Costs and Outcomes of AIDS Treatment Delivery Models

Sydney Rosen ab, Lawrence Long b, Ian Sanne bc

aCenter for International Health and Development, Boston University, Boston, MA USAbHealth Economics Research Office, Wits Health Consortium, Johannesburg, South AfricacClinical HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa

February 2008

Background

Rationale For This Study• Despite rapid expansion of national antiretroviral

treatment (ART) programs, little is known about the economics of providing ART in Africa.

• Most available cost estimates are based on pre-rollout experience, atypical providers, and/or clinical trials.

• Most cost-effectiveness analyses compare treatment to no-treatment scenarios or model different drug or monitoring regimens. Delivery models and settings are usually not considered.

• Better information is needed about the costs and outcomes of treatment under different delivery models and in different settings.

• Here we present:– Methodology for estimating cost/outcome ratios using

routinely collected data– Results using this methodology at four sites in South

Africa.

• For various models of treatment delivery, as represented by specific study sites, estimate the average cost:– Per patient initiated on ART.– To produce a patient who is in care and responding to

therapy after 12 months (or 24, or 36...)• Identify the main drivers of ART costs and differences

between sites.• Explore the relationship between outcomes and costs.

(Does investing more resources by the provider produce better outcomes, or is it all about the patients?)

• Develop an easily understandable and implementable methodology for analyzing and presenting differences in the outcomes and costs of different ART delivery models.

Objectives

Methods

• Cost-outcome analysis (not standard cost-effectiveness analysis).

• Medical record review only—no contact with patients required.• Cost estimates include all resources used by provider. (Not

limited to resources paid for by site or cost to funder or donor.)• Steps:

– Select sites representing common or promising models of treatment delivery.

– Select a representative sample of ART patients from each site.

– Calculate the cost of all resources used to treat each subject for the 12 months following ART initiation.

– Determine each study subject’s outcome 12 months after ART initiation.

– Estimate the average cost per patient treated and per outcome achieved.

Overview

Site Selection and Study Population

• Site selection criteria– >100 adult patients initiated on ART more than 12

months before analysis.– Patient records computerized or well maintained hard

copy files.– Agreement with the site and relevant authorities.

• Sample selection criteria– >18 years old. – Initiated ART at site.– Did not transfer to another treatment site in the first 12

months.– Enrol a random or representative sample of eligible patients at

each site.

Data Collection

• Medical record review for patients in sample:– Patient characteristics (as available)– Baseline health data (t = 0)– Resource usage data (t = 0 …12)– Outcome health data (t = 12).

• Unit cost estimates:– Obtain from site management and site records– Variable costs (drugs, labs, and clinicians’ time)– Fixed costs (infrastructure, utilities, equipment,

administrative staff, etc.).

Data Analysis: Outcomes

• Outcomes are assessed 12 months + / - 2 months (i.e. 10-14 months) after date of starting ARVs.

• All outcomes are based on patient status at the initiating clinic.

• Patients are excluded from the sample if they:– are known to have transferred to another site within 12

months of starting ART.– were eligible for treatment but were never dispensed

any ARVs.

Data Analysis: Outcomes (Cont.)

• NIC: “No longer in care at study clinic”– Died (with confirmation in file); or – No longer attending initiating clinic (missing a doctor’s

visit or medication pickup > 3 months, reason unknown).• NR: “In care but not responding”

– Condition: WHO Stage III or IV condition at last visit; or– Viral load: detectable (>400 copies); or– If no viral load done, CD4 change: < 50 cells increase.

• IC: “In care and responding” – Viral load: undetectable (<400 copies); or– If no viral load done, CD4 change: > 50 cells increase; or– If no viral load or CD4 done, no current WHO Stage III or

IV condition at last visit.

Data Analysis: Outcomes (Cont.)

Decision point 12 months after ART initiation

Indicator at 12 month point

Patient outcome

Current WHO Stage III or IV condition at last visit

Yes

Increase ≥ 50

Increase < 50

Viral load reported in 12 +/- 2 months of starting point?

No

Yes Detectable

Undetectable In care and responding

CD4 count reported in 12 +/- 2 months of starting point? Yes

In care but not responding

Subject still attending study clinic at end of month 12?

Yes

Died No longer in careNo

No

Stopped attending No longer in care

In care but not responding

In care and responding

In care but not responding

No WHO Stage III or IV condition at last visit

Yes In care and responding

No

Data Analysis: Costs

• For patients remaining in care for the full year, include all fixed and variable costs for full 12 months following treatment initiation.

• For patients no longer in care, include all variable costs; pro-rate fixed costs until death or final visit.

• Estimate costs at prices for a specified year (e.g. 2007).

Data Analysis: Cost-Outcome Ratios

Ratio Formula

Average cost per patient treated (N)All costs of all subjects in study

N = all subjects in study

Average cost per patient in care and responding (IC)

All costs of subjects in care and respondingNic = only subjects in care and responding

Average cost per patient in care but not responding (NR)

All costs of subjects in care but not respondingNnr = only subjects in care but not responding

Average cost per patient no longer in care at study clinic (NIC)

All costs of subjects not in careNnic = only subjects not in care

Average cost to produce a patient in care and responding

All costs of all subjects in study Nic = only subjects in care and responding

Results from Four Sites in South Africa

Sites

Site Description Location in South Africa

# on ART (mid 2007)

1Large, urban, public academic hospital

Gauteng Province 5,700

2Donor-funded contract between ≈ 30 private GPs and treatment NGO

Multiple 1,400

3NGO dedicated AIDS clinic in a rural area

Mpumalanga Province 900

4NGO primary care clinic serving informal settlements

Gauteng Province 700

OutcomesOutcome at month 12 Site 1

(Public hospital)

