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

Conditional expression of HIV-1 tat in the mouse alters the onset and progression of tonic, inflammatory and neuropathic hypersensitivity in a sex-dependent manner

BACKGROUND

At least one-third of HIV-1-afflicted individuals experience peripheral neuropathy. Although the underlying mechanisms are not known, they may involve neurotoxic HIV-1 proteins.

METHODS

We assessed the influence of the neurotoxic HIV-1 regulatory protein, Tat, on inflammatory and neuropathic nociceptive behaviours using transgenic male and female mice that conditionally expressed (or did not express) HIV-1 Tat_1-86 in fibrillary acidic protein-expressing glia in the central and peripheral nervous systems.

RESULTS

Tat induction significantly attenuated the time spent paw-licking following formalin injection (2.5%, i.pl.) in both male and female mice. However, significant sex differences were observed in the onset and magnitude of inflammation and sensory sensitivity following complete Freund's adjuvant (CFA) injection (10%, i.pl.) after Tat activation. Unlike female mice, male mice showed a significant attenuation of paw swelling and an absence of mechanical/thermal hypersensitivity in response to CFA after Tat induction. Male Tat(+) mice also showed accelerated recovery from chronic constrictive nerve injury (CCI)-induced neuropathic mechanical and thermal hypersensitivity compared to female Tat(+) mice. Morphine (3.2 mg/kg) fully reversed CCI-induced mechanical hypersensitivity in female Tat(-) mice, but not in Tat(+) females.

CONCLUSIONS

The ability of Tat to decrease oedema, paw swelling, and limit allodynia suggests a sequel of events in which Tat-induced functional deficits precede the onset of mechanical hypersensitivity. Moreover, HIV-1 Tat attenuated responses to inflammatory and neuropathic insults in a sex-dependent manner. HIV-1 Tat appears to directly contribute to HIV sensory neuropathy and reveals sex differences in HIV responsiveness and/or the underlying peripheral neuroinflammatory and nociceptive mechanisms.

Acute Trigeminal Neuralgia Associated with Initiation of Emtricitabine/Tenofovir for HIV Pre-Exposure Prophylaxis

HIV pre-exposure prophylaxis (PrEP) with emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) fixed-dose combination (FTC/TDF) is undergoing rapid scale-up in the United States. While FTC/TDF is typically well tolerated, to our knowledge, cranial nerve pathology associated with FTC/TDF has not been previously described. We report the case of a 35-year-old patient who began FTC/TDF PrEP and developed acute trigeminal neuralgia. The neurologic symptoms resolved after treatment discontinuation and recurred upon rechallenge, resulting in permanent discontinuation of PrEP treatment.

Drug-induced liver steatosis in patients with HIV infection

Drug-induced liver injury (DILI) due to the use of prescription and non-prescription medication by HIV-positive and HIV-negative patients is one of the main causes of acute liver failure and transplantation in Western countries and, although rare, has to be considered a serious problem because of its unforeseeable nature and possibly fatal course. Drug-induced steatosis (DIS) and steatohepatitis (DISH) are infrequent but well-documented types of DILI. Although a number of commonly used drugs are associated with steatosis, it is not always easy to identify them as causative agents because of the weak temporal relationship between the administration of the drug and the clinical event, the lack of a confirmatory re-challenge, and the high prevalence of non-alcoholic fatty liver disease (NAFLD) in the general population, which often makes it difficult to make a differential diagnosis of DIS and DISH. The scenario is even more complex in HIV-positive patients not only because of the underlying disease, but also because the various anti-retroviral regimens have different effects on liver steatosis. Given the high prevalence of liver steatosis in HIV-positive patients and the increasing use of drugs associated with a potential steatotic risk, the identification of clinical signs suggesting liver damage should help to avoid the possible misdiagnosis of "primary" NAFLD in a patient with DIS or DISH. This review will therefore initially concentrate on the current diagnostic criteria for DIS/DISH and their differential diagnosis from NAFLD. Subsequently, it will consider the different clinical manifestations of iatrogenic liver steatosis in detail, with specific reference to HIV-positive patients. Finally, the last part of the review will be dedicated to the possible effects of liver steatosis on the bioavailability of antiretroviral and other drugs.

