Iron deficiency anemia (IDA) is the most common. IDA, several changes in platelets have been reported. So, a relationship between iron metabolism and

Transcription

1 Platelet Parameters in Women with Iron Deficiency Anemia Gurhan Kadikoylu, MD; Irfan Yavasoglu, MD; Zahit Bolaman, MD; and Taskin Senturk, MD Aydin, Turkey Background: In iron deficiency anemia (IDA), several changes in platelets have been reported. Therefore, a relationship between iron metabolism and thrombopoiesis should be considered. The aim of this study was to evaluate the platelet parameters in women with IDA. Materials and Methods: Eighty-six women of mean age 37 ± 13 (16-70) years with IDA were enrolled this study. The relationship between serum iron parameters (such as iron, iron-binding capacity, iron saturation and fenitin) and platelet parameters (such as platelet counts, platelet crit, mean platelet volume and platelet distribution width) were evaluated by using Pearson correlation and stepwise logistic regression tests. Results: Thrombocytosis and thrombocytopenia were noted in 24 (27.9%) and two (2.3%) patients, respectively. Platelet counts were increased when serum iron, iron saturation, ferritin and mean platelet volume were decreased in this study. There was a linear relationship between platelet counts and platelet crit (p<0.001) but inverse relationships between platelet counts and both mean platelet volume and iron saturation (p<0.001, for both). Also there were a linear relationship between platelet distribution width and mean platelet volume (p<0.001) and an inverse correlation between platelet distribution width and mean corpuscular volume (p<o.o01). We did not find any correlation between platelet crit and studied iron parameters (p). Conclusions: In IDA, the most important factor affecting platelet counts was iron saturation. These changes in the platelet parameters may be related to low levels of tissue iron. This study suggested that decreased iron saturation might stimulate megakaryopoiesis. Moreover, iron may have an inhibitor effect on platelet counts. Key words: iron deficiency anemia U platelets U women U thrombocytosis From Adnan Menderes University Medical Faculty, Divisions of Hematology (Kadikoylu, associate professor; Yavasoglu, fellow in Hematology; Bolaman, professor) and Immunology (Senturk, professor), Aydin, Turkey. Send correspondence and reprint requests forj NatI Med Assoc. 2006;98: to: Dr. Gurhan Kadikoylu, Associate Professor, Adnan Menderes University Medical Faculty, Division of Hematology, Aydin, Turkey; phone: ; fax: ; gurhan@medscape.com INTRODUCTION Iron deficiency anemia (IDA) is the most common hematological disorder in the community.' In IDA, several changes in platelets have been reported. So, a relationship between iron metabolism and thrombopoiesis should be considered.23 A diphasic pattern of platelet response was noted in patients with IDA. Moderate IDA is usually associated with reactive thrombocytosis.4-6 Thrombocytopenia can be seen in patients with severe IDA, especially when hemoglobin level is <7 g/dl.3'7-9 Both thrombocytosis and thrombocytopenia may disappear after iron supplementation.5-8 Several studies reported an inverse relationship between mean platelet volume and platelet counts in patients with IDA.9-4' This may be related to morphological features of platelets. To the best of our knowledge, there was no such detailed previous study on platelet and iron parameters. The aim of this study was to evaluate the platelet parameters in women with IDA. MATERIALS AND METHODS Patients This study was performed at Adnan Menderes University Medical Faculty, Division of Hematology, Aydin, Turkey. Eligible female patients with IDA were enrolled in this prospective study. The inclusion criteria were: hemoglobin level <12 g/dl, serum ferritin level <15,tg/L, iron saturation <16%, and correction of anemia after iron supplementation. Patients with acute hemorrhage and infections, neoplastic and chronic inflammatory disorders such as rheumatoid arthritis, ankylosing spondylitis and systemic lupus erythematosus were excluded. Informed consents were obtained from all patients. Methods Blood specimens for hematological parameters, including hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean cor- 398 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 98, NO. 3, MARCH 2006

