Evolution of HRQoL and its predictors

First, we analysed the change between the three repeated measures of the battery of HRQoL predictors and the dimensions of HRQoL collected from the participants (n = 30). Concerning the predictors of HRQoL, a significant positive evolution was found in almost all facets except for avoidant coping. The largest effect sizes were observed in decreased dissatisfaction with sexuality, internalised stigma, HIV-related stress, depressive mood, and negative HIV representation. Also, increased social support, optimism, and problem-focused coping showed remarkable effect sizes. Decreases in emotional loneliness and the experience of rejection, increased information about HIV, and positive re-evaluation of HIV were observed with a moderate effect size. Lastly, although the effect size was lower, there was a positive change in personal values and personal autonomy, and a decrease in the perception of rejection and economic problems (Table 3).

Table 3 Results of the repeated measures ANOVA of health-related quality of life predictors (ScreenPLHIV)

Regarding HRQoL, the results showed a significant positive evolution in all its dimensions; participants had higher scores in overall health, physical health, psychological health, level of independence, social relations, environmental health, and spirituality (Table 4; Fig. 1).

Table 4 Results of the repeated-measures ANOVA of health-related quality of life (WHOQOL-HIV-Bref) Fig. 1

Evolution of the dimensions of HRQoL during the peer intervention. SRPB: spirituality, religion, and personal beliefs

Covariates of the positive evolution in the HRQoL dimensions

We analysed the association of the differential scores in the quality of life predictor facets with the change in each of the dimensions of HRQoL after the intervention. Concerning the protective facets of quality of life, differential scores in disease information, personal autonomy, and positive re-evaluation were significantly associated with positive developments in overall health perception, F(2,17) = 3.587, p = .050, ɳ2 = 0.297; F(2,17) = 11.720, p(2,17) = 0.001, ɳ2 = 0.580; F(2,17) = 6.435, p(2,17) = 0.008, ɳ2 = 0.431, respectively. Also, the differential problem-focused coping score was associated with the positive evolution of psychological health, F(2,17) = 3.402, p = .057, ɳ2 = 0.286. The differential score in social support was associated with a positive change in the spirituality dimension, F(2, 17) = 3.863, p = .041, ɳ2 = 0.312.

Regarding the risk facets of quality of life, it was observed that the decrease in depressive mood was associated with a positive change in overall health perception, F(2,17) = 3.879, p = .041, ɳ2 = 0.313. The decrease in the perception of rejection was associated with the change in physical health, F(2,17) = 3.686, p = .047, ɳ2 = 0.303. Decreased dissatisfaction with sexuality was associated with the improved social relations dimension, F(2,17) = 3.201, p = .066, ɳ2 = 0.274. The decrease in emotional loneliness was associated with a positive change in the environmental health dimension, F(2,17) = 7.183, p = .005, ɳ2 = 0.458. Finally, the decrease in the negative representation of the disease and the perception of rejection was associated with a positive change in the spiritual dimension of quality of life, F(2,17) = 6.022, p = .011, ɳ2 = 0.415; F(2,17) = 4.853, p = .022, ɳ2 = 0.363, respectively.

The differential scores on the immune markers and viral load obtained over time were included as covariates in the model. It was observed that the increase in CD4/CD8 ratio interacted significantly with the increase in the score of the social relations dimension, F(2,21) = 4.846, p = .019, ɳ2 = 0.316.

Evolution in the Immunological and virological status: The association of improvement in HRQoL and its predictors

The participants’ immunological status improved during the intervention and assessment period. A significant increase was observed in CD4 cells/mm3 lymphocytes (Mbaseline = 377.91 ± 226.19 vs. Mpost = 642.45 ± 311.01; t = − 6.863, p < .0001; Cohen’s d = − 0.923) and in the CD4/CD8 ratio (Mbaseline = 0.51 ± 0.31 vs. Mpost = 0.88 ± 0.47, t = − 4.713, Cohen’s d = − 0.887).

HRQoL

The ANCOVA results showed that positive differential scores in the psychological health and social relationship HRQoL dimensions influenced the increase in CD4 cells/mm3 lymphocytes, F(1,21) = 7.554, p = .012, ɳ2 = 0.265 and F(1,21) = 7.350, p = .013, ɳ2 = 0.259, respectively. Besides, it was found that the increase in the score of the social relations dimension and overall health perception influenced the recovery of the CD4/CD8 ratio, F(1,21) = 4.586, p = .044; ɳ2 = 0.179 and F(1,21) = 3.712, p = .068, ɳ2 = 0.150, respectively. Subsequent ANCOVAs were then performed with quality of life predictors as covariates. About the protective facets, we observed that the improvement in self-esteem and optimism was positively and significantly associated with the increase in the CD4/CD8 ratio, F(1,23) = 4.819, p = .039, ɳ2 = 0.224; F(1,24) = 3.298, p = .082, ɳ2 = 0.121, respectively. Regarding the risk facets of quality of life, it was observed that the decrease in score of internalised stigma was significantly associated with the increase of CD4 cells/mm3, F(1,20) = 8,610, p = .008, ɳ2 = 0.301, and also that the decrease in the experience of rejection was marginally significantly associated with the increase of the CD4/CD8 ratio, F(1,24) = 3.598, p = .070, ɳ2 = 0.130.

As for the viral load, we confirmed that the reduction in the median (Mbaseline = 1,122.240, range 2,380 to 11,000.000; Mpost = 20, range 20 to 6,250) of the viral load was significant (p < .0001). Thus, at baseline, 100% of patients had a detectable viral load, whereas, at the last measurement taken at the end of the programme, 68.3% had a viral load < 20 copies mm3, 22% < 50 copies mm3, and only 9.8% still had a detectable viral load.

It was observed that none of the quality of life dimensions was associated with a decreased viral load. The facets of the different protective or risk facets of quality of life were not associated with a reduced viral load, except for a marginally significant influence of the differential score of the economic problems facet, F(1,24) = 4.157, p = .053, ɳ2 = 0.148.