Test-treatment strategies for patients suspected of having Lyme disease: a cost-effectiveness analysis.

PURPOSE: To examine the cost-effectiveness of test-treatment strategies for patients suspected of having Lyme disease.

DATA SOURCES: The medical literature was searched for information on outcomes and costs. Expert opinion was sought for information on utilities.

STUDY SELECTION: Articles that described patient population, diagnostic criteria, dose and duration of therapy, and criteria for assessment of outcomes.

DATA EXTRACTION: The decision analysis evaluated the following strategies: 1) no testing-no treatment; 2) testing with enzyme-linked immunosorbent assay (ELISA) followed by antibiotic treatment of patients with positive results; 3) two-step testing with ELISA followed by Western blot and antibiotic treatment for patients with positive results on either test; and 4) empirical antibiotic therapy. Three patient scenarios were considered: myalgic symptoms, rash resembling erythema migrans, and recurrent oligoarticular inflammatory arthritis. Results were calculated as costs per quality-adjusted life-year and were subjected to sensitivity analysis. Adjustment was made for the diagnostic value of common clinical features of Lyme disease.

DATA SYNTHESIS: For myalgic symptoms without other features suggestive of Lyme disease, the no testing-no treatment strategy was most economically attractive (that is, had the most favorable cost-effectiveness ratio). For rash, empirical antibiotic therapy was less costly and more effective than other strategies. For oligoarticular arthritis with a history of rash and tick bite, two-step testing was associated with the lowest cost-effectiveness ratio. Testing with ELISA and empirical antibiotic therapy cost an additional $880,000 and $34,000 per quality-adjusted life-year, respectively. For oligoarticular arthritis with one or no other features suggestive of Lyme disease, two-step testing was most economically attractive.

CONCLUSIONS

Neither testing nor antibiotic treatment is cost-effective if the pretest probability of Lyme disease is low. Empirical antibiotic therapy is recommended if the pretest probability is high, and two-step testing is recommended if the pretest probability is intermediate.