Hyperlactatemia and antiretroviral therapy: the Swiss HIV Cohort Study

Safety and efficacy of switching to alternative nucleoside analogues following symptomatic hyperlactatemia and lactic acidosis

OBJECTIVE

To evaluate the safety and efficacy of rechallenging patients who have recovered from nucleoside reverse transcriptase inhibitor (NRTI)-induced symptomatic hyperlactatemia or lactic acidosis with alternative NRTI-containing regimens.

METHODS

Data in this case series was collected from patients followed at the UCSD Owen Clinic from July 1998 through September 2002. Cases of symptomatic hyperlactatemia were HIV-infected adults receiving NRTI who had symptoms compatible with hyperlactatemia and two lactates > 2 times the upper normal limit. Lactic acidosis was defined as lactate > 5 mmol/l with bicarbonate < 20 mmol/l. The suspected offending NRTI in the prior regimen were replaced with other NRTI thought to have equivalent antiviral potency but less mitochondrial toxicity.

RESULTS

Ten patients diagnosed with symptomatic hyperlactatemia and two with lactic acidosis were later restarted on antiretrovirals that included new NRTI. The NRTI that patients were receiving when symptomatic hyperlactatemia or lactic acidosis was diagnosed included stavudine and lamivudine (n = 6), stavudine and didanosine (n = 4), and stavudine and abacavir (n = 2). The median (range) peak lactate was 5.4 (4.7-19.1) mmol/l. Five patients were rechallenged with abacavir and lamivudine, five with zidovudine, abacavir and lamivudine, and two with zidovudine and lamivudine. Among the 12 patients contributing over 22 years of cumulative reexposure to NRTI-containing therapy, one developed symptomatic hyperlactatemia again yielding a recurrence rate of 45.5 cases/1000 patient-years. Virologic control was maintained in all patients.

CONCLUSIONS

This data supports the strategy that in cases of symptomatic hyperlactatemia or lactic acidosis in which the toxicity is associated with stavudine, didanosine or both, it is safe and efficacious to reintroduce NRTI that are less potent inhibitors of mitochondria.

Update on chronic hepatitis C in HIV/HCV-coinfected patients: viral interactions and therapy

With highly active antiretroviral therapy (HAART), HIV-infected patients can now live longer and healthier lives, and other comorbid diseases, such as chronic hepatitis C, have emerged as a significant health concern. Coinfection with the hepatitis C virus (HCV) may limit life expectancy because it can lead to serious liver disease including decompensated liver cirrhosis and hepatocellular carcinoma. HCV-induced fibrosis progresses faster in HIV/HCV-coinfected persons, although HAART may be able to decrease this disease acceleration. Combination therapy for HCV with interferon and ribavirin can achieve a sustained viral response, although at a lower rate than in HCV-monoinfected patients. Combination treatment with pegylated interferon and ribavirin will probably emerge as the next HCV therapy of choice for HIV/HCV-coinfected patients. HCV combination therapy is generally safe, but serious adverse reactions, like lactic acidosis, may occur. Cytopenia may present a problem leading to dose reductions, but the role of growth factors is under study. All HIV/HCV-coinfected patients should be evaluated for therapy against the hepatitis C virus. A sustained viral load will probably lead to regression of liver disease, and even interferon-based treatment without viral clearance may slow down progression of liver disease. HIV/HCV-coinfected patients who have progressed to end-stage liver disease have few therapeutic options other than palliative care, since liver transplants are generally unavailable. The mortality post-transplant may be higher than in HCV-monoinfected patients. We are entering an era where safe and effective HCV therapy is being defined for HIV/HCV-coinfected patients, and all eligible patients should be offered treatment.

Cardiovascular risk factors in HIV-infected patients

Highly active antiretroviral therapy (HAART) commonly leads to persistent dyslipidemia and insulin resistance that appear likely to confer an increased incidence of cardiovascular disease (CVD). Both protease inhibitors (PIs) and, to a lesser extent, nucleoside analog reverse transcriptase inhibitors (NRTIs) appear to be involved, through direct metabolic effects of PIs and an indirect effect of PI and NRTI-related lipodystrophy. Several studies have found a variable relationship between CVD incidence and HAART, but these studies were not prospective and may not have been adequately powered. A variety of treatment strategies have been evaluated for dyslipidemia and insulin resistance, including lifestyle changes, drugs, and antiretroviral switching, but their relative safety, efficacy and roles are unclear. Although treatment of dyslipidemia and insulin resistance is commonly recommended, it should be remembered that such therapy is likely to be of greater benefit in those with a greater perceived CVD risk (i.e., multiple risk factors) and the lowest risk of HIV disease progression.

Factors associated with mitochondrial dysfunction in circulating peripheral blood lymphocytes from HIV-infected people

Nucleoside analogue reverse transcriptase inhibitor (NRTI)-associated mitochondrial toxicity is an important issue in the clinical management of HIV infection. The aim of this study was the detection of mitochondrial dysfunction by flow cytometry in lymphocytes from HIV-infected individuals and its association with blood lactate levels, clinical and virologic status, and the different NRTI-based therapies. Lower peripheral blood lymphocytes with mitochondrial dysfunction (PBLmd) percentages were observed in healthy controls (1.2, interquartile range [IQR] = 0.4-1.9) than in patients (2.2, IQR = 0.9-3.7; P < 0.01). Stavudine-containing therapy showed higher PBLmd percentages (3.0, IQR = 1.1-4.5) than no treatment (2.1, IQR = 0.8-2.8; P < 0.05) or zidovudine-based therapy (0.9, IQR = 0.3-1.4; P < 0.01). A significant inverse correlation was found between PBLmd and CD4 T-cell percentage and absolute count. Patients with an AIDS diagnosis had higher PBLmd percentage (2.7, IQR = 1.1-4.4) than HIV-positive non-AIDS patients (1.4, IQR = 0.6-3.0; P = 0.012). In multivariate analysis, use of stavudine (odds ratio [OR] = 5.86, 95% CI = 1.81-19.01, P = 0.003) and CD4 T-cell counts <200/microL (OR = 4.51, 95% CI = 1.38-14.70, P = 0.012) were independent predictors of high PBLmd percentage. This cross-sectional study shows that antiretroviral drugs can impair the in vivo mitochondrial function of PBLs.