2 puscular hemoglobin concentration, red blood cell counts, red cell distribution width, white blood cell counts, platelet counts, platelet crit, mean platelet volume and platelet distribution width, were collected in tubes with EDTA and were analyzed after 1-2 hours. These tests were determined with Coulter Counter STKS.'2 Blood specimens for serum iron parameters, including serum iron, iron-binding capacity, iron saturation and ferritin, were collected in tubes without anticoagulant and were analyzed after 4 hours. These tests, with the exception of ferritin, were measured by spectrophotometric method and ILAB-900 instrument.'3 Serum ferritin level was measured by chemiluminescent method and Immulite instrument.'4 The hemoccult slide test was used for three consecutive days for the determination of chronic silent bleedings in both groups. Rectosigmoidoscopy, upper-gastrointestinal endoscopy and gynecological examinations were performed in all patients for the determination of the bleeding foci. STATISTICAL METHODS Data were recorded and analyzed using SPSS Values were shown as means ± standard deviation. The correlation of platelet counts, platelet crit, mean platelet volume and platelet distribution width with other variables, including hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red blood cell and white blood cell counts, serum iron, iron-binding capacity, iron saturation and ferritin, were analyzed by Pearson's correlation test (r> and p<o.o5). Stepwise logistic regression test was performed for each significant correlation between platelet parameters and the studied variables. P values <0.05 were considered as statistically significant. PLATELET PARAMETERS AND IRON DEFICIENCY ANEMIA RESULTS Patients Eighty-six women of mean age (16-70) years with IDA were enrolled. In the etiology of IDA, chronic gastrointestinal blood loss due to hemorrhoid, peptic ulcus, polyp and vaginal blood loss due to myoma uteri; and dysfunctional hemorrhage of uterus were detected in 38 and 44 patients, respectively. Any cause was not found in four patients. Table 1 summarizes the hematological data of patients, while the results of Pearson's correlation and stepwise logistic regression tests are shown in Tables 2 and 3, respectively. Platelet counts were normal in 60 patients with IDA. Thrombocytosis and thrombocytopenia were detected in 24 (27.9%) and two (2.3%) patients, respectively. When Pearson's correlation test was performed, inverse correlations between platelet counts and hemoglobin, hematocrit, mean platelet volume, ferritin, iron saturation, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration; and linear correlations between platelet counts and platelet crit, red cell distribution width were determined. In the stepwise logistic regression test, there was a linear relationship between platelet counts and platelet crit (p<o.ool) but inverse relationships between platelet counts and both mean platelet volume and iron saturation (p<0.001, for both). There was no correlation between platelet counts and studied other iron parameters (p). Table 1. Hematological data in patients with iron deficiency anemia Hematological Parameters Patients (n=86) Normal Values White blood cell counts (x103/pl) 6.4 ± Red blood cell counts (x103/pl) 2.8 ± Hemoglobin (g/dl) 10.3 ± Hematocrit (%) 32.0 ± Mean corpuscular volume (fl) 70.7 ± Mean corpuscular hemoglobin (pg) 23.4 ± Mean corpuscular hemoglobin concentration (g/dl) 32.4 ± Red cell distribution width (%) 16.5 ± Platelet counts (x103/pl) 326 ± Mean platelet volume (fl) 8.7 ± Platelet crit (%) 0.28 ± 0.07 Platelet distribution width (%) 16.6 ± 0.6 Serum iron (pg/dl) Iron saturation (%) 4.4 ± Iron-binding capacity (pg/dl) ± Ferritin (pg/l) JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 98, NO. 3, MARCH

3 In the correlation test, inverse correlations between platelet crit and ferritin, serum iron, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration; and linear correlation between platelet crit and platelet counts, red cell distribution width, iron-binding capacity were detected. In the logistic regression test, an inverse relationship between platelet crit and mean corpuscular volume (p<0.05), and a linear relationship between platelet counts and platelet crit (p<0.001) were confirmed. There was no correlation between studied iron parameters and platelet crit (p>o.o5). Although linear correlations between mean platelet volume and both hematocrit and platelet distribution width, and an inverse correlation between mean platelet volume and platelet counts were noted in correlation test, only the relationship between mean platelet volume and platelet distribution width was confirmed by logistic regression test (p<0.001). In correlation test, linear correlations between platelet distribution width and both mean corpuscular volume and mean corpuscular hemoglobin concentration, and an inverse correlation between platelet distribution width and mean platelet volume were detected. Logistic regression test confirmed only the inverse relationship between platelet distribution width and mean corpuscular volume (p<0.001). We did not find a relationship