The studies making comparisons among individuals included 5129 participants (1911 ART-naïve participants and 3218 ART–experienced participants). The studies making within-individual comparisons included 1024 participants were included. The participants’ duration on ART ranged from 3–36

months (median six months and interquartile range 6–12

months). Figure presents the results of the meta-analysis of any sexual activity in relation to ART experience. Although two studies [
23,
24] showed a statistically significant increase in sexual activity among ART-experienced as compared with ART-naïve participants, the overall analysis portrayed no association of sexual activity in either of the study types (OR

=

1.14; 95% CI, 0.91 to 1.43). However, the proportion of sexually active people was higher among ART-experienced than ART-naïve participants in three of the four studies that made comparisons among individuals [
23,
24,
28].
The within-individual studies were more inconsistent than studies that made comparisons between individuals. Two studies [
21,
27] found statistically significant decreases in sexual activity post-ART while another two studies [
22,
25] found increased sexual activity pre-ART.
Sensitivity analysis attested to the stability of the overall odds ratio; it oscillated in the range of 1.07 to 1.21 (changed by

±

0.07 from the overall odds ratio). The test of heterogeneity showed a significant variation among the included studies (Q

=

74.7; I
2
=

87.9%), signifying that the variation was due to heterogeneity rather than chance. The impact of duration on ART and recall time on the overall odds ratio was assessed by the random effect meta-regression model. As shown in Table

, these variables were not found to have a significant effect; the regression coefficient of the log odds ratio of sexual activity was not significantly different from zero in either the analysis of average time while on ART (regression coefficient

=

−0.016; 95% CI, -0.033 to 0.002; P

=

0.078) or the analysis of recall time (regression coefficient

=

0.042; 95% CI, -0.020 to 0.104; P

=

0.185).
| Table 2Summary of meta-regression analysis findings, 2011 |
As shown in Figure , all studies [
21-
23,
26,
27,
29-
33] but one showed a statistically significant reduction in rates of unprotected sex among people on ART. The divergent study showed a statistically significant increase in unprotected sex among those on ART. The overall odds ratio in the meta-analysis demonstrated a statistically significant reduction in unprotected sex while on ART (OR

=

0.437; 95% CI, 0.315 - 0.607). The association appears a bit stronger in the studies comparing rates of unprotected sex among different individuals (OR

=

0.414; 95% CI, 0.287 - 0.598). In the sensitivity analysis, the overall odds ratio was very little changed by omitting individual studies (maximum

±

0.06).
The studies included in the meta-analysis of unprotected sex also found to have significant variation due to heterogeneity rather than to chance (Q

=

124.4; I
2
=

92.0%). Meta-regression found no statistically significant interaction between unprotected sex and duration on ART (regression coefficient

=

−0.0328; 95% CI, -0.069 to 0.003; P

=

0.076) or between unprotected sex and recall time (regression coefficient

=

0.0029; 95% CI, -0.151 to 0.157; P

=

0.97). But the meta-regression incorporating six studies [
21,
22,
26,
27,
30,
31] which analyzed the relationship of rates of unprotected sex with the percentage of married or cohabiting participants included in the study demonstrated a significant reduction of unprotected sex as the percentage of married participants increases (regression coefficient

=

−0.032; 95% CI,-0.059 to −0.004; P

=

0.023).
Figure shows the results of the meta-analysis of the relationship of ART experience to rates of multiple sexual partners. The overall odds ratio, including all eight studies which reported this information, indicated that rates of multiple sexual partners were significantly decreased among people on ART (OR

=

0.47; 95% CI, 0.248 to 0.888). When considered separately by study type, however, the combined odds ratios were not statistically significant, although two studies of each type [
27,
31-
33] independently showed a statistically significant reduction in rates of multiple sexual partners with ART experience. In other words, rates of multiple sexual partners were not found to be significantly different either when comparing ART-experienced people to ART-naïve people; or when comparing the same individuals’ behavior before and after ART initiation. The sensitivity analysis supports the findings of the sub-group analysis; exclusion of Sarna and
et al. study from the analysis leads to a finding of an insignificant association of ART experience with rates of having multiple sexual partners.
Linear meta-regression analysis showed that neither duration of ART (regression coefficient

=

0.0457; 95% CI, -0.028 to 0.119; P

=

0.22), recall time (regression coefficient

=

0.018; 95% CI, -0.074 to 0.111; P

=

0.697) nor percentage of married participants (regression coefficient

=

0.0313; 95%CI, -0.017 to 0.080; P

=

0.21) were significantly associated with having multiple sexual partners.
Of the 14 studies included, only four [
22,
25,
26,
28] reported rates of unprotected sex with HIV-negative or unknown HIV status persons (Figure ). The meta-analysis of the relationship between ART experience with rates of unprotected sex with HIV negative or unknown HIV serostatus showed a statistically significant reduction among people on ART (OR

=

0.55; 95% CI, 0.303 to 0.994).