Study of the role of vitamin B12 and folinic acid supplementation in preventing hematologic toxicity of zidovudine

Progression of non-anemic macrocytosis to anemia in HIV-positive persons receiving zidovudine-containing regimens in a resource-limited setting

BACKGROUND

Non-anemic macrocytosis is frequently observed among HIV-positive persons treated with zidovudine in resource-limited settings. Although zidovudine-associated anemia is well recognized, the probability and predictors of progression from non-anemic macrocytosis to anemia are still unknown.

METHODS

A retrospective cohort study was conducted among HIV-positive persons receiving zidovudine-containing antiretroviral therapy (ART) with non-anemic macrocytosis. Kaplan-Meier and Cox regression analyses were used to determine the probability and predictive factors of progression from non-anemic macrocytosis to anemia, respectively.

RESULTS

Of 318 HIV-positive persons, 59.4% were male; mean age was 44.3 years. The median follow-up duration was 5.8 years. The probabilities of progression to anemia at 1, 3 and 4 years were estimated at 9.4, 17.3 and 21.3%, respectively. Almost all anemia was mild asymptomatic. Duration of zidovudine use [hazard ratio (HR) = 1.141; 95% confidence interval (CI),1.036-1.256; p = .007], CD4 count prior to start zidovudine [HR = 0.991; 95%CI,0.982-0.999; p = .038], and hematocrit level at development of macrocytosis [HR = 0.683; 95%CI,0.541-0.861; p = .001] were significant factors to predict progression to anemia.

CONCLUSION

Non-anemic macrocytosis in HIV-positive persons receiving zidovudine-containing ART can progress to anemia. Longer duration of zidovudine use, lower CD4 cell counts at ART initiation, and lower hematocrit level at development of macrocytosis are predictive factors for progression to anemia.

Glutathione, glutathione peroxidase and some hematological parameters of HIV-seropositive subjects attending clinic in University of Calabar teaching hospital, Calabar, Nigeria

BACKGROUND

Despite the numerous intervention programmes, HIV still remains a public health concern with a high impact in Sub-Saharan Africa region. Oxidative stress has been documented in HIV subjects as viral infection promotes prolonged activation of immune system, hence, production of increased reactive oxygen species.

METHODS

We studied 180 subjects. Of these, 60 were HIV-infected on antiretroviral therapy (ART), 40 were ART naïve HIV-infected and 80 were apparent healthy non HIV-infected subjects. The complete blood count was performed by automated hemoanalyzer, the CD4⁺ T-cell count was performed by cyflow cytometer, while the antioxidant assay was performed using ELISA technique.

RESULT

All evaluated parameters; glutathione (GSH), glutathione peroxidase (GPX), CD4⁺ T-cell count, haemoglobin (Hb), total white blood cell count (WBC) and platelet count were significantly (P < 0.05) reduced in the HIV-infected subjects. All assessed parameters were found to be significantly (P < 0.5) reduced in the HIV-infected subjects that are ART naive when compared with those on ART. HIV-infected subjects with CD4⁺ T-cell count < 200 cells/mm³ had significantly (P < 0.05) reduced values in all assessed parameters when compared to those with CD4⁺ T-cell count ≥200 cells/mm³. GSH and WBC were found to be significantly (P < 0.05) increased in the female HIV-infected subjects when compared with the male counterpart. Anemia prevalence of 74 and 33% were recorded for the HIV-infected and control subjects, respectively. Gender and ART treatment were found to be associated with anemia in HIV. Male HIV-infected subjects on ART were found to be more likely to have anemia.

CONCLUSION

Antioxidants; GSH and GPX were found to be significantly reduced in HIV infection. Further probe showed that the antioxidant status was improved in the HIV-infected group on ART.

Safety considerations and potential interactions of vitamins: should vitamins be considered drugs?

OBJECTIVE

To examine adverse effects, adverse events, and potential interactions of vitamins in light of their current prevalence of use, and to discuss whether vitamins should be considered over-the-counter drugs or natural health products/dietary supplements.

