A marginal structural model for estimation of the effect of HIV positivity awareness on risky sexual behavior

Abstract

In this paper, a Marginal Structural Model (MSM) with inverse probability of treatment weights was used to estimate the causal effect of HIV positivity awareness on condom use and multiple sexual partners using data from the Malawi Longitudinal Study of Families and Health (MLSFH). Cumulative awareness of HIV positivity was measured as the number of times an individual was aware of their positive HIV status. Awareness of HIV positivity was associated with increased condom use (OR=2.22, 95%: (1.79, 2.75)). Only among women was it associated with multiple sexual partners (OR=1.76, 95%: (1.36, 2.28)). The use of MSM (over standard regression models for repeated measures) should be encouraged as it is more suited for assessing the cumulative treatment effects while controlling for time-varying confounders in longitudinal studies. There is a need to up-scale interventions that promote HIV testing, awareness of HIV status, and prevention of HIV transmission.

Keywords:

• Marginal structural models
• HIV positivity
• condom use
• multiple sexual partners

Acknowledgments

This work was partially supported through the DELTAS Africa Initiative, Sub-Saharan Africa Consortium for Advanced Biostatistics Training (SSACABT) (The DELTAS Africa Initiative is an independent funding scheme of the African Academy of Sciences (AAS)'s Alliance for Accelerating Excellence in Science in Africa (AESA) and supported by the New Partnership for Africa's Development Planning and Coordinating Agency (NEPAD Agency) with funding from the Wellcome Trust [SSACABT] and the UK government), and by the L'Oréal-UNESCO for Women in Science Sub-Saharan Africa Young Talents Programme through the Young Talents award provided to Ms. Twabi. Ms. Twabi also thanks the South African Medical Research Council (SAMRC) for funding part of her research visits. The views expressed in this publication are those of the author(s) and not those of the funders (AAS, NEPAD Agency, Wellcome Trust or the UK government, L'Oreal, SAMRC). We further thank the MLSFH team led by Professor Hans-Peter Kohler for granting us access to the MLSFH data.

Data availability statement

The data is available upon request from the Principal investigator of the MLSFH that can be done through email: [email protected].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical approval and consent to participate

The data collections of the MLSFH have been approved by the IRB Board at the University of Pennsylvania (IRB Protocols no. 815 016 and no. 826828), and in Malawi, the MLSFH research has been approved by the Ethics Committee of the College of Medicine, Malawi (COMREC, Protocols no. P01/12/1165 and no. P.04/17/2160) and the National Health Sciences Research Committee (NHSRC, Protocol no. 19/01/2214).

Additional information

Funding

HT thanks the Biostatistics Research Unit of the South Africa Medical Research Council (SAMRC) for hosting her Ph.D research visits.

Notes on contributors

Halima S. Twabi

Halima S. Twabi performed data analysis, interpretation, and drafting of the manuscript.

Samuel O. M. Manda

Samuel O.M. Manda conceptualized, reviewed the statistical analysis and provided critical revisions.

Dylan S. Small

Dylan S. Small helped with the concept, direction and revisions.

Hans-Peter Kohler

Hans-Peter Kohler helped with providing the substantive concept of the paper and the revisions of the manuscript. All authors have read and approved the final manuscript.