Characteristics of a population of COPD patients identified from a population-based study. Focus on previous diagnosis and never smokers

Abstract

Objective: To identify factors associated with diagnosis and health-related quality of life (HRQL) impairment in chronic obstructive pulmonary disease (COPD) patients from a population-based epidemiological study.

Design and participants: This was an epidemiologic, multicenter, population-based study. Three hundred and sixty-three individuals diagnosed with COPD from a randomly general population sample of 4035 individuals aged 40-69 were included in the analyses.

Interventions: Forced spirometry was performed on eligible subjects, and the European Commission for Steel and Coal (ECSC) and the St. George's Respiratory Questionnaires (SGRQ) were completed. Logistic regression models were constructed to identify variables associated with the previous diagnosis of COPD and with COPD in never smokers. A multiple linear regression model attempted to identify variables influencing HRQL impairment.

Results: Only 79 (21.7%) COPD patients had been previously diagnosed. Disease severity based on FEV(1), worse SGRQ score, previous respiratory disease, as well as the presence of wheezing were significantly associated with previous diagnosis. Being a woman, older than 55, with previous respiratory disease and without expectoration or wheezing characterized COPD in never smokers. A worse HRQL was associated with chronic symptoms, especially dyspnea; and with older age, cardiac comorbidity and impairment in lung function.

Conclusions: Diagnosis of COPD in the community is more likely in patients with worse lung function and HRQL, and wheezing is the symptom most strongly associated with a diagnosis of COPD. Women older than 55, with previous respiratory diseases, without respiratory symptoms and mild airflow obstruction constitute the majority of individuals with COPD who have never smoked. Chronic respiratory symptoms are strongly associated with impairment in HRQL.