Predicting adherence to combination antiretroviral therapy for HIV in Tanzania

A test of an extended theory of planned behaviour model

Kasia Banas, Ramsey A. Lyimo, Harm J. Hospers, André van der Ven, Marijn de Bruin

Research output: Contribution to journalArticle

3 Citations (Scopus)
3 Downloads (Pure)

Abstract

Objectives: Combination antiretroviral therapy (cART) for HIV is widely available in sub-Saharan Africa. Adherence is crucial to successful treatment. This study aimed to apply an extended theory of planned behaviour (TPB) model to predict objectively measured adherence to cART in Tanzania.

Design: Prospective observational study (n = 158) where patients completed questionnaires on demographics (Month 0), socio-cognitive variables including intentions (Month 1), and action planning and self-regulatory processes hypothesised to mediate the intention–behaviour relationship (Month 3), to predict adherence (Month 5).
Main outcome measures: Taking adherence was measured objectively using the Medication Events Monitoring System (MEMS) caps. Model tests were conducted using regression and bootstrap mediation analyses.
Results: Perceived behavioural control (PBC) was positively (β = .767, p < .001, R2 = 57.5%) associated with adherence intentions. Intentions only exercised an indirect effect on adherence (B = 1.29 [0.297–3.15]) through self-regulatory processes (B = 1.10 [0.131–2.87]). Self-regulatory processes (β = .234, p = .010, R2 = 14.7%) predicted better adherence.

Conclusion: This observational study using an objective behavioural measure, identified PBC as the main driver of adherence intentions. The effect of intentions on adherence was only indirect through self-regulatory processes, which were the main predictor of objectively assessed adherence.
Original languageEnglish
Pages (from-to)1249-1265
Number of pages17
JournalPsychology & Health
Volume32
Issue number10
Early online date13 Feb 2017
DOIs
Publication statusPublished - 2017

Fingerprint

Tanzania
HIV
Observational Studies
Therapeutics
Africa South of the Sahara
Demography
Outcome Assessment (Health Care)
Prospective Studies

Keywords

  • adherence
  • antiretroviral therapy
  • HIV/AIDS
  • Theory of Planned Behaviour
  • Tanzania

ASJC Scopus subject areas

  • Medicine(all)
  • Psychology(all)

Cite this

Predicting adherence to combination antiretroviral therapy for HIV in Tanzania : A test of an extended theory of planned behaviour model. / Banas, Kasia; Lyimo, Ramsey A. ; Hospers, Harm J.; van der Ven, André; de Bruin, Marijn.

In: Psychology & Health, Vol. 32, No. 10, 2017, p. 1249-1265.

Research output: Contribution to journalArticle

Banas, Kasia ; Lyimo, Ramsey A. ; Hospers, Harm J. ; van der Ven, André ; de Bruin, Marijn. / Predicting adherence to combination antiretroviral therapy for HIV in Tanzania : A test of an extended theory of planned behaviour model. In: Psychology & Health. 2017 ; Vol. 32, No. 10. pp. 1249-1265.
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abstract = "Objectives: Combination antiretroviral therapy (cART) for HIV is widely available in sub-Saharan Africa. Adherence is crucial to successful treatment. This study aimed to apply an extended theory of planned behaviour (TPB) model to predict objectively measured adherence to cART in Tanzania.Design: Prospective observational study (n = 158) where patients completed questionnaires on demographics (Month 0), socio-cognitive variables including intentions (Month 1), and action planning and self-regulatory processes hypothesised to mediate the intention–behaviour relationship (Month 3), to predict adherence (Month 5).Main outcome measures: Taking adherence was measured objectively using the Medication Events Monitoring System (MEMS) caps. Model tests were conducted using regression and bootstrap mediation analyses.Results: Perceived behavioural control (PBC) was positively (β = .767, p < .001, R2 = 57.5{\%}) associated with adherence intentions. Intentions only exercised an indirect effect on adherence (B = 1.29 [0.297–3.15]) through self-regulatory processes (B = 1.10 [0.131–2.87]). Self-regulatory processes (β = .234, p = .010, R2 = 14.7{\%}) predicted better adherence.Conclusion: This observational study using an objective behavioural measure, identified PBC as the main driver of adherence intentions. The effect of intentions on adherence was only indirect through self-regulatory processes, which were the main predictor of objectively assessed adherence.",
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AB - Objectives: Combination antiretroviral therapy (cART) for HIV is widely available in sub-Saharan Africa. Adherence is crucial to successful treatment. This study aimed to apply an extended theory of planned behaviour (TPB) model to predict objectively measured adherence to cART in Tanzania.Design: Prospective observational study (n = 158) where patients completed questionnaires on demographics (Month 0), socio-cognitive variables including intentions (Month 1), and action planning and self-regulatory processes hypothesised to mediate the intention–behaviour relationship (Month 3), to predict adherence (Month 5).Main outcome measures: Taking adherence was measured objectively using the Medication Events Monitoring System (MEMS) caps. Model tests were conducted using regression and bootstrap mediation analyses.Results: Perceived behavioural control (PBC) was positively (β = .767, p < .001, R2 = 57.5%) associated with adherence intentions. Intentions only exercised an indirect effect on adherence (B = 1.29 [0.297–3.15]) through self-regulatory processes (B = 1.10 [0.131–2.87]). Self-regulatory processes (β = .234, p = .010, R2 = 14.7%) predicted better adherence.Conclusion: This observational study using an objective behavioural measure, identified PBC as the main driver of adherence intentions. The effect of intentions on adherence was only indirect through self-regulatory processes, which were the main predictor of objectively assessed adherence.

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