Assessment of Preserved Ratio Impaired Spirometry Using Pre- and Post-Bronchodilator Spirometry in a Randomly Sampled Symptomatic Cohort

Mild airways obstruction: spirometric diagnostic pitfalls and solutions

PURPOSE OF REVIEW

Spirometry is a validated tool in the diagnosis of obstructive airways disease. However, it may be insufficiently sensitive in detecting airflow limitation in the small airways. This review highlights common clinical scenarios wherein airflow limitation may be missed or overlooked.

RECENT FINDINGS

This article covers recent literature on the interpretation of lung function test, focusing on detection of mild obstructive airways disease. It also sheds light on the contextual difficulties of defining mild airflow limitation on spirometry.

SUMMARY

We highlight the consensus definition of mild obstructive airways disease and emphasize that this definition does not necessarily mean mild in certain disease-specific contexts. Several spirometric findings outside of a reduced forced expiratory volume in one second/forced vital capacity ratio should raise suspicion of mild obstruction.

Association of preserved ratio impaired spirometry with mortality: a systematic review and meta-analysis

BACKGROUND

Preserved ratio impaired spirometry (PRISm) is prevalent within the general population. Increased mortality has been reported among subjects with PRISm, but the evidence has never been summarised. This systematic review aims to synthesise evidence on the association between PRISm and the risk of all-cause, cardiovascular and respiratory-related mortality.

METHODS

We systematically searched MEDLINE, Embase and Web of Science for population-based cohort studies from inception to April 2023 using the terms related to impaired spirometry and mortality. Titles and abstracts were screened to identify eligible studies that reported mortality estimates for individuals with PRISm. We excluded studies that adopted other definitions of impaired spirometry, had a specific study setting (e.g. HIV patients), had an insufficient follow-up period (<1 year) or reported duplicated data. Random-effects meta-analysis was used to produce pooled hazard ratio (HR) with 95% confidence intervals. Between-study heterogeneity was assessed with I2.

RESULTS

Eight studies met the inclusion criteria involving 40 699 individuals with PRISm. All included studies reported increased risk of all-cause mortality among adults with PRISm. Meta-analysis showed that PRISm was associated with an increased risk of all-cause mortality (pooled HR 1.71, 95% CI 1.51-1.93; I2=64%), cardiovascular mortality (pooled HR 1.57, 95% CI 1.44-1.72; I2=35%) and respiratory-related mortality (pooled HR 1.97, 95% CI 1.55-2.49; I2=0%).

CONCLUSIONS

Individuals with PRISm have a significantly increased risk of mortality compared with those with normal spirometry.