Risk factors and costs associated with an asthma attack

Background-A study was undertaken to identify asthma patients at risk of an attack and to assess the economic impact of treatment strategies. Methods-A retrospective cohort analysis of a representative data set of 12 203 patients with asthma in the UK over a one year period was performed. Lo gistic multiple regression was used to model the probability of an attack o ccurring using a set of categorised predictor factors. Health service costs were calculated by applying published average unit costs to the patient re source data. The main outcome measures were attack incidence, health servic e resource use, drug treatment, and cost estimates for most aspects of asth ma related health care. Results-Children under five years of age accounted for 597 patients (5%), 3 362 (28%) were aged 5-15 years, 4315 (35%) 16-44, 3446 (28%) 45-74, and 483 (4%) were aged over 74 years. A total of 9016 patients (74%) were on some form of:prophylactic asthma medication; 2653 (22%) experienced an attack in the gear data collection occurred. Overall health care expenditure was est imated at pound 2.04 million. The average cost per patient who had an attac k was pound 381 compared with pound 108 for those who did not, an increase of more than 3.5 times. In those aged under five and those over 75 years of age there were no significant markers to identify risk, but both groups we re small in size. The level of treatment step in the British Thoracic Socie ty (BTS) asthma guidelines was a statistically significant factor for all o ther age groups. Night time symptoms were significant in the 5-15, 16-44 an d 45-74 age groups, exercise induced symptoms were only significant for the 5-15 age group, and poor inhaler technique in the 16-44 age group. Conclusions-Patients at any treatment step of the BTS asthma guidelines are at risk of an asthma attack, the risk increasing as the treatment step inc reases. Poorly controlled asthma may have a considerable impact on health c are costs. Appropriate targeting of preventive measures could therefore red uce overall health care costs and the growing pressures on hospital service s associated with asthma management.