Performance characteristics of clinical, immunological and virologic criteria in monitoring response to antiretroviral therapy among HIV infected Patients in Dar - es - salaam, Tanzania

Abstract

Background: WHO recommends the use of clinical assessment and/or CD4+ T-cell count as surrogate markers to monitor response to antiretroviral therapy (ART) in resource-limited settings. There is limited published data regarding the performance of clinical, immunological and virologic criteria in monitoring the response to ART in the local settings. Objectives: To determine the performance characteristics of clinical, immunological and virologic criteria in monitoring response to ART among HIV- infected patients in Dar es Salaam, Tanzania. Methodology: Prospective cohort study was carried out from August 2012 to May 2013.Patients initiating ART at Care and Treatment Center at IDC, Amana and Mwananyamala were recruited in the study after obtaining informed consents. Data on socio-demographic characteristics, clinical and laboratory parameters was obtained using standardized case report forms. Blood samples were collected to determine CD4+ T-cell count and plasma viral load at baseline and six months after initiation of ART. Data was analyzed using the SPSS version 17.0. Sensitivity, specificity, positive and negative predictive values of clinical and immunological monitoring were determined using virologic criteria as gold standard. Logistic regression analysis to assess the predictors associated with treatment failures was performed. A p-value of <0.05 was regarded as statistically significant. Ethical clearance and informed consent were obtained prior to the enrolment in the study. Data was analyzed using the SPSS version 17.0. vii Results: A total of one hundred and forty HIV-infected patients were enrolled in the study. The overall mean age (SD) was 40.0 (9.8) years. Majority of patients were females 95 (67.9%). Seventy nine (56.4%) were in WHO clinical stage III at enrollment. The median CD4+ T-cell count (IQR) was 255 (147-255). Of eighty three patients with complete follow up data 34.9% and 31.3% experienced virological and immunological failure respectively. Clinical failure was detected in 7.2% of the patients. The sensitivity and specificity of immunological criteria in detecting virological failure were 34.5%, 95%CI (19.9%-52.7%) and 70.4%, 95%CI (57.1%- 83.9%) respectively. The sensitivity and specificity of clinical criteria were 17.2%, 95%CI (7.1%-35.0%) and 98.1%, 95%CI (89.3%-100%) respectively. Patients with CD4 count below 200 cells/μl at enrollment were more likely to experience virologic failure than those with CD4 count equal or above 350 cells/ μl. Conclusion and Recommendation: This study further highlights low sensitivity and specificity of immunological and clinical criteria in detecting virological failure in HIV- infected patients in the first six months on ART in Dar es salaam, Tanzania. The low performance of clinical and immunological criteria may lead to misclassification of response to treatment, accumulation of resistance mutations and even poorer treatment outcomes A CD4 T cell count of < 200 cells/ul was shown to be significantly associated with treatment failure thus HIV- infected patients with such baseline count should have close laboratory monitoring including viral load testing to better improve treatment outcomes. However more data is required from larger studies to support the findings so that they can eventually translate into policy guidelines.