Hyperlactataemia and lactic acidosis in HIV-infected patients receiving antiretroviral therapy

Metformin for the prevention of diabetes among people with HIV and either impaired fasting glucose or impaired glucose tolerance (prediabetes) in Tanzania: a Phase II randomised placebo-controlled trial

AIMS/HYPOTHESIS

In sub-Saharan Africa (SSA), 5% of adults are living with type 2 diabetes and this is rising sharply, with a greater increase among people with HIV. Evidence on the efficacy of prevention strategies in this cohort is scarce. We conducted a Phase II double-blind placebo-controlled trial that aimed to determine the impact of metformin on blood glucose levels among people with prediabetes (defined as impaired fasting glucose [IFG] and/or impaired glucose tolerance [IGT]) and HIV in SSA.

METHODS

Adults (≥18 years old) who were stable in HIV care and found to have prediabetes (IFG and/or IGT) and who were attending hospitals in Dar es Salaam, Tanzania, were randomised to receive sustained-release metformin, 2000 mg daily, or matching placebo between 4 November 2019 and 21 July 2020. Randomisation used permuted blocks. Allocation was concealed in the trial database and made visible only to the Chief Pharmacist after consent was taken. All participants, research and clinical staff remained blinded to the allocation. Participants were provided with information on diet and lifestyle and had access to various health information following the start of the coronavirus disease 2019 (COVID-19) pandemic. Participants were followed up for 12 months. The primary outcome measure was capillary blood glucose measured 2 h following a 75 g glucose load. Analyses were by intention-to-treat.

RESULTS

In total, 364 participants (182 in each arm) were randomised to the metformin or placebo group. At enrolment, in the metformin and placebo arms, mean fasting glucose was 6.37 mmol/l (95% CI 6.23, 6.50) and 6.26 mmol/l (95% CI 6.15, 6.36), respectively, and mean 2 h glucose levels following a 75 g oral glucose load were 8.39 mmol/l (95% CI 8.22, 8.56) and 8.24 mmol/l (95% CI 8.07, 8.41), respectively. At the final assessment at 12 months, 145/182 (79.7%) individuals randomised to metformin compared with 158/182 (86.8%) randomised to placebo indicated that they had taken >95% of their medicines in the previous 28 days (p=0.068). At this visit, in the metformin and placebo arms, mean fasting glucose levels were 6.17 mmol/l (95% CI 6.03, 6.30) and 6.30 mmol/l (95% CI 6.18, 6.42), respectively, and mean 2 h glucose levels following a 75 g oral glucose load were 7.88 mmol/l (95% CI 7.65, 8.12) and 7.71 mmol/l (95% CI 7.49, 7.94), respectively. Using a linear mixed model controlling for respective baseline values, the mean difference between the metformin and placebo group (metformin-placebo) was -0.08 mmol/l (95% CI -0.37, 0.20) for fasting glucose and 0.20 mmol/l (95% CI -0.17, 0.58) for glucose levels 2 h post a 75 g glucose load. Weight was significantly lower in the metformin arm than in the placebo arm: using the linear mixed model adjusting for baseline values, the mean difference in weight was -1.47 kg (95% CI -2.58, -0.35). In total, 16/182 (8.8%) individuals had a serious adverse event (Grade 3 or Grade 4 in the Division of Acquired Immunodeficiency Syndrome [DAIDS] adverse event grading table) or died in the metformin arm compared with 18/182 (9.9%) in the placebo arm; these events were either unrelated to or unlikely to be related to the study drugs.

CONCLUSIONS/INTERPRETATION

Blood glucose decreased over time in both the metformin and placebo arms during the trial but did not differ significantly between the arms at 12 months of follow up. Metformin therapy was found to be safe for use in individuals with HIV and prediabetes. A larger trial with longer follow up is needed to establish if metformin can be safely used for the prevention of diabetes in people who have HIV.

TRIAL REGISTRATION

The trial is registered on the International Standard Randomised Controlled Trial Number (ISRCTN) registry ( www.isrctn.com/ ), registration number: ISCRTN76157257.

FUNDING

This research was funded by the National Institute for Health Research using UK aid from the UK Government to support global health research.

Current ARTs, Virologic Failure, and Implications for AIDS Management: A Systematic Review

Antiretroviral therapies (ARTs) have revolutionized the management of human immunodeficiency virus (HIV) infection, significantly improved patient outcomes, and reduced the mortality rate and incidence of acquired immunodeficiency syndrome (AIDS). However, despite the remarkable efficacy of ART, virologic failure remains a challenge in the long-term management of HIV-infected individuals. Virologic failure refers to the persistent detectable viral load in patients receiving ART, indicating an incomplete suppression of HIV replication. It can occur due to various factors, including poor medication adherence, drug resistance, suboptimal drug concentrations, drug interactions, and viral factors such as the emergence of drug-resistant strains. In recent years, extensive efforts have been made to understand and address virologic failure in order to optimize treatment outcomes. Strategies to prevent and manage virologic failure include improving treatment adherence through patient education, counselling, and supportive interventions. In addition, the regular monitoring of viral load and resistance testing enables the early detection of treatment failure and facilitates timely adjustments in ART regimens. Thus, the development of novel antiretroviral agents with improved potency, tolerability, and resistance profiles offers new options for patients experiencing virologic failure. However, new treatment options would also face virologic failure if not managed appropriately. A solution to virologic failure requires a comprehensive approach that combines individualized patient care, robust monitoring, and access to a range of antiretroviral drugs.

