Population-Based Study on the Prevalence of Spirometric Obstructive Pattern in Porto, Portugal

Abstract

BACKGROUND: The diagnosis of obstructive lung disease (OLD) based on clinical grounds is challenging. There have been no population-based COPD studies that collected pulmonary function data in Portugal, a country in transition between phases 2 and 3 of the smoking epidemic. OB-JECTIVE: To estimate the prevalence of obstructive pattern on spirometry in a representative sample of adults from Porto, Portugal. METHODS: We conducted a health survey between 2001 and 2003, and 758 participants > 40 years old had reliable spirometry. We used a structured questionnaire to collect demographic, clinical, social, and behavioral data. Obstructive pattern was defined as FEV 1 /FVC < 70%. Logistic regression was performed to quantify the association between socio-demographic and clinical factors and outcome. RESULTS: The participants' mean ؎ SD age was 58.5 ؎ 11.5 years, and 62% were women. The prevalence of spirometric obstructive pattern was 10.7%, 95% CI 8.6 -13.1%; 13.4% in men, and 9.1% in women (P ‫؍‬ .08). The age-adjusted odds ratios for cumulative smoking exposure of less than and more than 20 pack years, in comparison with never smokers, were 3.49 (95% CI 1.02-11.92) and 3.91 (95% CI 1.29 -11.89) among men, and 1.47 (95% CI 0.53-4.08) and 2.68 (95% CI 1.07-6.68) among women, respectively. Previously diagnosed OLD was reported by 30.9% (95% CI 21.1-42.1%) of the participants with spirometric obstructive pattern. Spirometry confirmed the OLD diagnosis in 20.5% (95% CI 13.7-28.7%) of subjects who self-reported OLD (kappa ‫؍‬ 0.14, 95% CI 0.07-0.20). CONCLUSIONS: The prevalence of spirometric obstructive pattern was high. Considering Portugal's position in the smoking epidemic, together with the aging of the population, we can expect an increase in the prevalence of OLD in older people and in women. Our results confirm the limited validity of self-reported OLD in epidemiological studies.

Prevalence of chronic obstructive pulmonary disease in general practice patients in the Central Region of Portugal

“…We identified 24,148 patients that were classified with ICPC-2 "Chronic Obstructive Pulmonary Disease (R95)" out of 937,817 individuals, resulting in a prevalence of COPD of 2.57 per 100,000. The calculated prevalence of COPD in the Central Region of Portugal was significantly lower than the prevalence estimated for this disease in past studies, both worldwide and in Portugal [9,10,[26][27][28][29]. There are many aspects that can contribute to such a low prevalence in this study: the methodology used in most observational studies being different from the clinical one we used, which is based on existing records.…”