. Ventilation can be a difficult treatment to have, as it is sometimes noisy and can be uncomfortable. Despite this, nearly all our patients (96%) were glad they had been treated with a ventilator when asked. 95% of the patients would accept ventilation again in future if they need it. Most (72%) were happy with their overall quality of life. This proves to doctors and healthcare staff that ventilation is not too much of a burden for patients to manage and that we should encourage patients to use it when it is required.
Symptoms of anxiety and depression are common in people living with COPD. We found that over half (54%) of patients in NIVO had high anxiety levels and just under half (44%) had symptoms of depression. Having either anxiety or depression was linked with an increase the chance of being re-admitted to hospital over the year. This is important because treatments for both anxiety and depression have been shown to be helpful in patients living with COPD and may also reduce the number of times people need to be admitted with COPD.
REC name
North East - Tyne & Wear South Research Ethics Committee
REC reference
16/NE/0213
Date of REC Opinion
6 Jul 2016
REC opinion
Favourable Opinion