DATA SOURCES

We performed a MEDLINE/PubMed search, explored 4 online databases (Medline Plus, Drug Digest, Natural Medicine Comprehensive Database, and the database of the University of Maryland), and examined reference lists of included studies published from 1966 through October 2009.

STUDY SELECTION AND DATA EXTRACTION

The studies were reviewed, with an emphasis on randomized controlled clinical trials. We included articles with the most clinically important information with regard to adverse events and interactions.

DATA SYNTHESIS

Vitamins are used by over one third of the North American population. Vitamins have documented adverse effects and toxicities, and most have documented interactions with drugs. While some vitamins (biotin, pantothenic acid, riboflavin, thiamine, vitamin B(12), vitamin K) have minor and reversible adverse effects, others, such as fat-soluble vitamins (A, E, D), can cause serious adverse events. Two water-soluble vitamins, folic acid and niacin, can also have significant toxicities and adverse events.

CONCLUSIONS

Our recommendation is that vitamins A, E, D, folic acid, and niacin should be categorized as over-the-counter medications. Labeling of vitamins, especially those intended for children and other vulnerable groups, should include information on possible toxicities, dosing, recommended upper intake limits, and concurrent use with other products. Vitamin A should be excluded from multivitamin supplements and food fortificants.

Potential vitamin-drug interactions in children: at a pediatric emergency department

BACKGROUND

A significant increase in vitamin use has been observed in recent years and interactions between vitamins and medications have been reported.

OBJECTIVE

To determine the frequency and types of potential interactions between vitamins and medications in children arriving at a large tertiary, pediatric emergency department. We also compared family characteristics of children with potential interactions with those of children with no potential interactions, in order to determine children at a higher risk.

METHODS

A cross-sectional study in which a survey was conducted of parents/caregivers and/or patients aged 0-18 years registered at a large pediatric emergency department in Canada. A total of 1804 families underwent a face-to-face interview. The main outcome measure was the rate of potential vitamin interactions in the preceding 3 months.

RESULTS

A considerable number of patients (11% of our cohort) had potential vitamin-medication interactions in the preceding 3 months, which could theoretically result in adverse events, and over one-third of these children had more than one potential interaction. Patients with potential interactions and their parents were significantly older (p < 0.001 for the child and mother, p = 0.02 for the father), the children were much more likely to have a chronic illness (p < 0.001) and concurrently receive prescribed or over-the-counter medication (p < 0.001), and more children with potential interactions were completely immunized (p = 0.02). The child's sex, parental education, employment status, family income, and primary language spoken at home were not associated with potential interactions.

CONCLUSIONS

Taking into account the high rate of potential vitamin-drug interactions, especially among older children and patients with chronic illness, parents and healthcare providers need to balance the potential benefit of concurrent vitamin-medication use with its potential harms.

Potential interactions of drug-natural health products and natural health products-natural health products among children

OBJECTIVE

To determine the frequency of concurrent use of conventional medications and natural health products (NHP) and their potential interactions in children arriving at an emergency department.

STUDY DESIGN

A survey of parents and patients 0 to 18 years at a large pediatric ED in Toronto, Ontario, Canada.

RESULTS

A total of 1804 families were interviewed in this study. Concurrent drug-NHP use was documented in 355 (20%) of patients and 269 (15%) of NHP users were receiving more than one NHP simultaneously. Theoretically possible NHP-drug or NHP-NHP interactions in the preceding 3 months were identified in 285 (16%) children. There were 35 different NHP-medication interaction pairs and 41 NHP-NHP interaction pairs. NHP-medication interactions were predominantly pharmacokinetic (modified absorption, 35%); potential NHP-NHP interactions were mostly pharmacodynamic (increased risk of bleeding, 47%).

