Self-reported smoking status and urinary cotinine levels in patients with asthma

Pinheiro, Gabriela Pimentel; Souza-Machado, Carolina de; Fernandes, Andréia Guedes Oliva; Mota, Raquel Cristina Lins; Lima, Liranei Limoeiro; Vasconcellos, Diego da Silva; Luz Júnior, Ives Pereira da; Silva, Yvonbergues Ramon dos Santos; Lima, Valmar Bião; Oliva, Sérgio Telles de; Mello, Luane Marques de; Couto, Ricardo David; Chatkin, José Miguel; Cruz, Constança Margarida Sampaio; Cruz, Álvaro Augusto

ABSTRACT Objective:

To determine the frequency of active smoking among patients with asthma and individuals without asthma by self-report and urinary cotinine measurement.

Methods:

This was a cross-sectional study conducted in the city of Salvador, Brazil, and involving 1,341 individuals: 498 patients with severe asthma, 417 patients with mild-to-moderate asthma, and 426 individuals without asthma. Smoking status was determined by self-report (with the use of standardized questionnaires) and urinary cotinine measurement. The study variables were compared with the chi-square test and the Kruskal-Wallis test.

Results:

Of the sample as a whole, 55 (4.1%) reported being current smokers. Of those, 5 had severe asthma, 17 had mild-to-moderate asthma, and 33 had no asthma diagnosis. Of the 55 smokers, 32 (58.2%) were daily smokers and 23 (41.8%) were occasional smokers. Urinary cotinine levels were found to be high in self-reported nonsmokers and former smokers, especially among severe asthma patients, a finding that suggests patient nondisclosure of smoking status. Among smokers, a longer smoking history was found in patients with severe asthma when compared with those with mild-to-moderate asthma. In addition, the proportion of former smokers was higher among patients with severe asthma than among those with mild-to-moderate asthma.

Conclusions:

Former smoking is associated with severe asthma. Current smoking is observed in patients with severe asthma, and patient nondisclosure of smoking status occurs in some cases. Patients with severe asthma should be thoroughly screened for smoking, and findings should be complemented by objective testing.

RESUMO Objetivo:

Descrever a frequência de tabagismo ativo entre pacientes com asma e indivíduos sem asma, usando questionários padronizados e dosagem da cotinina urinária.

Métodos:

Estudo transversal realizado em Salvador (BA), com 1.341 indivíduos, sendo 498 com asma grave, 417 com asma leve/moderada e 426 sem asma. O tabagismo foi identificado por meio de autorrelato utilizando questionários e por mensuração da cotinina urinária. Para a comparação das variáveis estudadas, utilizaram-se os testes do qui-quadrado e de Kruskal-Wallis.

Resultados:

Dos 55 participantes (4,1%) que se declararam tabagistas atuais, 5, 17 e 33 eram dos grupos asma grave, asma leve/moderada e sem asma, respectivamente. Desses 55, 32 (58,2%) eram tabagistas diários e 23 (41,8%) eram tabagistas ocasionais. Observaram-se níveis elevados de cotinina urinária entre não fumantes autodeclarados e tabagistas pregressos, especialmente no grupo asma grave, o que sugere omissão do hábito atual de fumar. A carga tabágica entre os fumantes e a proporção de ex-tabagistas foram maiores no grupo asma grave do que no grupo asma leve/moderada.

Conclusões:

O tabagismo pregresso esteve associado à asma grave. Tabagismo atual também foi observado em alguns pacientes com asma grave e detectou-se omissão em alguns casos. A investigação de tabagismo deve ser meticulosa em pacientes com asma grave e a entrevista desses deve ser complementada por uma avaliação objetiva.