Bronchitis in the United Kingdom and the United States of America

Abstract

ACCORDING to official mortality statistics, chronic bronchitis in the United Kingdom ranks third as a cause of death in middle-aged males, whereas in most other countries this disease is of little importance as a cause of death, except in the very old. Various studies on comparability have identified some of the more important limitations on direct inter-country comparisons of death rates from bronchitis. In a study of the practice of coding and classification of medical certifications of death, Morrison [I] found differences that materially affected the comparability of the official mortality statistics on bronchitis among several European countries, all carrying out coding and classification according to the ICD. Disparities between countries in medical opinion and clinical tradition are an important factor as illustrated by the following statement by Ustvedt [2] : “In Norway a patient, according to medical tradition, does not die from chronic bronchitis, but from the cardiorespiratory conditions characterizing the terminal stages of the disease”. The influence of this factor was clearly demonstrated in a study in which physicians in three different countries, i.e. the United Kingdom, the United States and Norway, were presented with identical case histories and asked to fill in the death certificates. There was a clear trend among British doctors to assign chronic bronchitis as the underlying cause of death more frequently than their American and Norwegian colleagues [3]. This being the situation, the arbitrary tabulation of only the underlying cause of death is particularly unsatisfactory when dealing with chronic non-specific respiratory diseases. Moriyama [4] has pointed out that in the U.S.A., coding the underlying cause from statements by physicians on death certificates, has minimized the importance of diseases, such as emphysema, which often appears on the death certificates only as contributory or associated causes. However, the major factor limiting the comparability of mortality statistics for chronic bronchitis, is probably the lack of general agreement on terminology. Although many efforts have been made within the last few years to establish a precise clinical definition [S-S], no such definition has been internationally accepted or generally adopted. A name given to a clinical syndrome in one country may still frequently be applied to a somewhat different syndrome in other countries. In comparing mortality figures one cannot exclude the possibility that observed differences in rates may be due to different opinions and traditions in the medical communities, rather than reflections of true differences in mortality from bronchitis in the populations concerned. Particularly in comparing mortality statistics for chronic bronchitis and other chronic non-specific lung diseases, it is worth bearing in mind the