Early versus delayed antiretroviral therapy in patients with HIV infection : a review of the current guidelines from an immunological perspective

The development and implementation of highly active antiretroviral therapy (HAART) for the treatment of the human immunodeficiency virus has revolutionised the care of patients with this disease. Despite the positive impact that antiretroviral therapy has had on the lives of individuals with HIV infection, the adverse effects, potential long-term toxicities, complexity of regimens, development of drug resistance and cost have made decisions about when to initiate HAART difficult. The benefits and risks of antiretroviral therapy vary considerably among patients at different stages of disease, mainly as a result of the irreversible destruction of the immune system that occurs as HIV infection progresses. In acute HIV infection, the primary aim of treatment is preservation and reconstitution of HIV-specific immune function. In symptomatic or late-stage disease, the goal is control of viral replication with resulting improvement in non-HIV-specific immunity, which leads to decreased morbidity and increased survival. The most controversial decision involves when to start therapy in persons with asymptomatic chronic HIV, where the benefits are less well established and may be outweighed by the drawbacks, depending on the individual patient. In all patients, the advantages and disadvantages must be considered carefully, and the readiness and ability of the individual to adhere to a complex multidrug regimen needs to be assessed before the initiation of therapy.

Dilated cardiomyopathy in an adult human immunodeficiency virus type 1-positive patient treated with a zidovudine-containing antiretroviral regimen

We describe an adult woman infected with human immunodeficiency virus type 1 (HIV-1) who developed dilated cardiomyopathy (DCM) with histologically confirmed mitochondrial damage while receiving anti-HIV-1 combination therapy that included nelfinavir, lamivudine, and zidovudine. DCM resolved after discontinuation of the regimen, and cardiac function remained normal after initiation of treatment with nelfinavir, lamivudine, and abacavir, which indicates that DCM was induced by mitochondrial toxicity, most likely caused by zidovudine.

Mitochondrial Toxicity in the Era of HAART: Evaluating Venous Lactate and Peripheral Blood Mitochondrial DNA in HIV-Infected Patients Taking Antiretroviral Therapy

Nucleoside analogs can induce mitochondrial toxicity by inhibiting the human DNA polymerase gamma. This can lead to a wide range of clinical toxicities, from asymptomatic hyperlactatemia to death. Despite their technical and physiological variability, we propose that random venous lactate measurements can be useful to monitor the development of nucleoside-related mitochondrial toxicity. Recently, we have developed an assay that can measure changes in mitochondrial DNA levels in peripheral blood cells. Using this assay we have characterized changes in mitochondrial DNA (mtDNA) relative to nuclear DNA (nDNA) in peripheral blood cells of patients with symptomatic nucleoside-induced hyperlactatemia. Our results demonstrate that symptomatic hyperlactatemia was associated with markedly low mtDNA/nDNA ratios, which were on average 69% lower than HIV-uninfected controls and 45% lower than HIV-infected asymptomatic/antiretroviral naive controls. A statistically significant (p = .016) increase in mtDNA/nDNA ratio was observed following discontinuation of antiretroviral therapy. The mtDNA/nDNA ratio remained stable among selected patients who reintroduced antiretroviral therapy with stavudine (d4T)-sparing regimens. Of note, the decline in mtDNA preceded the increase in venous lactate levels. More recently we have evaluated changes in the mtDNA/nDNA ratio in relation to selected antiretroviral drug regimens in a cross-sectional study on a non-random sample of participants within the British Columbia Centre for Excellence in HIV/AIDS Drug Treatment Program. Eligible patients had continuously received saquinavir plus ritonavir with either nevirapine (n = 20), lamivudine (n = 15), d4T (n = 53) or lamivudine + d4T (n = 69), for 4 to 30 months. d4T-sparing regimens were associated with a higher median mtDNA/nDNA ratio than d4T-containing regimens (p = .016), despite the fact that study patients had received d4T-containing regimens for a shorter median time than patients taking d4T-sparing regimens (13 versus 25 months, p = .002). In summary, mtDNA levels are significantly decreased among patients who develop symptomatic, nucleoside-related hyperlactatemia, an effect reversed upon therapy discontinuation. Furthermore, mtDNA/nDNA ratios were statistically significantly lower in patients taking d4T-containing regimens than in those taking selected d4T-sparing regimens in a population setting. These results suggest that measurement of this parameter should be investigated as a potential clinical management tool.

Hyperlactatemia in human immunodeficiency virus-infected children receiving antiretroviral treatment

BACKGROUND

Hyperlactatemia and lactic acidosis occur in HIV-infected adults receiving antiretroviral treatment. Our objective was to determine the incidence, course and risk factors for hyperlactatemia in our HIV-infected pediatric patients.

DESIGN

A prospective observational study of venous lactate concentrations during a 28-month period in 80 HIV-infected children, most of whom were receiving antiretrovirals.

METHODS

Venous blood lactate concentrations were measured every 6 months under optimal sample-obtaining conditions. Alanine values from the same blood sample were performed when lactate concentrations were elevated. Hyperalaninemia is observed only when mitochondrial oxidative phosphorylation is chronically disturbed.

RESULTS

Twenty-three patients (29%) were identified with hyperlactatemia, in 9 of the cases with normal alaninemia, probably caused by difficult venous punctures. The other 14 children (17%) had pathologic alanine concentrations with a mean lactate peak of 2.67 mmol/l (range, 2.05 to 4.9 mmol/l); none of them showed metabolic acidosis, and they were all symptom-free. Treatment was continued in all cases, and lactate has progressed spontaneously to normal values in 5 patients.

CONCLUSIONS

Symptom-free hyperlactatemia was observed in HIV-infected children receiving nucleoside analog reverse transcriptase inhibitors. In our study, only a younger age at the beginning of antiretroviral treatment was a statistically significant risk factor for hyperlactatemia. Random measurements of blood lactate concentrations should be included in the clinical follow-up of those HIV-infected children <3 years of age who are treated with nucleoside analog reverse transcriptase inhibitors, symptomatic or not.

Lactic acidemia in human immunodeficiency virus-uninfected infants exposed to perinatal antiretroviral therapy

OBJECTIVE

To investigate potential mitochondrial toxicity in HIV-uninfected infants exposed to highly active antiretroviral therapy (HAART) in utero and/or neonatal zidovudine.

DESIGN

A prospective observational study performed in a tertiary referral center for HIV-infected women and their infants and children.

