Risk factors for near-fatal asthma--a case-control study in a Western Cape teaching hospital

To evaluate risk factors for asthma death such as access to health care, over-use of beta 2-agonists or under-use of inhaled corticosteroids in the Western Cape (WC) population, using near-fatal asthma (NFA) as a surrogate marker.

Patients with NFA (cases) admitted to a WC teaching hospital were compared with patients with acute asthma in a case-control study using a structured questionnaire, clinical examination, arterial blood gas measurements, chest radiograph and pulmonary function measurements.

Sixteen patients with NFA (cases) and 55 with acute asthma (controls) were prospectively enrolled. Duration of asthma, gender, smoking status and ethnicity were similar. Cases had significantly more previous mechanical ventilation (P < 0.05) and a trend towards more previous intensive care unit (ICU) admissions. No significant differences were found in primary health care variables.

Our study demonstrates that patients with NFA constitute a significant number of emergency room (ER) admissions for acute asthma (30%) in our population. Similar to other studies, there was a trend for NFA toward more previous ICU admissions and mechanical ventilation. Relative under-use of beta 2-agonists the day before admission and fewer ER visits during the previous year in the NFA group, suggests an impaired perception of the severity of disease or a more rapid onset of symptoms. Negative factors such as inability to access health care or lack of medication supply were similar in both groups. The challenge remains to identify and manage high-risk patients effectively.