Purposes: to assess the results of tuberculosis treatment in the routine setting in Japan, and to study applicability of the method of cohort analysis for the individualized treatment practice in the industrialized countries.
Setting: In Japan smear positive tuberculosis patients are mostly treated first in the tuberculosis hospital and are followed up in the outpatient department there or by the general practitioners. The drug regimens are standardized and controlled by the health centers, thoughnot very severely. It can be modified according to the results of drug sensitivity test that is done any time on positive culture.
Subjects: A total of 78 hospitals having tuberculosis ward volunteered to participate in the study. Interested doctors of these hospitals filled in the forms of the questionnaire on the patients they treated. The patients studied were smear-positive pulmonary tuberculosis cases who were put under treatment during April through September, 1995. Only patients having no past treatment of tuberculosis, were analyzed in this report. Also, patients who were referred to the other medical services for any reason were excluded from the analysis. Categorization of the treatment outcomes was made according to the WHO's system of the cohort analysis, with neccessary modifications, mainly for the 9 month regimen most commonly used in Japan.
Results:
A total of 922 cases were analyzed. 75% of them were males, and 50% were those aged 60 years or older. Almost all of them were hospitalized in the beginning of the treatment. For the entire cohort, the treatment outcomes at the end of nine months are as follows; Cured 61.8%, Treatment completed 16.6%, Failure 2.5%, Defaulter 7.2%, Died 11.9%. Treatment success rate including "cure" and "completed" was only 78%. For those aged 10-59 years treatment success rate was 86% and defaulter rate was as high as 9.5%, while for those aged 60 years or older the rate were 58.6% and 4.8% respectively. Death rate were 2.4% and 21.6% for respective age groups.
Smear negative conversion by the mid-second treatment month was 59% and by the mid-third month 71.3%, while culture negative conversion was 66% and 79.6%, respectively.
Of all death cases (110), 47(43%) were due to tuberculosis and the others were due to any non-tuberculosis cause. In the younger age group (10-59 years) about half (6/11) of the deaths were tuberculous, while for the elderly patients tuberculosis occupied 42% of all deaths. The tuberculous deaths occurred early in the treatment course; 51% of them occurred during the first month, 78% by the end of the third months. Of all the non-tuberculosis deaths pneumonia & bronchitis was most common (27%), followed by cancer (21%) and heart disease (11.3%).
Discussion: At first sight it was surprising that the fatality of the smear positive tuberculosis patients in Japan is so high, especially among aged persons, and at the same time, that there are so many defaulter cases. In all deaths tuberculosis occupied a considerable part which suggests that there are many such cases that are detected at so serious atage, possibly due to either failure in diagnosis or the immunocompromized status of the cases. Further analysis must be done concerning the causes or contributing factors for the high level of defaulter rate that was also not expected before the study. That the younger patients are more likely to default should be critically discussed, in the point of view of hospital utilization. The treatment failure rate was rather low, and it is possible that it may be eventually still lower, because many of the thus categorized patients are further treated with personal tailoring, thus would be led to the later cure. Also, in the powerful chemotherapy there are many cases with positive smear and negative culture examinations during the course of chemotherapy, as confirmed in our series by the faster negative conversion in culture results than in the smear examination results.
Conclusion: The WHO system of cohort analysis would be well applicable for the industrialized countries' situation with some reservations, especially for the age-components of the patients. Culture examination results should also be considered for the categorization of the treatment outcomes. It gives an important clue for the problem finding of the routine treatment services as well as in the developing countries.
Updated 99/06/07