Skip to main content

Advertisement

SpringerLink
Log in

Parameters for Sample Size Estimation from a Group-Randomized HIV Prevention Trial in HIV Clinics in Sub-Saharan Africa

  • Original Paper
  • Published:
AIDS and Behavior Aims and scope Submit manuscript

Abstract

Sample size calculations for a group-randomized trial (GRT) require an estimate of the expected intraclass correlation coefficient (ICC). However, few ICC estimates from GRTs in HIV/AIDS research have been published, leaving investigators with little data on which to base expectations. We used data from a multi-country study to estimate ICCs for variables related to physical and mental health and HIV risk behaviors. ICCs for perceptions of physical and mental health tended to be higher than those for HIV risk behavior variables, which were higher than ICCs for CD4 count. Covariate adjustment for country and socio-demographic variables reduced most ICC estimates. For risk behavior variables, adjustment for country and socio-demographic variables reduced ICC estimates by as much as 84 %. Variability in ICC estimates has important implications for study design, as a larger ICC reduces power. ICC estimates presented in this analysis will allow more precise sample size estimates for future GRTs.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. Lyles CM, Kay LS, Crepaz N, Herbst JH, Passin WF, Kim AS. Best-evidence interventions: findings from a systematic review of HIV behavioral interventions for US populations at high risk, 2000–2004. Am J Public Health. 2007;97:133–43.

    Article  PubMed Central  PubMed  Google Scholar 

  2. Herbst JH, Beeker C, Matthew A, McNally T, Passin WF, Kay LS, et al. The effectiveness of individual-, group-, and community-level HIV behavioral risk-reduction interventions for adult men who have sex with men: a systematic review. Am J Prev Med. 2007;32:S38–67.

    Article  PubMed  Google Scholar 

  3. Corbett EL, Makamure B, Cheung YB, Dauya E, Matambo R, Bandason T, et al. HIV incidence during a cluster-randomized trial of two strategies providing voluntary counselling and testing at the workplace, Zimbabwe. AIDS. 2007;21:483–9.

    Article  PubMed  Google Scholar 

  4. Jewkes R, Nduna M, Levin J, Jama N, Dunkle K, Puren A, et al. Impact of stepping stones on incidence of HIV and HSV-2 and sexual behaviour in rural South Africa: cluster randomised controlled trial. Br Med J. 2008;337:a506.

    Article  Google Scholar 

  5. Gregson S, Adamson S, Papaya S, Mundondo J, Nyamukapa CA, Mason PR, et al. Impact and process evaluation of integrated community and clinic-based HIV-1 control: a cluster-randomised trial in eastern Zimbabwe. PLoS Med. 2007;4:e102.

    Article  PubMed Central  PubMed  Google Scholar 

  6. Ross DA, Changalucha J, Obasi AI, Todd J, Plummer ML, Cleophas-Mazige B, et al. Biological and behavioural impact of an adolescent sexual health intervention in Tanzania: a community-randomized trial. AIDS. 2007;21:1943–55.

    Article  PubMed  Google Scholar 

  7. Quigley MA, Kamali A, Kinsman J, Kamulegeya I, Nakiyingi-Miiro J, Kiwuwa S, et al. The impact of attending a behavioural intervention on HIV incidence in Masaka, Uganda. AIDS. 2004;18:2055–63.

    Article  PubMed  Google Scholar 

  8. van Griensven GJ, Limanonda B, Ngaokeow S, Ayuthaya SI, Poshyachinda V. Evaluation of a targeted HIV prevention programme among female commercial sex workers in the south of Thailand. Sex Transm Dis. 1998;74:54–8.

    Article  Google Scholar 

  9. Fontanet AL, Saba J, Chandelying V, Sakondhavat C, Bhiraleus P, Rugpai S, et al. Protection against sexually transmitted diseases by granting sex workers in Thailand the choice of using the male or female condom: results from a randomized controlled trial. AIDS. 1998;12:1851–9.

    Article  CAS  PubMed  Google Scholar 

  10. Grosskurth H, Mosha F, Todd J, Mwijarubi E, Klokke A, Senkoro K, et al. Impact of improved treatment of sexually transmitted diseases on HIV infection in rural Tanzania: randomised controlled trial. Lancet. 1995;346:530–6.

    Article  CAS  PubMed  Google Scholar 

  11. Kamali A, Quigley M, Nakiyingi J, Kinsman J, Kengeya-Kayondo J, Gopal R, et al. Syndromic management of sexually-transmitted infections and behaviour change interventions on transmission of HIV-1 in rural Uganda: a community randomised trial. Lancet. 2003;361:645–52.

    Article  CAS  PubMed  Google Scholar 

  12. Wawer MJ, Sewankambo NK, Serwadda D, Quinn TC, Paxton LA, Kiwanuka N, et al. Control of sexually transmitted diseases for AIDS prevention in Uganda: a randomised community trial. Rakai Project Study Group. Lancet. 1999;353:525–35.

