Cost-effectiveness analysis of partner notification program for human immunodeficiency virus infection in Japan

Successful implementation of partner notification program (PNP) as a part of human immunodeficiency virus (HIV) prevention strategies in some developed countries motivated the execution of cost-effectiveness analysis of this program in Japan. Total number of HIV infected individuals and best estimated number of their partners in 1995 were used to elicit incremental cost-effectiveness ratio over no partner notification program. Index cases and their HIV positive partners world change their sex practice to safer one, thus preventing HIV transmission at a certain rate. This was translated to prevention of certain number of new HIV carriers and finally life years gained were calculated for it. The incremental cost-effectiveness ratio was US$ 4,930 per life year gained. Sensitivity analysis indicated that partner notification program was cost-effective over a wide range of assumptions. These results compare favorably with other medical interventions in Japan. In conclusion, the results of this analysis strongly support the implementation of partner notification program as a part of HIV prevention strategies in Japan.


Analysis of effectiveness
The analysis of effectiveness was based on intention to treat.The primary health outcome was the number of HIV preventable cases.

Effectiveness results
The number of HIV preventable cases was 55 (47 HIV carriers with an average new HIV per HIV infected individual of 0.17.From this 47 HIV positive partners, another 8 could be traced).

Modelling
Not considered.

Outcomes assessed in the review
Effectiveness estimates derived from a review were the average new HIV per HIV infected individual, initial T4 cell distribution of the carrier and life expectancy of the HIV infected individuals according to the T4 cell distribution.

Study designs and other criteria for inclusion in the review
No specific study designs were stipulated by the authors as inclusion/exclusion criteria.

Sources searched to identify primary studies
Not stated.

Criteria used to ensure the validity of primary studies
Not stated.

Methods used to judge relevance and validity, and for extracting data
Not stated.

Number of primary studies included
10 studies were included in the review.

Methods of combining primary studies
Narrative method.

Investigation of differences between primary studies
Not undertaken.

Estimates of effectiveness and key assumptions
The initial T4 cell distribution among the HIV carrier was assumed to be similar to that found among 1,665 asymptomatic persons in the Multicentre Cohort Study:T4>500 cells/mm?3,59%; T4=201-500 cells/mm?3,36.4%;T4<200 cells/mm?3,4.6%.The mean time to develop AIDS was 10.75 years, 9 years and 2 years in the T4>500 cells/mm?3,T4=201-500 cells/mm?3 and T4<200 cells/mm?3groups, respectively.All partners notified were assumed to test ELISA and those with positive result to have additional ELISA and western blot test for confirmatory purposes.Ancillary costs were assumed to be 25% of the medical care cost.

Measure of benefits used in the economic analysis
The outcome measure was the number of years gained being the sum of the life expectancy of the HIV prevented individuals discounted at standard rate.

Direct costs
Costs of counselling of the index cases, locating partners, counselling and testing of the partners, initial check-up, follow-up and treatment of the newly found HIV carriers among the partners, treatment of AIDS and treatment of individuals during their life years gained were included in the analysis.Resource and cost data were reported separately.An annual discount rate of 5% was applied.The quantity/cost boundary adopted was the hospital.The price year was 1997.

Statistical analysis of costs
Not undertaken.

Indirect Costs
Not considered.

Sensitivity analysis
A one-way sensitivity analysis was undertaken on the number of newly found HIV positive individuals per index case, acceptance of HIV testing among the notified partners, average number of partners per index case, costs for counselling, physician visits costs, laboratory tests costs, drugs and locating partners costs and ancillary costs.

Estimated benefits used in the economic analysis
The net life years gained by the PNP was 181.

Cost results
The costs for follow-up and antiviral treatment of newly found HIV carriers were $1.8 million (39%), costs for the treatment of AIDS till death were $0.69 million (36%), costs for medical care during the gained life years were $0.48 million (10%), costs for ancillary care were $0.49 million (11%) and costs for locating, counselling and testing of the partners were $0.18 million (4%).An annual discount rate of 5% was applied.

Synthesis of costs and benefits
The incremental cost-effectiveness ratio was $4,930 per life year gained over "no PNP strategy".Sensitivity results indicated that PNP was cost-effective over a wide range of assumptions.Compared with other medical interventions (Fecal Occult Blood Test, Total Colonoscopy, Screening for gastric cancer in male/female and HIV screening for the population with 1% prevalence), the PNP strategy was far more cost-effective.The sensitivity analysis results were again favourable for the PNP strategy.