Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

12th World AIDS Conference

Abstracts 24122-24125 465

480*/24122 Costing HIV/AIDS: The Canadian HIV/AIDS
economic research initiative
Janet Dubrack1, T. Albert2, B. Jones3, J. Martin3, R. Shearer3, G. Williams2.
11844B, Jeanne Mance Building, Tunney's Pasture, Postal Locator 1918B1
Ottawa, Ontario K1A 1B4; 2Canadian Policy Researxh Networks Inc. (CPRN)
Ottawa, Ontario; 3Health Canada, HIV/AIDS Policy, Coordination and Programs
Division Ottawa, Ontario, Canada
Issue: A critical need to measure the economic implication of HIV/AIDS in Canada
in order to enable all stakeholders to choose the best, most cost effective practices
gave rise to this initiative.
Project: The Government of Canada has conducted a four-year Economic
Research Initiative to obtain a comprehensive portrait of the costs and benefits of
HIV/AIDS care, treatment and support, and to determine the costs and benefits
of HIV prevention. The initiative was developed in consultation with researchers,
the community, the insurance industry and federal and provincial governments.
The initiative consists of 13 research projects, and annual symposia attended by
all stakeholders to share research results and to discuss the program and policy
implications of the research findings. An interim paper, The Economic Burden of
HIV/AIDS in Canada (November 1997), and a final synthesis report (March 1998)
have been published. The research includes: comprehensive costing studies of
institutional and informal care (societal perspective); cost-benefit and cost-utility
analyses of treatment options; care patterns and costs for marginalized populations; comparative study of international prevention programs (Canada, France,
United Kingdom, Australia, United States, Spain and Italy); mathematical model
of HIV prevention; evaluation of prevention programs for street-involved intravenous drug users; and the development of a national HIV prevention database.
An important thrust of the initiative has been research capacity building in the HIV
community and the recruitment of young researchers into the field of HIV health
economics.
Results: This initiative will influence policy formulation at all levels of government, and program development in terms of best practices which are most
cost-effective for all stakeholders. This global initiative by a national government
is the first of its kind in the world.
Lessons learned: The magnitude of the economic burden of HIV/AIDS from
a societal perspective has been estimated in detail according to populations and
geographic regions (total national cost is $570 CDN million annually; cumulative
cost to date of $36.4 CDN billion. Direct cost per HIV episode is $153,000 CDN).
The cost benefit of preventing infection relative to treating it has been estimated:
in order to break even on public sector investment in prevention, we need only
prevent 106 cases per year (present incidence is an average of 3,900 cases a
year).
24123 The economic impact of the change in prescribing
antiretroviral therapy
Nikola Ostrop12, W. Davidson2, M.J. Gill2. 1Southern Alberta Clinic, 231, 906 8
Avenue S.W., Calgary, Alberta, T2P 1H9; 2Southern Alberta Clinic, Foothills
Medical Centrem, Calgary, Alberta, Canada
Objective: To determine the economic impact of changes in antiretroviral prescribing through a comparison of drug and in-patient costs correlated to CD4 cell
counts between 1995 and 1997.
Methodology: Data was collected from the above time period for all HIVinfected patients actively followed at the Southern Alberta Clinic (S.A.C.). Prescribing patterns and costs of drugs and hospitalizations per patient were assessed
between 1995 and 1997 data according to CD4 cell counts.
Results: On February 1, 1995, 515 patients were followed at S.A.C.; 38%
were receiving antiretroviral therapy (of these 79% were on mono, 8% on double
and none on triple combination therapy; 13% were enrolled in clinical trials). On
December 31, 1997, 77% of 533 active patients were being treated (1% on mono,
29% on double and 69% on triple combination therapy, 1% in clinical trials).
A\ cr ( tc ('ost of Anliretrovirals(('an$)/pt/mo Average Cost of Hospitalhzaions(('anS)/pt/m(
700~ 160 O f i
600 140.
500 120,
4000
200 1.19971 60
40.:.