Zidovudine-Mediated Autophagy Inhibition Enhances Mitochondrial Toxicity in Muscle Cells

Nucleoside reverse transcriptase inhibitors (NRTI), such as zidovudine (AZT), are constituents of HIV-1 therapy and are used for the prevention of mother-to-child transmission. Prolonged thymidine analogue exposure has been associated with mitochondrial toxicities to heart, liver, and skeletal muscle. We hypothesized that the thymidine analogue AZT might interfere with autophagy in myocytes, a lysosomal degradation pathway implicated in the regulation of mitochondrial recycling, cell survival, and the pathogenesis of myodegenerative diseases. The impact of AZT and lamivudine (3TC) on C2C12 myocyte autophagy was studied using various methods based on LC3-green fluorescent protein overexpression or LC3 staining in combination with Western blotting, flow cytometry, and confocal and electron microscopy. Lysosomal and mitochondrial functions were studied using appropriate staining for lysosomal mass, acidity, cathepsin activity, as well as mitochondrial mass and membrane potential in combination with flow cytometry and confocal microscopy. AZT, but not 3TC, exerted a significant dose- and time-dependent inhibitory effect on late stages of autophagosome maturation, which was reversible upon mTOR inhibition. Inhibition of late autophagy at therapeutic drug concentrations led to dysfunctional mitochondrial accumulation with membrane hyperpolarization and increased reactive oxygen species (ROS) generation and, ultimately, compromised cell viability. These AZT effects could be readily replicated by pharmacological and genetic inhibition of myocyte autophagy and, most importantly, could be rescued by pharmacological stimulation of autophagolysosomal biogenesis. Our data suggest that the thymidine analogue AZT inhibits autophagy in myocytes, which in turn leads to the accumulation of dysfunctional mitochondria with increased ROS generation and compromised cell viability. This novel mechanism could contribute to our understanding of the long-term side effects of antiviral agents.

Review article: long-term safety of oral anti-viral treatment for chronic hepatitis B

BACKGROUND

Safety profile of nucleos(t)ide analogues is an important issue in view of its widespread use for decades in patients with chronic hepatitis B (CHB).

AIM

To review and evaluate the latest evidence on the safety profiles of the six approved nucleoside analogues.

METHODS

Relevant articles related to nucleoside analogue safety were selected for review following extensive language- and date-unrestricted, electronic searches of the literature.

RESULTS

Nephrotoxicity has been well reported in patients receiving older generations of nucleotide analogues, namely adefovir dipivoxil and tenofovir disoproxil fumarate (TDF). Yet risks of renal failure and renal replacement therapy were similar in patients treated with nucleoside analogues versus nucleotide analogues in real-life setting. Bone toxicity is closely related to nucleoside analogue effect on renal proximal tubular and phosphaturia. Real-life data demonstrated increased risk of hip fracture in patients receiving adefovir but not TDF. The newly approved tenofovir alafenamide (TAF) has improved renal and bone safety profiles compared to TDF. Long-term use of nucleoside analogues eg entecavir does not increase the risk of other cancers. Muscular toxicity may be seen in telbivudine-treated patients so regular monitoring is advised. Peripheral neuropathy and lactic acidosis are rare adverse events. Latest international guidelines support the use of TDF, telbivudine and lamivudine during pregnancy; breastfeeding is not contraindicated during TDF therapy.

CONCLUSIONS

Long-term safety profile of nucleoside analogues is now better defined with more data from large real-life cohorts and clinical trials with long-term follow-up. The new nucleotide analogue, TAF is now available with favourable renal and bone safety profiles.

DNA polymerase inhibitors for treating hepatitis B: a safety evaluation

INTRODUCTION

Oral nucleoside/ nucleotide analogues (NAs) are currently the mainstay of treatment for patients with chronic hepatitis B virus (HBV) infection. They are generally safe to use. However, since their approval in the last decade and a half, the literature has reported adverse effects associated with the use of NA in HBV patients. A comprehensive review on the drug safety is lacking.

