The cost-effectiveness of expanded HIV counselling and testing in primary care settings: a first look.

OBJECTIVE: To estimate the cost-effectiveness of approaches to expanded HIV counselling and testing.
DESIGN: A cost-effectiveness analysis.
SETTING: Primary care practices in the USA. PARTICIPANTS: New patient visits.
INTERVENTIONS: Two approaches were examined: (i) requesting all patients to complete an HIV-risk screening instrument, with counselling as well as testing offered only to patients disclosing risk factors ('risk histories' option); and (ii) routine offering of voluntary testing to all patients, with consent obtained but no pre-test counselling ('routine testing'). MAIN OUTCOME MEASURES: The primary outcome was the cost per infection identified. We also examined: (i) the costs and numbers of infections averted if individuals change their risk behaviours; and (ii) the additional years of life and quality-adjusted life years (QALY) gained as a result of earlier HIV testing and treatment for infected individuals.
RESULTS: Routine testing is the most cost-effective approach to identifying infected individuals at an incremental cost of US$4200 per infection identified. Although using risk histories is more costly and less effective than routine testing, it becomes similarly cost-effective using plausible ranges for sensitivity analyses. If at least 10% of HIV-positive individuals change their behavior, both routine testing and using risk histories would save money. If testing identifies infected individuals one year earlier than they otherwise would have been diagnosed, routine testing would cost US$22000 per QALY gained.
CONCLUSION: Routine testing is the most cost-effective approach to identifying new HIV infections. However, using risk histories may be similarly cost-effective under various assumptions. Both routine testing and using risk histories are more cost-effective than current practices.