Rheumatology Advance Access published online on November 25, 2008
Rheumatology, doi:10.1093/rheumatology/ken425
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Screening for Mycobacterium tuberculosis prior to anti-TNF therapy––an audit of impact of the British Thoracic Society guidelines on rheumatology practice in an area of low Mycobacterium tuberculosis prevalence
1Rheumatology Department, Norfolk and Norwich University Hospital, Norwich, 2Rheumatology Department, Ipswich Hospital, Ipswich, 3Respiratory Medicine Department and 4Clinical Audit Department, Ipswich Hospital, Ipswich, UK
Correspondence to:
J. D. Pradeep, East Block, Level 1 Outpatients, Colney Lane, Norfolk and Norwich University Hospital, Norwich, NR4 7UY, UK. E-mail: drjohnpd{at}btinternet.com
SIR, Anti-TNF drugs have revolutionized rheumatology practice. However, a major concern is the propensity for patients taking these drugs to develop reactivation of latent Mycobacterium tuberculosis (MTB) infection. The British Thoracic Society (BTS) has provided guidelines [1] on risk assessment for TB prior to commencing anti-TNF treatment, but how relevant is it in areas of low MTB incidence?
We examined the pre-treatment screening methods adopted at two UK hospitals situated in the East Anglia region, an area of low MTB prevalence, from August 2000 to August 2005 and applied the BTS guidelines retrospectively to patients otherwise screened in order to evaluate whether it would have had an impact on our clinical practice.
Patients with RA prescribed an anti-TNF drug at the Norfolk and Norwich and Ipswich Hospitals NHS Trust were identified from a pre-existing database and case notes reviewed with regards to pre-treatment screening methods employed. This included a detailed clinical history and physical examination, tuberculin skin testing (Heaf test was done at Ipswich only) and a chest radiograph. We also examined in detail the records of patients diagnosed as having latent MTB at the time of screening to see if there were any subsequent cases of active MTB.
Three hundred and thirty-nine patients were screened and 326 were started on anti-TNF therapy (121 etanercept, 46 adalimumab and 159 infliximab), 329 were Caucasian, 1 Asian British, 1 Chinese and 8 did not have their ethnicity recorded. Three hundred and nine patients (91%) were taking additional immunosuppressive medication. Eighty-one (24%) had tuberculin testing done (Ipswich = 78, Norwich = 3), 7 out of 81 tests (8.64%) were found to be Heaf Grade 3–4, 41 of 81 tests (51%) were negative. Six patients (1.7%) had a previous history of MTB or treatment for it, 238 of 339 (92%) had a chest radiograph done prior to treatment and 4 (1.2%) had an abnormal chest radiograph consistent with old MTB.
Fifteen patients out of 339 (4.4%) were referred to a local TB specialist of which 10 (66%) were diagnosed as having latent TB. Six of 10 (60%) patients suspected as having latent TB started isoniazid chemoprophylaxis. Four chose not to have anti-TNF treatment. None of the patients were found to have active MTB at the time of screening and after a median follow-up time of 4.35 yrs no patients have had reactivation of MTB.
When we retrospectively applied screening algorithms provided by BTS guidelines, we would have needed to have done 30 additional tuberculin tests and 26 chest radiographs within a 3-month period of starting anti-TNF. Four additional patients would have needed an MTB specialist opinion which would probably have been unnecessary given the low prevalence of MTB in our population. (The prevalence rate of MTB infection in the east of England in 2006 was 8/100 000 vs 44.8/100 000 in the London region. In the UK, MTB surveillance is done by the Health Protection Agency [2], which provides an annual report on the regional epidemiology of MTB.)
These results indicate that MTB infection is not a clinical problem in our patient population treated with anti-TNF therapy in the East Anglia region, therefore we are of the opinion that adhering to the BTS guidelines may be an unnecessary practice in areas where MTB prevalence is low. This audit highlights the fact that BTS guidelines might need to be modified to take into consideration the regional variation in the MTB prevalence.
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Acknowledgments |
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Disclosure statement: K.G.'s Rheumatology Department, Norfolk and Norwich University Hospital has received research funding from Wyeth, Schering-Plough and Abbott Pharmaceuticals. All other authors have declared no conflicts of interest.
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 Top References |
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- Ormerod LP, Milburn HJ, Gillespie S, Ledingham J, Rampton D. BTS recommendations for assessing risk, and for managing M.tuberculosis infection and disease in patients due to start anti-TNF-alpha treatment. Thorax (2005) 60:800–5.
[Abstract/Free Full Text] - Health Protection Agency. 9 August 2008, date last accessed. http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1194947354279.
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