Lactic Acidosis as an Unusual Finding in Undifferentiated Carcinoma

Lactic acidosis associated with solid neoplasms is a rare complication; its occurrence is poorly described, and it is associated with a poor prognosis. We present the case of an 84-year-old woman who was admitted to the internal medicine department with a diagnosis of urinary tract infection accompanied by a blood gas analysis showing lactic acidosis. During her admission, an abdominal mass was evidenced and finally diagnosed as undifferentiated carcinoma. We wanted to emphasize the importance of correlating clinical and laboratory data at the time of making a diagnostic approach and also highlight other possible explanations of lactic acidosis that should be considered in addition to hypoperfusion due to sepsis, especially in the elderly who are at increased risk of malignancy.

Nausea after Repeated Sprints: Is Lactic Acidosis Really the Culprit?

INTRODUCTION

Nausea caused by exhaustive sprinting is associated with high lactate ([La-]) and hydrogen ion concentrations ([H+]) and fall in blood pCO2, thus raising the issue of whether there is a causal link between nausea and these variables. For this reason, this study aimed to determine whether interspersing repeated sprints (RS) with periods of active, compared with passive, recovery results in lower levels of both nausea and changes in [La-], [H+], and pCO2.

METHODS

Twelve male participants completed two separate sessions comprising four 30-s sprints separated by 20 min of either active (AR; cycling at 40% V˙O2peak) or passive recovery (PR). At 6 and 18 min of each recovery period, nausea was assessed via a visual analog scale (VAS), and blood samples were collected to measure [La-], [H+], and pCO2.

RESULTS

RS significantly increased VAS score in both AR (P < 0.001) and PR (P < 0.01). After the first sprint, VAS was higher than preexercise in only AR (P < 0.01). AR was associated with lower VAS, [La-], [H+], and higher pCO2 (all P = 0.001) compared with PR after sprints 2-4. Linear mixed modeling indicated that each of the variables significantly predicts VAS scores (P < 0.0001). Repeated-measures correlation (rrm2) indicated that [La-] had the closest association with VAS (rrm2 = 0.22, P < 0.0001).

CONCLUSION

The lower levels of both nausea and changes in [La-], [H+], and pCO2 in response to AR suggest that nausea associated with RS may be causally related with these variables. However, the absence of a close relationship between these variables after the first sprint and the findings that [La-], [H+], and pCO2 only account for 13%-22% of the variation in VAS indicate that other mechanisms may also mediate nausea.

Effects of exercise training and statin on hemodynamic, biochemical, inflammatory and immune profile of people living with HIV: a randomized, double-blind, placebo-controlled trial

BACKGROUND

The aim of this study is to evaluate the effect of exercise training (ET) and statins on the hemodynamic, biochemical, inflammatory and immune profile of people living with HIV (PLHIV).

METHODS

This was a randomized, double-blind, placebo-controlled clinical trial in which 83 PLHIV were assigned to either placebo (PL), statins (STA), placebo + ET (PLET), or statins + ET (STAET) groups. Volunteers assigned to STA and STAET groups were administered 10 mg of rosuvastatin, whereas the PL and PLET groups were administered a placebo. The PLET and STAET groups performed ET three times a week. Before and after the 12-week follow-up, volunteers underwent blood collection to assess the biochemical, inflammatory, and immune profile.

RESULTS

There were significant time x group interaction effects (P<0.05) for all variables except for diastolic blood pressure. The PLET and STAET groups had significantly (P<0.05) decreased systolic blood pressure, resting heart rate, fasting glucose, glycated hemoglobin, fasting insulin, homeostatic model assessment for insulin resistance, creatine kinase, lactate, and TNF-α levels, and increased adiponectin, CD4⁺, and CD8⁺ levels. There was also a significant group effect (P<0.05) for CK levels among the exercised (PLET and STAET) and STA groups. The latter had a significant increase in fasting glucose (P<0.05) and creatine kinase (P<0.05).

CONCLUSIONS

ET improved the hemodynamic, biochemical, inflammatory, and immune profile of PLHIV and this effect was not dependent on the use of statins.

