The 12 city HIV Surveillance Survey among MSM in Brazil 2016 using respondent-driven sampling: a description of methods and RDS diagnostics.

INTRODUCTION: This paper details the methods used in the second national Biological and Behavioral Surveillance Survey (BBSS) of HIV, syphilis, and hepatitis B and C among men who have sex with men in Brazil. METHODS: Respondent-driven sampling (RDS) was used in 12 cities in 2016. The targeted sample size was initiated with five to six seeds in each city. HIV, syphilis, and Hepatitis B and C rapid tests were offered to participants. RDS Analyst with Gile's successive sampling (SS) estimator was used to adjust results as recommended and a weight for each individual was generated for further analysis. Data for the 12 cities were merged and analyzed using Stata 14.0 complex survey data tools with each city treated as its own stratum. RESULTS: Duration of data collection varied from 5.9 to 17.6 weeks. 4,176 men were recruited in the 12 cities. Two sites failed to achieve targeted sample size due to a six-month delay in local IRB approval. No city failed to reach convergence in our major outcome variable (HIV). CONCLUSION: The comprehensive BBSS was completed as planned and on budget. The description of methods here is more detailed than usual, due to new diagnostic tools and requirements of the new STROBE-RDS guidelines.

The 12 city HIV Surveillance Survey among MSM in Brazil 2016 using respondent-driven sampling: a description of methods and RDS diagnostics / Inquérito sobre o HIV entre HSH no Brasil em 2016 usando respondent-driven sampling (RDS): descrição dos métodos e dos diagnósticos do RDS

ABSTRACT: Introduction: This paper details the methods used in the second national Biological and Behavioral Surveillance Survey (BBSS) of HIV, syphilis, and hepatitis B and C among men who have sex with men in Brazil. Methods: Respondent-driven sampling (RDS) was used in 12 cities in 2016. The targeted sample size was initiated with five to six seeds in each city. HIV, syphilis, and Hepatitis B and C rapid tests were offered to participants. RDS Analyst with Gile's successive sampling (SS) estimator was used to adjust results as recommended and a weight for each individual was generated for further analysis. Data for the 12 cities were merged and analyzed using Stata 14.0 complex survey data tools with each city treated as its own stratum. Results: Duration of data collection varied from 5.9 to 17.6 weeks. 4,176 men were recruited in the 12 cities. Two sites failed to achieve targeted sample size due to a six-month delay in local IRB approval. No city failed to reach convergence in our major outcome variable (HIV). Conclusion: The comprehensive BBSS was completed as planned and on budget. The description of methods here is more detailed than usual, due to new diagnostic tools and requirements of the new STROBE-RDS guidelines.

RESUMO: Introdução: Este artigo detalha os métodos utilizados na segunda Pesquisa Nacional de Vigilância Biológica e Comportamental (BBSS) do HIV, sífilis e hepatite B e C entre os homens que fazem sexo com homens no Brasil. Métodos: O método Respondent-driven Sampling (RDS) foi utilizado em 12 cidades em 2016. A amostra foi iniciada com cinco a seis sementes em cada cidade. Testes rápidos para o HIV, sífilis e Hepatite B e C foram oferecidos aos participantes. O software RDS Analyst com o estimador de amostragem sucessiva (SS) de Gile foi utilizado para ajustar os resultados como recomendado, gerando um peso para cada indivíduo para análises. Osdados das 12cidades foram unidos em um único banco e analisados usando as ferramentas de dados complexos do Stata 14.0, com cada cidade sendo tratada como seu próprio estrato. Resultados: A duração da coleta de dados variou de 5,9 a 17,6 semanas e 4.176 homens foram recrutados nas 12 cidades. Dois sites não alcançaram o tamanho da amostra alvo devido a uma demora de seis meses na aprovação local do Comitê de Ética. Todas as cidades atingiram a convergência na principal variável estudada (HIV). Conclusão: O BBSS foi representativo e concluído conforme planejado e dentro do orçamento. A descrição dos métodos aqui é mais detalhada do que o habitual, devido às novas ferramentas e requisitos de diagnóstico das novas diretrizes do STROBE-RDS.