Demographic characteristics of patients with severe life threatening asthma: comparison with asthma deaths

Studies of mortality from asthma have suggested that a very severe asthma attack identifies a group at greatly increased risk of subsequent death from the disease. This study compares the demographic characteristics of asthmatic patients who required management in an intensive care unit for a severe life threatening attack between 1981 and 1987 with a group who died of asthma between 1980 and 1986. The outcome of the group admitted to an intensive care unit is described.

The groups comprised all cases aged between 15 and 49 years arising from the Auckland Area Health Board (AAHB) population who required admission to an intensive care unit for asthma between 1981 and 1987 (n = 413) and all deaths from asthma in those aged 15 to 49 years arising from the New Zealand population between 1980 and 1986 (n = 466). Details of age, sex, and information on the day and month of the attack were collected. For the group requiring admission to an intensive care unit, outcome in terms of mortality and readmission to intensive care was determined.

The age distributions of the two groups were dissimilar, with the severe life threatening attack group having an excess of asthmatic patients under 30 years old. The distribution of events by calendar month was uniform in both groups, but there was an unexpected increase in frequency of attacks on Sundays in both groups. Over the study period, mortality fell from 5.3 per 100,000 to 3.5 per 100,000 but the admission rate to intensive care increased from 10.8 per 100,000 to 17.9 per 100,000. At least 24% of asthma deaths occurring in the AAHB region during the study period had previously experienced a severe life threatening attack.

The similarities between the groups suggest that asthmatic patients who experience severe life threatening attacks are likely to come from the same subgroup of the asthma population as those who die. The group who experience severe life threatening attacks are at high risk of subsequent morbidity and mortality and further studies may produce information relevant to reducing mortality from asthma.