The Role of Oxidative Stress in Physiopathology and Pharmacological Treatment with Pro- and Antioxidant Properties in Chronic Diseases

Oxidative stress (OS) has the ability to damage different molecules and cellular structures, altering the correct function of organs and systems. OS accumulates in the body by endogenous and exogenous mechanisms. Increasing evidence points to the involvement of OS in the physiopathology of various chronic diseases that require prolonged periods of pharmacological treatment. Long-term treatments may contribute to changes in systemic OS. In this review, we discuss the involvement of OS in the pathological mechanisms of some chronic diseases, the pro- or antioxidant effects of their pharmacological treatments, and possible adjuvant antioxidant alternatives. Diseases such as high blood pressure, arteriosclerosis, and diabetes mellitus contribute to the increased risk of cardiovascular disease. Antihypertensive, lipid-lowering, and hypoglycemic treatments help reduce the risk with an additional antioxidant benefit. Treatment with methotrexate in autoimmune systemic inflammatory diseases, such as rheumatoid arthritis, has a dual role in stimulating the production of OS and producing mitochondrial dysfunction. However, it can also help indirectly decrease the systemic OS induced by inflammation. Medicaments used to treat neurodegenerative diseases tend to decrease the mechanisms related to the production of reactive oxygen species (ROS) and balance OS. On the other hand, immunosuppressive treatments used in cancer or human immunodeficiency virus infection increase the production of ROS, causing significant oxidative damage in different organs and systems without widely documented exogenous antioxidant administration alternatives.

Role of lactic acidosis as a mediator of sprint-mediated nausea

This study aims to determine whether there is a relationship between nausea level and lactic acidosis during recovery from sprinting. In all, 13 recreationally active males completed a 60 s bout of maximal intensity cycling. Prior to and for 45 min following exercise, blood pH, pCO2 , and lactate levels were measured together with nausea. In response to sprinting, nausea, lactate, and H+ concentrations increased and remained elevated for at least 10 min (p < .001), whereas pCO2 increased only transiently (p < .001) before falling below pre-exercise levels (p < .001), with all these variables returning toward pre-exercise levels during recovery. Both measures of nausea adopted for analyses (nausea profile, NP; visual analogue scale, VAS), demonstrated significant repeated measures correlation (rmcorr) post-exercise between nausea and plasma lactate (VAS and NPrrm > 0.595, p < .0001) and H+ concentrations (VAS and NPrrm > 0.689, p < .0001), but an inconsistent relationship with pCO2 (VAS rrm  = 0.250, p = .040; NP rrm  = 0.144, p = .248) and bicarbonate levels (VAS rrm  = -0.252, p = .095; NP rrm  = -0.397, p = .008). Linear mixed modeling was used to predict the trajectory of nausea over time, with both lactate and H+ concentrations found to be key predictors of nausea (p < .0001). In conclusion, this study reveals a strong positive relationship between nausea and both H+ and lactate concentrations during recovery from sprinting, a finding consistent with H+ and lactate being potential mediators of nausea post-sprinting. However, as the timing of the recovery of both H+ and lactate was delayed, compared to that of nausea, further research is required to confirm these findings and investigate other potential mechanisms.

Lactate serum concentrations during treatment with nucleos(t)ide analogues in hepatitis B with or without cirrhosis

OBJECTIVE

The aim of this study is to evaluate the clinical implications of lactate concentrations in patients with hepatitis B with or without cirrhosis during treatment with nucleos(t)ide analogues.

PATIENTS AND METHODS

One hundred and seven consecutive patients with chronic hepatitis B and median age 57 (24-85) years were prospectively included. Lactate concentrations were measured at baseline and at 12, 24, 36, 48, and 60 months following the baseline measurements. Eight (n=8, 7.5%) patients received lamivudine, 38 (n=38, 35.5%) patients received tenofovir, 34 (n=34, 31.8%) patients received entecavir, and 27 (n=27, 25.2%) patients received combined therapy.

RESULTS

None of the patients developed lactic acidosis during follow-up [median: 58 (6-155) months]. Overall, no trends of the lactic acid evolution were observed over time; however, there was a nonsignificant increasing trend in patients with cirrhosis up to 24 months of treatment. This increasing trend was significant in female patients with cirrhosis (P=0.016). The age of the patients, the presence of cirrhosis, and hepatocellular carcinoma were strongly associated with the survival of all patients. In the group of cirrhotic patients, the only independent prognostic factor that was associated with patients' survival was the Child-Pugh class.

CONCLUSION

None of the patients developed lactic acidosis. There is an indication of an increasing trend of lactic acid levels up to 24 months of therapy in female cirrhotic patients.

Nucleotide Reverse Transcriptase Inhibitors: A Thorough Review, Present Status and Future Perspective as HIV Therapeutics

BACKGROUND

Human immunodeficiency virus type-1 (HIV-1) infection leads to acquired immunodeficiency syndrome (AIDS), a severe viral infection that has claimed approximately 658,507 lives in the US between the years 2010-2014. Antiretroviral (ARV) therapy has proven to inhibit HIV-1, but unlike other viral illness, not cure the infection.

OBJECTIVE

Among various Food and Drug Administration (FDA)-approved ARVs, nucleoside/ nucleotide reverse transcriptase inhibitors (NRTIs) are most effective in limiting HIV-1 infection. This review focuses on NRTIs mechanism of action and metabolism.

