Do patients with severe asthma run an increased risk from ischaemic heart disease?

Abstract

Background: Knowledge of the mortality outcome of asthma is limited to hospital case series follow-up.

Methods: To provide estimates of the mortality and cause of death in patients with asthma comparison of observed and expected number of deaths in patients with asthma for the observation period 1962-1986 was made. The study group was 262 patients aged 19-81 years with severe asthma. The group was a total sample of patients with a daily treatment of oral steroids more than one year, 1962-1963, from the city of Göteborg.

Results: Mortality from all causes was significantly raised among the asthmatics (179 deaths versus 83.5 expected, relative risk (RR) - 2.1, 95% confidence interval (CI) : 1.8-2.5). There was an excess mortality from ischaemic heart disease 58 versus 29.9 deaths (RR = 1.9, 95% CI : 1.4-2.4), especially among women (RR = 2.4, 95% CI : 1.7-2.2). However, there was also an increased mortality from asthma (39 versus 0.4 deaths) and chronic obstructive pulmonary disease (11 versus 0.5 deaths).

Conclusions: These findings suggest that subjects with severe asthma, especially women, have an increased mortality from ischaemic heart disease. The results may reflect confounding, mainly smoking and physical inactivity. Other explanations may be side effects of the antiasthmatic drugs or an effect of longstanding airway obstruction.