between platelet distribution width and studied iron parameters (p). DISCUSSION Platelet counts were increased when serum iron, iron saturation, ferritin and mean platelet volume were decreased in this study. There was an inverse relationship between platelet counts and iron saturation, but no relationship between platelet counts and studied other iron parameters was noted. Moreover, there was no relationship between the iron parameters such as serum iron, iron-binding capacity, ferritin and the platelet parameters such as platelet crit, mean platelet volume and platelet distribution width. The duration and the degree of IDA may play a role in determining the mechanism of platelet production. It was reported that megakaryopoiesis was stimulated in IDA. In moderate IDA, the causes of thrombocytosis may be: 1) increased rate of influx of precursor cells into the megakaryocyte compartment with an increased rate of efflux; 2) shortening of megakaryocyte maturation; 3) stem-cell shunt due to inhibition of erythropoiesis, resulting in increased production of other pluripotent cells (hemostatic compensatory mechanism); 4) stimulator effect of transferrin on megakaryopoiesis; and 5) inhibition of iron on megakaryocyte maturation In our study, although serum iron and ferritin levels had effects on platelet counts, iron saturation was the most important determinant ofplatelet counts in IDA. This study suggested that decreased iron saturation might stimulate megakaryopoiesis. Moreover, iron may have an inhibitor effect on platelet counts. In recent studies, it was reported that increased levels of endogenous erythropoietin (Epo) would stimulate megakaryopoiesis in moderate IDA, whereas high Epo response could cause thrombocytopenia in severe IDA.4'5'8 While Epo therapy increases platelet counts initially, higher Epo doses cause thrombocytopenia in humans and rats with chronic renal failure.5'8"8 In severe IDA, as Table 2. The results of Pearson's correlation test in patients with iron deficiency anemia Parameters Serum Iron Iron Saturation Iron-Binding Capacity Ferritin r p < <0.05 r p < < r p <0.05 r p JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 98, NO. 3, MARCH 2006

4 Table 3. Stepwlse logistic regression test in patients with iron deficiency anemia Mean Platelet Mean Platelet Platelet Platelet Distribution Corpuscular Iron Parameters Counts Crit Volume Width Volume Saturation B p - <0.001 < <0.001 B p < <0.05 B p < < B p - - < <0.001 megakaryocyte numbers decrease, megakaryocyte sizes increase. This may be due to the shortening of megakaryocyte maturation and the reduction in influx ofprecursors.15"6 In two patients with thrombocytopenia, hemoglobin levels were <6.5 g/dl. Although we did not measure it in this study, thrombocytopenia might be related to high serum Epo levels. The relationship between platelet counts and mean platelet volume has been of special interest in IDA and healthy persons in literature.9-""'9-2' In some studies, an inverse correlation between platelet counts and mean platelet volume, and a linear correlation between platelet counts and platelet crit were detected.9'20,22-25 In rats with moderate IDA, an increase in megakaryocyte polyploidy formation had been detected by using megakaryocyte labeling index. However, no changes in either megakaryocyte numbers or sizes had been shown. As megakaryocyte sizes increase, labeling and mitotic index and megakaryocyte numbers decrease in severe IDA. This may suggest that higher polyploidy of megakaryocytes and production of more platelets per cell result with maintenance of circulating platelet mass. For this reason, megakaryocyte size is proportional to polyploidy and cytoplasmic mass. "1'5,1621,26 On the other hand, a 35% decrease in megakaryocyte number can cause a 40% increase in megakaryocyte size and ploidy."1"6 In one clinical study, while platelet distribution width in patients with IDA was higher than controls, mean platelet volume was not different.27 In this study, mean platelet volume and platelet distribution width in patients with 13-thalassemia trait were higher than both controls and IDA. It was interpreted as peripheral destruction of red blood cells. In our study, inverse correlation between platelet counts and mean platelet volume and linear correlations between platelet crit and mean platelet volume, platelet distribution width and mean platelet volume might be due to shortened maturation time and increased polyploidy of megakaryocytes with normal lifespan, as it is well known that the youngest platelets have the largest size.6',0"' However, we were unable to explain the inverse relationships between platelet crit, platelet distribution width and mean corpuscular volume. The limitations of the study were to not