Preventive therapy for tuberculosis in Western Australia.

SETTING

State Tuberculosis Control Programme, Western Australia.

OBJECTIVE

To ascertain baseline information, applicability and efficacy of preventive therapy for tuberculosis (TB) under indirectly supervised treatment in Western Australia.

DESIGN

Retrospective analyses of records of persons with TB infection who were prescribed preventive therapy for the period 1993-1996 inclusive, using simple descriptive statistics.

RESULTS

Preventive therapy was given to 411 persons after screening for TB due to on-arrival migrant surveillance (269), contact tracing (59), tuberculin surveys (59) and other reasons (24). Six-month isoniazid monotherapy (HMT) was prescribed for 403 and multidrug regimens for the remaining eight. Excepting 34 whose compliance was unknown, varying degrees of treatment non-adherence were found in 90 (24%) of the remaining 369 persons given HMT, including 36 (10%) with under five months of total medication. Minor adverse drug effects occurred in 32 (9%) subjects and contributed to the non-adherence in 23 of these. One person has since developed active TB.

CONCLUSIONS

Preventive therapy in Western Australia conformed to generally accepted guidelines. Varying degrees of non-adherence to HMT occurred in 24% of persons, but 90% completed adequate therapy under indirect supervision. Non-adherence is significantly related to adverse drug effects.