Assessment of intervention outcome in the absence of baseline data: 'reconstruction' of condom use time trends using retrospective analysis of survey data

Abstract

BackgroundAvahan, the India AIDS Initiative, is a large-scale targeted intervention. Data on condom use prior to Avahan are unavailable. The authors used a novel method of analysing cross-sectional survey data to ‘reconstruct’ condom use rates in presurvey years, and to assess the relationship between Avahan and time trends in condom use among female sex workers (FSWs).MethodsAmong FSWs reporting consistent condom use (CCU) with clients in surveys from 21 districts in southern India (n=7358), data on length of time using condoms, and length of time selling sex, were converted into number of FSWs using condoms (numerator) and selling sex (denominator) by year, to give yearly rates of CCU from 2001 to year of survey. Linear regression with generalised estimating equations was used to assess time trends and to compare the rate of increase in condom use before and after Avahan initiation in 2003.ResultsIn all 21 districts, the rate of increase in CCU from 2001 to time of the surveys was highly significant. Overall CCU increased from 27% (22%) with occasional (regular) clients in 2001, to 76% (68%) in 2006, respectively. The yearly rate of increase in CCU was significantly greater after (slope 2003–2006: 12.7% (12.0%) per year for occasional (regular) clients) than prior to Avahan (slope 2001–2003: 5.1% (5.3%) per year for occasional (regular) clients) implementation (p<0.0001).ConclusionsThe findings indicate a positive relationship between implementation of the Avahan programme and rates of CCU increase among FSW. This method of analysis may be useful in other contexts where preintervention data are lacking.

Increases in self-reported consistent condom use among male clients of female sex workers following exposure to an integrated behaviour change programme in four states in southern India

“…First, a geographically stable population reported consistently high exposure to the initiative over a 2.5-year period; second, anecdotal evidence suggests that no other major interventions were concurrently targeting the population of interest. However, in the same timeframe and in the same programme areas, the availability of condoms doubled15 and other partners of the Avahan initiative implemented programmes to increase condom use among FSWs 16. It is likely that these interventions contributed to some degree to the observed increase in condom use among clients of FSW.…”

High prevalence of HIV and syphilis and associated factors among low-fee female sex workers in mainland China: a cross-sectional study

“…The actual rate of condom use may be even lower since participants may have self-reported an inflated condom use rate [29]. Inconsistent condom use increases the infection risk of STI like syphilis, which facilitates HIV transmission [30,31].…”

Who mixes with whom among men who have sex with men? Implications for modelling the HIV epidemic in southern India

“…Based on statistical analyses reconstructing historical condom use trends (Lowndes et al, 2010), condom use was assumed to change over time in a linear piecewise manner according to the following equation$f_{C}false(tfalse)=\{\begin{array}{cc}leftleft{\pi }_1,& leftt\ge 2006\\ leftfalse(t-t_{0}false){\Delta }_c,& left{t}_0<t<2006,\pi >{\pi }_0\\ left{\pi }_0,& left\mathrm{normalotherwise}\end{array}$where ${\pi }_1$ is the proportion of sex acts in which condoms are used correctly in the year 2006 (from 2006 IBBA survey data (Brahmam et al, 2008)), $t_0$ is the year in which condom use would have been zero when reconstructed condom use trends are extrapolated backwards in time, ${\Delta }_c$ is the yearly increase in the proportion of sex acts in which condoms are used correctly (Lowndes et al, 2010) and ${\pi }_0$ is the initial baseline level of condom use assumed in the population prior to the recently recorded increase.…”