Study of isoniazid-resistant tuberculosis including outcomes in a high prevalence area in London

Background: Isoniazid resistance is the most common form of mono drug resistance in tuberculosis (TB). There has been an outbreak of isoniazid-resistant TB in North London.An outbreak committee has made recommendations¹. Aim: To study isoniazid resistant TB patients attending Newham community chest clinic. Methods: The notes of 31 isoniazid-resistant TB patients treated between 2004 to 2009 were studied. The reference laboratory gave confirmation of resistance. Results: The age range was 17 to 73 (median 32). Male: female - 2.1:1. 7(23%) patients had the North London outbreak strain. Of the 31 patients, 20(65%) had pulmonary involvement, 11(35%) had extensive disease and 8(26%) were sputum smear positive. The extra-pulmonary presentations were lymphadenopathy, abscesses and miliary TB. 10(32%) patients had risk factors for resistance - HIV, previous TB, alcohol, drug abuse and being in prison. 14(45%) patients with risk factors for non-adherence were given directly observed therapy. 17(55%) had treatment supervised weekly by community pharmacists. Patients received a 12month regime containing rifampicin, pyrazinamide and ethambutol, or a 9-month regime that also included moxifloxacin. 7 (23%) patients had drug adverse effects. 30(97%) patients completed treatment successfully. Conclusion: The majority of our patients were not associated with the outbreak. Treatment completion rates were satisfactory, and exceeded the target (90%) set by the TB outbreak control committee. There was no difference in treatment completion rates between the two regimes. Reference: 1.Maguire H, Forrester S, Adam S. Progress report and updated recommendations of the London Outbreak Control Committee May 2006 1 .