CONCLUSIONS

Medications are used concurrently with NHP in every fifth pediatric patient in the emergency department and many NHP users are receiving more than 1 NHP simultaneously. One quarter of all paired medication-NHP or NHP-NHP could potentially cause interactions. Although we can not confirm that these were true interactions resulting in clinical symptoms, parents and health care providers need to balance the potential benefit of concurrent NHP-medication use with its potential harms.

Micronutrients in HIV-positive persons receiving highly active antiretroviral therapy

In HIV-infected persons, low serum concentrations of vitamins and minerals, termed micronutrients, are associated with an increased risk of HIV disease progression and mortality. Micronutrient supplements can delay HIV disease progression and reduce mortality in HIV-positive persons not receiving highly active antiretroviral therapy (HAART). With the transition to more universal access to HAART, a better understanding of micronutrient deficiencies and the role of micronutrient supplements in HIV-positive persons receiving HAART has become a priority. The provision of simple, inexpensive micronutrient supplements as an adjunct to HAART may have several cellular and clinical benefits, such as a reduction in mitochondrial toxicity and oxidative stress and an improvement in immune reconstitution. We reviewed observational and trial evidence on micronutrients in HIV-positive persons receiving HAART to summarize the current literature and suggest future research priorities. A small number of observational studies have suggested that some, but not all, micronutrients may become replete after HAART initiation, and few intervention studies have found that certain micronutrients may be a beneficial adjunct to HAART. However, most of these studies had some major limitations, including a small sample size, a short duration of follow-up, a lack of adjustment for inflammatory markers, and an inadequate assessment of HIV-related outcomes. Therefore, few data are available to determine whether HAART ameliorates micronutrient deficiencies or to recommend or refute the benefit of providing micronutrient supplements to HIV-positive persons receiving HAART. Because micronutrient supplementation may cause harm, randomized placebo-controlled trials are needed. Future research should determine whether HAART initiation restores micronutrient concentrations, independent of inflammatory markers, and whether micronutrient supplements affect HIV-related outcomes in HIV-positive persons receiving HAART.

Anemia in HIV infection: clinical impact and evidence-based management strategies

Anemia in human immunodeficiency virus (HIV)-infected patients can have serious implications, which vary from functional and quality-of-life decrements to an association with disease progression and decreased survival. In 2002, 16 members of the Anemia in HIV Working Group, an expert panel of physicians involved in the care of HIV-infected patients that met first in 1998, reconvened to assess new data and to translate these data into evidence-based treatment guidelines. The group reached consensus on the prevalence of anemia in the highly active antiretroviral therapy era; the risk factors that are independently associated with the development of anemia; the impact of anemia on quality of life, physical functioning, and survival; the impact of the treatment of hepatitis C virus coinfection on anemia in HIV-infected patients; evidence-based guidelines for treatment of anemia in HIV-infected patients, including the therapeutic role of epoetin alfa; and directions for future research.

A clinical review of micronutrients in HIV infection

This article reviews current literature on the role of micronutrients in human immunodeficiency virus (HIV) infection. Deficiencies of micronutrients are common in HIV-infected persons. They occur due to malabsorption, altered metabolism, gut infection, and altered gut barrier function. There is a compelling association of deficiencies of micronutrients in HIV-infection with immune deficiency, rapid disease progression, and mortality. Also, there is increased risk of vertical HIV transmission from mother to child with deficiency of vitamin A, and of neurological impairment with vitamin B12. The last five years have been exciting in micronutrient research, and there is promise that some micronutrients may be key factors in maintaining health in HIV immunodeficiency, and in reducing mortality. Selenium appears important in reducing virulence of HIV and slowing disease progression. Vitamin A supplementation in pregnant women with HIV may reduce maternal mortality and improve birth outcomes. Supplementation in children with HIV may accelerate growth. Carotenoid supplementation is being evaluated. Vitamin B12 may slow HIV immune deficiency disease progression, and reverse neurological compromise. Clinical benefit of supplementation with some micronutrients may be measurable in the presence of pre-existing deficiency. Apart from improved general nutrition, the impact of micronutrient supplements on health and their optimal use in HIV infection is controversial because there are so few controlled clinical trials. Further research is needed to elucidate the role of micronutrient deficiencies on the course of HIV infection, and the preventive and therapeutic role of supplementation in its clinical management. Nevertheless, current knowledge supports the use of routine multivitamin and trace element supplementation as adjuvant to conventional antiretroviral drug treatment as a relatively low-cost intervention.