METHODS

Plasma lactate was measured repeatedly during the first 6 months of life in a consecutive cohort of infants exposed to HAART in utero and/or neonatal zidovudine. Maternal CD4, HIV RNA concentration, antiretroviral and substance use histories, mode of delivery, infant gender, cord pH, Apgar score and birth weight were collected.

RESULTS

The plasma lactate was above normal on at least 1 occasion in 35 of 38 (92%) infants and reached levels > or =5 mmol/l in 10 (26%) infants. Overall 78 of 117 (68%) lactate measurements were elevated, with 11 (10%) in the serious (> or =5 mmol/l) range. None of the infants received antiretrovirals beyond 6 weeks, yet elevated lactates persisted up to age 6 months. Two infants had reversible symptoms consistent with those of lactic acidemia. No association was found between the infant peak lactate and the type of therapy during pregnancy, its duration or maternal substance use.

CONCLUSION

Transient lactic acidemia was observed in the majority of HIV uninfected infants exposed to HAART in utero and/or zidovudine neonatally. We hypothesize that the hyperlactatemia is a consequence of persistent, primarily subclinical, mitochondrial toxicity from the transplacental and neonatal exposure to antiretrovirals and of impaired hepatic lactate clearance. Although the clinical relevance of our findings is unknown, we recommend lactate monitoring in these infants, considering discontinuation of neonatal zidovudine in symptomatic infants with lactate > or =5 mmol/l and careful long term follow up of these children.

Antiretroviral Therapy-associated Serious and Life-threatening Toxicities

In the late 1980s and early 1990s, when HIV/AIDS had become the leading cause of death in 25- to 44-year-old persons in the United States, it was acceptable to prescribe newer antiretroviral therapy such as zidovudine, which has significant bone marrow toxicities but can potentially improve patient survival. Although current antiretroviral therapy is not likely to eradicate HIV-1 infection, the advances in the use of combination antiretroviral therapy (including protease inhibitors and non-nucleoside reverse transcriptase inhibitors) have dramatically improved the overall survival, immune status, and productivity of HIV-infected individuals in developed countries. Instead of prevention and treatment of HIV-associated complications, many of the patients" clinic visits are focused on finding strategies to manage and prevent antiretroviral therapy-associated complications. Because only a few HIV-infected persons fulfilling stringent inclusion criteria were included in premarketing clinical trials and because the US Food and Drug Administration"s (FDA) accelerated approval process for antiretroviral therapy requires only 24-week safety and efficacy data, newly emerging and previously unrecognized adverse effects of antiretroviral therapy continue to surface when these drugs are administered to a larger patient population for a longer duration. Unfortunately, some of these adverse effects can be unpredictable and serious, and, if not recognized early and managed aggressively, can lead to fatality. This article reviews four of the most serious, life-threatening toxicities associated with antiretroviral therapy.

Lactic acidosis related to nucleoside therapy in HIV-infected patients

The incidence of nucleoside analogue-related lactic acidosis has been estimated in 0.57 - 8.5 cases/1000 person years of antiretroviral therapy. The onset of lactic acidosis is usually insidious and patients complain of nausea, vomiting, abdominal pain, fatigue and weight loss. When lactate levels are high enough, a catastropic clinical situation develops, resulting in multiorgan failure. The mortality rate of patients with lactic acidosis related to nucleoside therapy is very high, 33 - 60%. Although all nucleoside analogues have been implicated in lactic acidosis, most cases are associated with stavudine. At present, there are no controlled trials to evaluate the treatment of nucleoside-induced lactic acidosis. Therapy is based on supportive measures and discontinuation of all antiretroviral drugs. Administration of essential vitamin coenzymes, electron acceptors and L-carnitine may be useful in some cases.

Fatal nucleoside-associated lactic acidosis in an obese woman with human immunodeficiency virus type 1 infection on a very low-calorie diet

This study reports the case of an obese woman with human immunodeficiency virus type 1 (HIV-1) infection who developed fatal nucleoside-associated lactic acidosis 10 d after she started a weight-loss dietary regimen containing 600 kcal/d. This case suggests that very low-calorie diets may be life threatening for HIV-infected patients receiving nucleoside analogues.

Lactate levels in children with HIV/AIDS on highly active antiretroviral therapy

A total of 251 venous lactate levels were obtained from 127 children with HIV/AIDS; 104 on highly active antiretroviral therapy, and 23 not on therapy. Asymptomatic hyperlactatemia (> 2 mmol/l) was found in 41 children; no hepatic dysfunction or life-threatening lactic acidosis occurred. Asymptomatic hyperlactatemia is associated with treatment with nucleoside reverse transcriptase inhibitors or protease inhibitors and with undetectable viral loads regardless of treatment regimen, suggesting that elevated lactate levels are useful in evaluating adherence.

Quantitative analysis of human mitochondrial DNA using a real-time PCR assay

OBJECTIVES

Known for their ability to inhibit the human DNA polymerase-gamma, nucleoside analogues induce toxic effects on mitochondria ranging from increased serum lactate levels to fatal lactic acidosis. DNA polymerase-gamma ensures the mitochondrial DNA (mtDNA) replication and, thus, its inhibition leads to the decrease of the mtDNA. We describe a real-time PCR assay for mtDNA quantification associating DNA extraction procedures applied on peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissues and to study the antiretroviral effect on mitochondria.

METHODS

Total DNA was extracted from PBMCs and subcutaneous adipose tissues. Nuclear and mitochondrial genes were amplified to determine the number of copies of mtDNA per cell using a cyt-b recombinant plasmid as standard control. We analysed eight HIV-infected asymptomatic patients never treated, four patients who had been treated for 6 months with highly active antiretroviral therapy (HAART) and six non-infected donors.

RESULTS

The mtDNA quantification gave rise to reproducible results as the mean coefficients of variation were 1.09% for replicates of samples undertaken 10 times within the same run, and 5.78% and 3.7% for replicates tested in five different runs at 1:100 and 1:1000 dilutions, respectively. Median levels of mtDNA in PBMCs of healthy donors, naive and treated HIV-infected patients were 2.94, 2.78 and 1.93 log HIV-1 RNA copies/mL, respectively. Whereas DNA from PBMCs was shown to be devoid of inhibitors, subcutaneous adipose tissues needed an extra treatment as they were found to be highly inhibited.

