Smoking makes asthma expensive: a register-based study in Finland

Chronic bronchitis and chronic obstructive pulmonary disease (COPD)/emphysema occur frequently among middle-aged and elderly asthma patients who smoke.

To test how much this comorbidity increases the use and costs of health services in comparison with asthma alone.

A sample of 6000 adults with a clinical diagnosis of asthma was extracted from a nationwide health insurance register for a postal inquiry. Comorbidity and the use of health services were measured using a questionnaire. Data on medication expenses were obtained from the national prescription register.

Altogether 4956 individuals replied, of whom 3160 asthma patients aged > or =40 years (response rate 85%) were chosen for this investigation. Asthma patients with COPD/emphysema (12% of the series) accounted for 21% of all doctor consultations, 39% of the total number of hospital in-patient days and 27% of the total expenses, of which one third were medication costs. The mean annual gross expenditure on treatment services and anti-asthma medications was euro754 per patient for those with asthma alone and euro2107 for those with concurrent COPD/emphysema. Current smoking further increased costs among COPD patients.

To prevent pulmonary comorbidity and the related high costs, cessation of smoking should be an integral part of the treatment provided for asthma patients.