Terms and Definitions Used to Describe Recurrence, Treatment Failure and Recovery of Acute Exacerbations of COPD: A Systematic Review of Observational Studies

Abstract

Introduction Acute exacerbations of chronic obstructive pulmonary disease (AECOPDs) are important clinical events, with many patients experiencing multiple AECOPDs annually. The terms used in the literature to define recurring AECOPD events are inconsistent and may impact the ability to describe the true burden of these events. We undertook a systematic review to identify and summarize terms and definitions used in observational studies to describe AECOPD-related events occurring after an initial AECOPD (hereafter “subsequent AECOPD”). Methods PubMed was searched (2000–2019) for observational studies on subsequent AECOPD events using broad search strings for “COPD”, “exacerbation”, and “subsequent exacerbation events”. Only English-language studies were included. Small studies (n<50) and studies focusing on hospital re-admission only were excluded. Extracted data were analyzed descriptively to generate a narrative summary, using a thematic approach to group studies utilizing similar terms for subsequent AECOPD. Results Forty-seven studies were included. No single, distinct terms or definitions were used to define and identify multiple occurrences of AECOPDs, though most (46) studies used one or more of four clustered terms and definitions: reapse (n = 13), recurrence/re-exacerbation (n = 11), treatment failure (n = 12) and non-recovery/time to recovery (n = 16). Heterogeneity was observed within and between the four clusters with respect to study setting, starting point for observing subsequent AECOPDs, time frame to identify a subsequent AECOPD (except for studies using “time to recovery”), and basis for identifying a subsequent exacerbation. Conclusion Our review demonstrates that subsequent AECOPDs (including events such as relapse, recurrence/re-exacerbation, treatment failure, non-recovery/time to recovery) are ill-defined in the observational study literature, emphasizing the need to reach consensus on precise and objective definitions (for example, when one AECOPD ends and another begins). Use of standardized terminology and definitions may aid comparability between, and synthesis of, studies, thus improving the understanding of the natural history and burden of exacerbations in COPD patients.

Impact of SARS-CoV-2 infective exacerbation of chronic obstructive pulmonary disease on clinical outcomes in a prospective cohort study of hospitalised adults

“…Positive pressure support was more frequently required in SARS-CoV-2 AECOPD compared with non-SARS-CoV-2 infective AECOPD and NI-COPD (18.5% and 11.7% vs. 7.5%, respectively). Despite similar age, CCI and frailty scores, patients admitted with SARS-CoV-2 AECOPD had longer hospitalisation stays (median 7 [3][4][5][6][7][8][9][10][11][12][13][14][15] days vs. 5 [2][3][4][5][6][7][8][9][10] and 4 [2][3][4][5][6][7][8][9]) and increased 30-day mortality (16.9% vs. 11.1% and 5.9%) than those with non-SARS-CoV-2 infective AECOPD or NI-COPD, respectively (Table 1, Figure 1, Supplementary Data 4).…”

“…1 Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) lead to increased healthcare utilisation, reduced health-related quality of life and accelerated loss of lung function, with severe exacerbations increasing the risk of death. 2 Viral infections are the commonest cause of AECOPD, though there can also be bacterial, non-infective or combined triggers. 3 Viral AECOPD cause more prolonged symptoms and longer hospital stays 4 than non-viral exacerbations.…”

Analysis of the Clinical Efficacy and Molecular Mechanism of Xuefu Zhuyu Decoction in the Treatment of COPD Based on Meta-Analysis and Network Pharmacology

“…Significant airway inflammation, mucus secretion and gas trapping, and even systemic inflammation are present during AECOPD compared to the stable phase [60,61]. Frequent AECOPD events can significantly reduce pulmonary function, affect quality of life, and increase the risk of death of patients [62]. With AECOPD, the medications used in the stable phase are no longer applicable for the clinical management of patients, and therefore, the 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD) document defines AECOPD as "an acute worsening of respiratory symptoms 13 Computational and Mathematical Methods in Medicine that leads to additional treatment" [63].…”

Consensus Conference on Standardizing Terminology for Venous Leg Ulcers: Increasing Clarity and Communication in Clinical Practice

“…The terms used in scientific literature to describe an acute, chronic, and recurring disease can sometimes be inconsistent. The need to clarify this issue has been attempted in several studies for other diseases such as chronic obstructive pulmonary disease (COPD) 6 , traumas in orthopaedic field 7 , surveillance-based studies of sports injuries 8 , with the aim of gaining a formal consensus on terminology.…”