Dried Plasma/blood Spots for Monitoring Antiretroviral Treatment Efficacy and Pharmacokinetics: a Cross-sectional Study in Rural Burundi

Aims: In limited resource settings monitoring antiretroviral (ARV) treatment efficacy is restrained by the lack of access to technological equipment. The aim of the study was to assess the use of dried plasma (DPS) and blood spots (DBS) to facilitate ARV monitoring in remote settings where clinical monitoring is the primary strategy.

Methods: A cross-sectional study in HIV-positive ARV-treated patients in Kiremba, Burundi was performed. DBS were used for HIV-1 viral load (limit of the assay 250 copies ml(-1)) and genotypic drug resistance tests and dried plasma spots were used for concentration measurements.

Results: Three hundred and seven patients [201 female (88.6%), 14 children (4.5%)] were enrolled. HIV-1 viral load was <250, 250-1000 and >1000 copies ml(-1) in 250 (81.7%), 33 (10.8%) and 23 patients (7.5%). Eleven samples out of 23 were successfully amplified revealing nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI)-resistance associated mutations [in seven (58.3%) and six patients (50%)]. Nevirapine trough concentrations were <3000 ng ml(-1) in 28/189 patients (14.8%) and efavirenz 12 h concentrations were <1000 ng ml(-1) in 2/16 patients (12.5%). Children and patients with nevirapine exposure <3000 ng ml(-1) presented a higher risk of viral replication.

Conclusions: Viral loads <250 copies ml(-1) were observed in 81.7% of patients (83.6% adults and 42.9% children). Children and patients with low nevirapine concentrations had higher risk of viral replication. Dried blood and plasma spots may be useful for monitoring HIV-positive patients including viral load and drug level measurement as part of treatment management in remote areas.