Characteristics Associated with Accelerated Lung Function Decline in a Primary Care Population with Chronic Obstructive Pulmonary Disease

Abstract

Background

Estimates for lung function decline in chronic obstructive pulmonary disease (COPD) have differed by study setting and have not been described in a UK primary care population.

Purpose

To describe rates of FEV₁ and FVC decline in COPD and investigate characteristics associated with accelerated decline.

Patients and Methods

Current/ex-smoking COPD patients (35 years+) who had at least 2 FEV₁ or FVC measurements ≥6 months apart were included using Clinical Practice Research Datalink. Patients were followed up for a maximum of 13 years. Accelerated rate of lung function decline was defined as the fastest quartile of decline using mixed linear regression, and association with baseline characteristics was investigated using logistic regression.

Results

A total of 72,683 and 50,649 COPD patients had at least 2 FEV₁ or FVC measurements, respectively. Median rates of FEV₁ and FVC changes or decline were −18.1mL/year (IQR: −31.6 to −6.0) and −22.7mL/year (IQR: −39.9 to −6.7), respectively. Older age, high socioeconomic status, being underweight, high mMRC dyspnoea and frequent AECOPD or severe AECOPD were associated with an accelerated rate of FEV₁ and FVC decline. Current smoking, mild airflow obstruction and inhaled corticosteroid treatment were additionally associated with accelerated FEV₁ decline whilst women, sputum production and severe airflow obstruction were associated with accelerated FVC decline.

Conclusion

Rate of FEV₁ and FVC decline was similar and showed similar heterogeneity. Whilst FEV₁ and FVC shared associations with baseline characteristics, a few differences highlighted the importance of both lung function measures in COPD progression. We identified important characteristics that should be monitored for disease progression.

Keywords:

• pulmonary disease
• chronic obstructive
• spirometry
• lung function

Acknowledgments

The protocol for this research was approved by the Independent Scientific Advisory Committee (ISAC) for MHRA Database Research (protocol number 18_249R) and the approved protocol was made available to the journal and reviewers during peer review. This study is based in part on data from the Clinical Practice Research Datalink obtained under licence from the UK Medicines and Healthcare products Regulatory Agency. The data is provided by patients and collected by the NHS as part of their care and support. The interpretation and conclusions contained in this study are those of the author/s alone. Linked pseudonymised data was provided for this study by CPRD. Secondary care data are linked to primary care data by NHS Digital, the statutory trusted third party for linkage, using identifiable data held only by NHS Digital. Select general practices in England consent to this process at a practice level with individual patients having the right to opt-out. This study is based in part on data from the Clinical Practice Research Datalink (CPRD) obtained under licence from the UK Medicines and Healthcare products Regulatory Agency. The data is provided by patients and collected by the National Health Service (NHS) as part of their care and support. The Office for National Statistics (ONS) was the provider of the ONS Data contained within the CPRD Data and maintains a Copyright © 2019, re-used with the permission of The Health & Social Care Information Centre, all rights reserved. The interpretation and conclusions contained in this study are those of the authors alone. This research was supported by the NIHR Imperial Biomedical Research Centre (BRC). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. Steven J Kiddle and Jennifer K Quint are co-last authors for this study.

Data Sharing Statement

Data are available on request from the Clinical Practice Research Datalink (CPRD). Their provision requires the purchase of a license and our license does not permit us to make them publicly available to all. We used data from the version collected in January 2018 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 (http://www.cprd.com): The Clinical Practice Research Datalink Group, The Medicines and Healthcare products Regulatory Agency, 10 South Colonnade, Canary Wharf, London E14 4PU.

Disclosure

HRW & JKQ received funding from GSK for this work. JKQ also reports grants from Asthma UK, personal fees from AZ, MRC, Chiesi, BI, and The Health Foundation, outside the submitted work. JMP is a full-time employee of GSK and holds shares in GSK. SJK reports personal fees from DIADEM and AstraZeneca, outside the submitted work. The authors report no other conflicts of interest in this work.