Human Immunodeficiency Virus Hematology

The advent of potent antiretroviral therapy has altered the expected natural history of human immunodeficiency virus (HIV) infection and of many previously associated opportunistic complications, including malignancies. At the same time, HIV suppression hasn’t affected all of these complications equally and the longer expected survival of infected patients may allow the development of newer complications. Additionally, the use of potent antiretroviral combination therapy may itself lead to hematological toxicities. Together these changes affect the consultation role of the hematology-oncology specialist in comprehensive HIV care and demand ongoing education.

In Section I, Dr. Paul Volberding reviews the biology of antiretroviral drug development and the progression in discovering new agents as the viral life cycle is further elucidated. He briefly summarizes the process of combining agents to achieve the degree of viral suppression required for long-term clinical benefit.

In Section II, Dr. Kelty Baker reviews the effects of HIV and its therapy on hematologic dyscrasia and clotting disorders. She summarizes how therapy may decrease certain previously common manifestations of HIV disease while adding new problems likely to result in referral to the hematologist. In addition, she addresses the role of secondary infections, such as parvovirus, in this spectrum of disorders.

In Section III, Dr. Alexandra Levine discusses the still challenging aspects of HIV associated non-Hodgkin’s lymphoma and the association between HIV infection and Hodgkin’s disease. She addresses current controversies in the pathogenesis of HIV related lymphomas and summarizes a number of recent trials of combination chemotherapy, with or without monoclonal antibodies, in their management. Additionally, she reviews the complex relationship of HIV disease with multicentric Castleman’s disease and recent attempts to manage this disorder.

Cognitive function in HIV-1-infected drug users

Loss of cognitive ability, the most common neuropsychological complication in HIV-1 disease, may influence compliance with treatment and has been associated with decreased functional capacity, as well as an increased risk of mortality. In HIV-1-infected drug users, cognitive impairment affecting attention, memory, planning of complex tasks, information processing, and motor processes, has been reported, similar to findings in predominantly HIV-1-infected nondrug-using cohorts. The issue of whether early signs of cognitive dysfunction can be identified in asymptomatic HIV-1-infected drug users remains controversial. Evaluation of potential confounding factors, such as drug abuse, age, education, nutritional status, which may influence cognitive function, is essential for determining the dominant cause of neuropsychological abnormalities. There is evidence for a time-limited, protective effect against the development of AIDS dementia with zidovudine therapy. The potential ability of other therapies (e.g., antioxidants, B-complex vitamins) to prevent neuronal damage and protect the brain remains to be determined.

Dyshaemopoiesis in adults: a practical classification for diagnosis and management

Dyshaemopoiesis is a heterogeneous disease that may be classified into non-clonal and clonal dyshaemopoiesis. Non-clonal dyshaemopoiesis comprises reversible disorders with DNA synthesis impairment in dividing cells of the bone marrow by avitaminosis through various mechanisms or direct DNA damage from multiple causes. Complete haematologic recovery is obtained after vitamin supplementation or suppression of a myelotoxic agent. On the contrary, clonal dyshaemopoiesis is a group of chronic and usually irreversible diseases that may culminate in acute leukaemia (AL). These so called myelodysplastic syndromes (MDS) and their variants may be classified as primary, secondary and other diseases with doubtful clonality. A detailed classification of dyshaemopoiesis in adults may offer partial help in the diagnosis and management of dyshaemopoiesis. Pathobiological studies in progress allow better understanding of MDS and consequently the establishment of new modalities of treatment.