METHODS

A search of PubMed (1982-2016) was performed to capture relevant articles regarding NRTI pharmacology.

RESULTS

The current classical NRTIs pharmacology for HIV-1 prevention and treatment are presented. Finally, various novel strategies are proposed to improve the efficacy of NRTIs, which will increase therapeutic efficiency of present-day HIV-1 prevention/treatment regimen.

CONCLUSION

Use of NRTIs will continue to be critical for successful treatment and prevention of HIV-1.

Tenofovir exposure alters associations of serum bicarbonate with chronic kidney disease risk in HIV-infected veterans

OBJECTIVE

Among HIV-infected persons, tenofovir disoproxil fumarate (TDF) use is associated with higher risk of developing chronic kidney disease (CKD). Because lower serum bicarbonate concentrations may precede CKD onset, this study investigated the associations between TDF use and bicarbonate concentrations, and between bicarbonate with CKD risk among TDF users and nonusers.

METHODS

Retrospective cohort study of 16,070 HIV-infected US veterans who initiated antiretroviral therapy between 1997-2011. The association between TDF use with longitudinal bicarbonate concentrations and associations between bicarbonate with incident CKD stratified by TDF use (never, initial, and later user) were evaluated.

RESULTS

Compared with TDF users, never users had faster declines in bicarbonate concentrations: change in bicarbonate -0.11 mmol/l per year (95% confidence interval -0.16, -0.05), compared with -0.04 mmol/l per year (-0.06, 0.05) in initial users and -0.02 mmol/l per year (-0.05, 0.01) in later users. Low baseline bicarbonate (<22 mmol/l) was significantly associated with CKD risk among TDF never users (1.80; 1.21, 2.68), but not among TDF users (0.98; 0.69, 1.38). Similarly, declining bicarbonate concentrations were associated with higher CKD risk among never users (hazard ratio 1.67 per mmol/l; 1.34, 2.08), but not among TDF users (1.09; 0.98, 1.22). Interactions were highly significant for both analyses (P value = 0.001).

CONCLUSION

Despite associations with nephrotoxicity, TDF use was associated with higher serum bicarbonate concentrations longitudinally. Additionally, TDF use obscured the strong associations of bicarbonate with CKD risk in HIV-infected persons. Therefore, the role of bicarbonate concentrations as a tool to monitor kidney health in HIV-infected persons may be limited in the setting of TDF use.

Naringin Reverses Hepatocyte Apoptosis and Oxidative Stress Associated with HIV-1 Nucleotide Reverse Transcriptase Inhibitors-Induced Metabolic Complications

Nucleoside Reverse Transcriptase Inhibitors (NRTIs) have not only improved therapeutic outcomes in the treatment of HIV infection but have also led to an increase in associated metabolic complications of NRTIs. Naringin’s effects in mitigating NRTI-induced complications were investigated in this study. Wistar rats, randomly allotted into seven groups (n = 7) were orally treated daily for 56 days with 100 mg/kg zidovudine (AZT) (groups I, II III), 50 mg/kg stavudine (d4T) (groups IV, V, VI) and 3 mL/kg of distilled water (group VII). Additionally, rats in groups II and V were similarly treated with 50 mg/kg naringin, while groups III and VI were treated with 45 mg/kg vitamin E. AZT or d4T treatment significantly reduced body weight and plasma high density lipoprotein concentrations but increased liver weights, plasma triglycerides and total cholesterol compared to controls, respectively. Furthermore, AZT or d4T treatment significantly increased oxidative stress, adiposity index and expression of Bax protein, but reduced Bcl-2 protein expression compared to controls, respectively. However, either naringin or vitamin E significantly mitigated AZT- or d4T-induced weight loss, dyslipidemia, oxidative stress and hepatocyte apoptosis compared to AZT- or d4T-only treated rats. Our results suggest that naringin reverses metabolic complications associated with NRTIs by ameliorating oxidative stress and apoptosis. This implies that naringin supplements could mitigate lipodystrophy and dyslipidemia associated with NRTI therapy.

Elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate single-tablet regimen (Stribild®): a review of its use in the management of HIV-1 infection in adults

