Abstract
Introduction Acute exacerbations of COPD (AECOPD) complicated by acute (acidaemic) hypercapnic respiratory failure (AHRF) requiring ventilation are common. When applied appropriately, ventilation substantially reduces mortality. Despite this, there is evidence of poor practice and prognostic pessimism. A clinical prediction tool could improve decision making regarding ventilation, but none is routinely used.
Methods Consecutive patients admitted with AECOPD and AHRF treated with assisted ventilation (principally non-invasive ventilation) were identified in two hospitals serving differing populations. Known and potential prognostic indices were identified a priori. A prediction tool for in-hospital death was derived using multivariable regression analysis. Prospective, external validation was performed in a temporally separate, geographically diverse 10-centre study. The trial methodology adhered to TRIPOD recommendations.
Results Derivation cohort, n=489, in-hospital mortality 25.4%; validation cohort, n=733, in-hospital mortality 20.1%. Using 6 simple categorised variables; extended Medical Research Council Dyspnoea score (eMRCD)1–4/5a/5b, time from admission to acidaemia >12 h, pH<7.25, presence of atrial fibrillation, Glasgow coma scale ≤14 and chest radiograph consolidation a simple scoring system with strong prediction of in-hospital mortality is achieved. The resultant NIVO score had area under the receiver operated curve of 0.79 and offers good calibration and discrimination across stratified risk groups in its validation cohort.
Discussion The NIVO score outperformed pre-specified comparator scores. It is validated in a generalisable cohort and works despite the heterogeneity inherent to both this patient group and this intervention. Potential applications include informing discussions with patients and their families, aiding treatment escalation decisions, challenging pessimism, and comparing risk-adjusted outcomes across centres.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflict of interest: Dr Tom Hartley reports grants from Philips Respironics and Pfizer OpenAIr during the conduct of the study.
Conflict of interest: Dr. Lane reports non-financial support from Chiesi, grants from Bright Northumbria, grants from The ResMed Foundation, outside the submitted work;.
Conflict of interest: Dr. Steer reports grants from Chiesi Ltd, outside the submitted work;.
Conflict of interest: Dr. Elliott reports personal fees from Philips, personal fees from Resmed, outside the submitted work;.
Conflict of interest: Dr. Sovani reports grants from Radiometer, other from Resmed, other from Philips Respironic, personal fees from Chiesi, personal fees from AstraZeneca, personal fees from Boehringer Ingelheim, outside the submitted work;.
Conflict of interest: Dr. Curtis has nothing to disclose.
Conflict of interest: Dr. Fuller has nothing to disclose.
Conflict of interest: Dr. Murphy reports grants and personal fees from Philips, grants and personal fees from ResMed, grants and personal fees from F&P, grants and personal fees from B&D Electromedical, personal fees from Santhera, grants from GSK, personal fees from Chiesi, outside the submitted work;.
Conflict of interest: Dr. Shrikrishna has nothing to disclose.
Conflict of interest: Dr. Lewis reports other from Respiratory Innovation Wales, outside the submitted work;.
Conflict of interest: Dr. ward has nothing to disclose.
Conflict of interest: Dr. Turnbull reports personal fees from Bayer, outside the submitted work.
Conflict of interest: NH reports unrestricted grants from Philips and Resmed outside the area of work commented on here with the funds held and managed by Guy's & St Thomas' NHS Foundation Trust; financial support from Philips for development of the MYOTRACE technology that has patent approved in Europe and US outside the area of work commented on here; personal fees for lecturing from Philips-Respironics, Philips, Resmed, Fisher-Paykel outside the area of work commented on here; NH is on the Pulmonary Research Advisory Board for Philips outside the area of work commented on here with the funds for this role held by Guy's & St Thomas' NHS Foundation Trust.
Conflict of interest: Prof. Bourke reports grants from Philips Respironics and Pfizer OpenAir during the conduct of the study; grants from GSK and ResMed, personal fees from Astra Zeneca, Chiesi, Novartis, Pfizer and ResMed, and non-financial support from Astra Zeneca, Boehringer Ingelheim, Chiesi and GSK, outside the submitted work.
- Received November 1, 2020.
- Accepted December 29, 2020.
- ©The authors 2021. For reproduction rights and permissions contact permissions{at}ersnet.org
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