Reviewer's report
Title:HIV risks vary according to type of sex work in a cross-sectional survey
from Nagaland, India
Version:1Date:27 April 2014
Reviewer: Valerio Bacak
Reviewer's report:
Major Compulsory Revisions
1. The authors provide no arguments for why place of solicitation/sex work would
matter for HIV, STIs, and condom use behavior. The authors need to provide
arguments and empirical rationale for their reasons to focus on place and explain
to the readers what are the processes through which it is related to sexual health
outcomes. For example, why would moving between places of solicitation and
sex work be related to condom use? Why combine the two?
2. Related to the previous point, there is no discussion of the possible
confounders of the potential effects of place. Even though authors control for
some variables in the regression model, it is not clear why these and not other
variables. Not explicitly addressing confounding gives little credence to their
models. The authors should discuss which covariates were available and why
they used the ones they have in the models.
3. There is very little theoretical and/or empirical grounding of the study. The
authors should more completely relate their analyses to previous research on the
topic and highlight how their study builds on previous work. The section
“Comparison with other sex worker typology studies in India” seems to be more
appropriate for the Introduction/Background section.
Minor Essential Revisions
4. Perhaps in the Limitations section, the authors should discuss to what extent
do the typologies they found reflect the actual composition of sex work in
Dimapur and not simply that the typology reflects the types of sex workers who
were willing to be recruited into the survey. This is particularly important given
that place of solicitation and sex work are likely related to the probability of being
recruited into the survey through respondent-driven sampling.
5. In the Introduction, the authors should qualify the statements about HIV
prevalence among sex workers in Dimapur since it's not possible to find
representative samples of hidden populations such as sex workers. The authors
should highlight the sources of these estimates (i.e. what kind of samples they
were based on).
6. Why did the authors decide to combine the three STIs into one category?
7. On page 8, authors say that RDSAT does not allow for multivariate analysis.
While it is a standard practice to carry out analysis unadjusted for sampling
design, there are some ways to do it. From page 50 in the Users Manual for the
latest version of RDSAT: “Both weights are used by statistics programs (e.g.
SAS, SPSS) to adjust for an individual’s probability of being sampled.
Individualized weights are recommended for multivariate analysis.” It would be
good to at least compare unweighted analysis with analysis that uses the RDSAT
weights.
You can consult these two papers for examples: Johnston, L., O’Bra, H., Chopra,
M., Mathews, C., Townsend, L., Sabin, K., ... & Kendall, C. (2010). The
associations of voluntary counseling and testing acceptance and the perceived
likelihood of being HIV-infected among men with multiple sex partners in a South
African township. AIDS and behavior, 14(4), 922-931. And Broz, D., Pham, H.,
Spiller, M., Wejnert, C., Le, B., Neaigus, A., & Paz-Bailey, G. (2013). Prevalence
of HIV Infection and Risk Behaviors Among Younger and Older Injecting Drug
Users in the United States, 2009. AIDS and Behavior, 1-13.
8. Related to the previous comment, since you are using a convenience samples,
hypothesis testing with the chi-square and ANOVA are not entirely appropriate.
You should note these limitations in the Discussion section. The same limitation
holds for regression analysis. However, if you attempted to use weights in
regression analysis to make the sample probabilistic, you may be able to validly
use these tests.
9. You should consider that some variables have very small cells – see how wide
the confidence intervals are. This needs to be considered and some categories
collapsed. Otherwise, results with so little precision are not very meaningful.
10. In logistic regression tables, show the coefficients for the covariates (e.g.,
age and duration of sex work). It also seems like you should control for how
much sex workers are paid for sex – this may be related to both risk
behaviors/STIs and place of work/solicitation.
11. There is no reason to present descriptive statistics for variables that are not
used in the regression model.
12. The authors should provide more information about the sampling process,
even though this information may be available elsewhere. First, were incentives
offered to all participants (not only seeds) and what type and/or amount was
involved; how do these incentives compare to what sex workers typically earn?
How many seeds did the study start with and how were these seeds chosen and
recruited?
13. In the Measures section, you need to completely describe all the measures,
including covariates used in the regression models.
14. The second paragraph on page 3 seems redundant. Information about
Avahan is something that should go in a special section on funding sources or
acknowledgments.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests.