Our analysis of gender difference found significant clinical and social-demographic variations between females and males. Similar as in other studies, males were reporting for care with a more advanced disease than females. Sex differences in health seeking behaviour are known to exist as indicated in several studies . This can be attributed, in part; due to the fact that females are having extra entry points to HIV services e.g. through PMTCT services, however this was not the case in this study, where the majority of the patients were tested after a long term illness. The most common reason for HIV testing was AIDS related syndrome, more than voluntary testing, and this was more pronounced in males, denying the patients time for care at CTC prior to ART.
While there was a difference in disease stage at registration for care at CTC, both genders were presenting late and there was not much difference on the period of illness before starting ART between the two groups. Males however were better informed about the use of ARVs than females. For both males and females, late presenting resulted in a median CD4 at initiation of therapy below 150 cells/ml, where in ideal situation the majority of patients on follow up will start ART with a higher CD4 count and a less advanced disease. Starting ART with low CD4 counts has been shown to be associated with early mortality mainly caused by immune Reconstitution Inflammatory Syndrome (IRIS), which appears after starting ART at advanced HIV disease (WHO stage IV), CD4 count below 50 cells/ul and BMI below 16 kg/m2 which could also have happened to some of the patients in this cohort. Another study has indicated that a low CD4 cell count at ART initiation was a strong predictor of mortality  and this could be the case in our study.
Despite the facts that all the patients were prepared to start ART, there were still a significant proportion of patients who were using traditional medicine, alcohol and injection drug abuse. The history of using traditional medicine and alcohol was high among our study participants, particularly among males. This may also be a reason of delaying medical treatment until late at WHO stage III and stage IV when the patients had already developed opportunistic infections. Injection drug use (IDU) is also associated with both, non-adherence to ART and HIV disease progression, and many IDU live in unstable housing, have undiagnosed mental illness, high rates of incarceration, and street-involved survival-lifestyles, which may all complicate delivery of HIV-related treatments .
Overall, females were found to start ART at a less advanced disease stage, with higher CD4 count and higher BMI, and with lower viral loads than males. Similar findings are reported by other studies . Given the high proportion of drug abuse and alcohol in our study, our patients may have been predisposed to poor adherence . There was no significant difference on ART adherence as measured by consistency on keeping appointments, but it was indeed low in both groups. Drug and alcohol consumption may also influence survival of HIV-infected individuals by exacerbating immunosuppression, enhancing the toxicity of ARV on liver cells and accelerating liver damage and may depress the immune system leading to increased multiplication of the virus in mononuclear cells . After one year of treatment, immune recovery was good in both males and females; however, despite the better start for women, there was no difference in clinical (including survival) or immunological condition at one year. Although a higher proportion of males died (not statistically significant), the males who survived were found to have significantly higher mean CD4 increase than females, despite a better virological treatment response in women. This is in contrast with the findings of other studies which found better survival, less disease progression and better immunological recovery among females on HAART [10, 16, 22]. The difference could be due to a shorter follow up (one year) in our study, a bias among the high proportion of patients lost to follow-up or true differences in our setting. The fact that men recovered quickly during ART, despite their late presentation is encouraging. It is however unclear why the women in our study lost their advantage so quickly, which is in contrast with other studies. It may be related to the fact that they are less educated with lower monthly income, as it has been found through other studies in Tanzania .
The differences that we found will need further evaluation as this may need redefining the time to initiate ART in the two groups and the methods to monitor treatment response. The possibility of initiating ART at lower viral loads in women, especially during the early stages of infection, merits further study. Although the relative viral load has a similar predictive value for progression to AIDS for men and women, the same absolute viral load seems to confer different risks for AIDS between the sexes . Because manifestations of HIV infection stem from the interplay between viral and host factors, sex differences in immune modulation will likely play instrumental roles in determining the course of disease. Both groups reported opportunistic infections; but more fever and oral candidiasis was reported by females than males, however, the difference was not statistically significant. Because of the late presentation to CTC, care and treatment services like prophylaxis against opportunistic infections may be suboptimal.
Our study findings are limited by the following issues: our cohort was rather small and may not necessarily represent all HIV-infected patients in need of treatment. We also missed some of the clinical information that may be useful on comparing the differences between females and males HIV patients. Due to the high number of Lost to follow-up (LTF), mortality is likely underestimated.