Site 2 (Private

GPs)

Site 3 (Rural NGO

clinic)

Site 4 (Periurban NGO clinic)

In care and responding (IC) 67 52 63 76

Undetectable viral load 37 27 41 54

CD4 increase ≥ 50 4 1 6 5

No WHO stage III or IV condition 26 24 16 17

In care but not responding (NR) 7 3 9 11

WHO stage III or IV condition 1 0 2 5

Detectable viral load 6 3 1 3

CD4 increase < 50 0 0 6 3

No longer in care at study clinic (NIC)

26 45 28 13

Died 2 19 13 7

Stopped attending 24 26 15 6

All subjects 100 100 100 100

Outcomes (Cont.)Outcome at month 12 Site 1

(Public hospital)

Site 2 (Private

GPs)

Site 3 (Rural NGO

clinic)

Site 4 (Periurban

NGO clinic)

In care and responding (IC)

% of sample 67% 52% 63% 76%

Median starting CD4 count 96 89 39 111

In care but not responding (NR)

% of sample 7% 3% 9% 11%

Median starting CD4 count 88 74 53 110

No longer in care (NIC)

% of sample 26% 45% 28% 13%

Median starting CD4 count 103 78 107 55

Relative risk of being NIC, compared to Site 1 [95% CI]

1.00 1.73 [1.17-2.57]

1.08 [0.68-1.70]

0.50 [0.27-0.92]

Average Cost Per Outcome, Months 0-12

All costs are in 2006 USD (R6.8=$1).

*Difference from Site 1 significant at 5% level.

Outcome Site 1 (Urban public

hospital)

Site 2 (Private

GPs)

Site 3 (Rural clinic)

Site 4 (Periurban

clinic)

All outcomes (cost per patient treated) (N)

$716 $896* $932* $1,126*

In care and responding (IC) $850 $1,186* $1,157* $1,210*

In care but not responding (NR)

$951 $1,108* $1,113* $1,297*

No longer in care (NIC) $306 $567* $368 $489

Cost-Outcome Ratios

RatiosSite 1

(Public hospital)

Site 2 (Private

GPs)

Site 3 (Rural clinic)

Site 4 (Periurban

clinic)

Average cost per patient treated (= all costs / all patients)

$716 $896 $932 $1,126

Proportion of patients IC 67% 52% 63% 76%

Average cost to produce a patient in care and responding (= all costs / IC patients)

$1,068 $1,723 $1,480 $1,482

If every patient could be kept in care and responding, average cost/patient treated

$850 $1,186 $1,157 $1,210

Distribution of Cost Per Patient Treated (Site 1)

R 0

R 1,000

R 2,000

R 3,000

R 4,000

R 5,000

R 6,000

R 7,000

R 8,000

R 9,000

Site 1 subjects

Ave

rag

e c

ost

/su

bje

ct

In care and responding In care but not responding No longer in care

Breakdown of Cost Per Patient Treated

Item Site 1 (Urban public

hospital)

Site 2 (Private

GPs)

Site 3 (Rural clinic)

Site 4 (Periurban

clinic)

Drugs $331 (46%) $500 (56%) $399 (43%) $465 (41%)

Lab tests $197 (27%) $74 (8%) $111 (12%) $309 (27%)

Outpatient visits $116 (16%) $79 (9%) $185 (20%) $216 (19%)

Fixed costs $72 (10%) $242 (27%) $238 (26%) $136 (12%)

Total $716 (100%) $896 (100%) $932 (100%) $1,126 (100%)

Resource Utilization

Resource utilization per patient treated (12 months following ART initiation)

ResourceSite 1

(Urban public hospital)

Site 2 (Private

GPs)

Site 3 (Rural clinic)

Site 4 (Periurban

clinic)

Doctor/ nurse visit 6.1 2.7 9.1 10.9

Pharmacy visit 9.0 n.a. 8.3 10.4

Viral load 1.4 1.2 1.0 2.8

Liver function test 2.8 1.3 1.2 3.3

Lactate test 0.2 0.1 0.0 0.7

Pap smear 0.2 0.0 0.0 0.9

CD4 count 2.7 1.2 2.0 4.0

Full blood count 2.8 1.2 1.8 3.2

Conclusions

Preliminary Conclusions

• It is possible to generate useful information from routinely collected data using simple methods.

• Outcomes and costs of ART differ by site and presumably by model; magnitude of differences varies.

• Cost-effectiveness of ART can be sabotaged by high costs, high patient attrition, or both.

• Patient characteristics are probably an important determinant of outcomes.

• Treatment facility scale is likely an important determinant of costs.

• Once outcomes are considered, perceptions of resource investments and needs may change (e.g., greater investment in retaining patients in care would likely be cost effective, though more expensive).

Limitations of These Findings

• Only 4 sites completed so far; generalizability limited.• Sample size at each site is too small for stratification.• Estimates are of average, not marginal, costs.• Does not take patient differences into account.• Excludes some potentially important costs:

– Inpatient care – Care provided by other facilities (e.g. for TB)– Costs to patients themselves– Treatment programme management above the level

of the individual facility or project.

Ongoing Study

• Analyzing new sites in South Africa representing other models of treatment delivery (e.g. nurse-driven, primary health clinic-based, etc.).

• Extending the analysis to 24+ months after ART initiation.

• Expanding the analysis to pediatric treatment delivery models.

• Implementing the same evaluation in Kenya and Zambia.

Acknowledgements

• Participating clinics and their medical directors, staff, and patients

• Gauteng Department of Health• Right to Care • USAID (South Africa Mission and HIDN/HaRP)• PEPFAR• Colleagues at Boston University and the University of

the Witwatersrand

HERO Health Economics Research Office

Wits Health Consortium University of the Witwatersrand