Background: Published reports of the prevalence of asymptomatic hyperlactatemia among HIV-infected individuals have ranged from 4%–36%. The significance of these elevations in lactate in the absence of symptoms remains uncertain. In addition, the variability in the reported AH prevalence may reflect cohort differences in risk factors for hyperlactatemia and/or techniques for venous lactate collection.

Methods: We examined the prevalence of elevated venous lactate levels among HIV-infected, NRTI-treated subjects with one or more risk factors associated with hyperlactatemia including previous hyperlactatemia; anion gap > 15 mmol/L; HCO3 < 20 mmol/L; d4T use for > 6 months (mos); recently elevated ALT, CK or LDH; mild-moderate nausea, fatigue, or abdominal discomfort; peripheral neuropathy; lipoatrophy or osteopenia/porosis. Venous lactate levels were collected in accordance with strict Adult AIDS Clinical Trials Group guidelines without tourniquet or fist clenching. Hyperlactatemia was defined as a level above 1.5x the upper limit of normal (ULN). ULN at the study sites ranged from 2.2–2.4 mmol/L. Subjects with documented hyperlactatemia underwent repeat testing within 2 wks.

Results: Eighty-three (83) subjects (14% women, 66% non-white) were enrolled. At entry 75% were receiving d4T, 61% had increased anion gap, 17% had ALT > ULN, 14% had self-described lipoatrophy, 11% had peripheral neuropathy, 6% had low HCO3, and 2% had osteopenia. Mild abdominal discomfort was reported in 10% and nausea in 2%. All 83 subjects had multiple risk factors reported with 97% having > 4 risk factors. The median initial venous lactate levels for the cohort was 1.2 mmol/L. An entry lactate level above the ULN was detected in 6 subjects (range 1.04–2.1X ULN). The 1 subject with a level > 1.5X ULN had a repeat lactate of 1.2X ULN when tested again within 14 days. No cases of symptomatic hyperlactatemia or lactic acidosis were diagnosed.

Conclusions: Asymptomatic hyperlactatemia among subjects with multiple risk factors previously associated with hyperlactatemia was not observed when venous lactate levels were measured in a standardized fashion. Our findings suggest that asymptomatic hyperlactatemia is either very rare or an artifact of collection technique.