arv adherence model

Presentation Developed by Doreen Ofosu

3 – 5 October, 2011

Frontiers of Retrovirology2011


The Dose-Adherence Model:

A Critical Review of the Computation of Level of Adherence to Antiretroviral Drug Regimen

By: Doreen Ofosu Kwame Nkrumah University of Science & Technology

Kumasi, Ghana


Outline

• Research Objectives

• Research Background

• Literature Review

• Further Research

• Significance of Study

• The Study


Outline Cont'd• Questionnaire

• Resultso Result of Objective Ao Results of Objective B

• Conclusion

• Recommendation

• Bibliography

• Acknowledgment

• Further Information


Research Objectives

• Objective ATo develop a model for determining long-term dose-adherence

•Objective BTo determine the dose-adherence levels of ART clients in the Eastern Region of Ghana


Research Background

Adherence Defined• Usually taking 80% or more of the prescribed regimen. (Chesney, 1997)

• In people with HIV infection, reports of adherence range from 25% to 85%.

(Bachiller et al., 1998)


Research Background Cont'd

HIV treatment adherence is essential

Source: YouTube Video Uploaded by Mindset Health

https://www.youtube.com/watch?v=lCU1Bl2Vh_w


Literature Review

1. Bachiller et al., 1998... reports of adherence range from 25% - 85%.

2. Weiser et al., 2003... adherence for ARV therapy ranges from 40% to 60% with an average of 50% adherence level.


Literature Review Cont'd

3. Haubrich et al., 1999... labeled patients as adherent if at least 80% of the prescribed doses are taken.

4. Paterson et al., 2000... it has been estimated that at least 95% of the prescribed dose is needed to maintain HIV viral suppression and to prevent the occurrence of drug resistance.


Further Research

• No known model for computing long-term adherence

• Sample tweets on next slide confirms this


Tweets


Significance of Model

Considers

• Long-term default frequency

• Short-term recall of missed doses or self-report


The Study

• Study Populationo ART clients

• Inclusion Criteriao Must be 18 years and aboveo Must be an outpatiento Must be willing to participate

• Exclusion Criteriao Below 18 yearso Weak clients


The Study Cont'd Ethical Considerations

• Permission sought from regional, district and facility administrations before commencement of study

• Client consent sought

• Consent form explained to client in detail

• Willing clients sign consent forms and given a copy


The Study Cont'd

Study Area• Eastern Region of Ghana

Facts About the Eastern Region of Ghana• Highest HIV prevalence n the country

• 2004 HIV Sentinel Survey puts HIV prevalence of the Region at 6.5% against the national figure of 3.1%

• 2008 regional prevalence 4.5% against national rate of 1.7%

Study Coverage• Fifteen of the then seventeen districts


The Study Cont'd

Study Sites• Social support groups – eleven • Ten districts

ART facilities - three

• Regional hospital

• District hospital

• Mission hospital


The Study Cont'd

Methodology

Study Design• Cross-sectional

Data Collection Tool• Standardized questionnaires

Data Collection Technique• Exit interviews


Questionnaire Administration On Dose-Adherence

Questions Asked and Responses


Questionnaire

• Q. ART duration (expected doses)A. One month to three years

• Q. Missed dosesA. Yes or no

• Q. Reasons for missing if yes A. Forgetfulness Carelessness Stopping the drug when feeling better / worse Other (Specify)


Questionnaire Cont'd• Q. Ever re-started if defaulted

A. Yes or no

• Q. Reasons for re-starting if yesA. I got my drugs Returned from journey I was feeling weak Frequent rashes Headaches Swellings Anxiety Frequent coughs Other (Specify)


Questionnaire Cont'd

• Q. Difficulty in adhering to dose regimenA. Yes or no

• Q. Frequency at which doses were missed (Default Frequency)A. Defaulted continuously for weeks Missed often Missed a few times Never missed


