Comparison of nucleoside reverse transcriptase inhibitor use as part of first-line therapy in a Serbian and a UK HIV clinic.

Background: Use of dideoxynucleoside reverse transcriptase inhibitors (dNRTIs) may lead to increased mitochondrial toxicity. We compared nucleoside reverse transcriptase inhibitor (NRTI) use as part of antiretroviral therapy (ART) in two HIV clinics: one in a low-middle income (HIV Centre Belgrade [HCB], Serbia) and one a high income (ICDC, Royal Free Hospital, London, UK) country. Methods: Antiretroviral-naive patients starting ART from 2003 to 2005 were included. Specific NRTIs were compared between centers, focusing on dNRTI use. Kaplan-Meier estimates of the percentage of patients making changes to their NRTI backbone (a) for any reason or (b) for mitochondrial toxicity (peripheral neuropathy, pancreatitis, lactic acidosis) were calculated. Results: Of 287 HCB patients, 89 (31.0%) received didanosine (ddl)-containing, 39 (13.6%) stavudine (d4T)-containing, and 39 (13.6%) ddl+d4T-containing regimens; for 539 ICDC patients, these were 18 (3.3%), 66 (12.2%), and 0 (0.0%), respectively (p < .0001). After 12 months, 57.5% and 52.6% at HCB and ICDC had switched their NRTI backbone. This was reduced to 34.5% at HCB after excluding changes due to drug supply interruption and to 11.2% and 1.3% at HCB and ICDC after changes were made for mitochondrial-related reasons. At 6 months, 73/80 (91.3%) and 385/488 (78.9%) had viral load below 50 copies/mL at HCB and ICDC, respectively. Conclusion: Patients treated at HCB faced higher levels of mitochondrial-related toxicity, likely due to greater dNRTI use.