Effectiveness of Antiretroviral Treatment on the Transition Probability of Immunological State of HIV/AIDS Patients: A Markov Chain Model on the Iranian “National Registry of HIV/AIDS Care” Database

Abstract

Antiretroviral therapy (ART) has improved survival and clinical course amongst HIV/AIDS patients. CD4 cell count is one of the most critical indicators of the disease progression. With respect to the dynamic nature of CD4 cell count during the clinical history of HIV/AIDS, modeling the CD4 cell count changes, which represents the likelihood of disease progression, is of interest to establish or revise treatment strategies and, specifically, to determine the stage at which giving ART is more clinically effective. In this historical cohort study on 917 HIV/AIDS patients in the Iranian “National Registry of HIV/AIDS Care” database, we used the Markov chain model to predict the effectiveness of the ART based on the transition probability of CD4 cell count, measured before and after initiating ART. We found that when the ART was initiated in the earlier stages of HIV infection, good prognosis might be more accessible; that is, after initiating ART at state CD 4 ≥ 500 , the probability of staying at this state was statistically increased than before the treatment ( P < 0.001 ). Also, it was found that initiating ART significantly decreased the probability of CD4 cell count transition to the lower counts ( P CD 4 ≥ 500 ‐ to ‐ 350 ≤ CD 4 < 500 < 0.001 , P 350 ≤ CD 4 < 500 ‐ to ‐ 200 ≤ CD 4 < 350 < 0.001 , and P 200 ≤ CD 4 < 350 ‐ to ‐ CD 4 < 200 < 0.001 ). In addition, initiating ART showed a statistically significant increase in the probability of CD4 cell count transition from a lower state ( 350 ≤ CD 4 < 500 ) to a higher state ( CD 4 ≥ 500 ) ( P = 0.009 ). Furthermore, When CD4 count reaches under 200, even after the initiation of therapy, the probability of CD4 cell count transition to higher levels was not significant ( P > 0.05 ). In summary, these results have a message for primary healthcare organizations to extensively identify HIV patients and initiating ART as early as possible.

Factors associated with late initiation of antiretroviral therapy in Iran’s HIV/AIDS surveillance data

“…Antiretroviral Treatment (ART) since 1996 has substantially improved outcomes for PLWH, including suppressing viral loads to an undetectable level, restoring CD4+ T-cell counts, and decreasing AIDS-related morbidity and mortality 4 – 7 . Additionally, early ART initiation is associated with a higher probability of good prognosis 8 , serving as the main predictor of virological suppression 9 , and can substantially decline HIV transmission rate by 96% in couples with one HIV-infected partner, compared to late ART initiation 10 , 11 . Conversely, late or delayed ART initiation in linked to weakened immune function, clinical progression, increased risk of opportunistic infections, and higher AIDS and non-AIDS related morbidity and mortality among PLWH, as well as higher pressure on healthcare systems 12 – 15 .…”