CONCLUSIONS

The method generated consistent and reproducible results and was successfully applied to DNAs extracted from PBMCs and subcutaneous adipose tissues with adapted extraction. The mtDNA changes in PBMCs were found to be fast as they fall off after 6 months' therapy, decreasing from 2.78 to 1.93 log copies/mL.

Frequency, risk factors, and outcome of hyperlactatemia in HIV-positive persons: implications for the management of treated patients

BACKGROUND

The nucleoside reverse transcriptase inhibitors used for the treatment of HIV-positive persons are now clearly associated with metabolic disorders. We determined the prevalence of and risk factors for hyperlactatemia in HIV-positive persons to assess the relevance of lactate venous blood concentrations during antiretroviral therapy.

METHODS

We conducted a prospective cross-sectional study of venous lactate determinations with 282 consecutive HIV-positive persons who, in addition to a physical examination, had blood samples taken every 3-4 months for routine biochemical, immunologic, and viral assessment. The frequencies of hyperlactatemia and lactic acidosis were determined, and the risk factors were analyzed by a multivariate logistic regression model. The effect of modification of antiretroviral therapy in patients with moderate hyperlactatemia was also assessed.

RESULTS

From 782 blood lactate determinations, we identified 65 (23%) patients with moderate hyperlactatemia and 5 (1.8%) with lactate concentrations >5 mmol/L (2 with severe lactic acidosis; 0.7%). Older age, drug regimens containing stavudine [adjusted odds ratio (OR) = 2.5] or a combination of stavudine-didanosine (adjusted OR = 3.1), and the use of buprenorphine (adjusted OR = 14.7) were independent predictors of hyperlactatemia. Among 65 patients with moderate hyperlactatemia, 39 did not have their treatments changed, and 26 had a new combination therapy that was associated with a clinical improvement and a more pronounced decrease in lactate (-1.66 vs -0.99 mmol/L; P <0.05).

CONCLUSIONS

Chronic compensated and moderate hyperlactatemia was common in our population study. Measurement of lactate, under standardized conditions, may be useful in optimizing management of HIV-positive persons on antiretroviral therapy.

HIV lipodystrophy: prevalence, severity and correlates of risk in Australia

OBJECTIVE

To establish the prevalence, severity and factors associated with the HIV lipodystrophy syndrome.

METHODS

Cross-sectional study of lipodystrophy conducted in high HIV caseload primary care sites and HIV outpatient clinics. A subset of patients was examined using dual energy X-ray absorptiometry (DEXA) and single cut abdominal computerized tomography (CT) at the L4 vertebral level to quantify regional and total body fat. Factors associated with lipodystrophy, lipoatrophy and lipohypertrophy were assessed using multiple logistic regression based on assignment of cases and non-cases.

RESULTS

One thousand, three hundred and forty-eight patients (95% male) were surveyed, 20% had AIDS, the mean CD4 lymphocyte count was 486 cells/microL, and 55% had <500 HIV-1 RNA copies/mL. Most participants (87%) had previously received or were currently receiving combination antiretroviral therapy, 73% with at least one protease inhibitor (PI) and 14% a non-PI-containing regimen. Lipodystrophy prevalence was 53% and of these, 55% reported both peripheral lipoatrophy and central lipohypertrophy, 31% experienced peripheral lipoatrophy only and 14% had central lipohypertrophy only. The prevalence of any body habitus change was 62% in PI-experienced patients, 33% in PI-naive patients and 21% in antiretroviral-naive patients. Lipodystrophy severity was less in antiretroviral-naive patients and most severe in PI-experienced patients. Increasing severity of lipodystrophy was both positively and significantly correlated with elevated liver enzymes, decreased testosterone levels, decreased skin-fold thickness, lower levels of total and peripheral fat (DEXA) and higher levels of visceral fat (CT). Lipodystrophy was also significantly associated with increasing age, symptomatic HIV disease, effective viral suppression, and increasing duration of therapy with both nucleoside reverse transcriptase inhibitors and PIs.

CONCLUSIONS

The prevalence and severity of lipodystrophy reflects both length and type of treatment with antiretroviral therapy and is associated with decreased testosterone, increases in liver enzymes and greater suppression of HIV RNA. The reports of lipodystrophy in a small percentage of antiretroviral-naive patients suggests that factors other than antiretroviral therapy may be involved in the aetiology of this syndrome or that some conditions, such as wasting or age-associated obesity, may mimic lipoatrophy and lipohypertrophy, respectively.

Human immunodeficiency virus infection with human granulocytic ehrlichiosis complicated by symptomatic lactic acidosis

Lactic acidosis has been reported as a complication associated with antiretroviral therapy; in particular, usually with use of nucleoside reverse-transcriptase inhibitors. We describe a human immunodeficiency virus (HIV)-infected patient with a history of lipodystrophy who presented with hepatic insult associated with documented human granulocytic ehrlichiosis (HGE). Despite a normal serum lactate level before the onset of acute coinfection, the patient developed symptomatic hyperlactatemia while receiving appropriate treatment for HGE. To date, this is the first presentation of symptomatic hyperlactatemia in a patient with HIV infection and HGE.

Hyperlactataemia syndromes associated with HIV therapy

Hyperlactataemia is seen in 8-18.3% of HIV-infected patients taking nucleoside-analogue reverse transcriptase inhibitors (NRTIs). Recent epidemiological studies suggest that most episodes are transient and subclinical. However, symptomatic and occasionally life-threatening cases accompanied by metabolic acidosis and hepatic steatosis (ie, lactic acidosis syndrome) have also been described. Though yet to be fully elucidated, the proposed mechanism is NRTI-induced inhibition of mitochondrial DNA polymerase culminating in derangements in oxidative phosphorylation and lactate homeostasis. Signs and symptoms range from mild hyperlactataemia accompanied by nausea, abdominal discomfort, and weight loss to severe, intractable lactic acidosis complicated by coma and multi-organ failure. Significant progress has recently been made with regard to the natural history of NRTI-related hyperlactataemia. However, other important aspects of the disorder, such as its pathogenesis, predisposing conditions, and management, remain poorly understood. This article reviews the current published work on these issues, identifies areas of controversy, and addresses directions for future research.

