BackgroundHighly Active Antiretroviral therapy (HAART) plays significant role in reduction of mortality among children infected with HIV. Despite the inevitable impact of HAART on inflammation and toxicity, there is limited evidence on its impact among children in Ethiopia. Moreover, evidence on contributing factors to toxicity has been poorly described. Hence, we evaluated HAART induced inflammation and toxicity among children taking HAART in Ethiopia.MethodThis cross-sectional study was conducted among children (<15 years old) taking HAART in Ethiopia. Stored plasma samples and secondary data from a previous study on HIV-1 treatment failure were used for this analysis. By 2018, a total of 554 children were recruited from randomly selected 43 health facilities in Ethiopia. The different levels of liver (SGPT), renal (Creatinine) and hematologic toxicity (Hemoglobin) toxicity were assessed using established cut-off value. Inflammatory biomarkers (CRP and vitamin-D) were also determined. Laboratory tests were done at the national clinical chemistry laboratory. Clinical and baseline laboratory data were retrieved from the participant's medical record. Questionnaire was also administered to study guardians to assess individual factors to inflammation and toxicity. Descriptive statistics was used to summarize the characteristics of the study participants. Multivariable analysis was conducted and considered significant at P < 0.05.ResultOverall 363 (65.6%) and 199 (36%) of children taking HAART in Ethiopia developed some level of inflammation and vitamin-D in-sufficiency, respectively. A quarter of the children 140 (25.3%) were at Grade-4 liver toxicity while renal toxicity were 16 (2.9%). A third 275 (29.6%) of the children also developed anemia. Children who were on TDF+3 TC + EFV, those who were not virally suppressed and children with liver toxicity were at 17.84 (95%CI = 16.98, 18.82), 2.2 (95%CI = 1.67, 2.88) and 1.20 (95%CI = 1.14, 1.93) times risk of inflammation, respectively. Children on TDF+3 TC + EFV, those with CD4 count of <200 cells/mm3and with renal toxicity were at 4.10 (95%CI = 1.64, 6.89), 2.16(95%CI = 1.31, 4.26) and 5.94 (95%CI = 1.18, 29.89) times risk of vitamin-D in-sufficiency, respectively. Predictors of liver toxicity were history of HAART substitution (AOR = 4.66; 95%CI = 1.84, 6.04) and being bedridden (AOR = 3.56; 95%CI = 2.01, 4.71). Children from HIV positive mother were at 4.07 (95%CI = 2.30, 6.09) times risk of renal toxicity while the different type of HAARTs had different level of risk for renal toxicity AZT+3 TC + EFV (AOR = 17.63; 95%CI = 18.25, 27.54); AZT+3 TC + NVP (AOR = 22.48; 95%CI = 13.93, 29.31); d4t+3 TC + EFV (AOR = 4.34; 95%CI = 2.51, 6.80) and d4t+3 TC + NVP (AOR = 18.91; 95%CI = 4.87, 27.74) compared to those who were on TDF+3 TC + NVP. Similarly, children who were on AZT+3 TC + EFV were at 4.92 (95%CI = 1.86, 12.70) times risk of anemia compared to those who were on TDF+ 3 TC + EFZ.ConclusionThe high level of HAART induced inflammation and liver toxicity among children calls for the program to consider safer regimens for pediatric patients. Moreover, the high proportion of vitamin-D in-sufficiency requires program level supplement. The impact of TDF+3 TC + EFV on inflammation and vitamin-D deficiency calls for the program to revise this regimen.