Lung function decline in people with serious mental illness: A call to action

Abstract

This prospective observational study aimed to evaluate the rate of change in forced expiratory volume in the first second (FEV1) and to explore the factors associated with changes in FEV1 in people with serious mental illness (SMI). Sixty subjects diagnosed with schizophrenia or bipolar disorder who were smokers and without history of respiratory illness agreed to participate. The mean (range) follow-up period was 3.54 (3.00-4.98) years. The mean (standard deviation) annual rate of change in FEV1 decreased by 39.1 (105.2) mL/year. Thirty-one (51.7 %) patients experienced a decrease in the FEV1 ≥40 mL/year (i.e. a rapid decline). The factors associated with the absolute change in FEV1 were the baseline International Physical Activity Questionnaire activity score in metabolic equivalents of tasks (β 0.145, 95 % confidence interval [CI] 0.043 to 0.246; p = 0.005), baseline FEV1 (β -0.025, 95 % CI -0.076 to 0.027; p = 0.352), and the interaction term of both variables (β -3.172e-05, 95 % CI -6.025e-05 to -0.319e-05; p = 0.029). The factors associated with rapid FEV1 decline were income (odds ratio [OR] 0.999, 95 % CI 0.995 to 1.003; p = 0.572), the rate of change in abdominal circumference (OR 0.000, 95 % CI 0.000 to 0.890; p = 0.081), and the interaction term of both variables (OR 1.038, 95 % CI 1.010 to 1.082; p = 0.026). In conclusion, a substantial proportion of people with SMI experienced a rapid decrease in FEV1. If our results are confirmed in larger samples, the routine evaluation of lung function in people with SMI would be an opportunity to identify individuals at greater risk of morbidity and mortality.