Background HIV attacks the CD4 cells which are responsible for the body’s immune response to infectious agents. The main objective of this study was to identify predictors of viral load status over time among HIV patients under HAART in Zewditu Memorial Hospital. Methods A retrospective institutional-based cohort study design was conducted on 161 HIV-infected adults under HAART whose follow-ups were from January 2014 up to December 2017. A generalized linear mixed-effects model was conducted to infer predictors of the status of viral load at 95% of CI). Results The descriptive statistics revealed that about 55.9% of the adults under treatment had a detected viral load status. Among the potential predictors, visiting time of patients (AOR = 0.731, 95%: (0.634,0.842) and p-value <0.01), age of patients (AOR = 1.0666, 95% CI: (1.0527,1.0917) and p-value <0.01), weight (AOR=. 0.904, 95% CI: (0.862, 0.946) and p-value <0.01), baseline CD4 cell count (AOR = 0.996, 95% CI: (0.994, 0.998) and P-value <0.01), educated patients (AOR = 0.030, 95% CI: (0.002, 0.385) and p-value=0.0053), rural patients (AOR = 6.30,95% CL: (1.78, 2.25) and p-value=0.0043), working status patients (AOR = 0.5905, 95% CI: (0.547,0.638), p-value <0.01), poor adherent patients (AOR = 1.120, 95% CI; (1.035,1.391) and p-value = 0.016) and patients disclosed the disease status (AOR = 0.195, 95% CI: (0.023, 0.818) and p-value=0.0134) significantly affected the detection status of viral loads, keeping all other covariates constant. Conclusion The predictor variables; visiting times, the weight of patients, residence area, age of patients, educational level, clinical stages, functional status, baseline CD4 cell count, adherence status, and disclosure status of the disease statistically and significantly affected the status of viral load. Hence, health-related education should be given for patients to disclose their disease status, to be good adherents based on the prescription given to the health staff. Due attentions should be given for rural and uneducated patients. Attention should be forwarded to for non-adherent patients to follow the instruction given by the health staff.

The main objective of this study was to identify variables jointly affected for CD4 count and hazard time to death of HIV-infected children under ART at Felege Hiwot Referal and Specialized Hospital. A retrospective cohort study design was conducted on 202 HIV-infected children under ART whose follow-ups were from January 2014 up to December 2018. The descriptive statistics revealed that about 25.2% of HIV-infected children under ART in the study period(Jaunary 2014–December 2018) died and 74.8% were censored. The estimated association parameter in the joint model was − 0.8339 and statistically significant (p value = 0.025). There was a negative relationship between the two response variables namely CD4 count and the risk for death on HIV-positive children under treatment. The level of education of children's parents, level of disclosure of the disease, baseline CD4 count, functional status, and adherence level were statistically and significantly affected for the two response variables, CD4 count and risks for the death of children. Separate and joint models have been compared interims of standard error and the joint model had a small standard error as compared to the separate models. The small standard errors in joint models indicate that the joint model was better in detecting variables that affected the two responses in this regard. Health-related education should be conducted to parents of children for easy recovery of CD4 count and for reducing risks for the death of children.