Development and evaluation of a clinical algorithm to monitor patients on antiretrovirals in resource-limited settings using adherence, clinical and CD4 cell count criteria

Abstract

BackgroundRoutine viral load monitoring of patients on antiretroviral therapy (ART) is not affordable in most resource-limited settings.MethodsA cross-sectional study of 496 Ugandans established on ART was performed at the Infectious Diseases Institute, Kampala, Uganda. Adherence, clinical and laboratory parameters were assessed for their relationship with viral failure by multivariate logistic regression. A clinical algorithm using targeted viral load testing was constructed to identify patients for second-line ART. This algorithm was compared with the World Health Organization (WHO) guidelines, which use clinical and immunological criteria to identify failure in the absence of viral load testing.ResultsForty-nine (10%) had a viral load of >400 copies/mL and 39 (8%) had a viral load of >1000 copies/mL. An algorithm combining adherence failure (interruption >2 days) and CD4 failure (30% fall from peak) had a sensitivity of 67% for a viral load of >1000 copies/mL, a specificity of 82%, and identified 22% of patients for viral load testing. Sensitivity of the WHO-based algorithm was 31%, specificity was 87%, and would result in 14% of those with viral suppression (<400 copies/mL) being switched inappropriately to second-line ART.ConclusionAlgorithms using adherence, clinical and CD4 criteria may better allocate viral load testing, reduce the number of patients continued on failing ART, and limit the development of resistance.

Development of an algorithm for determination of the likelihood of virological failure in HIV-positive adults receiving antiretroviral therapy in decentralized care

“…We consider this parameter to be reliable and easy to measure compared with more complex assessments of adherence level. A similar criterion was part of clinical algorithm for VF developed in Uganda [17], and associated with VF in a study from South Africa [32]. …”

“…There have been previous attempts to construct algorithms for targeted viral load testing based in Sub-Saharan Africa [15–17,35,36] and Cambodia [14]. Compared with these algorithms, the VLTC has few parameters, does not require any calculations, and only use information that can be available point-of-care.…”

“…A clinical predictor score developed in Cambodia [14] achieved comparable sensitivity (78%) in a subsequent validation in Cambodia [38], but the sensitivity was low (51%) when validated in Uganda [15]. The clinical algorithms constructed in Sub-Saharan Africa (2 in Uganda and 1 in South Africa), had sensitivities ranging from 67% to76% [15–17], external validations of these algorithms are yet to be published. The sensitivity of the 2013 WHO criteria was higher in this cohort (67%) compared with previously reported data [15,16,18].…”

“…This approach is also used in HIV care, especially for estimation of the risk of tuberculosis co-infection [12,13]. Some groups have also attempted to develop algorithms for determination of VF [14–17], but to our knowledge these algorithms are hitherto not in general use nor recommended in ART guidelines.…”

Detecting virological failure in HIV-infected Tanzanian children

“…[6] However, there may be no clear benefit to routine measurement of viral load to ascertain virological failure in adults. [7] Data on clinical and immunological monitoring to detect virological failure in children are limited. Where methods for detecting virological failure are available, they are not affordable.…”