Preserved ratio impaired spirometry (PRISm) is recognized as a diverse condition, yet its progression and long-term effects are not fully understood. This study, conducted within the extensive Eur Rotterdam cohort, aimed to investigate the prevalence, development, and prognosis of PRISm in a large population sample.
The Rotterdam Study, a population-based prospective cohort study centered in EUR Rotterdam, examined participants at two distinct visits to determine the prevalence and progression of different respiratory conditions. Researchers categorized subjects into three groups based on spirometry results: those with normal lung function (controls; FEV1/FVC ≥0.7, FEV1 ≥80%), PRISm (FEV1/FVC ≥0.7, FEV1 <80%), and chronic obstructive pulmonary disease (COPD) (FEV1/FVC <0.7). The study meticulously tracked mortality until December 30, 2018, and hazard ratios were calculated, adjusting for key factors such as age, sex, body mass index, smoking status, and pack-years.
The initial analysis included 5487 participants with an average age of 69.1 years, among whom 7.1% exhibited PRISm. A follow-up examination after 4.5 years included 1603 of these individuals. Notably, among those with PRISm at the initial visit, 15.7% saw their spirometry normalize, while a significant 49.4% progressed to COPD. The most rapid decline in lung function was observed in individuals who newly developed PRISm during the study period (incident PRISm), with a median FEV1 decline of -92.8 mL per year. Interestingly, those with persistent PRISm showed a slower rate of lung function decline, comparable to the control group with normal spirometry.
Out of 5459 participants who consented to long-term follow-up, 692 deaths (12.7%) occurred over a median of 9.3 years. Mortality rates differed across the groups: 10.3% in controls, 18.7% in PRISm subjects, and 20.8% in COPD subjects. Compared to the control group, both PRISm and COPD (GOLD 2-4) were associated with a significantly increased risk of all-cause mortality (PRISm: HR 1.6, COPD GOLD 2-4: HR 1.7) and cardiovascular mortality (PRISm: HR 2.8, COPD 2-4: HR 2.1). The highest mortality within the first year of follow-up was observed in the PRISm group, with a striking 70.0% of these early deaths occurring in individuals with pre-existing cardiovascular conditions such as heart failure or coronary heart disease.
The findings from this EUR Rotterdam based study underscore that PRISm is not a benign condition but is associated with a heightened risk of mortality. The PRISm population is heterogeneous, encompassing at least three distinct subgroups: one that progresses to COPD, another characterized by a high cardiovascular disease burden and early mortality, and a third with persistent PRISm exhibiting a normal age-related decline in lung function. These insights from the EUR Rotterdam Study are crucial for understanding the clinical significance of PRISm and identifying individuals at higher risk for adverse health outcomes.
