Tuberculosis surveillance among new immigrants in Montreal

Foreign-born persons account for over 60% of Canadian tuberculosis (TB) incidence; immigrants with TB-related lung scarring ('inactive TB') are at particularly high risk, and represent an important target for preventive efforts.

To document the performance of the immigrant surveillance programme for inactive TB in Montreal.

All immigrants arriving with inactive TB are referred by the public health department to the Montreal Chest Institute. We prospectively recorded clinical and radiographic data for those evaluated in 1999 and 2000. We examined physicians' adherence to Canadian guidelines. We also evaluated concordance of chest radiographic interpretation.

Of 1444 immigrants notified, 792 (55%) were sent referral letters. Most of the others lacked valid addresses. Of the 654 (45%) who were examined, 322 (22%) were diagnosed with untreated latent TB, 215 (15%) were recommended therapy, and 156 (11%) completed it. Of 388 potential candidates for treatment of latent TB, 274 (71%) underwent tuberculin tests. Treatment decisions followed guidelines for 87% of patients with full testing. Agreement between clinicians and chest radiologists as to TB-related radiographic abnormalities was frequent (K 0.63). Six 'high volume' clinicians performed better than others with respect to management and radiographic interpretation.

Centralised post-immigration surveillance requires more accurate referrals, and more consistent provider performance.