Iron,folate and vitamin B12 parameters in HIV-1 infected patients with anaemia in southern Brazil

Introduction

Anaemia is common in those suffering from human immunodeficiency virus (HIV) infection and has been associated with increased progression to AIDS and a lower survival rate. ¹ Anaemia can impact on the quality of life of patients by inducing symptoms such as loss of stamina, rapid heart rate and shortness of breath. It has also been shown to be an indicator of an increased risk of earlier death in HIV-infected patients. ² Its diagnosis and treatment are essential and, therefore, it is important for clinicians treating HIV-infected patients to recognise the differential diagnosis of anaemia in order for them to provide the appropriate treatment.

In HIV-infected populations from the developing countries, it is unclear what proportion of anaemia is attributable to iron, folate or vitamin B12 deficiency. Only a few studies have originated from the developing countries in which the prevalence of anaemia in HIV-infected patients is high. ^3,4

We conducted this study in order to determine the role played by iron, folate and vitamin B12 in HIV-infected patients with anaemia attending a tertiary-care hospital in southern Brazil.

Materials and methods

Our study was composed of HIV-infected patients receiving medical care at the Hospital das Clínicas de Porto Alegre, a tertiary-care teaching hospital in the southern region of Brazil from January 2002 to September 2002. As part of a cross-sectional descriptive study to examine the aetiological factors responsible for anaemia in HIV-infected patients, 34 patients were recruited from the HIV clinic if a routine haemoglobin measurement indicated anaemia, which was defined as having a haemoglobin concentration of < 14.0 g/dL for men and 12 g/dL for women. Serum ferritin concentrations were determined by immunoenzymometric assay (Ramco, Houston, USA). Serum vitamin B12 and iron folate concentrations were measured with the SimulTRAC Radioassay Kit (Becton Dickinson, Orangeburg, NY, USA). Serum ferritin was determined by immunoenzymometric assay (detection limit of 0.6 µg/dL, Ramco).

All subjects completed a questionnaire requesting details of age, occupation, exercise, nutritional supplement use and the type of diet consumed. Estimates of current and previous dietary intakes were obtained using a semiquantitative food frequency questionnaire and 24-hour recall. An interviewer-administered food frequency questionnaire (FFQ) was used to assess the usual diet during the two years preceding the serum determination of the micronutrients, in order to estimate intake of selected nutrients.

Statistical analysis of the data was performed by using SPSS for Windows and Excel for Windows. The study was approved by our Institutional Committee before commencement.

Results

The characteristics of the 34 HIV-infected patients with anaemia are shown in Table 1. The mean age was 37 years and ranged from 23 to 53 years. Men and women were equally distributed in the study group, and approximately half of the HIV-infected patients were taking antiretroviral medication. The mean haemoglobin and haematocrit levels of the patients were 9.4 g/dL and 28%, respectively. Our patients presented a mean CD4 lymphocyte count of 235 cells/mm³ (range from 6–1035 cells/mm³). Nineteen (56%) and 12 (35%) patients presented with a dietary intake of folate and iron, respectively, below the level of the US recommended dietary allowance (RDA)

The results of the iron, folate and vitamin B12 analyses of the sample are presented in Table 2. Low serum folate levels were found in 14 (41%) HIV-infected patients; parameters of iron deficiency, such as low transferring saturation index and ferritin, were found in 10 (30%). Combined folate and iron deficiency were found in five (14%) patients. Those with iron deficiency presented a low mean corpuscular volume (MCV), even though 50% were taking antiretroviral medications such as zidovudine, lamivudine and stavudine that frequently increase the MCV. Vitamin B12 deficiency was seen in only two (6%) patients who presented with MCV within the normal range.

Discussion

Anaemia may result from the indirect effects of HIV infection, such as adverse reactions to medications, opportunistic infections, neoplasms, or nutritional abnormalities stemming from anorexia, malabsorption or metabolic disorders. ⁵ Although many drugs used to treat HIV-related disorders are myelosuppressive, severe anaemia is most often related to the use of zidovudine. Alterations in the components of normal erythropoiesis, which include an adequate supply of iron, folate and vitamin B12, intact bone marrow and the essential hematopoietic growth factor, erythropoietin, may produce anaemia. Multivitamin supplements provided during pregnancy and in the postpartum period results in significant improvements in the haematological status among HIV-infected women and their children. This provides further support for the value of multivitamin supplementation in HIV-infected adults. ⁶

Folate and iron deficiencies were the most common causes of anaemia in our HIV-infected patients, followed by vitamin B12 deficiency in a small proportion. In contrast to folate deficiency, iron deficiency has been commonly noted in HIV-infected and non-HIV-infected patients, especially in pregnant women and infants, in developing countries in Africa. ^7,8 Our findings of folate and iron deficiency related anaemia were in agreement with the low daily folate intake of our patients. Interestingly, fruits and vegetables, the main source of folate, are not the main components of the daily diet of our patients from southern Brazil. In contrast, the excellent sources of iron, such as beans, poultry and meat, are important components of the diet in Brazil. Whether iron deficiency in this population was primarily the result of dietary insufficiency or problems with absorption, is difficult to establish.

The characteristically high mean corpuscular volume for folate and vitamin B12 deficiency were not observed in our patients. In fact, in patients with either vitamin B12 or folate deficiency, the MCV tended to increase before the haemoglobin level decreased significantly. ⁹ However, even when there is biochemical evidence of vitamin deficiency, the MCV often remains within the reference range, especially if concurrent iron deficiency or thalassemia is present. The MCV also lacks specificity for the diagnosis of vitamin B12 or folate deficiency. In a study of 100 patients with an MCV greater than 115 fL (much higher than the usual upper limit of the reference range), only 50% had subnormal values of serum vitamin B12, erythrocyte folate, or both and only an MCV of 130 fL or higher was found to reliably predict the presence of low vitamin levels. ¹⁰

Conclusion

Our study has shown that folate and iron deficiencies were frequently detected in HIV-infected patients from our institution, and should be considered in the differential diagnosis of anaemia in HIV-infected patients independent of their HIV stage of progression. MCV was not a very useful parameter in the initial assessment, especially of folate deficiency, and therefore measurements of folate serum levels should be routinely performed in HIV-infected patients in developing countries such as Brazil.