Inappropriate self treatment with bronchodilators is likely to delay the initiation of corticosteroid and oxygen therapy in acute severe attacks, and the major cause of preventable deaths in the New Zealand epidemic was related to the delays in receipt of potentially life-saving care in emergencies. This commonly occurred in association with inadequate maintenance therapy and long-term management. Increased awareness among doctors and their patients of the potential dangers of poor acute and long-term care may have contributed to the subsequent decline in deaths.
Considerable attention has been devoted to the New Zealand asthma epidemic, and it is gratifying that the mortality rates are now declining. However, this study highlights two important issues which require further investigation. First, despite the favorable trends in New Zealand, the asthma mortality rate there remains over ten times higher than the lowest rate described, and there is a more than sixfold variation in mortality among the other countries examined. Second, although deaths from asthma, particularly in this age group, are essentially preventable, and despite the resources devoted to the treatment of asthmatics, many countries appear to be experiencing an increase in reported asthma mortality. fully
If the international mortality differences and the recent mortality trends can be shown to be real, then the variations in mortality between countries and with time must be due either to differences in prevalence or case fatality. International comparisons of asthma prevalence in children suggest that any differences between countries and changes over time are small. Most mortality from asthma occurs in adults, however, and prevalence data among adults of various countries are very sparse,and perhaps, unreliable. Based on childhood studies, it seems unlikely that international variations in prevalence would account for the mortality differences. By exclusion, this suggests preventable factors relating to asthma management are involved.
It is clearly of considerable importance to ascertain in countries with increasing reported asthma mortality rates, whether these trends are real or due to changes in accuracy of certification or in diagnostic fashions. The central issue is the validity of mortality data. It would be useful to establish a uniform international protocol to examine the accuracy of death certificates in terms of false positive and false negative coding. In addition, standardized asthma prevalence studies in adults similar to those recently carried out in children in New Zealand, Australia, and Canada may help to clarify whether validated international mortality differences are a function of asthma prevalence, severity or variations in management.