Questionnaire Cont'dFrame of long-term default frequency question

• Educational level

• Occupation

Seasons Used• Religious

• Traditional

• Farming

• Fishing

• Academic calendars

• National holidays


Results


Result Of Objective A

The Dose-adherence model developed from

• Expected doses

• Default frequency

• Observed doses


Results of Objective A Cont'dComputation of Expected Doses (E)

• Number of weeks on ART (ART duration) multiplied by 14

Computation of Default Frequency (Literature Based)

• 25% [1]

• 50% [2]

• 80% [3]

• 100% [4]

Respondent frequency synonymous with doses missed


Results of objective A Cont'd

Computation of Observed Doses (O)

• Defaulted continuously for weeks = E multiplied by 25% [1]

• Missed often = E multiplied by 50% [2]

• Missed a few times = E multiplied by 80% [3]

• Never missed = E multiplied by 100% [4]


The Dose-Adherence Model



• A Mathematical Model for Determining Long-term Level of Adherence to Dose Regimen:

"Level of adherence is the ratio of the observed doses (O) and the expected doses (E)." - Ofosu et al., (2008)

Otherwise stated as:

"Level of adherence is directly proportional to the frequency at which doses are missed." - Ofosu et al., (2008)


The Dose-Adherence Model Cont'd

Mathematically:

• Level of Adherence (%) = O / E

•Level of Adherence (%) = Default Frequency


Results of Objective BRespondents' statistically significant at p-value of 0.051

• 25% - 1.1% of respondents





Conclusion


• Complements other methods of deducing adherence level

• Considers long-term default frequency and short-term recall


Recommendation

• Digitising long-term adherence computation using the Dose-adherence Model


Bibliography1. Bachiller, P., Arrando, F.R., Liceago, G., Iribarren, J.A. & Olloquiegui, E. (1998).

Drug Compliance in Patients Starting Saquinavir. 12th World AIDS Conference,Geneva, Abstract 32392.

2. Chesney, M.A. (1997). New HAART Therapies: Adherence Challenges and Strategies Evolving HIV Treatments: Advances and the Challenges of Adherence of Adherence. 37th ICAAC Symposium, Toronto, Canada.

3. Haubrich R.H., Little S.I., Currier J.S., Forthal D.N., Kemper C.A. and Beall G.N. (1999).The Value of Patient-Reported Adherence to Antiretroviral Therapy in Predicting Virologic and Immunologic Response. California Collaborative Treatment Group. AIDS; 13(9):1099-107.

4. Paterson D.L., Swindels S. & Mohr J. (2000). Adherence to Protease Inhibitor Therapy andOutcomes in Patients with HIV Infection. Annals of Internal Medicine, 133, 21A.

5. Weiser S., Wolfe W., Bangsberg D., Thior I., Gilbert P., Makhema J. (2003). Barriers toAntiretroviral Adherence for Patients Living with HIV Infection and AIDS in Botswana.Acquired Immune Deficiency Syndrome; 34(3):281-8.

6. http://twitter.com. Tweets on Drug Adherence (September, 2011).

7. http://youtube.com. HIV Treatment Adherence is Essential. Video uploaded by Mindset Health (August 5, 2009).


AcknowledgmentCo-Authors

• Mr. P. Agyei-Baffour (Academic Supervisor, KNUST)

• Rev. Dr. E. Browne (Fmr Head, Community Health, KNUST)

• Mr. J.A. Amankwah (Administration, KATH)

• Dr. G. Acquah-Hagan (Medical Doctor, KATH)

Special Thanks

• Dr. S.B. Ofori (Field Supervisor, Regional ART coordinator)

• Dr. Akyeampong (HIV Clinic, KATH)


Further Information• www.bit.ly/gi8Awh

• ww.doseadherencemodel.wordpress.com

Do You Have Questions And / Or Comments? Go to:

• http://portal.sliderocket.com/Dose-Adherence-Model-Presentation

http://portal.sliderocket.com/Dose-Adherence-Model-Presentation

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arv adherence model

Health & Medicine

study presentation

doses presentation

research background

responses presentation

research significance

study coverage

selfreport presentation

mindset health presentation