RELATIONSHIP RELATIONSHIPBETWEEN BETWEENADHERENCE ADHERENCETO TO ANTIRETROVIRAL ANTIRETROVIRALTHERAPY THERAPYAND ANDTHE THECOSTCOSTEFFECTIVENESS EFFECTIVENESSOF OFANTIRETROVIRAL ANTIRETROVIRALTHERAPY THERAPY

Habib MJ, Lawson KA, Summers KK, Eakin RT, Barner JC, Brown CM, Shepherd MD

University of Texas, Austin South Texas Veterans Health Care System

Introduction : Adherence Clinical and Economic Impact

Non-adherence to HAART is typical [1-10] Adherence is the critical determinant of survival [11] Mixed economic results [12-20]

Introduction: Objectives Adherence to ARV Therapy Cost-effectiveness of ARV regimens

1

Methodology Study Design Retrospective clinical data Markov model

Methodology : Inclusion Sample Texas Department of Veterans Affairs (VA) October, 1 1997 and September, 30 2003

Identifying HIV Infection Post 1994 ICD 9 Codes - 042, V08, 795.71 Pharmacy Claims

National Drug Code ARV

Methodology : Inclusion Prescription < 2 consecutive ARV prescriptions Rx/Dx CD4 350

200 < CD4 350

(A)

(B)

CD4 200 Asympt AIDS (C)

Symp AIDS

(D)

Methodology : Costs HERC

Inpatient & Outpatient [21-22]

Inpatient ICD codes

Outpatient CPT

Other Pharmacy (PBM) HIV-related medications

3

Methodology : QALYs

HIV-Related Utility Scores [23] Clinical State Baseline A

0.90

B

0.90

C

0.75

D

0.56

Results : Descriptive Characteristics Characteristics

Texas Gender Race Mean Veterans N N Age Healthcare (%) (%) (SD) Region Male Female Black White Other Missing North, 48 648 38 112 162 37 375 Central, (10.2) (95.0) (5.0) (16.3) (23.6) (5.4) (54.7) South Treatment Round N

HAART Refractory AIDS

Treatment Round N

HAART Refractory AIDS

Results : Descriptive Adherence Markov MarkovState StateDiagram Diagram

Frequency

150

100

50

0 0.00

0.20 0.40 0.60 0.80 Adjusted Patient Overall Adherence Ratios

1.00

4

Results : Annual Costs Overall HIV Medical Total

Clinical State A

Median Mean 95% Cl ($) Cost ($) Cost ($) 11,570 14,568 13,071 16,065

0

Max ($) 193,852

B

14,066

20,285

17,871

22,700

0

193,289

C

18,039

31,708

26,345

37,072

0

261,954

D

22,091

38,352

30,123

46,580

0

356,014

All

14,240

22,751

20,924

24,578

0

356,014HAART

Treatment Round N

Min

Refractory AIDS

Results : Clinical Annual Transition Probability-Adherent

From Clinical State

A

Annual Transition Probability To Clinical State B C D

DEAD

A

0.8571

0.1167

0.0004

0.0258

0.0000

B

0.3717

0.4521

0.1101

0.0556

0.0105

C

0.0001

0.4621

0.3122

0.1576

0.0680

D

0.1509

0.2550

Treatment0.1170 0.4080 Round N

HAART 0.0691 Refractory AIDS

Results : Clinical Annual Transition Probability-Non-Adherent Markov MarkovState StateDiagram Diagram From Clinical State

A

Annual Transition Probability To Clinical State B C D DEAD

A

0.8115

0.1478

0.0040

0.0238

0.0129

B

0.2049

0.5511

0.1838

0.0315

0.0287

C

0.0090

0.2460

0.4782

0.1976

0.0692

D

0.1192

0.1304

Treatment 0.3915

0.2011

HAART 0.1578 Refractory

Round N

AIDS

5

Methodology : Modeling Assumptions

Six year ARV Treatment Duration Effect

Adjusted Clinical Efficacy of ARV using a RelativeRisk

Results : Markov Cohort 20-Year Simulations

Adherence Behavior Adherent Non-Adherent Adherent Non-Adherent

Total Costs ($)

Cost ($) Per QALY

QALYs

Six-Year Effect 228,984 10.65 209,766 8.77 Continuous Effect 227,329 10.87 211,709 9.08Treatment

QALY: Quality Adjusted Life Years

10,240 8,722 -

Round N

HAART Refractory AIDS

Results : Markov Cohort 5-Year Simulations

Cost ($) Per QALY Continuous Antiretroviral Treatment Duration Effect Adherent 75,362 3.82 Dominant Non-Adherent 75,941 3.66 Adherence Behavior

Total Costs ($)

QALYs

QALY: Quality Adjusted Life Years Treatment Round N

HAART Refractory AIDS

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Discussion Study design

Prospective naturalistic vs Expert Panel vs Literature

VS

Hybrid Retrospective, Modeling

Association between adherence and improved health outcomes Lifetime costs of adherent behavior > than non-adherent behavior Implications

Interventions to improve adherence

Limitations

Generalizability Adherence measures Sample size, power Extrapolation using short-term data Incomplete model

