Prevalence, risk factors, and clinical implications of preserved ratio impaired spirometry: a UK Biobank cohort analysis


Poor spirometry in preserved ratio (PRISm) is defined as FEV1 Less than 80% expected and FEV1/ Forced vital capacity ratio (FVC) 0 70 or higher. Previous research has indicated that PRISm is associated with respiratory symptoms and is a precursor to chronic obstructive pulmonary disease (COPD). However, these results are based on relatively small selective groups with short follow-up. We aimed to determine the prevalence, risk factors, clinical implications, and mortality of PRISm in a large adult population.


For this cohort analysis, we used data from UKBiobank to assess the prevalence of PRISm, associated risk factors and symptoms, and associated comorbidities in a large adult population. Participants with spirometry are considered acceptable by the investigator (best FEV قياس1 and FVC) at baseline. Participants were excluded if they did not have acceptable spirometry or were missing data on BMI or smoking status. Spirometry control was defined as FEV1 80% or more expected and FEV1/ FVC ratio of 0 70 or higher. Airflow obstruction was defined as FEV1/FVC ratio less than 0 70. We used multivariate regression to identify risk factors for PRISm and associated comorbidities. Individuals who lived close to the assessment center were invited for follow-up, with repeated spirometry. Only participants who were included at baseline were examined in the follow-up. This allowed a longitudinal analysis of PRISm over time and risk factors for transition to airflow obstruction. We also analyzed 12-year survival.

the findings

Participants were recruited by the UK Biobank between 19 December 2006 and 10 October 2010. We included 351,874 UK Biobank participants (189247 women and 162,627 men) in our study, with an average follow-up of 9 years (0 ) (IQ 8 · 0-10 · 0). 38,639 (11 0%) of 351,874 participants had PRISm at baseline. After adjustment, PRISm was strongly associated with obesity (odds ratio [OR] 2 40 [2·26–2·55], p < 0 0001), current smoking (1 48 [1·36–1·62], p < 0 0001), and the patient reported that the physician had a diagnosis of asthma (1 76 [1·66–1·88], p < 0 0001). Among other identified risk factors, female sex, weight gain, trunk fat mass, and trunk fat percentage. PRISm was strongly associated with symptoms and comorbidity including an increased risk of dyspnea (OR 2 0 [95% CI 1·91–2·14], p < 0 0001) and cardiovascular disease (rate or 1 71 [1·64–1·83], p < 0 0001 for heart attack). Longitudinal analysis showed that 241 (12 2%) of the participants in 1973 who had PRISm at baseline had transitioned to airflow obstruction consistent with COPD. PRISm was associated with increased all-cause mortality (adjusted hazard ratio 1 61 .). [95% CI 1·53–1·69], p < 0 0001) versus control participants.


PRISm has been associated with shortness of breath, multiple illnesses and an increased risk of death, which does not appear to be explained by smoking, obesity, or existing lung disease. Although PRISm is transient for many patients, it is important to understand which individuals are at risk for progressive lung function abnormalities. Further research into the genetic, structural and functional pathophysiology of PRISm is warranted.


UK Medical Research Council and University of Bristol.

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