Abstract:
Background: Monitoring viral loads among patients receiving antiretroviral therapy is crucial 
for early detection of treatment failures, drug resistance development and inappropriate
switching to second-line therapy. It also helps to identify patients needing more intensive 
adherence support. It is considered as virological failure if a viral load above 1000 cells/ml. 
There is a dearth of evidence on the determinants of viral failure among human immune 
deficiency virus patients at the Hiwot Fana Comprehensive Specialized University Hospital.
Objectives: To determine the factors that contributes to virological failure in adult people living 
with human immunodeficiency virus receiving highly active antiretroviral therapy at Hiwot Fana
Specialized University Hospital in eastern Ethiopia, from November 28 to December 11, 2022.
Methods: An unmatched case control study was conducted among all eligible 246 cases (patient 
with viral load above 1000 cell/ml) and a randomly selected 246 record of control (patient with 
viral burden below 1000 cell/ml). The data were collected from the patient's charts including 
ART intake form, follow up, and the anti-retroviral treatment registration. Data management and 
analysis were handled using EPIDATA version 7 and STATA version 14.Binary logistic 
regression was employed. Factors with a p-value less than 0.2 in Bivariable model were 
candidate for the multivariable model. Factors with P-value below 0.05 in the multivariable 
model were considered statistical significant.
Results: This study showed that patients with age under 35 years (AOR =1.99, 95%CI: 1.22,
3.25),CD4 count of less than 200 cells/mm3 (AOR=6.46, 95% CI: 3.19,13.09) and CD4 from 
200-499 cells/mm3 (AOR=2.44, 95% CI: 1.37, 4.35), WHO clinical stage II (AOR=6.57, 95% 
CI: 3.72, 11.62) or III (AOR = 4.54, 95% CI: 1.41, 14.58), opportunistic infection (AOR = 5.03, 
95% CI: 2.02, 12.50), poor adherence to treatment (AOR=6.38, 95% CI: 2.64, 15.39) and 
duration on ART for ≥48 month (AOR =8.27, 95% CI: 3.03, 21.13) had higher odds of 
virological failure compared to the counterpart.
Conclusions: Poor adherence to therapy, longer ART duration, younger age, and a low baseline 
CD4 count, clinical stages II or III, and presence of opportunistic infection had significant impact 
on virological failure. Adherence counseling and careful monitoring of patients with these 
factors are required to achieve adequate viral load suppression