AREAS COVERED

Significant adverse effects associated with NA use in HBV patients including muscle toxicity, peripheral neuropathy, nephrotoxicity and lactic acidosis are discussed. The reported prevalence of each adverse effect, as well as their predictive factors, reversibility and their use in pregnancy and lactating mothers are covered in this review. Novel data regarding reno-protective effect of telbivudine are also discussed.

EXPERT OPINION

Use of NA in HBV is generally safe. Uncommon adverse effects can be minimized or detected early if clinicians exercise adequate precautions when using NA for at-risk populations with regular monitoring.

Optimizing antiretroviral therapy for women living with HIV

PURPOSE OF REVIEW

This review considers the evidence available to guide clinicians in their choice of optimal antiretroviral therapy (ART) for women with HIV.

RECENT FINDINGS

Cohort and clinical trial data indicate that ART is as efficacious in women as men, although women are more likely to discontinue therapy, which compromises effectiveness. For many drugs, women have higher plasma levels than men, although whether this is secondary to differing metabolism in women or because on average women have a lower body mass than men is not clear. For many drugs, women experience more adverse events secondary to ART. Opinion on the use of efavirenz in pregnancy differs between countries. The average age of women with HIV is increasing. Although virological responses to ART are not affected by age, immunological responses may be poorer. Older women with HIV face issues such as neurocognitive impairment, early menopause, osteoporosis and polypharmacy, which will have the potential to impact on their use of ART.

SUMMARY

When planning ART regimes with women, clinicians need to be mindful of the woman's social situation and stage in the life course, as well as the scientific data on individual drug effectiveness according to sex.

Causes and determinants of mortality in HIV-infected adults with tuberculosis: an analysis from the CAMELIA ANRS 1295-CIPRA KH001 randomized trial

BACKGROUND

Shortening the interval between antituberculosis treatment onset and initiation of antiretroviral therapy (ART) reduces mortality in severely immunocompromised human immunodeficiency virus (HIV)-infected patients with tuberculosis. A better understanding of causes and determinants of death may lead to new strategies to further enhance survival.

METHODS

We assessed mortality rates, causes of death, and factors of mortality in Cambodian HIV-infected adults with CD4 count ≤200 cells/µL and tuberculosis, randomized to initiate ART either 2 weeks (early ART) or 8 weeks (late ART) after tuberculosis treatment onset in the CAMELIA clinical trial.

RESULTS

Six hundred sixty-one patients enrolled contributed to 1366.1 person-years of follow-up; 149 (22.5%) died. There were 8.3 deaths per 100 person-years (95% confidence interval [CI], 6.4-10.7) in the early-ART group and 13.8 deaths per 100 person-years (95% CI, 11.2-16.9) in the late-ART group (P = .002). Tuberculosis was the primary cause of death (28%), followed by other HIV-associated conditions (19%). Factors independently associated with mortality in the first 26 weeks were the age, body mass index, hemoglobin, interrupted or ineffective tuberculosis treatment before identification of drug resistance, disseminated tuberculosis, and nontuberculous mycobacterial disease. After 50 weeks in the trial, the most frequent causes of death were non-HIV related or tuberculosis related, including drug toxicity; factors associated with mortality were late ART, loss to follow-up, and absence of cotrimoxazole prophylaxis.

CONCLUSIONS

Despite ART introduction, mortality remained high, with tuberculosis as the leading cause of death. Reducing tuberculosis-related mortality remains a challenge in resource-limited settings and requires innovative strategies. Clinical Trials Registration. NCT00226434.

Hyperlactatemia in a group of HIV patients living in Yaounde-Cameroon

Background and aim

Prolonged exposure to highly active antiretroviral therapy (HAART) is associated with adverse effects such as hyperlactatemia. We determined the prevalence and risk factors for developing hyperlactatemia among human immunodeficiency virus (HIV)-infected cameroonians on antiretroviral therapy (ART).

