Antibiotic prophylaxis for haematogenous bacterial arthritis in patients with joint disease: a cost effectiveness analysis.

OBJECTIVE To assess the cost effectiveness of antibiotic prophylaxis for haematogenous bacterial arthritis in patients with joint disease. METHODS In a decision analysis, data from a prospective study on bacterial arthritis in 4907 patients with joint disease were combined with literature data to assess risks and benefits of antibiotic prophylaxis. Effectiveness and cost effectiveness calculations were performed on antibiotic prophylaxis for various patient groups. Grouping was based on (a) type of event leading to transient bacteraemia-that is, infections (dermal, respiratory/urinary tract) and invasive medical procedures-and (b) the patient's susceptibility to bacterial arthritis which was increased in the presence of rheumatoid arthritis, large joint prostheses, comorbidity, and old age. RESULTS Of the patients with joint disease, 59% had no characteristics that increased susceptibility to bacterial arthritis, and 31% had one. For dermal infections, the effectiveness of antibiotic prophylaxis was maximally 35 quality adjusted life days (QALDs) and the cost effectiveness maximally $52 000 per quality adjusted life year (QALY). For other infections, the effectiveness of prophylaxis was lower and the cost effectiveness higher. Prophylaxis for invasive medical procedures seemed to be acceptable only in patients with high susceptibility: 1 QALD at a cost of $1300/QALY; however, the results were influenced substantially when the level of efficacy of the prophylaxis or cost of prophylactic antibiotics was changed. CONCLUSION Prophylaxis seems to be indicated only for dermal infections, and for infections of the urinary and respiratory tract in patients with increased susceptibility to bacterial arthritis. Prophylaxis for invasive medical procedures, such as dental treatment, may only be indicated for patients with joint disease who are highly susceptible.