Natural history of hyperlactataemia in human immunodeficiency virus-1-infected patients during highly active antiretroviral therapy

A study on the course of hyperlactataemia during highly active antiretroviral therapy (HAART) and the association between hyperlactataemia and antiretroviral drugs was conducted at the outpatient department, Rigshopitalet, Copenhagen. Lactate levels were monitored in 848 patients during a study period of 1 y. Longitudinal analysis was performed on all human immunodeficiency virus-1-infected patients who had plasma lactate > 2.1 mM. Hyperlactataemia was found in 178 patients (21%), of whom 7 patients needed treatment modification, owing to symptomatic hyperlactataemia in 3 and neuropathy in 4 patients, while 171 remained on unchanged therapy. Lactate levels increased in 20 patients during the study period, but the increases were modest with a mean of 0.6 mM (range 0.1-1.7 mM). The association between antiretroviral drugs and hyperlactataemia was studied using logistic regression in 263 patients with data on their treatment regimen available in electronic form. Only stavudine and ritonavir were significantly associated with hyperlactataemia, with odds ratios of 5.1 and 2.6, respectively. In conclusion, symptomatic hyperlactataemia is uncommon, while asymptomatic hyperlactataemia is a frequent and apparently benign condition unlikely to progress to lactic acidosis. A significant association between stavudine and hyperlactataemia was confirmed. The unexpected association between ritonavir and hyperlactataemia will need confirmation in future studies.

Miller Fisher variant of Guillain-Barré syndrome associated with lactic acidosis and stavudine therapy

We describe the first case of Miller Fisher syndrome (opthalmoplegia, ataxia, and areflexia) associated with lactic acidosis as an adverse effect of receipt of an antiretroviral regimen containing stavudine. We review this syndrome in the context of recent descriptions of neuromuscular toxicities attributed to nucleoside analogue reverse-transcriptase inhibitor-induced mitochondrial toxicity.

Risk factors for lactic acidosis in HIV-infected patients treated with nucleoside reverse-transcriptase inhibitors: a case-control study

A case-control study was undertaken to determine risk factors for lactic acidosis in human immunodeficiency virus-infected patients treated with nucleoside reverse-transcriptase inhibitors (NRTIs). From May 1996 to June 2000, 9 patients with lactic acidosis (defined as a plasma lactic acid level of >5 mM and plasma pH of <7.38) were identified. Control patients were randomly selected from among a large cohort of patients who initiated a dual NRTI regimen in 1996 or after. Two factors were associated with an increased risk of lactic acidosis: first, a creatinine clearance of <70 mL/min before lactic acidosis (OR, 15.8 [range, 3.0-86.5], P<10(-4)), and, second, a low nadir CD4+ T lymphocyte count before the inception of NRTI therapy (OR, 8.4 [range, 1.2-infinity], P=.03). The total cumulative exposure to NRTIs was not associated with an increased risk of lactic acidosis, nor was the cumulative exposure to any of the 4 NRTIs studied. According to these results, monitoring of creatinine clearance, especially in patients with a low nadir CD4+ T lymphocyte count, could lead to modifications in antiretroviral therapy in order to diminish the risk of occurrence of lactic acidosis.

Antiretroviral-associated liver injury

ART-related hepatotoxicity can manifest in a variety of ways. Although benign, asymptomatic LEEs predominate, liver injury occurring in the context of either hypersensitivity or hyperlactatemia, represents a medical emergency and mandates immediate cessation of ART. Underpinning this broad spectrum of presentations are several, as yet poorly understood, mechanisms of liver damage that reflect contributions by constituents of HAART and host factors. Thus far, the most significant predisposing condition to emerge from clinical studies is chronic viral hepatitis. A more precise understanding, however, of the processes and factors that underlie ART-related hepatotoxicity is critical not only to the management of liver injury from current antiretroviral drugs but also to the design of safer drugs in the future.

Fatal lactic acidosis and acute renal failure after addition of tenofovir to an antiretroviral regimen containing didanosine

We describe a 49-year-old man with human immunodeficiency virus infection and stable chronic renal insufficiency who developed acute oliguric renal failure and severe lactic acidosis and who died several weeks after tenofovir was added to an antiretroviral regimen that included didanosine. Although the role of tenofovir in precipitating acute renal failure is unclear, progressive accumulation of the drug and pharmacologic interaction that caused increased levels of didanosine were the likely antecedents of increased mitochondrial toxicity that led to lactic acidosis.

Stroke in HIV-infected patients: a clinical perspective

The occurrence of stroke in patients with human immunodeficiency virus (HIV) infection has been traditionally associated with opportunistic infections and tumors, and advanced stages of immunosuppression. However, this reality is undergoing major changes. Effective antiretroviral regimens are now able to forestall the progression of HIV infection and avoid early mortality. As HIV-infected patients are growing older, clinicians are facing new challenges, including an increasing incidence of vascular complications. The use of protease inhibitors is associated with a variety of metabolic derangements that could produce accelerated atherosclerosis. Cerebrovascular hemodynamic function is impaired in HIV-infected patients with evidence of abnormal vasoreactivity even in otherwise healthy individuals. The potential contribution from these novel mechanisms should be added to the high incidence of classic vascular risk factors in the HIV-infected population and the cardiac abnormalities frequently observed in these patients. Large-scale epidemiological studies should be carried out to define the true incidence of stroke in HIV-infected patients and the factors associated with its occurrence.

Lactic acidemia in infection with human immunodeficiency virus

Lactic acidosis in patients infected with the human immunodeficiency virus was initially identified as a rare complication of therapy with nucleoside analog reverse transcriptase inhibitors (NRTIs). The only patient group that appears to be at greater risk is pregnant women. More recently, milder elevations in lactate (i.e., lactic acidemia or hyperlactatemia) have been found to be more common and to be associated with numerous illnesses. Mild asymptomatic lactic acidemia is common, but it appears to lead to more severe illness only rarely. This suggests that routine measurement of plasma lactate should be limited to patients with previous acidemia who reinitiate NRTI therapy and to pregnant women. For symptomatic lactic acidemia (generally >5 mmol/L), NRTIs and other antiretroviral therapy should be ceased. Currently, asymptomatic lactic acidemia should not be treated and should not lead to a change in antiretroviral therapy.

