Intercountry comparability is better for mortality in the 9th revision of the ICD than in the 8th revision. Unfortunately, only a few years of time trend data are available to date and it will be necessary to continue this observation during a longer period. Results of the present analysis suggest that it is necessary to extend mortality tabulations beyond ICD/9 codes 490-493 by including mortality from chronic airways obstruction (code 496) when comparing COPD and asthma mortality among countries. That gives the most comparable COPD and asthma category possible for 1979 and beyond. International comparisons of COPD and asthma mortality should not rely only on mortality reported in WHO publications. To do so would repeat the error that occurred in the 1969 to 1978 trend in the US under the 8th revision: without the special code 519.3 for COLD, a decrease in COPD mortality was observed principally in men, whereas with inclusion of this code, there was a marked increase in mortality from COPD.
In each country, COPD death rates are higher in men than in women, but male/female differentials are relatively small in France. According to a number of studies, men have an enhanced risk of developing bronchitis and airways obstruction and their risk of bronchitis is reported in some investigations to be more than three times greater than for women. After cigarette smoking and age, “male sex is the risk factor most closely associated with the presence of airways obstruction.”
Between 1969 and 1983, COPD and asthma death rates increased faster in women than in men for the three age groups studied in the US and Canada. The changes in smoking habits of women could be responsible, at least in part. In France, the proportion of adult women who smoke increased for the generations studied. The prevalence of smoking in the US is described in the 1985 Surgeon Generals Report where the estimate for American women was 18 percent in France. Petty also noted that COPD is precipitated and aggravated by external factors such as smoking, but development of disease probably takes 30 years or more in the majority of cases. Consequently, the changes in smoking habits mentioned above are likely to involve modifications in mortality rates from COPD in the coming decades. tadacip 20
Some differences between the three countries can be partly explained by coding practices and ICD revisions. These problems are known to complicate mortality analyses, especially between countries. Results of international comparisons, therefore, have to be interpreted cautiously. Even though different diagnostic categories are used to define COPD and asthma, death rates were obviously higher in the US and Canada than in France from 1969 to 1983, and differences persisted when allowance was made for use of different categories. A more definitive analysis will be possible as additional mortality data under the 9th revision of the ICD become available.