Test-Treatment Strategies for Patients Suspected of Having Lyme Disease: A Cost-Effectiveness Analysis

doi:10.1059/0003-4819-128-1-199801010-00007

Test-Treatment Strategies for Patients Suspected of Having Lyme Disease: A Cost-Effectiveness Analysis

From Ottawa Civic Hospital, University of Ottawa, and Ottawa General Hospital, Ottawa, Ontario, Canada; National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; University of Kentucky, Lexington, Kentucky; and New England Medical Center and Tufts University Medical Center, Boston, Massachusetts. Acknowledgments: The authors thank Karen Kuntz, ScD, for interim advice, and Gary Bryant, MD, Ray Dattwyler, MD, and Len Sigal, MD, for assistance in the estimation of utilities. Requests for Reprints: Peter Tugwell, MD, Department of Medicine, Ottawa General Hospital, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada. Current Author Addresses: Drs. Nichol and Wells and Ms. Shea: Clinical Epidemiology Unit, Ottawa Civic Hospital, 1053 Carling Avenue, Ottawa, Ontario K1Y 4E9, Canada.

Abstract

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.