External Validation Of The Updated ADO Score In COPD Patients From The Birmingham COPD Cohort

Abstract

Background

Reviews suggest that the ADO score is the most discriminatory prognostic score for predicting mortality among chronic obstructive pulmonary disease (COPD) patients, but a full evaluation and external validation within primary care settings is critical before implementation.

Objectives

To validate the ADO score in prevalent and screen-detected primary care COPD cases at 3 years and at shorter time periods.

Patients and methods

One thousand eight hundred and ninety-two COPD cases were recruited between 2012 and 2014 from 71 United Kingdom general practices as part of the Birmingham COPD Cohort study. Cases were either on the practice COPD register or screen-detected. We validated the ADO score for predicting 3-year mortality with 1-year and 2-year mortality as secondary endpoints using discrimination (area-under-the-curve (AUC)) and calibration plots.

Results

One hundred and fifty-four deaths occurred within 3 years. The ADO score was discriminatory for predicting 3-year mortality (AUC= 0.74; 95% CI: 0.69–0.79). Similar performance was found for 1- (AUC= 0.73; 0.66–0.80) and 2-year mortality (0.72; 0.67–0.76). The ADO score showed reasonable calibration for predicting 3-year mortality (calibration slope 0.95; 0.70–1.19) but over-predicted in cases with higher predicted risks of mortality at 1 (0.79; 0.45–1.13) and 2-year (0.79; 0.57–1.01) mortality.

Discussion

The ADO score showed promising discrimination in predicting 3-year mortality in a primary care population including screen-detected cases. It may need to be recalibrated if it is used to provide risk predictions for 1- or 2-year mortality since, in these time-periods, over-prediction was evident, especially in cases with higher predicted mortality risks.

Keywords:

• pulmonary disease
• chronic obstructive
• mortality
• prognosis
• validation studies

Acknowledgments

We would like to acknowledge the GPs and patients for taking part in BLISS. We would also like to thank our patient advisory group and programme steering committee. We thank the Clinical Research network West Midlands at the University of Birmingham for recruiting the GPs. We thank Alexandra Enocson (University of Birmingham), Sue Jowett (University of Birmingham), Jen Marsh (University of Birmingham), Jon G Ayres (University of Birmingham), Sheila Greenfield (University of Birmingham), Stanley Siebert (University of Birmingham), Amanda Daley (Loughborough University), KK Cheng (University of Birmingham), Richard Riley (Keele University), Martin R Miller (University of Birmingham), Brendan G Cooper (University Hospitals Birmingham), and Kate Jolly (University of Birmingham) for their roles in BLISS. Richard Riley provided statistical advice. Martin R Miller, Robert Stockley (University Hospitals Birmingham), Brendan G Cooper, and Kate Jolly commented on the final draft. Finally, we would like to acknowledge all BLISS team members for facilitating the study and conducting the assessment visits.

Abbreviations

ADO, Age, dyspnoea, and obstruction score; AUC, area-under-the-curve; BLISS, Birmingham Lung Improvement Studies; BMI, body mass index; CITL, Calibration-in-the-large; COPD, chronic obstructive pulmonary disease; CI, confidence interval; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; mMRC, modified Medical Research Council.

Ethics Approval

The cohort received ethical approval from the National Research Ethics Service Committee West Midlands, Solihull (ref.: 11/WM/0304)

Data Availability

STATA code used for data manipulation and analyses can be provided upon request.

Disclaimer

The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The Birmingham COPD Cohort study is part of The Birmingham Lung Improvement StudieS – BLISS.

Author Contributions

All authors contributed to data analysis, drafting and revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Funding

This work was supported by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (grant number: RP–PG–0109–10061). NIHR had no involvement in the study design, the data collection, analysis, interpretation, writing of the manuscript, or in the decision to submit the article for publication.

Disclosure

FV currently supervises two Ph.D. students who are employed with F. Hoffmann La Roche Ltd. Basel, Switzerland. He has not received any reimbursements for this and the Ph.D. topics are not related to this paper. FMEF reports personal fees from AstraZeneca, personal fees from Boehringer Ingelheim, personal fees from Chiesi, personal fees from GlaxoSmithKline, grants and personal fees from Novartis, grants and personal fees from MedImmune, personal fees from TEVA, outside the submitted work. AS reports grants from Astra Zeneca, outside the submitted work, grants from NIHR, during the conduct of the study. AMT reports grants from Linde REAL fund, grants from Alpha 1 Foundation, non-financial support from GSK, personal fees and non-financial support from Boehringer Ingelheim, grants, personal fees and non-financial support from Chiesi, grants, personal fees and non-financial support from AstraZeneca, grants from Grifols Biotherapeutics, outside of submitted work, personal fees from CSL Behring, personal fees from Pfizer, during the conduct of the study. PA, DF, AS, and REJ hold a grant from NIHR (Programme Grant, 2010–2018) that supported the development of the Birmingham COPD Cohort analysed in the submitted paper. PA holds other NIHR grants and is Deputy chair of the NIHR PHR Funding committee. The authors report no other conflicts of interest in this work.