Methods

We conducted a cross-sectional study from January to April 2012 involving 91 HIV-infected patients receiving ART for at least 12 months and 30 HIV-infected patients who have never received ART (ART-naïve patients). Plasma lactate levels were determined after at least 12 hours of overnight fasting and hyperlactatemia defined as lactate concentrations ≥ 3 mmol/L. The prevalence of hyperlactatemia was determined and the risk factors were analyzed by a multivariate logistic regression model.

Results

The mean lactataemia was significantly higher in the group of HIV patients currently taking ART than in the ART-naïve one (2.3 ± 1.3 and 1.7 ± 0.7 mmol/L respectively, p = 0.002). Patients on first line ART regimens had significantly higher lactatemia than those on second line regimens (2.5 ± 1.5 and 1.9 ± 0.7 mmol/L respectively, p = 0.014). The prevalence of hyperlactatemia in HIV patients receiving ART and in ART-naïve HIV patients was respectively 18.7 and 6.7% (p = 0.095). ART-exposure (adjusted odds ratio (aOR) 5.44, 95% confidence interval (CI) 1.06 – 27.84; p = 0.042) and being on a first line regimen (aOR 16.22, 95% CI 1.57 – 167.91; p = 0.019) were independent strong predictors of hyperlactatemia.

Conclusion

Hyperlactatemia was not rare in our study population. Being on a first line regimen constitutes an important risk factor for developing hyperlactatemia. Measurement of plasma lactate may be useful in optimizing the management of HIV-positive persons on ART.

Drug-induced steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disease in the United States. The term NALFD was first used by Ludwig in 1980 to describe the presence of hepatic steatosis and steatohepatitis in a series of patients with no identifiable cause. Since then, our insight into the pathogenesis of NAFLD has expanded significantly. We now know that NAFLD is closely related to metabolic syndrome and chronic low-grade inflammation. In the following review, the authors summarize the current evidence about drugs that lead to hepatic steatosis and steatohepatitis and pathogenic mechanisms thereof.

Lactic acidosis during telbivudine treatment for HBV: A case report and literature review

All oral nucleoside analogues against hepatitis B virus, with an exception of telbivudine, have been reported causing lactic acidosis (LA). Here we report the first case of chronic hepatitis B developing severe refractory LA during telbivudine monotherapy. A 36-year-old man of Chinese origin received telbivudine antiviral treatment for chronic hepatitis B. After 11 mo of therapy, he developed anorexia, nausea, and vomiting with mild muscle weakness. The patient was found with elevated serum creatine phosphokinase up to 3683 U/L (upper limit of normal 170 U/L) and marked LA. LA did not resolve immediately following discontinuation of telbivudine. His condition began to improve after hemodialysis treatment for 16 times and usage of glucocorticosteroid. The patient fully recovered after 16 wk of treatment. This is the first documented case with severe LA caused by telbivudine monotherapy. Besides serum creatine phosphokinase, blood lactate level should also be closely monitored in patients receiving telbivudine.

Autophagy inhibition due to thymidine analogues as novel mechanism leading to hepatocyte dysfunction and lipid accumulation

OBJECTIVES

Prolonged nucleoside reverse transcriptase inhibitors (NRTI) exposure can lead to microvesicular steatosis. We hypothesized that thymidine analogues might interfere with autophagy in hepatocytes, a lysosomal degradation pathway implicated in cell survival and regulation of hepatocyte lipid metabolism.

DESIGN

Using HepG2 and HUH7 cell lines and primary human hepatocytes, we performed a comprehensive analysis of NRTI-mediated effects on autophagy.

METHODS

The impact of zidovudine (ZDV), stavudine (d4T) and lamivudine (3TC) on constitutive and induced autophagy was analyzed by fluorescent and electron microscopy, western blotting and flow cytometry. Effects on hepatocyte autophagy were correlated to cellular viability, mitochondrial dysfunction and intracellular lipid accumulation.