Hyperlactataemia during antiretroviral therapy: incidences, clinical data and treatment

Lactic acidosis is a serious complication of antiretroviral therapy. Symptomatic hyperlactataemia is a milder form of this syndrome, but its incidence is unclear. In this prospective ongoing observational study of a large cohort of HIV-infected adults, hyperlactataemia was diagnosed in 64 patients. Incidences were 18.3/1000 person-years with antiretroviral therapy, and 35.8/1000 person-years for stavudine (d4T) regimens. Ten of the 64 patients developed lactic acidosis during the first 13 months of treatment (incidence 2.9/1000 treated person-years). In four of ten patients, symptoms were absent or mild. More patients on d4T first-line therapy developed lactic acidosis than patients previously treated with other drugs (p = 0.008). Despite the occurrence of one death, the subsequent outcome for the remaining patients was favourable after antiretroviral therapy was stopped and supportive treatment with vitamins and antioxidants initiated. The early diagnosis of cases was the result of great vigilance and, combined with routine measurements of the anion gap, might be the most crucial factor explaining the low mortality rate observed here.

K65R with and without S68: A New Resistance Profile in Vivo Detected in Most Patients Failing Abacavir, Didanosine and Stavudine

Antiretroviral treatment with three nucleoside reverse transcriptase inhibitors (NRTIs) is widely used, but the combination of abacavir, didanosine and stavudine has never been investigated.

We describe the surprising and consistent genotypic and phenotypic outcome in patients failing this combination. As part of a Danish multicentre study, 60 antiretroviral-naive patients were randomized to treatment with abacavir, didanosine and stavudine. Failure was defined as one HIV-1 RNA >400 copies/ml. Genotyping was performed using TrueGene™ HIV-1 assay (Visible Genetics, London, UK). Phenotypic susceptibilities were determined with the Virco Antivirogram assay.

Eight patients failed treatment with a median viral load of 2.980 copies/ml (range 478-5.950).

At baseline, five patients were wild-type. Three patients harboured nucleoside excision mutations (NEMs), but phenotypic susceptibilities were within normal range.

All five patients with wild-type virus developed K65R and four of these patients also acquired the S68G mutation. Phenotypic susceptibility decreased towards abacavir (median 8.9-fold) and didanosine (median 3.2-fold), while susceptibility towards stavudine was unchanged (median 0.8-fold). Susceptibility towards lamivudine and tenofovir decreased median 14.2- and 4.0-fold, respectively. In two patients with baseline resistance mutations, further accumulation of NEMs and V75T or L74V was observed. One patient developed Q151M.

Failure of a triple NRTI regimen is possible and frequent with only the K65R mutation. Under adequate selection pressure K65R can easily emerge in vivo and may compromise several future treatment options including newer NRTIs. The unexpected high incidence of S68G suggests a functional role of this mutation in viruses harbouring K65R.

First-line therapy and mitochondrial damage: different nucleosides, different findings

BACKGROUND

Antiretroviral therapy has been associated with the development of morphologic body-shape changes and metabolic abnormalities, including dislipemia, insulin resistance, and hyperlactatemia. Mitochondrial damage secondary to the use of nucleoside analogue reverse transcriptase inhibitors (NRTIs) has been related to some of these complications, although the role of different NRTIs in their development is not well established.

OBJECTIVES

To assess the incidence of hyperlactatemia and lipodystrophy body-shape changes in drug-naïve HIV-infected patients who began highly active antiretroviral therapy (HAART) based on a backbone of two different NRTI combinations.

METHOD

Prospective, longitudinal, observational study of all consecutive drug-naïve HIV-infected individuals who started HAART with zidovudine (AZT) plus lamivudine (3TC) or didanosine (ddI) plus stavudine (d4T) between June 2000 and June 2001 at one single institution. Serum lactate levels and lipodystrophy body-shape changes were monitored periodically during 12 months.

RESULTS

At 1 year, mean lactate values remained <2 mmol/L in all 26 patients who received AZT+3TC, but they significantly increased (mean, 2.6 mmol/L) in 50 patients treated with ddI+d4T. The percentage of patients with hyperlactatemia (lactate >or=2 mmol/L) steadily increased in those on ddI+d4T (from 30% at 3 months to 71% at 12 months), whereas it remained below 10% in patients treated with AZT+3TC. Two patients on ddI+d4T developed lactic acidosis. Mean serum lactate dehydrogenase (LDH), gamma-glutamyltransferase (GGT), and amylase significantly increased in patients treated with ddI+d4T, whereas they remained unaltered in patients under AZT+3TC. Significant correlations were found between lactate and LDH, alkaline phosphatase (AP), and GGT. In the multivariate analysis, treatment with ddI+d4T, LDH, and AP was significantly associated with lactate levels. At 12 months, subcutaneous lipoatrophy was significantly more frequent in patients treated with ddI+d4T than in those on AZT+3TC (35% vs. 8%; p =.01).

CONCLUSION

In drug-naïve HIV-infected patients who start antiretroviral therapy, ddI+d4T-based combinations produce a greater increase in serum lactate and lipoatrophy than therapies based on AZT+3TC within the first year of therapy. An increase in LDH, amylase, GGT, and AP levels may signal an increase in lactate, which may be harmful.

[Severe lactic acidosis in HIV-infected patients treated with nucleosidic reverse transcriptase analogs: a report of 9 cases]

PURPOSE

Symptomatic lactic acidosis requiring intensive care is a rare and severe adverse event related to the mitochondrial toxicity of the nucleoside analog reverse transcriptase inhibitors (NRTIs).

METHOD

We retrospectively investigated the clinical and biological features of HIV-infected patients who developed severe lactic acidosis syndrome at the University teaching hospital of Bordeaux and the regional community hospital, during 1996-2000.

RESULTS

Nine patients were identified (incidence: 0,9/1000 NRTI treated patient-years), 4 men and 5 women with a median age of 36 years. They had a moderate immunodeficiency (median CD4+ T lymphocyte counts: 197/mm(3)) and only one of them presented a virological failure. The causes of hospital admission were abdominal pain (n = 6), dyspnea (n = 6), asthenia (n = 5), jaundice (n = 4), and vomiting (n = 2). Hepatomegaly was present in 6 patients. Lactic acidosis was found in all cases: median pH: 7.28, bicarbonate: 12 mmol/l, anion gap: 27 mEq/l, plasma lactic acid: 13 mmol/l. Cytolysis (n = 8), cholestasis (n = 6), hepatic failure (n = 4), rhabdomyolysis (n = 4) and pancreatitis (n = 2), were also present. Despite medical intensive care, seven patients died. The only two post-mortem examinations revealed severe hepatic steatosis. Median duration of NRTI therapy was 4 years. At presentation, five patients were receiving lamivudine, five didanosine, four stavudine and three zidovudine. Six patients were coinfected by HCV and/or HBV, four had chronic renal failure and five an immediately preceding infectious disease.

