Analysis of US, Canadian and French mortality data shows lower death rates for COPD and asthma in France and dissimilar patterns by sex among these countries. The proportion of deaths from bronchitis was higher in France, while an increased use of generalized terms for COPD in death certificates was observed in Canada and the US. The likely reason is differing diagnostic fashion and coding practice. Death rates for COPD increased faster in women than in men in the US and Canada; the difference was less in France. Unlike the US and Canada, where COPD and asthma mortality generally increased over the 1969 to 1983 period, especially in women, trends in France were relatively flat and were lower than rates in the US and Canada. For the 1969-78 period, the trend would also be downwards in the US and Canada if it were not for inclusion of the special category COLD. By including the category ICD/8 code 519.9 in COPD and asthma mortality for France between 1969 and 1978, comparability with Canadian and US mortality is still not very good. Using a broad diagnostic category to define COPD and asthma in France (Fig 5), death rates in middle-aged men and women (age 55-84) are clearly lower in France than in the US (and Canada), and trends are generally level in France, upwards in the US and Canada.
The reliability of any comparison of mortality data depends on several factors. Four are very important: accuracy of diagnosis, death certificate entries by physicians, coding practices, and changes in the ICD. cialis canadian pharmacy
FIGURE 5. Death rates for COPD and asthma by age and sex, US and France, 1969-1983.
In each country it can be difficult for a physician to choose between similar diagnoses and to specify underlying or contributory cause of death, and the coding practices are not simple. This is why, in some countries, the doctor is contacted if there is doubt about a code. This is being tested in France now. In addition, death certification varies among countries and certificates of death are not actually standardized. Some comparisons were made in the European Economic Community of coding by the usual national center and by a reference center in London. Large differences in the coded causes of death were found within and between countries. For instance, there was a net overestimate of 13 percent in deaths from asthma in the United Kingdom. The most common error was failure to follow the procedure advised for completion of death certificates. Revisions in the ICD also complicate these comparisons, especially when related diseases are reported on the same certificate. For instance, under the 8th revision, the deaths certified as being due to asthma with mention of bronchitis, bronchiolitis, or emphysema were to be attributed to the other condition. Under the 9th revision, deaths certified as being due to asthma, whether or not other conditions coexisted, are to be attributed to asthma. Nevertheless, some authors believe there is a very limited discontinuity in trends in mortality statistics for chronic bronchitis. They show that a dual coding of a sample of deaths in 1978 suggests that deaths ascribed to chronic bronchitis under the 9th revision would have formed 97 percent of those coded to the equivalent codes under the 8th revision.