    Article  CAS  PubMed  Google Scholar 

  13. Donner A, Birkett N, Buck C. Randomization by cluster. Sample size requirements and analysis. Am J Epidemiol. 1981;114:906–14.

    CAS  PubMed  Google Scholar 

  14. Murray DM, Hannan PJ, Baker WL. A Monte Carlo study of alternative responses to intraclass correlation in community trials. Is it ever possible to avoid Cornfield’s penalties? Eval Rev. 1996;20:313–37.

    Article  CAS  PubMed  Google Scholar 

  15. Murray DM, Blitstein JL. Methods to reduce the impact of intraclass correlation in group-randomized trials. Eval Rev. 2003;27:79–103.

    Article  PubMed  Google Scholar 

  16. Resnicow K, Zhang N, Vaughan R, Reddy S, James S, Murray D. When intraclass correlation coefficients go awry: a case study from a school-based smoking prevention study in South Africa. Am J Public Health. 2010;100:1714–8.

    Article  PubMed Central  PubMed  Google Scholar 

  17. Campbell MK, Elbourne DR, Altman DG. group C. CONSORT statement: extension to cluster randomised trials. Br Med J. 2004;328:702–8.

    Article  Google Scholar 

  18. Pals SL, Wiegand RE, Murray DM. Ignoring the group in group-level HIV/AIDS intervention trials: a review of reported design and analytic methods. AIDS. 2011;25:989–96.

    PubMed  Google Scholar 

  19. Kidder D, Bachanas P, Medley A, Pals S, Nuwagaba-Biribonwoha H, Ackers M, et al. HIV prevention in care and treatment settings: baseline risk behaviors among HIV patients in Kenya, Namibia and Tanzania. PLoS One. 2013;8:e57215.

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  20. Ware JE, Kosinski M, Dewey JE, Gandek B. How to score and interpret single-item health status measures: a manual for users of the SF-8 health survey. Lincoln: Quality Metric Incorporated; 2001.

    Google Scholar 

  21. Roberts B, Browne J, Ocaka KF, Oyok T, Sondorp E. The reliability and validity of the SF-8 with a conflict-affected population in northern Uganda. Health Qual Life Outcomes. 2008;6:108.

    Article  PubMed Central  PubMed  Google Scholar 

  22. Radloff LS. The CES-D scale: a self-report depression scale for research in the general population. Appl Psychol Meas. 1977;1:385–401.

    Article  Google Scholar 

  23. Babor TF, Higgins-Biddle JC, Saunders JB, Monteiro MG. The alcohol use disorders identification test: guidelines for use in primary care. In: Geneva: World Health Organization; 2001.

  24. Murray DM. Design and analysis of group-randomized trials. New York: Oxford University Press; 1998.

    Google Scholar 

  25. SAS Institute Inc. SAS/STAT Software for PC (Version 9.2). In: Cary: SAS Institute; 2008.

  26. Searle SR. Linear models. New York: Wiley; 1971.

    Google Scholar 

  27. Pals SL, Beaty BL, Posner SF, Bull SS. Estimates of intraclass correlation for variables related to behavioral HIV/STD prevention in a predominatly African American and hispanic sample of young women. Health Educ Behav. 2009;36:182–94.

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

We would like to express our gratitude for the extraordinary efforts of the study interviewers, program coordinators, and data management staff in the three countries without whom this study could not have taken place. We would also like to thank the Ministries of Health in Kenya, Tanzania, and Namibia as well as ICAP and CDC staff in these three countries for the support they provided to this project. Finally, we appreciate the efforts of the health care providers, lay counselors, and HIV-positive clinic patients who participated in this study, and their willingness to share their experiences with us.

Author information

Authors and Affiliations

  1. Division of Global HIV/AIDS, Center for Global Health, Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, MS E-30, Atlanta, GA, 30333, USA

    Jun Zhang, Sherri L. Pals, Amy Medley, Catherine Nichols & Pam Bachanas

  2. ICF MACRO, Atlanta, GA, USA

    Jun Zhang

  3. Namibia CDC Office, Windhoek, Namibia

    Deon van Zyl

  4. Namibia Ministry of Health and Social Services, Windhoek, Namibia

    Frieda Katuta

  5. Tanzania Ministry of Health and Social Welfare, Dar es Salaam, Tanzania

    James Juma

Authors
  1. Jun Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Sherri L. Pals
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Amy Medley
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Catherine Nichols
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Pam Bachanas
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Deon van Zyl
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Frieda Katuta
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. James Juma
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Sherri L. Pals.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Zhang, J., Pals, S.L., Medley, A. et al. Parameters for Sample Size Estimation from a Group-Randomized HIV Prevention Trial in HIV Clinics in Sub-Saharan Africa. AIDS Behav 18, 2359–2365 (2014). https://doi.org/10.1007/s10461-013-0631-9

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10461-013-0631-9

Keywords

Search

Navigation