Definitions of early COPD and markers and tools for predicting progression: a systematic review protocol

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality globally. Early diagnosis and intervention are crucial for preventing disease progression. The concept of early COPD is considered to represent the initial phase of the disease course. However, different terms are used, and a standardised definition is lacking. This has hindered research and clinical utility. This systematic review aims first to examine current early COPD research and outline the definitions and terms used to help reach consensus and direct future clinical research. Second, it will identify currently proposed markers and tools for predicting the progression of early COPD and the quality of evidence to help direct future research and facilitate the development of novel management strategies.

This study will search for all clinical studies on early COPD, using a standardised search strategy, searching CENTRAL (the Cochrane Library), MEDLINE (Ovid), PubMed, Scopus, Web of Science and Google Scholar. Titles and abstracts will be reviewed and compared against inclusion and exclusion criteria. Stage 1 of this review will assess the terms and definitions used for early COPD. Stage 2 will assess studies presenting additional markers or tools for predicting the progression of early COPD. Study quality will be assessed using a modified Downs and Black checklist for observational studies and the risk of bias (RoB) 2 tool for randomised controlled trials. This protocol has been registered in PROSPERO (CRD42025645320).

This systematic review will use freely available data within the literature and will not directly involve human participants; therefore, ethical approval is not required. The results of this systematic review will be prepared and submitted for presentation as conference presentation(s) and for publication as a peer-reviewed article.

CRD42025645320.