RESULTS

ZDV and d4T, but not 3TC, significantly inhibited both constitutive as well as stimulated autophagic activity in a dose-dependent and time-dependent manner. Inhibition of autophagy at therapeutic drug concentrations led to accumulation of dysfunctional mitochondria, increased ROS production, increased apoptosis, decreased proliferation and increased intracellular lipid accumulation. These NRTI effects could be readily resembled by pharmacological and genetic inhibition of hepatocyte autophagy.

CONCLUSION

Our data suggest that thymidine analogues inhibit autophagy in hepatocytes, which in turn leads to increased ROS production, lipid accumulation and hepatic dysfunction. This novel mechanism could contribute to nonalcoholic fatty liver disease in HIV-infected patients.

Risk factors for symptomatic hyperlactatemia and lactic acidosis among combination antiretroviral therapy-treated adults in Botswana: results from a clinical trial

Nucleoside analogue reverse transcriptase inhibitors are an integral component of combination antiretroviral treatment regimens. However, their ability to inhibit polymerase-γ has been associated with several mitochondrial toxicities, including potentially life-threatening lactic acidosis. A total of 650 antiretroviral-naive adults (69% female) initiated combination antiretroviral therapy (cART) and were intensively screened for toxicities including lactic acidosis as part of a 3-year clinical trial in Botswana. Patients were categorized as no lactic acidosis symptoms, minor symptoms but lactate <4.4 mmol/liter, and symptoms with lactate ≥ 4.4 mmol/liter [moderate to severe symptomatic hyperlactatemia (SH) or lactic acidosis (LA)]. Of 650 participants 111 (17.1%) developed symptoms and/or laboratory results suggestive of lactic acidosis and had a serum lactate drawn; 97 (87.4%) of these were female. There were 20 events, 13 having SH and 7 with LA; all 20 (100%) were female (p<0.001). Cox proportional hazard analysis limited to the 451 females revealed that having a higher baseline BMI was predictive for the development of SH/LA [aHR=1.17 per one-unit increase (1.08-1.25), p<0.0001]. Ordered logistic regression performed among all 650 patients revealed that having a lower baseline hemoglobin [aOR=1.28 per one-unit decrease (1.1-1.49), p=0.002] and being randomized to d4T/3TC-based cART [aOR=1.76 relative to ZDV/3TC (1.03-3.01), p=0.04] were predictive of the symptoms and/or the development of SH/LA. cART-treated women in sub-Saharan Africa, especially those having higher body mass indices, should receive additional monitoring for SH/LA. Women presently receiving d4T/3TC-based cART in such settings also warrant more intensive monitoring.

Effect of HIV-1 infection and sex on the cellular pharmacology of the antiretroviral drugs zidovudine and lamivudine

The cellular pharmacology of zidovudine (ZDV) and lamivudine (3TC) in vivo is not completely understood. This prospective longitudinal study investigated the relationship between HIV-1 serostatus, sex, race, and time on therapy with intracellular and plasma ZDV and 3TC concentrations. Of 20 HIV-seronegative and 23 HIV-seropositive volunteers enrolled, 16 (8 women) and 21 (5 women) completed all 12 study days, respectively. Volunteers began ZDV-3TC therapy (plus a third active drug in HIV-seropositive volunteers), and steady-state concentrations (C(ss)) were determined after days 1, 3, 7, and 12. A repeated-measures mixed model was utilized. HIV-seronegative status was associated with 22% (95% confidence interval [CI], 0%, 50%) and 37% (15%, 67%) higher C(ss) estimates compared to those of HIV-seropositive individuals for intracellular ZDV-TP and 3TC-TP levels, respectively. African-Americans had 36% (8%, 72%) higher ZDV-TP estimates than non-African-Americans. Sex was not associated with ZDV-TP or 3TC-TP (P > 0.19). Women had 36% (4%, 78%) higher plasma ZDV, but the effect was lessened when normalized by lean body weight (5% [-19%, 38%]; P = 0.68). Plasma 3TC was 19% (0%, 41%) higher in HIV-seropositive volunteers and 22% (0%, 48%) higher in African American volunteers, but these effects were not significant when corrected for creatinine clearance (7% [-9%, 20%] and -5% [-26%, 12%] for HIV serostatus and race, respectively; P > 0.35). These results suggest that HIV-seropositive status decreases and African American race elevates the cellular triphosphates of ZDV and 3TC. This information extends knowledge of ZDV and 3TC cellular pharmacology in vivo and provides new leads for future cellular pharmacology studies aimed at optimizing HIV prevention/treatment with these agents.