A new single-tablet, fixed-dose formulation consisting of elvitegravir, an HIV-1 integrase strand transfer inhibitor (INSTI); cobicistat, a pharmacokinetic enhancer; emtricitabine, a nucleoside reverse transcriptase inhibitor; and tenofovir disoproxil fumarate (tenofovir DF), a nucleotide reverse transcriptase inhibitor (elvitegravir/cobicistat/emtricitabine/tenofovir DF 150 mg/150 mg/200 mg/300 mg; Stribild®) is available in some countries for the once-daily treatment of HIV-1 infection in antiretroviral therapy-naïve adults. Elvitegravir/cobicistat/emtricitabine/tenofovir DF is the first INSTI-based single-tablet regimen available for the complete initial treatment of adults with HIV-1 infection. In two large, randomized, double-blind, phase III trials, once-daily treatment with elvitegravir/cobicistat/emtricitabine/tenofovir DF was effective in reducing plasma HIV-1 RNA levels to <50 copies/mL at the week 48 assessment and showed virological efficacy noninferior to that of the efavirenz/emtricitabine/tenofovir DF single-tablet regimen or a once-daily regimen of atazanavir plus ritonavir (ritonavir-boosted atazanavir) plus the fixed-dose combination of emtricitabine/tenofovir DF. Elvitegravir/cobicistat/emtricitabine/tenofovir DF also showed durable efficacy in terms of achieving sustained suppression of HIV-1 RNA levels to <50 copies/mL for up to 144 weeks in both of the phase III trials. Elvitegravir/cobicistat/emtricitabine/tenofovir DF is an important addition to the group of simplified once-daily single-tablet regimens currently available for the effective treatment of HIV-1 infection in antiretroviral therapy-naïve patients and is among the preferred regimens recommended for use as initial treatment. It offers advantages over more complex multiple-tablet regimens that may impair treatment adherence, which is fundamental to the successful management of HIV-1 infection.

A review of the toxicity of HIV medications

Antiretroviral therapy has changed human immunodeficiency virus (HIV) infection from a near-certainly fatal illness to one that can be managed chronically. More patients are taking antiretroviral drugs (ARVs) for longer periods of time, which naturally results in more observed toxicity. Overdose with ARVs is not commonly reported. The most serious overdose outcomes have been reported in neonates who were inadvertently administered supratherapeutic doses of HIV prophylaxis medications. Typical ARV regimens include a "backbone" of two nucleoside reverse transcriptase inhibitors (NRTI) and a "base" of either a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor. New classes of drugs called entry inhibitors and integrase inhibitors have also emerged. Older NRTIs were associated with mitochondrial toxicity, but this is less common in the newer drugs, emtricitabine, lamivudine, and tenofovir. Mitochondrial toxicity results from NRTI inhibition of a mitochondrial DNA polymerase. Mitochondrial toxicity manifests as myopathy, neuropathy, hepatic failure, and lactic acidosis. Routine lactate assessment in asymptomatic patients is not indicated. Lactate concentration should be obtained in patients taking NRTIs who have fatigue, nausea, vomiting, or vague abdominal pain. Mitochondrial toxicity can be fatal and is treated by supportive care and discontinuing NRTIs. Metabolic cofactors like thiamine, carnitine, and riboflavin may be helpful in managing mitochondrial toxicity. Lipodystrophy describes changes in fat distribution and lipid metabolism that have been attributed to both PIs and NRTIs. Lipodystrophy consists of loss of fat around the face (lipoatrophy), increase in truncal fat, and hypertriglyceridemia. There is no specific treatment of lipodystrophy. Clinicians should be able to recognize effects of chronic toxicity of ARVs, especially mitochondrial toxicity.

Metabolic complications and treatment of perinatally HIV-infected children and adolescents

The benefits of long-term antiretroviral therapy (ART) are recognized all over the world with infected children maturing into adults and HIV infection becoming a chronic illness. However, the improved survival is associated with serious metabolic complications, including lipodystrophy (LD), dyslipidemia, insulin resistance, lactic acidosis and bone loss. In addition, the dyslipidemia mainly seen with protease inhibitors may increase the risk of cardiovascular disease in adulthood and potentially in children as they mature into adults. Nucleoside reverse transcriptase inhibitors, particularly stavudine, zidovudine and didanosine are linked to development of LD and lactic acidosis. Perinatally infected children initiate ART early in life; they require lifelong therapy with multiple drug regimens leading to varying toxicities, all potentially impacting their quality of life. LD has a significant impact on the mental health of older children and adolescents leading to poor self-image, depression and subsequent poor adherence to therapy. Reduced bone mineral density (BMD) is reported in both adults and children on ART with the potential for children to develop more serious bone complications than adults due to their rapid growth spurts and puberty. The role of vitamin D in HIV-associated osteopenia and osteoporosis is not clear and needs further study. Most resource-limited settings are unable to monitor lipid profiles or BMD, exposing infected children and adolescents to on-going toxicities with unclear long-term consequences. Improved interventions are urgently needed to prevent and manage these metabolic complications. Longitudinal cohort studies in this area should remain a priority, particularly in resource-limited settings where the majority of infected children reside.

Surgical implications of human immunodeficiency virus infections

Pediatric HIV (human immunodeficiency virus) is a pandemic predominantly in sub-Saharan Africa. Approximately 2.2 million children aged less than 15 years are infected with HIV, representing almost 95% of the total number of children globally infected with HIV. Therefore, increasing numbers of HIVi or -exposed but uninfected children can be expected to require a surgical procedure to assist in the diagnosis of an HIV/acquired immune deficiency syndrome-related complication, to address a life-threatening complication of the disease, or for routine surgery encountered in HIV-unexposed children. HIVi children may present with both conditions unique to HIV infection and surgical conditions routine in pediatric surgical practice. HIV exposure confers an increased risk of complications and mortality for all children after surgery, whether they are HIV infected or not. This risk of complications is higher in the HIVi group of patients. These findings seem to be independent of whether patients undergo an elective or emergency procedure, but the risk of an adverse outcome is higher for a major procedure. Surgical implications of HIV infection are comprehensively reviewed in this article.

