05. tbl. 104. árg. 2018

Screening for tuberculosis before TNFα treatment in routine rheumatic care in Iceland. Result from the nationwide ICEBIO registry

Skimun fyrir berklum meðal gigtarsjúklinga sem hófu meðferð með TNFα-hemlum á Íslandi 1999-2014

Introduction: Treatment with TNFα inhibitors (TNFαi) greatly increases the risk of reactivation of tuberculosis in rheumatic patients. Therefore, it is recommended to screen patients for tuberculosis before initiating TNFαi treatment. Iceland has a low prevalence of tuberculosis and BCG vaccination is not routine praxis. The purpose of this study was to review the results from TB-screening in routine praxis and to analyze whether changes in the screening process are to be recommended.

Material and methods: All patients with RA, PsA and AS who were registered in ICEBIO (1999-2014) due to TNFαi treatment were included. Data collection consisted of age, sex, start date of TNFαi treatment and results from a tuberculin skin test (TST) and chest x-ray. The data were then crosschecked with the Berkill registry, a nationwide database for TB.

Results: 756 individuals (58% female, mean-age of 54 years) were included. TST was negative in 614 cases (81%), 41 positive (5.4%), 9 false positives (1.2%) and 92 were missing (12%). 119 patients were registered in Berkill whereof 72 had a history of positive TST and 55 had been vaccinated, while 14 patients had been diagnosed with tuberculo­sis (where of 7 had negative TST on screening). Three patients were diagnosed with tuberculosis after the TNFi treatment.

Conclusion: These results illustrate the importance of tuberculosis screening before initiating TNFαi treatment. Improvement in registration of TST results is necessary and whether interferon gamma release assays (IGRA) should be added to the screening process remains to be discussed.

Table I  shows diagnosis by age, sex and mean age at the start of treatment with TNF alfa inhib.

Table II demonstrates the annual distribution of study participants sorted according to which TNFα inhibitor they recieved as their first treatment

Table III shows the number of people with positive mantoux test, test reaction caused by BCG vaccination and active tuberculosis in the study group and number of people with history of positive mantoux test, BCG vaccination and tuberculosis in Berkill. The BCG and tuberculosis cases from Berkill are then sorted by results from mantoux testing according to patient journal and Berkill

Figure I illustrate number of Mantoux tests per year (positive and negative tests) and number of missing data

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