CONCLUSION

The prognosis of lactic acidosis is severe. Nucleosid-analog therapy needs clinical and biological monitoring, specially in patients with comorbidities.

Prevalence, risk factors and outcome of hyperlactataemia in HIV-infected patients

OBJECTIVE

We describe the prevalence, risk factors and outcome of hyperlactataemia (HL) in a cohort of 140 HIV-infected patients.

PATIENTS AND METHODS

Patients were enrolled consecutively within a 3-month period (July to September 1999) and followed until 31 October 2000. One hundred and forty HIV-infected patients had venous plasma lactate levels measured. HL was defined at baseline by two consecutive lactate levels > 2.1 mmol/L (upper limit of normal). We compared baseline demographic characteristics, immuno-virological parameters, antiretroviral therapy and outcome between patients with HL (cases) or without HL (controls). We described the clinical features of patients with HL.

RESULTS

Among 129 patients included in the analysis, HL was found in 11 patients (8.5%), all of whom were receiving nucleoside reverse transcriptase inhibitors (NRTIs). Cases were more likely than controls to receive didanosine or stavudine (82% vs. 19%, P= 2.7 x 10(-6) and 82% vs. 48%, P= 0.03, respectively). Only 4/11 cases (36%) had symptoms consistent with HL. After a median follow-up of 15 months, lactate level returned to normal in all three patients who discontinued NRTIs, but in only 2/8 patients who did not (P = 0.06). Only one case experienced lactic acidosis and died during follow-up. Mortality rate was similar in cases and controls.

CONCLUSION

HL is associated with NRTI use, in particular didanosine and stavudine, and discontinuation of NRTIs seems to be associated with rapid resolution of HL. Lactic acidosis remains rare and the long-term outcome of patients with HL does not seem to be poorer than controls.

Management of metabolic complications associated with antiretroviral therapy for HIV-1 infection: recommendations of an International AIDS Society-USA panel

OBJECTIVE

Alterations in glucose and lipid metabolism, lactic acidemia, bone disorders, and abnormal body fat distribution have been recognized recently as frequent complications associated with HIV-1 infection and potent antiretroviral therapy, but limited data are available regarding the appropriate management of these disorders. These recommendations were developed to guide physicians actively involved in HIV care in the management of metabolic complications that occur primarily within the context of potent antiretroviral therapy.

PARTICIPANTS

A 12-member panel representing international expertise in HIV-1 patient care, antiretroviral therapy, and endocrine and metabolic disorders was selected in the spring of 2000 by the International AIDS Society-USA, a not-for-profit physician education organization. Panel members met in closed meetings beginning in May 2000. All work was funded by the International AIDS Society-USA; the panel members are not compensated for their participation.

EVIDENCE

The panel reviewed published results of clinical, epidemiologic, and basic science studies and data and abstracts presented at research conferences, primarily from 1997 to 2002. The panel also considered studies of the pathophysiology and treatment of similar metabolic abnormalities in noninfected persons. Emphasis was placed on results from prospective, randomized, controlled clinical trials when available.

PROCESS

For each metabolic complication, 1 or more member(s) reviewed and presented all available evidence to the panel, and then wrote a summary of the evidence and preliminary recommendations. Final recommendations were determined by full group consensus. The summaries were combined into a single working document and all panel members edited and approved all subsequent drafts.

CONCLUSIONS

Carefully controlled studies to determine the incidence, etiology, risk factors, and most appropriate treatments for metabolic complications in HIV-1 infection are urgently needed. In the absence of these data, and to prevent acute illness and mitigate long-term risks, the panel recommends routine assessment and monitoring of glucose and lipid levels and assessment and monitoring of lactic acidemia and bone abnormalities if clinical signs or symptoms are detected. With the exception of body fat distribution abnormalities, specific treatments for these complications are also recommended. Successful long-term antiretroviral therapy will require diligent monitoring and preemptive treatment of metabolic complications to optimize the risk-benefit ratio of antiretroviral therapies.

Altered myocellular and abdominal fat partitioning predict disturbance in insulin action in HIV protease inhibitor-related lipodystrophy

HIV protease inhibitor-related lipodystrophy is characterized by peripheral fat loss, hyperlipidemia, and insulin resistance. Increased availability of lipid to muscle may be one of the mechanisms that induce insulin resistance. Regional fat, intramyocellular lipid (by (1)H-magnetic resonance spectroscopy), serum lipids, and insulin-stimulated glucose disposal (by hyperinsulinemic-euglycemic clamp) were quantified in 10 men who had HIV-1 infection with moderate to severe lipodystrophy and a control group of 10 nonlipodystrophic men who had HIV-1 infection and were naïve to protease inhibitors to examine the effects of lipodystrophy on glucose and lipid metabolism. Lipodystrophic subjects showed lower insulin-stimulated glucose disposal than control subjects (P = 0.001) and had increased serum triglycerides (P = 0.03), less limb fat (P = 0.02), increased visceral fat as a proportion of total abdominal fat (P = 0.003), and increased intramyocellular lipid (1.90 +/- 0.15 vs. 1.23 +/- 0.16% of water resonance peak area; P = 0.007). In both groups combined, visceral fat related strongly to intramyocellular lipid (r = 0.83, P < 0.0001) and intramyocellular lipid related negatively to insulin-stimulated glucose disposal (r = -0.71, P = 0.0005). Fasting serum cholesterol and triglycerides related positively to intramyocellular lipid and visceral fat in lipodystrophic subjects only. The data indicate that lipodystrophy is associated with increased lipid content in muscle accompanying impaired insulin action. The results do not establish causation but emphasize the interrelationships among visceral fat, myocyte lipid, and insulin action.

Hyperlactataemia and lactic acidosis during antiretroviral therapy: relevance, reproducibility and possible risk factors

OBJECTIVE

To evaluate the prevalence, outcome and possible risk factors for hyperlactataemia and lactic acidosis in HIV-positive persons receiving antiretroviral therapy.