Risk factors for fatality in HIV-infected patients with dideoxynucleoside-induced severe hyperlactataemia or lactic acidosis

BACKGROUND

Lactic acidosis (LA) and severe hyperlactataemia (HL) are infrequent but serious complications of antiretroviral therapy that have been associated with a high fatality rate.

METHODS

In a multinational retrospective cohort study, LA was defined as arterial blood pH<7.35, bicarbonate <20 mmol/l and lactate above normal, and HL as confirmed blood lactate >5 mmol/l. Logistic regression was used to identify factors associated with fatality. Sensitivity and specificity of different case definitions as predictors of death were compared.

RESULTS

The overall case-fatality rate was 19/110 (17.3%), but among acidotic patients it was 33% (16/49 cases). There were 10 asymptomatic patients and none of them died as a consequence of the event. The median lactate for fatal, non-fatal and all patients was 8.3 mmol/l (IQR 7.2-13.1), 6.4 mmol/l (IQR 5.4-7.8) and 6.7 mmol/l (IQR 5.5-8.1), respectively. After adjusting for age and current CD4(+) T-cell count, lactate >7 mmol/l (OR 6.27, 95% CI 1.13-34.93), blood bicarbonate <12 mmol/l (OR 10.02 relative to >18 mmol/l, 95% CI 1.33-75.65) and concurrent opportunistic infections (OR 8.69, 95% CI 1.45-52.22) were independently associated with case fatality. Blood lactate >7 mmol/l showed a sensitivity of 84% for fatality with a specificity of 60%, whereas bicarbonate <12 mmol/l showed a better specificity (85%) but a poorer sensitivity (42%). Bicarbonate <18 mmol/l appears to be as good as lactate <7 mmol/l at predicting death (sensitivity 90% and specificity 54%).

CONCLUSIONS

Our data suggest that blood lactate >7 mmol/l and blood bicarbonate <18 mmol/l appear to predict death and might help clinicians in selecting patients who may benefit from more intense monitoring.

Metabolic complications associated with antiretroviral therapy in HIV-infected and HIV-exposed uninfected paediatric patients

IMPORTANCE OF THE FIELD

HIV-infection has become a chronic disease in paediatric patients with the potential for long-term survival and exposure to antiretroviral (ARV) therapies for 2 decades longer than HIV-infected adults. On the other hand, the administration of ARV to HIV-infected pregnant women has greatly increased both treatment of HIV infection and prevention of perinatal HIV transmission. Therefore, researches aiming to evaluate the safety of ARV therapies in HIV-infected children as well as in HIV-uninfected infants born to HIV-infected mothers are emerging as a new challenge and urgent priority.

AREAS COVERED IN THIS REVIEW

The purpose of this review is to describe some of the more concerning metabolic complications associated with ARV in paediatric population: hyperlactataemia (HLA) syndromes, body shape abnormalities, disorders of glucose homeostasis and dyslipidaemia in HIV-infected children and adolescents. Frequency, risk factors, clinical findings, prevention and intervention strategies of the previously described abnormalities are discussed in depth.

WHAT THE READER WILL GAIN

This review covers our current understanding of HLA syndromes in ARV-exposed uninfected infants born to HIV-infected mothers.

TAKE HOME MESSAGE

Prevention of these metabolic complications should assume prominence and future researches should address several of the existing treatment gaps.

The role of serum lactate in the acute care setting

Acute care services are increasingly faced with the double burden of high patient acuity and limited resources. Early identification of patients who are sick or who have the potential to deteriorate rapidly is crucial so that these resources may be allocated to those in greatest need. Traditional measures of illness and end points of resuscitation, such as vital signs, often fail to identify occult hypoperfusion with certain disease processes associated with high morbidity and mortality. Thus, biochemical markers that may predict illness earlier are becoming more relevant. We present a review of the evidence behind use of the serum lactate level in this setting.

Metabolic and hepatobiliary side effects of antiretroviral therapy (ART)

Although antiretroviral therapy (ART) for human immunodeficiency virus (HIV) has been in use since 1987, the initiation of highly active ART has produced an increase in adverse drug reactions. This is a new challenge as many of the adverse drug reactions attributable to ART may be indistinguishable from non-drug-related illnesses. The emergency physician must be aware of the potential complications of ART as affected patients may present with nonspecific symptoms. The focus of this article is the metabolic and hepatobiliary adverse effects of ART.

Risk factors for and clinical characteristics of severe hyperlactataemia in patients receiving antiretroviral therapy: a case-control study

BACKGROUND

Symptomatic hyperlactataemia and lactic acidosis (SHLA) are potentially life-threatening complications associated with stavudine (d4T), an antiretroviral therapy (ART) drug widely used in developing countries.

