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TOPLINE:

Preserved ratio impaired spirometry (PRISm) was associated with the development of airway obstruction over 10 years of follow-up, independent of smoking habits, with comparable odds for disease development across smoking histories. 

METHODOLOGY:

• Researchers conducted a retrospective study to examine clinical traits, smoking habits, and lung function patterns leading to airway obstruction with a focus on PRISm (forced expiratory volume in 1 second [FEV1]/vital capacity [VC] ≥ 0.70 and FEV1 < 80% of predicted value).
• They used spirometry data from cohort studies conducted between 2002 and 2004 among patients who were examined for airway obstruction and were compared with a matched group of individuals without airway obstruction.
• Overall, 902 patients with airway obstruction (FEV1/VC < 0.70 and FEV1 < 80% of predicted; mean age, 54.9 years; 44.9% women) and 819 matched control individuals (FEV1/VC ≥ 0.70; mean age, 56.3 years; 45.1% women) were identified.
• Data on covariates such as age, sex, smoking habits, and body mass index were collected during the first examination using structured interview questionnaires.

TAKEAWAY:

• The proportion of individuals who had airway obstruction (45%) and PRISm (19%) at first examination was higher among those who developed airway obstruction a decade later than among matched control individuals.
• Factors associated with having airway obstruction were former smoking habit (adjusted odds ratio [aOR], 1.52; 95% CI, 1.12-2.05), current smoking habit (aOR, 4.07; 95% CI, 2.99-5.55), and PRISm (aOR, 3.48; 95% CI, 2.56-4.72).
• Stratification on the basis of smoking habits showed similar odds for PRISm among those with current smoking habit (aOR, 2.90; 95% CI, 1.60-5.25), former (aOR, 3.81; 95% CI, 2.27-6.40), and no (aOR, 3.66; 95% CI, 2.24-5.98) smoking habits.
• Having PRISm alone increased the odds of airway obstruction by four times, while combining PRISm with a restrictive spirometric pattern raised the odds by roughly three times.

IN PRACTICE:

“In clinical practice, PRISm may indeed be treated and/or diagnosed as COPD [chronic obstructive pulmonary disease]. Importantly, in our retrospective case-control study, we found that PRISm that transitioned into airway obstruction presented with more chronic bronchitis, dyspnea, and wheeze and a more rapid decline in FEV₁ than PRISm that did not transition into airway obstruction during follow-up,” the authors wrote.

SOURCE:

The study was led by Helena Backman, PhD, and Tomi Myrberg, PhD, both affiliated to Umeå University, Umeå, Sweden. It was published online on March 7, 2025, in CHEST.

LIMITATIONS:

The study relied on prebronchodilator spirometry. As PRISm is common in individuals with diabetes, the lack of comprehensive data on such comorbidities could have affected the findings. The sample size may not have been sufficient to detect meaningful associations, potentially introducing type 2 errors. 

DISCLOSURES:

The study was supported by grants from the Swedish Heart and Lung Foundation, a regional agreement between Umeå University and Region Vasterbotten, the Swedish Respiratory Society, VISARE NORR Fund Northern County Councils Regional Federation, and the Norrbotten County Council. Some authors reported receiving personal fees and advisory board fees from various healthcare and pharmaceutical companies, outside the submitted work.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.