Cost-effectiveness of screening compared to case-finding approaches to tuberculosis in long-term care facilities for the elderly.

BACKGROUND To determine if the more interventionist approach of screening with the tuberculin test and chemoprophylaxis for high-risk positive reactors to control tuberculosis in long-term care facilities is cost-effective when compared to the case-finding and treatment approach. METHOD A decision-analysis model was designed wherein systematic screening with the tuberculin skin test of all elderly patients newly admitted to facilities was compared to public health interventions restricted to investigation of cases and contacts with symptoms of tuberculosis after suspected exposure. Differences in life-years (LY), quality-adjusted life-years (QALY), cost per QALY and LY gained, annual cost per 1000 institutional patients were calculated in a health-care system perspective. RESULTS In every situation analysed, screening and chemoprophylaxis were more effective. The cost per LY gained was within an acceptable range: $3437 per LY with a 0.6% nosocomial transmission rate and $7552 per LY when no nosocomial transmission was postulated. CONCLUSION Screening plus chemoprophylaxis for high-risk reactors is more cost-effective than case-finding. This holds even when nosocomial transmission is assumed not to occur in facilities.