Background/Purpose: According to the report by WHO, Japan is still in moderately-prevailing countries of TB. The annual incidence of TB in Japan is approximately 15/100,000, which is 4 – 5 times higher than those in western countries. The incidence of TB in patients with RA is reported to be 2 – 3 times higher than that of general population. Moreover the TB incidence increases 4 – 5 times when bDMARDS are used for the treatment. Therefore, the TB incidence becomes approximately 10 times higher than that of general population when prevention of TB is not done properly. We, in this study, aimed to show the effectiveness of our strategy of TB prevention in patients with rheumatic diseases under the treatment with bDMARDS.

Methods: Subjects were 235 patients with rheumatic diseases who were introduced with bDMARDS, most of them were RA. The mean age was 62 with the range of 18 – 90 years. The duration of administration of bDMARD was 0.25 – 11.8 years, including 2^nd bDMARDS and thereafter, with the mean duration of 3.0 years, and the total duration of administration was 818 years. TB prevention by isoniazid (INH) was applied to patients who fit more than 1 of the following 5 items (risk factors). They are; 1. more than 70 years of age, 2. moderate or strong positive tuberculin skin test (STS), 3. positive or intermediate QuantiFerron (QFT) result (intermediate result was established by Japan Society for TB), 4. findings suggestive of old TB on chest CT, and 5. history of treatment of TB. In addition, there were patients who chose to had prevention after consulting attending physicians. The duration of INH administration was 9 months. The reasons why patients of more than 70 years of age was indicated for TB prevention are as follows; 1. more than 50 % of TB patients in Japan are more than 70 years of age, 2. TB incidence of more than 70 years of age is very high (approximately 50/100,000), and 3. compatible with the BTS guideline of TB prevention.

Results: Tb prevention was done for 166 patients (70 %). The number of patients who had 0, 1, 2, 3, 4, 5 risk factors listed above were 30, 91, 31, 6, 7, 1, respectively. Thirty patients took INH despite they did not have risk factors. In patients with one risk factor, the most risk factor was advanced age, followed by positive STS, chest CT findings, and positive QFT. Five patients did not take INH despite that they had risk factors. Predictive value of TB development was calculated from the annual incidence stratified by age and the duration of bDMARDS administration. It was estimated to be 2.2, but no TB developed actually.

Conclusion: Our strategy of preventing TB by INH is so far working well.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/our-strategy-of-preventing-tuberculosis-tb-in-patients-with-rheumatic-diseases-under-the-treatment-with-biologic-dmards/