316*/24124 Breast or bottle? A cost-effectiveness evaluation
of formula feeding for the prevention of postnatal
transmission of HIV in an urban South African
setting
Neil S6derlund', G.E. Gray2, K.J. Zwi3. Centre for Health Policy, PO Box 1038,
Johannesburg, 2000; 2Perinatal HIV Research Unit, Baragwanath,
Johannesburg; 3Community Paediatrics, University of Witwatersrand,
Johannesburg, South Africa
Introduction: Mother-to-child transmission of HIV by breast feeding has now
been well documented. Breastfeeding confers significant infant mortality and
morbidity reductions and it is unclear whether the risk of HIV infection from breast
milk outweighs the mortality and morbidity risks of formula feeding in developing
countries. This study sought to evaluate the cost effectiveness of formula feeding
as an intervention for the prevention of mother-to child transmission of HIV.
Methods: Data were taken from the actual community studied, and where
unavailable, from a synthesis of studies from other developing countries. Weibull
hazard functions, calibrated to existing infection and mortality data, were used
to simulate infection and mortality rates under various intervention assumptions.
Intervention costs, the costs of care for HIV and non-HIV related conditions were
estimated from data from the hospital serving the study community. Benefits
were measured in terms of deaths averted and life-years gained. The simulated
population was followed up for eight years, with costs and benefits discounted at
5% per annum.
Results: Prenatal screening and advocating formula for infected mothers, with
or without actually supplying formula was estimated to cost around $5000/childhood death averted, or $280/discounted life year saved. Estimates were sensitive
to HIV sero-prevalence levels, non-HIV infant mortality rates and the relative risk
of morbidity or mortality associated with formula feeding in non-infected children.
Screening costs made up between 44% and 94% of total programme marginal
costs, suggesting that the combination of formula-feeding with perinatal interventions might be highly cost effective since the screening expense is only incurred
once.
Conclusions: Compared to cost-effectiveness information in the 1993 World
Development Report, formula feeding interventions appear less cost effective than
most front-line public health programmes for children, but compare favourably
with typical adult screening programmes, and are more cost effective than many
curative clinical interventions recommended for middle income countries.
24125 Cost-effectiveness of protease inhibitors
Aslam Anis', J.J. Spinelli1, R.S. Hogg2, J.S.G. Montaner2,
M.V. O'Shaughnessy2, M.T. Schechter3. 1620-1081 Burrard St., St. Paul's
Hospital, Vancouver; 2Center for Excellence in HIV Vancouver; 3Canadian HIV
Trials Network, Vancouver, BC, Canada
Objective: To estimate cost effectiveness (c/e) ratios for protease inhibitors (PI).
Methods: The incremental effectiveness of PI modeled based on Hammer et
al. (1997). Years of life gained per individual were computed as the sum of the
estimated survival benefit over a 15 year period. Three models were estimated:
1) one-time benefit only, 2) continuous benefit, 3) exponentially decreasing benefit. The incremental annual cost of PI inclusive regimens was estimated from
a longitudinal cohort of enrollees in the province-wide drug treatment program
(DTP) who were receiving antiretrovirals (ARV) between 0596 & 0497. Incremental plasma viral load (pVL) testing costs were calculated according to the
DTP recommendations that pVL & CD4 counts be performed quarterly if CD4
< 500/cu mm or pVL > 10000 copies/ml so that the appropriate ARV regime
could be implemented. All other health care costs were assumed to be identical
regardless of ARV regime. All costs are in 1996 Canadian $'s ($1 US = $1.4Cdn).
A discount rate of 5% was used. Baseline analysis was the discounted present
value of costs divided by life years gained. Sensitivity analysis was performed by
varying costs & discounting survival.
Results: Incremental survival stratified by disease severity was (.46, 3.78 &
1.35; cd4 < 50), (.11,.91,.32; cd4 > 50) & (.29, 2.37,.86; all patients) years
under models 1, 2 & 3 respectively. The average annual incremental cost of PI
inclusive ARV regimes per DTP enrollee equaled $2318 which represents 39% of
the "hypothetical" annual cost of $5891 when assuming 100% tolerability & compliance. Incremental pVL cost equaled $192. Baseline c/e ratios equaled (61,598,
7,549, 21,125; cd4 < 50), (247,084, 31,250, 88,788, cd4 > 50) & (97,054, 12,064,
33,259; all patients) $'s/(life year gained) under models 1, 2 & 3 respectively.
Assuming drug costs double (80% of "hypothetical" & high pVI costs - $239),
c/e ratios were (123,289, 15,110, 42,282; cd4 < 50), (494,543, 62,548, 177,709;
cd4 > 50) & (194,255, 24,146, 66,569; all patients) $'s/(life year gained). When
survival is also discounted, c/e ratios equaled (78,362, 11,221, 28,969; cd4 < 50),
(333,290, 47,900, 127,570; cd4 > 500) & (127,913, 18,272, 46,986) respectively.
Conclusion: The c/e of PI are variable depending on the assumptions used to
model long term survival i.e., beyond the currently available follow-up data on PI
and disease severity as measured by CD4 counts. Nonetheless, the c/e ratio of
PI is within the range of currently funded drugs and other medical interventions
in the developed world.

100
0

<75 75-200 200- >500
500

I<75 75-200 200- >500
500

Conclusion: A significant change in prescribing of anitretroviral agents from
1995 to 1997 has lead to a considerable increase in cost, irrespective of CD4 cell
count. Costs of hopitalizations only decreased for the patient group with a CD4
less than 75 cell/mm3.