METHODS

Cases comprised all symptomatic patients with measured lactates >or= 5 mmol/L referred to a South African hospital between August 2003 and November 2005. Matched controls were selected according to facility and duration on ART.

RESULTS

Seventy-one cases and 142 controls were included in the study. The majority of cases presented between 6 and 18 months on ART. Female sex [adjusted odds ratio (AOR) 23.4; 95% confidence interval (CI) 4.0-136.6], a baseline weight between 60 and 75 kg (AOR 4.5; 95% CI 1.4-14.1) or, in particular, >or= 75 kg (AOR 19.4; 95% CI 4.1-82.5) at ART initiation and gaining >or= 6 kg in the first 3 months on therapy (AOR 3.5; 95% CI 1.3-9.5) were independent risk factors identifying patients who may subsequently develop SHLA. Weight loss of >or= 2 kg (AOR 6.1; 95% CI 2.0-18.3), a rise in alanine aminotransferase (ALT) >or= 10 U/L (AOR 3.1; 95% CI 1.1-8.9), the presence of at least one of three major symptoms (vomiting, nausea and abdominal pains) of SHLA (AOR 12.6; 95% CI 3.3-47.2) and peripheral neuropathy (AOR 3.4; 95% CI 1.1-9.8) were the clinical parameters that were most able to identify patients with early manifestations of SHLA.

CONCLUSIONS

This is the first case-control study for SHLA in Southern Africa. Given these findings, we advise that stavudine is avoided in overweight women. Weight loss, a rise in ALT, peripheral neuropathy and/or gastrointestinal symptoms should prompt healthcare workers to assess for SHLA, especially at between 6 and 18 months on ART.

Severe Hyperlactataemia Complicating Stavudine First-Line Antiretroviral Therapy in South Africa

Background

In the public sector antiretroviral therapy (ART) programme in South Africa the standardized first-line regimen includes stavudine (d4T). Severe symptomatic hyperlactataemia (SHL) is a potentially life- threatening complication of d4T.

Methods

GF Jooste Hospital is a referral centre for six ART clinics. We retrospectively reviewed cases referred with lactate levels ≥5 mmol/l that were attributed to nucleoside reverse transcriptase inhibitors from August 2003 to November 2005. We calculated cumulative ART exposure in patients attending these clinics to derive a referral rate.

Results

In total, 75 patients were referred with severe SHL (71 female). All had been on d4T and on ART for a median of 10 months. The referral rate for severe SHL was 17.5 cases per 1,000 patient-years. In 53 patients (71%), lactic acidosis (standard bicarbonate [SHCO3]<20 mmol/l) was confirmed, resulting in a referral rate of 12.3 cases per 1,000 patient-years. Twelve patients (16%) died during acute admission (≤30 days). SHCO3<15 mmol/l and pH<7.2 were the only factors associated with acute mortality (odds ratio [OR] 22.5, 95% confidence interval [CI] 2.8–1,045.7 and OR 13.9, 95% CI 2.7–86.9, respectively). A total of 30 less severe cases were rechallenged with zidovudine without recurrence of SHL.

Conclusions

This study confirms a high incidence of severe SHL in Africa, which has been shown in previous studies. Rechallenge with zidovudine in less severe cases was found to be safe.

Second assessment of NeuroAIDS in Africa

In July of 2006, the National Institute of Mental Health (NIMH) Center for Mental Health Research on AIDS (CMHRA) sponsored the second conference on the Assessment of NeuroAIDS in Africa, which was held in Arusha, Tanzania. The conference mission was to address the regional variations in epidemiology of HIV-related neurological disorders as well as the assessment and diagnosis of these disorders. Participants discussed and presented data regarding the relevance and translation of neuroAIDS assessment measures developed in resource intensive settings and the challenges of neuro-assessment in Africa, including the applicability of current tools, higher prevalence of confounding diseases, and the complexity of diverse cultural settings. The conference presentations summarized here highlight the need for further research on neuroAIDS in Africa and methods for assessing HIV-related neurological disorders.

Validation of the Accutrend lactate meter for hyperlactatemia screening during antiretroviral therapy in a resource-poor setting

BACKGROUND

The use of highly active antiretroviral therapy (HAART) results in multiple side effects that may jeopardize the life of the patient being treated with antiretroviral drugs. In resource-poor settings it is difficult to definitively diagnose lactic acidosis by laboratory measurement of lactate. Point-of-care (POC) devices are helpful in the measurement of lactate levels and have been validated in the intensive care unit setting, but not in a busy outpatient clinic. The objective of this study was to assess the sensitivity and specificity of the Accutrend lactate meter in the diagnosis of hyperlactatemia/lactic acidosis in patients on nucleoside reverse transcriptase inhibitor (NRTI)-containing regimens (stavudine).