The role of nucleoside reverse transcriptase inhibitors usage in the incidence of hyperlactatemia and lactic acidosis in HIV/AIDS patients

Hyperlactatemia and lactic acidosis (LA) are among the most dangerous and life-threatening side effect that occurs during therapy with some nucleoside reverse transcriptase inhibitors (NRTIs), mainly didanosine (ddI) and stavudine (d4T), also known as d-drugs. Therefore, we performed a prospective, follow-up study and aimed to examine the incidence rates (IR) and rate ratios (RR) of hyperlactatemia and LA for each NRTI. Three hundred and ninety-six HIV-patients were included in final analysis comprising 783.8 person-years of follow-up. Between 1st January 2000 and 1st January 2008, 19 cases of hyperlactatemia and 15 cases of LA were recorded. Between regimens with the significant impact for developing hyperlactatemia and LA the lowest IR was for didanosine (IR=2.87 per 100 person-years, 95%CI=0.45-9.25 and IR=4.31 per 100 person-years, 95%CI=1.07-13.91, respectively), and the highest for didanosine+stavudine (IR=10.17 per 100 person-years, 95%CI=1.02-19.76 and IR=7.39 per 100 person-years, 95%CI=1.02-13.05, respectively). Compared to didanosine alone the RR of hyperlactatemia was 2.67 (95%CI=1.11-12.52) for stavudine, and 4.06 (95%CI=1.31-15.48) for didanosine+stavudine. The RR of LA was 3.12 (95%CI=1.13-10.65) for stavudine, and 5.13 (95%CI=1.54-13.37) for didanosine+stavudine in comparison with didanosine alone. Other risk factors for AP were CD4 cell count less than 200 cells/mm³ and female sex. Our results suggest that the use of stavudine alone or in combination with didanosine should not be used as first-line therapy, especially in patients with CD4 cell count less than 200 cells/mm³ and females if other treatment options are available.

Effects of a reduced dose of stavudine on the incidence and severity of peripheral neuropathy in HIV-infected adults in South Africa

BACKGROUND

Although recent World Health Organization (WHO) guidelines recommend withdrawing stavudine (d4T) from first-line antiretroviral therapy (ART), it remains commonly used in resource-limited settings. In 2006, WHO recommended decreasing the dose of d4T from 40 mg to 30 mg to mitigate toxicities. We compared the incidence and severity of peripheral neuropathy by d4T dose in a retrospective cohort study.

METHODS

Patients' charts from an ART-naive population at a rural clinic in KwaZulu-Natal, South Africa, were retrospectively reviewed for signs and symptoms of incident peripheral neuropathy and were graded for severity using the DAIDS scale. Patients enrolled prior to the WHO guideline change were included in the study if they were on d4T 40 mg for ≥6 months. After the guideline change all patients were initiated on d4T 30 mg.

RESULTS

A total of 475 patients were analysed, including 235 in the 40 mg cohort (152.7 person-years [py]) and 240 in the 30 mg cohort (244.7 py). Incidence of peripheral neuropathy was 90.4/100 py (95% CI 75.9, 106.8) in the 40 mg cohort versus 40.5/100 py (95% CI 32.9, 49.3) in the 30 mg group (incidence rate ratio 0.45; P<0.0001). There was no difference in proportion of severe peripheral neuropathy cases (grade 3/4) between the cohorts: 8.3% in the 40 mg group and 8.9% in the 30 mg group (P=1.0). In a multivariate analysis, risk of peripheral neuropathy was associated with increasing age (hazard ratio [HR] 1.65, 95% CI 1.24, 2.19), 40 mg dose (HR 2.1, 95% CI 1.61, 2.74) and concurrent tuberculosis therapy (HR 1.41, 95% CI 1.06, 1.87).