HIV influence on hematopoiesis at the initial stage of infection

Alterations in the parameters responsible for the characteristic anemic condition of AIDS patients who are at the final stage of infection have already been established. However, the development of these alterations at the initial stage of infection, where no opportunistic infections occur, needs further study. The goal of this study was to verify whether laboratory alterations observed on patients at the final stages of the disease could already be seen at the beginning of HIV infection, or were the result of opportunistic infections. To that end, HIV-seropositive patients identified by the ELISA test and confirmed by immunofluorescence were screened by infectologist doctors and classified as per the Walter Reed Army Institute System. Results showed that thrombocytopenia occurred at an early stage during HIV infection. The number of leukocytes and erythrocytes diminished progressively as the disease advanced, and levels of hemoglobin, transferrin and serum iron were also diminished with the progression of the disease. These results indicate that the laboratory alterations observed in HIV-seropositive patients during the initial stages were, probably, due to virus infection, because these patients did not present opportunistic infections.

Selected vitamins in HIV infection: a review

In this article we review published studies on the role of serum micronutrient levels in the natural history of HIV infection. Specifically, we have focused on vitamins B12, E, A, and beta-carotene. Deficiencies of one or several of these vitamins have been associated with an accelerated progression of HIV infection to AIDS. Most investigators have used serum micronutrient levels as an indicator of vitamin nutriture. However, serum levels are not always the most sensitive or specific indicators of vitamin status. Nonetheless, serum vitamin levels are relatively easy to obtain and have been studied in various HIV-infected populations in individuals at different stages of disease. Low serum B12 levels have been associated with increased neurologic abnormalities, more rapid HIV disease progression, and increased AZT-related bone marrow toxicity. Low serum vitamin E levels have been associated with an increase in oxidative stress in HIV-infected individuals. However, early studies of vitamin E supplementation suggest that vitamin E may have important immunostimulatory properties. Studies of vitamin A deficiency in HIV-infected populations have shown that low serum vitamin A levels are associated with increased mortality, more rapid disease progression, and increased maternal-fetal transmission. However, there is little evidence that vitamin A supplementation, beyond the correction of deficiency, is beneficial in HIV infection. Finally, several clinical trials of beta-carotene supplementation have failed to show significant or sustained improvements in the immune response of patients with HIV infection or AIDS.

Hematologic complications of human immunodeficiency virus infection and the acquired immunodeficiency syndrome

The hematologic manifestations of HIV infection and AIDS are common and may cause symptoms that are life-threatening and impair the quality of life of these patients. The most important of these manifestations are cytopenias. Anemia and neutropenia are generally caused by inadequate production because of suppression of the bone marrow by the HIV infection through abnormal cytokine expression and alteration of the bone marrow microenvironment. Thrombocytopenia is caused by immune-mediated destruction of the platelets, in addition to inadequate platelet production. The incidence and severity of cytopenia are generally correlated to the stage of the HIV infection. Other causes of cytopenia in these patients include adverse effects of drug therapy, the secondary effects of opportunistic infections or malignancies, or other preexisting or coexisting medical problems that may be prevalent in the HIV-infected population. Diagnosis of the mechanism and cause of the cytopenia may allow for specific management. Optimal management of the underlying HIV infection is essential, and mild cytopenia in asymptomatic patients may need no specific management. Supportive care for anemia includes the use of erythropoietin in addition to the judicious use of red blood cell transfusions. Therapy for neutropenia includes the use of the myeloid growth factors G-CSF and GM-CSF. Immune-mediated thrombocytopenia may be treated with a combination of zidovudine, corticosteroids, IVGG, and splenectomy. Platelet transfusions are sometimes needed for the treatment of thrombocytopenia caused by decreased production. Other hematologic manifestations such as hypergammaglobulinemia and lupus anticoagulants are commonly asymptomatic and usually require no specific therapy, but they can rarely cause morbidity and require specific interventions.