References [1] Singh N, Squier C, Sivek C, Wagener M, Nguyen MH, Yu VL. Determinants of compliance with antiretroviral therapy in patients with human immunodeficiency virus: prospective assessment with implications for enhancing compliance. AIDS Care. 1996;8(3):261-9. [2] Frick PA, Gal P, Lane TW, Sewell PC. Antiretroviral medication compliance in patients with AIDS. AIDS Patient Care & Sexually Transmitted Diseases 1998;12(6):463-70. [3] Eldred LJ, Wu AW, Chaisson RE, Moore RD. Adherence to antiretroviral and pneumocystis prophylaxis in HIV disease. Journal of Acquired Immune Deficiency Syndromes 1998;18(2):117-25. [4] Friedland GH, Williams A. Attaining higher goals in HIV treatment: the central importance of adherence. Acquired Immune Deficiency Syndromes 1999;13(Suppl 1):S61-72. [5] Deeks SG. Determinants of virological response to antiretroviral therapy: implications for longterm strategies. Clinical Infectious Diseases. 2000;30(Suppl 2):S177-84. [6] Sethi AK, Celentano DD, Gange SJ, Moore RD, Gallant JE. Association between adherence to antiretroviral therapy and human immunodeficiency virus drug resistance. Clinical Infectious Diseases 2003;37(8):1112-8. [7] Martin-Fernandez J, Escobar-Rodriguez I, Campo-Angora M, Rubio-Garcia R. Evaluation of adherence to highly active antiretroviral therapy. Archives of Internal Medicine 2001;161(22):273940. [8] Fogarty L, Roter D, Larson S, Burke J, Gillespie J, Levy R. Patient adherence to HIV medication regimens: a review of published and abstract reports. Patient Education and Counseling 2002;46(2):93-108. [9] Paterson DL, Swindells S, Mohr J, Brester M, Vergis EN, Squier C, et al. Adherence to protease inhibitor therapy and outcomes in patients with HIV infection. Annals of Internal Medicine 2000;133(1):21-30.

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References [10] Hogg R, Yip B, Chan K, O'Shaughnessy MV, Montaner JSG. Nonadherence to triple combination therapy is predictive of AIDS progression and death in HIV-positive men and women. 7th Conference on Retroviruses and Opportunistic Infections; 2000; San Francisco. [11] Wood E, Hogg RS, Yip B, Harrigan PR, O'Shaughnessy MV, Montaner JSG. Effect of medication adherence on survival of HIV-infected adults who start highly active antiretroviral therapy when the CD4 cell count is 200 to 350 cells/microliter. Annals of Internal Medicine 2003;139 (10):810-6. [12] Vincent LG. A study of adherence to HIV antiretroviral therapies and the economic impact in a managed care organization. Minnesota, 2003. [13] Sullivan SD, Kreling DH, Hazlet TK. Noncompliance with medication regimens and subsequent hospitalizations: a literature analysis and cost of hospitalization estimate. Journal of Research in Pharmaceutical Economics 1990;2(2):19-33. [14] Coambs RB, Jensen P, Her MH, Ferguson BS, JL J, W WJS, et al. Review on the scientific literature on the prevalence, consequences, and health costs of noncompliance and inappropriate use of prescription medication in Canada: Pharmaceutical Manufacturers Association of Canada, 1995:103-20. [15] Einarson TR. Drug-related hospital admissions. Annals of Pharmacotherapy 1993;27(7-8):83240. [16] Cleemput I, Kesteloot K, DeGeest S. A review of the literature on the economics of noncompliance. Room for methodological improvement. Health Policy. 2002;59(1):65-94. [17] Billups SJ, Malone DC, Carter BL. The relationship between drug therapy noncompliance and patient characteristics, health-related quality-of-life, and health care costs. Pharmacotherapy 2000;20(8):941-9.

References

[18] Becker R, Shakur U. The impact of drug compliance on the cost of treating HIV/AIDS in Africa. ISPOR Fourth European Conference; 2001 November 11-13; Cannes, France. [19] Munakata J, Benner JS, Becker SL, Dezil CM, Hazard EH, Tierce JC. Clinical and economic outcomes of non-adherence to antiretroviral therapy in patients with HIV. International Society For Pharmacoeconomics and Outcomes Research; 2004 May 2005; Washington DC. [20] Huang X. Modeling costs and opportunistic infections for Maryland Medicaid HIV/AIDS patients:Effects of patient non-adherence to antiretroviral drugs. University of Maryland, 2001. [21] Phibbs CS, Yu W, Barnett PG. HERC S outpatient average cost dataset for VA care: Fiscal Years 1999-2002: Health Economic Resource Center, 2003. [22] Wagner TH, Chen S, Yu W, Barnett PG. HERC's inpatient average cost datasets for VA Care Version 4: Fiscal Years 1998-2002: Health Economic Research Center, 2003. [23] Honiden S, Sundaram V, Nease RF, Holodniy M, Lazzeroni LC, Zolopa A, et al. The Effect of Diagnosis with HIV Infection on Health-Related Quality of Life. Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation. 2006;15(1):69-82.

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