CONCLUSIONS

Incidence of peripheral neuropathy in the 40 mg cohort was extremely high and, although lower, the rate in the 30 mg cohort was nonetheless unacceptably high.

A risk-factor guided approach to reducing lactic acidosis and hyperlactatemia in patients on antiretroviral therapy

Background

Stavudine continues to be used in antiretroviral treatment (ART) regimens in many resource-limited settings. The use of zidovudine instead of stavudine in higher-risk patients to reduce the likelihood of lactic acidosis and hyperlactatemia (LAHL) has not been examined.

Methods

Antiretroviral-naïve, HIV-infected adults initiating ART between 2004 and 2007 were divided into cohorts of those initiated on stavudine- or zidovudine-containing therapy. We evaluated stavudine or zidovudine use, age, sex, body mass index (BMI), baseline CD4 cell count, creatinine, hemoglobin, alanine aminotransferase, and albumin as predictors of time to LAHL with Cox Proportional Hazards (PH) regression models.

Results

Among 2062 patients contributing 2747 patient years (PY), the combined incidence of LAHL was 3.2/100 PY in those initiating stavudine- and 0.34/100 PY in those initiating zidovudine-containing ART (RR 9.26, 95% CI: 1.28–66.93). In multivariable Cox PH analysis, stavudine exposure (HR 14.31, 95% CI: 5.79–35.30), female sex (HR 3.41, 95% CI: 1.89–6.19), higher BMI (HR 3.21, 95% CI: 2.16–4.77), higher creatinine (1.63, 95% CI: 1.12–2.36), higher albumin (HR 1.04, 95% CI: 1.01–1.07), and lower CD4 cell count (HR 0.96, 95% CI: 0.92–1.0) at baseline were associated with higher LAHL rates. Among participants who started on stavudine, switching to zidovudine was associated with lower LAHL rates (HR 0.15, 95% CI: 0.06–0.35). Subgroup analysis limited to women with higher BMI≥25 kg/m2 initiated on stavudine also showed that switch to zidovudine was protective when controlling for other risk factors (HR 0.21, 95% CI .07–0.64).

Conclusions

Stavudine exposure, female sex, and higher BMI are strong, independent predictors for developing LAHL. Patients with risk factors for lactic acidosis have less LAHL while on zidovudine- rather than stavudine-containing ART. Switching patients from stavudine to zidovudine is protective. Countries continuing to use stavudine should avoid this drug in women and patients with higher BMI.

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.

Reduced referral and case fatality rates for severe symptomatic hyperlactataemia in a South African public sector antiretroviral programme: a retrospective observational study

Background

Interventions to promote prevention and earlier diagnosis of severe symptomatic hyperlactataemia (SHL) were implemented in the Western Cape provincial antiretroviral programme (South Africa) from 2004. Interventions included clinician education, point-of-care lactate meters, switch from stavudine to zidovudine in high risk patients and stavudine dose reduction. This study assessed trends in referral rate, severity at presentation and case fatality rate for severe SHL.

Methods

Retrospective study of severe SHL cases diagnosed at a referral facility from 1 January 2003 to 31 December 2008. Severe SHL was defined as patients with compatible symptoms and serum lactate ≥ 5 mmol/l attributable to antiretroviral therapy (ART). Cumulative ART exposure at referring ART clinics was used to calculate referral rates.

Results

There were 254 severe SHL cases. The referral rate (per thousand patient years [py] ART exposure) peaked in 2005 (20.4/1000py), but fell to 1.3/1000py by 2008 (incidence rate ratio [IRR] = 0.07, 95%CI 0.04-0.11). In 2003, 66.7% of cases presented with a standard bicarbonate (SHCO₃) level <15 mmol/l, but this fell to 12.5% by 2008 (p for trend < 0.001). Case fatality rate fell from a peak of 33.3% in 2004 to 0% in 2008 (p for trend = 0.002).

Conclusions

These trends suggest the interventions were associated with reduced referral, less severe metabolic acidosis at presentation and improved survival.