446. Hyperlactatemia and Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTI): Still present even with modern antiretroviral therapy (ART)


 
 
 Hyperlactatemia and lactic acidosis represent a rare but dangerous manifestation of mitochondrial toxicity associated with NRTIs. Although mitochondrial toxicity has been linked to the NRTI class, it is more prevalent with older agents such as zidovudine (AZT), didanosine (ddI) and stavudine (d4t).
 
 
 
 Prompted by the diagnosis of symptomatic hyperlactatemia in 4 people with HIV on newer NRTIs between September 2019 and December 2021, we present a single-center case series to illustrate its subtle presentation and management. Hyperlactatemia was defined as a serum lactate of 1.6-4 mmol/L and lactic acidosis was defined as a serum lactate of > 4mmol/L.
 
 
 
 75% of the patients were male, the mean age was 57.8 years, and 100% were Caucasian. 75% (3/4) were either overweight or obese (body mass index > 25 kg/m2). 75% had a CD4 lymphocyte count < 200 cells/mm3 at the time of human immunodeficiency virus (HIV) diagnosis and 50% had the diagnosis for >10 years. The most common symptom reported was non-specific fatigue (100%), followed by widespread myalgias (75%). 1 patient reported severe peripheral neuropathy affecting activities of daily living and 1 patient reported palpitations and night sweats. The mean duration of symptoms prior to reporting was 27.5 months. At the time of diagnosis of symptomatic hyperlactatemia, 75% had a CD4 lymphocyte count > 200 cells/mm3, the mean serum lactate was 2.7 mmol/L (1.9 mmol/L - 3.9 mmol/L), 50% were on abacavir (ABC) and lamivudine (3TC), and 50% were on tenofovir alafenamide (TAF) and emtricitabine (FTC). After stopping ART for 2 weeks, mean serum lactate decreased to 0.6 mmol/L (0.4 mmol/L – 1.1 mmol/L). 100% reported an improvement in quality of life after NRTI cessation and were managed with an NRTI-sparing regimen. Clinical characteristics are noted in Table 1.
 
 
 
 This case series highlights the insidious nature of symptoms related to NRTI-associated mitochondrial toxicity including hyperlactatemia. Management strategies are not well defined for hyperlactatemia; however, NRTI-sparing regimens may offer improvement in quality of life. Despite improved tolerability of modern ART, clinicians should be aware of and monitor for symptoms of this potentially life-threatening side effect.
 
 
 
 Carlos Malvestutto, MD MPH, Gilead Sciences: Advisor/Consultant|Viiv Healthcare: Advisor/Consultant.