reevaluate statistical analysis of significant parameters in the end of treatment and there were no groups such as thalassemia and megaloblastic anemia to compare platelet parameters with iron parameters in this study. In conclusion, both thrombocytosis and thrombocytopenia may occur in IDA. Thrombocytosis is more evident in patients with lower iron saturation. Several changes between platelet parameters may be related to the morphological features of platelets. The most important factor affecting platelet counts was iron saturation in women with IDA. As iron saturation was decreased, platelet counts were increased. These changes in the platelet parameters may be related to low levels of tissue iron. REFERENCES 1. Beutler E, Hoffbrand AV, Cook JD. Iron deficiency and overload. Hematology (Am Soc Hematol Educ Program). 2003; Dincol K, Aksoy M. On the platelet levels in chronic iron deficiency anemia. Acta Hoemotol. 1963;41: Sonneborn D. Thrombocytopenia and iron deficiency. Ann Intern Med. 1974;80: JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 98, NO. 3, MARCH

5 4. Akan H, Guven N, Aydogdu 1, et al. Thrombopoietic cytokines in patients with iron deficiency anemia with or without thrombocytosis. Acta Haematol. 2000;103: Beguin Y. Erythropoietin and platelet production. Haematologica. 1999; 84: Hicsonmez G, Suzer K, Suluoglu G, et al. Platelet counts in children with iron deficiency anemia. Acta Haematol. 1978;60: Perlman MK, Schwab JG, Nachman JB, et al. Thrombocytopenia in children with severe iron deficiency. J PediatrHematol Oncol. 2002;24: Loo M, Beguin Y. The effect of recombinant human erythropietin on platelet counts is strongly modulated by adequacy of iron supply. Blood ;93: Levin J, Bessman JD. The inverse relation between platelet volume and platelet number. Abnormalities in hematologic disease and evidence that platelet size does not correlate with platelet age. J Lab Clin Med. 1983; 101: Giles C. The platelet count and mean platelet volume. Br J Hoematol. 1981;48: Bessman JD, Gilmer PR, Gardner FH. Use of mean platelet volume improves detection of platelet disorders. Blood Cells. 1985;1 1: Brittin GM, Grecher G, Johnson CA. Evaluation of Coulter Counter. Am J Clin Pathol. 1969;52: Worwood M. The laboratory assessment of iron status an update. Clinical Chimica Acta. 1997;259: Grail A, Hancock BW, Harrison P. Serum ferritin in normal individuals and in patients with malignant lymphoma and chronic renal failure measured with seven different 2;~~~~~~~~~~~~~~~~~~~~~~~~~~~..st-4MM... commercial techniques. J Clin Pathol ;35: Choi S, Simone JV. Platelet production in experimental iron deficiency anemia. Blood. 1974;42: Choi Si, Simone JV, Jackson CW. Megakaryocytopoiesis in experimental iron deficiency anemia. Blood. 1974;43: NMANational Association 1012 Tenth Street, N.W. * Washington, D.C For Regtat _ 'i. 17. Stenberg PE, Hill RJ. Platelets and megakaryocytes. In: Lee GR, Foerster J, Lukens J, et al, eds. Wintrobe's Clinical Hematology. Baltimore, Williams Wilkins, 1Oth ed. 1999: Eschbach JW, Abdulhadi MH, Browne JK, et al. Recombinant human erythropoietin in anemic patients with end-stage renal disease. Results of a phase Ill multicenter clinical tral. Ann Intem Med. 1989;1 1 1: Saga T, Aoyama T, Takekokoshi T. Changes in the number and volume of platelets in male elderly persons and effects of various factors on them. Nippon Konen lgakkai Zasshi. 1995;32: Graham SS, Traub B, Mink IB. Automated platelet sizing parameters on a normal population. Am J Clin Pathol. 1987;87: Bessman JD. The relation of megakaryocyte ploidy to platelet volume. Am J Hematol. 1984;1 6: Bain BJ. Platelet count and platelet size in males and females. Scand J Haematol. 1985;35: Lamparelli RD, Baynes RD, Atkinson P, et al. Platelet parameters Part 1. Platelet counts and mean platelet volume in normal and pregnant subjects. S Afr Med J. 1988;73: Lozano M, Narvaez J, Faundez A, et al. Platelet count and mean platelet volume in the Spanish population (Abstract). Med Clin. 1998; 110: Kurekci AE, Atay AA, Sarci SU, et al. Effect of iron therapy on the whole blood platelet aggregation in infants with iron deficiency anemia. Thromb Res. 2000;97: Kellar KL, Bridges NB, Monroe MC, et al. Maintenance of normal platelet mass in anemic Belgrade rats and their response to iron. Exp Hematol. 1990;18: Timuragaoglu A, Coban A, Erbasan F. The importance of platelet indexes in discriminating between B-thalassemia trait and iron deficiency anemia. Acta Haematol. 2004;1 1 1: A lme ical Annual Convention & Scientific Assembly AUGUST 5-10, 2006 Dallas,8-2C Housing information contact: ~~~~~ I w 1~~~~~~~~~~~~~~~~~~~~~1 For more information, visit www MAnetorg 402 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 98, NO. 3, MARCH 2006