Health-related quality of life and risk factors associated with spirometric restriction

The restrictive spirometric pattern is associated with a substantial morbidity and mortality burden. We sought to determine to what extent spirometric restriction is associated with impaired quality of life. We used data from two large population-based European cohorts: 6698 European Community Respiratory Health Survey (ECRHS) and 6069 Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) adult participants. The restrictive pattern was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) >= lower limit of normal (LLN) and FVC <LLN; an obstructive pattern was defined as FEV1/FVC <LLN independent of FVC. The Physical Component Summary and Mental Component Summary of quality of life were computed using the Short Form-36 questionnaire. In both cohorts, the restrictive pattern was associated with heavy smoking, being underweight or obese and the coexistence of respiratory symptoms. In univariate analyses, compared with the normal group, both the restrictive and obstructive pattern had significant Physical Component Summary deficits (-2.77 and -2.08, respectively, in ECRHS; -3.25 and -2.14, respectively, in SAPALDIA; all p-values <0.001). However, in models adjusted for sex, age, education, body mass index, smoking, comorbidities and respiratory symptoms, only the restrictive pattern remained significantly associated with Physical Component Summary deficits (p=0.004 in ECRHS; p=0.001 in SAPALDIA). The restrictive spirometric pattern is associated with deficits in the physical component of quality of life that are partly independent of the presence of respiratory symptoms.