DESIGN AND METHODS

This was a cross-sectional study of 120 patients on HAART (lamivudine, stavudine, efavirenz, or nevirapine) with symptoms of/or recovering from hyperlactatemia/lactic acidosis. Simultaneous testing of the same blood sample was undertaken on the Accutrend handheld lactate analyzer and a reference instrument (Beckman CX7 Synchron machine). A venous lactate level <2.2mmol/l was considered as normal.

RESULTS

The mean lactate value obtained from the Accutrend meter was 2.89mmol/l and from the reference instrument was 2.78mmol/l. The standard deviation for Accutrend meter was 1.14mmol/l vs.1.42mmol/l for the Beckman instrument. The sensitivity obtained for the Accutrend meter was 95.9% (95% CI 87.7-98.9%) and the specificity 63.8% (95% CI 48.5-76.9%). The positive predictive value was 80.5% (95% CI 70.3-87.9%) and the negative predictive value was 90.9% (95% CI 74.5-97.6%).

CONCLUSIONS

The Accutrend lactate meter is an appropriate device for screening patients on HAART with symptoms of hyperlactatemia/lactic acidosis. The use of this device decreases analytic and intervention time, preventing further morbidity and mortality in patients on an NRTI (stavudine)-based regimen.

Substitutions due to antiretroviral toxicity or contraindication in the first 3 years of antiretroviral therapy in a large South African cohort

INTRODUCTION

The patterns and reasons for antiretroviral therapy (ART) drug substitutions are poorly described in resource-limited settings.

METHODS

Time to and reason for drug substitution were recorded in treatment-naive adults receiving ART in two primary care treatment programmes in Cape Town. The cumulative proportion of patients having therapy changed because of toxicity was described for each drug, and associations with these changes were explored in multivariate models.

RESULTS

Analysis included 2,679 individuals followed for a median of 11 months. Median CD4+ T-cell count at baseline was 85 cells/microl. Mean weight was 59 kg, mean age was 32 years and 71% were women. All started non-nucleoside reverse transcriptase inhibitor-based ART (60% on efavrienz) and 75% started on stavudine (d4T). After 3 years, 75% remained in care on-site, of whom 72% remained on their initial regimen. Substitutions due to toxicity of nevirapine (8% by 3 years), efavirenz (2%) and zidovudine (8%) occurred early. Substitutions on d4T occurred in 21% of patients by 3 years, due to symptomatic hyperlactataemia (5%), lipodystrophy (9%) or peripheral neuropathy (6%), and continued to accumulate over time. Those at greatest risk of hyperlactataemia or lipodystrophy were women on ART > or =6 months, weighing > or =75 kg at baseline.

DISCUSSION

A high proportion of adult patients are able to tolerate their initial ART regimen for up to 3 years. In most instances treatment-limiting toxicities occur early, but continue to accumulate over time in patients on d4T. Whilst awaiting other treatment options, the risks of known toxicities could be minimized through early identification of patients at the highest risk.

Enantiomer separation of alpha-hydroxy acids in high-performance immunoaffinity chromatography

In this study, a monoclonal anti-d-hydroxy acid antibody was immobilized onto a synthetic high-flow-through chromatographic support material to produce a chiral stationary phase suitable for enantiomer separation of free alpha-hydroxy acids. Chiral separation of several aliphatic and aromatic members of this class of compounds was achieved in HPLC under mild isocratic buffer conditions using phosphate buffered saline, pH 7.4, as mobile phase. Due to the high degree of stereoselectivity exhibited by the immobilized antibody, in all cases the l-enantiomer eluted with the void volume, while the d-enantiomer was retained and eluted second. The effect of the mobile phase parameters flow rate, temperature, pH, and ionic strength on the enantiomer separation of the model analyte mandelic acid was investigated. While it was found that variations in the flow rate did not change the retention factor k2, dramatic effects on the interaction between the immobilized antibody and d-mandelic acid were observed when any of the other mobile phase parameters were modulated.

Tratamiento antirretroviral y toxicidad mitocondrial

The introduction of highly active antiretroviral therapy for the treatment of human immunodeficiency virus (HIV) infection has led to substantial reduction in morbidity and near-complete suppression of HIV-1 replication. This progress has been tempered by a growing number of new adverse effects. Mitochondrial toxicity is one aspect of these long-term toxicities of antiretroviral drugs, with the role of nucleoside analogs being particularly underlined. Some cases of impaired mitochondrial function have been clearly identified, such as pancreatitis, neuropathy, miopathy and lactic acidosis. Beyond the inhibition of DNA polymerase-g using nucleoside analogs, it appears that several physiopathologic mechanisms interact to explain the observed toxicity. At present there is no reliable method to detect subclinical mitochondrial toxicity. There is no proven effective therapy for antiretroviral therapy-associated mitochondrial toxicity other than ceasing the implicated agent, and even with this strategy, resolution of symptoms may be incomplete. Therefore, investigation of mitochondrial toxicity of new compounds or new combinations is of growing interest for the clinical application of antiretroviral agents.