Respiratory Muscle Strength and Mortality in Patients with COPD: A Systematic Review and Meta-Analysis

Area of Science:

• Pulmonology
• Respiratory Medicine
• Clinical Epidemiology

Background:

• Respiratory muscle weakness is prevalent in COPD, potentially impacting prognosis.
• Current clinical testing for respiratory muscle strength lacks standardization, and its prognostic value for survival is unclear.

Purpose of the Study:

• To evaluate the association between respiratory muscle strength and survival in patients with COPD.
• To summarize evidence on other indices for implementation.

Main Methods:

• Systematic literature search of PubMed/MEDLINE, CENTRAL, and Web of Science (1990-2025).
• Inclusion of observational cohorts and baseline-prognosis analyses in COPD patients reporting all-cause mortality.
• Meta-analysis of time-to-event estimates using random-effects models where applicable.

Main Results:

• Lower inspiratory strength correlated with higher mortality (pooled HR 0.97, 95% CI 0.95-0.99).
• Specific cut-offs (MIP ≤55 cmH2O, MEP ≤80 cmH2O) were associated with higher mortality in severity-restricted cohorts.
• Peak inspiratory flow rate (PIFR) <60 L/min linked to exacerbations and readmissions; MEP and sniff nasal inspiratory pressure showed inconsistent prognostic signals.

Conclusions:

• Maximal inspiratory strength (MIP) demonstrates a consistent association with survival in COPD patients.
• Standardized MIP measurement protocols and PIFR screening are recommended for risk stratification and guiding inhaler selection.