METHODS

Cross-sectional and longitudinal data from a prospectively collected clinical database. Associations with antiretroviral regimen, clinical and laboratory parameters were assessed using univariate and multivariate Cox's proportional hazards model.

RESULTS

Patients naive to therapy and patients on current therapy for a minimum of 4 months were assessed. Median lactate was 1.1 mol/l in 253 untreated individuals and 1.4 mmol/l in 1239 patients stable on therapy for at least 4 months. At least two on-therapy samples were available for 750 of the 1239 individuals, taken a median 92 days apart. Lactate measurement showed a low positive predictive value of 38.9% but a high negative predictive value (98%) for normal values. Lactate was elevated > or = 2.4 mmol/l in 102 individuals on at least one occasion. In the multivariate Cox's proportional hazards model, no demographic characteristics were associated with hyperlactataemia. Didanosine-containing regimens doubled the relative hazard of hyperlactataemia compared with those sparing didanosine. Abacavir-containing regimens reduced the hazard of hyperlactataemia. Choice of thymidine analogue did not influence risk. Hyperlactataemia was associated with acid-base disturbance. Use of didanosine and female sex were over-represented amongst nine patients with severe hyperlactataemia (> 5 mmol/l) or lactic acidosis.

CONCLUSIONS

Screening of lactate is of limited use in asymptomatic individuals on antiretroviral therapy. Raised lactate represents part of a spectrum of lactate and acid-base disturbance that infrequently includes lactic acidosis. Didanosine appears associated with an increased risk of hyperlactataemia.

Long-term exposure to lifelong therapies

Three categories of highly active antiretroviral therapy (HAART)-associated major toxic effects have been identified: nucleoside-related toxic effects (e.g., neuropathy, myopathy, pancreatitis, hepatic steatosis, lactic acidosis, and possibly lipoatrophy), metabolic complications (e.g., fat redistribution, insulin resistance, and hyperlipidemia), and bone disease (e.g., osteopenia and/or osteoporosis). The toxic effects caused by nucleosides are hypothesized to be a result of mitochondrial injury and include myopathy, pancreatitis, liver failure, and lactic acidosis. Alterations in lactic acid metabolism range from common instances of asymptomatic lactic acidemia to rare occurrences of life-threatening lactic acidosis with hepatic steatosis. A metabolic syndrome consisting of lipodystrophy (i.e., fat redistribution), hyperlipidemia and insulin resistance has been observed, particularly with protease inhibitor treatment. Some additive interaction between protease inhibitors and nucleosides has also been described. The potential relationship of these metabolic abnormalities to increased risk of cardiovascular disease and diabetes has broad implications on long-term patient management. Lipodystrophy associated with HAART is generally accompanied by potentially serious abnormalities, including dyslipidemia (i.e., hypercholesterolemia and hypertriglyceridemia) and altered glucose metabolism (i.e., insulin resistance). Regimens of HAART may have adverse effects on bone metabolism, as indicated by emerging reports of osteopenia, osteoporosis, and avascular necrosis.

Metabolic complications associated with antiretroviral therapy

Mortality rates in the HIV-infected patient population have decreased with the advent of highly active antiretroviral therapy (HAART) for the treatment of AIDS. Due to the chronic nature of HAART, long-term metabolic complications are associated with therapy, such as hyperlipidemia, fat redistribution and diabetes mellitus. Currently, all of these symptoms are classified as the lipodystrophy (LD) syndrome(s). However, hyperlipidemia and fat redistribution occur independently, indicating there may be multiple syndromes associated with HAART. Although fat gain/loss and dyslipidemia occur in protease inhibitor (PI) naïve patients treated with nucleoside reverse transcriptase inhibitors (NRTIs), combination therapies (PI and NRTI) accelerate the syndrome. Recent clinical trials, cell culture and animal studies indicate that these effects are not drug class specific and select PIs, NRTIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs) can be associated with metabolic complications. Moreover, the effects can vary between various members of the same class of antiretroviral agents (i.e. not all PIs cause the same adverse reactions) and may be influenced by duration of infection, genetics and environmental factors. Although HAART increases the risk of metabolic complications, this does not outweigh the benefits of survival. In this review, we summarize the latest clinical and scientific information on these metabolic complications, examine current hypotheses explaining the syndromes and comment on the existing methods available to manage these metabolic side effects.

Hyperlactataemia in HIV-Infected Patients: The Role of NRTI-Treatment

Background

Long-term treatment with nucleoside reverse transcriptase inhibitors (NRTIs) can induce mitochondrial dysfunction, most severely represented by lactic acidosis. Diagnostic tests for mitochondrial dysfunction are lacking, although persistently elevated serum lactate might be a surrogate marker.

Objectives

To determine the occurrence of hyperlactataemia in HIV-infected patients on NRTI-treatment and to evaluate the possible risk factors.

Methods

Cross-sectional analysis of lactic-acid levels in asymptomatic HIV-infected patients. Hyperlactactaemia was considered mild if between 2.0–5 mmol/l, serious if >5 mmol/l and lactic acidosis was defined as lactic acid levels >5 mmol/l with bicarbonate <20 mmol/l. Possible risk factors, such as current and preceding NRTI-treatment as well as treatment with non-nucleoside reverse transcriptase inhibitors or protease inhibitors and concurrent liver disease, were analysed.

Results

Two hundred and twenty three asymptomatic HIV-infected patients were studied, including 174 patients (78%) on NRTI treatment, 12 patients (5%) treated without NRTIs and 37 patients (17%) not treated. Mild hyperlactataemia was found in 42 patients (19%), from whom 38/42 (90%) were NRTI-treated and the remaining patients (4/42, 10%) received no treatment (χ2, P<0.05). The significant risk factors for hyperlactataemia in the univariate analysis were NRTI-treatment as a group ( P=0.03) and elevated ALT ( P=0.008). In multivariate analysis NRTI use ( P=0.05) and ALT level ( P=0.03) remained a significant determinant of hyperlactataemia. Among the different individual NRTIs, a stavudine-containing ( P=0.004) and a zalcitabine-containing ( P=0.07) regimen were most notably associated with the development of hyperlactataemia, whereas for the combinations of NRTIs, such association was only found for stavudine/lamivudine ( P=0.05).

Conclusions

A correlation between hyperlactataemia and NRTI treatment was found, but the value of routine lactate measurement for individual treatment monitoring remains uncertain.