Development of a clinical prediction rule for iron deficiency anemia in pregnancy

doi:10.1016/j.ajog.2004.12.008

American Journal of Obstetrics and Gynecology

Volume 193, Issue 2, August 2005, Pages 460-466

https://doi.org/10.1016/j.ajog.2004.12.008 Get rights and content

Objective

The purpose of this study was to elucidate if anemia in pregnancy caused by iron deficiency could be predicted by simple measures obtained on a complete blood count (CBC) using ferritin as the gold standard.

Study design

One hundred forty-one pregnant patients with anemia were recruited during their first prenatal visit. CBC and ferritin level were obtained and candidate-predictors identified. Receiver operator characteristic (ROC) curves, stratified analysis, and logistic regression analysis were used to develop a prediction rule with maximum specificity.

Results

A hemoglobin level ≤9.7 and a red cell distribution width (RDW) ≥15 (in gestational age <20 weeks) predicted iron deficiency with high specificity. Our final model correctly classified 79.43% of the patients (area under the ROC curve of 0.88 [95%CI 0.82–0.93], specificity of 95.74%).

Conclusion

Iron deficiency anemia can be predicted in pregnancy using lower cost tests, which could be an incredibly useful tool in areas with limited resources and a high prevalence of the disease. This study was limited to a mostly African American population in an urban setting, and the results may not be generalized to other populations.

Section snippets

Material and methods

The study population included all patients who visited the resident's clinic at the Hospital of the University of Pennsylvania (HUP) for first prenatal visit between October of 2002 and April of 2003. These patients were asked for their written consent to participate in our study. The written consent was obtained before screening for anemia, and from all patients who came to the resident's clinic. This study was approved by the hospital's Institutional Review Board (IRB). Our sample size was

Results

The mean hemoglobin level of the subjects included in our final cohort was 10.1 mg/dL (SD=0.8). Forty-seven subjects of our total cohort were considered iron deficient (33.3%), and 94 (66.7%) non-iron deficient, based on the level of ferritin. The characteristics of our final cohort are depicted in Table I. For 23.4% of our patients (n = 33), this was their first gestation. Likewise, 29.8% of our patients (n = 42) did not have a previous delivery (term or preterm). The mean age of our overall

Comment

Given the high prevalence of IDA in pregnancy, and the fact that it is customary in many parts of the world to treat empirically pregnant anemic patients with iron supplements, our study did not focus on achieving the most sensitivity, but was designed to reach maximum specificity for diagnosing IDA using easily collected and measured parameters obtained on a CBC. We found 2 useful candidate predictors for iron deficiency anemia in pregnancy, a RDW ≥15 and a Hb <9.7 mg/dL. Although a level of

Acknowledgments

This study was approved by the Institutional Review Board (IRB) of the Hospital of the University of Pennsylvania on August 25, 2002, Protocol #706618. Dr Casanova was supported by an Award from the National Institutes of Health funded by the Fogarty International Center and The National Institute of Child Health and Human Development (NICHD), grant # D43-TW01272. Dr Macones is supported by a Mid-Career Award in Patient Oriented Research from NICHD, grant # K24 HD01289. The authors would like

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Cited by (27)

Evaluation of hemoglobin performance in the assessment of iron stores in feto-maternal pairs in a high-risk population: Receiver operating characteristic curve analysis
2015, Revista Brasileira de Hematologia e Hemoterapia
Citation Excerpt :
It is important to emphasize that the results of similar studies in other populations vary widely. A correlation between Hb and SF was found in a study in African-American patients17 and a similar study carried out in Malaysia.18 These studies concluded that the use of Hb as a predictor of ID is an efficient and low cost alternative for countries with high prevalence of the disease and with limited resources and thus cannot afford to measure SF.
By applying receiver operating characteristic curve analysis, the objective of this study was to see whether hemoglobin levels reflect body iron stores in a group of pregnant women at term who, by using serum ferritin as the reference test, had a high pre-test probability of having iron deficiency anemia. Likewise, we evaluated the ability of hemoglobin and maternal serum ferritin levels to predict iron deficiency anemia in newborns.
Hemoglobin and serum ferritin were measured in 187 pregnant women at term belonging to a group with a high pre-test probability of iron deficiency anemia and their newborns. Women with Hb <11.0 g/dL and newborns with cord Hb <13.0 g/dL were classified as anemic. A serum ferritin <12.0 μg/L in women and a cord blood serum ferritin <35.0 μg/L were considered to reflect empty iron stores. Receiver operating characteristic curve analysis was applied to select the cut-off points that better reflected iron stores.
The Hb cut-off point selected by receiver operating characteristic curve analysis in women was <11.5 g/dL (sensitivity: 60.82, specificity: 53.33%, Youden Index: 0.450). Most of the newborns had normal Hb which precluded this analysis. Maternal Hb <11.0 g/dL was the cut-off point that best reflected iron deficiency anemia in newborns (sensitivity: 55.88%, specificity: 57.24%, Youden Index: 0.217). The best cut-off point of maternal serum ferritin to reflect empty iron stores in newborns was <6.0 μg/L (sensitivity: 76.47%, specificity: 31.58%, Youden Index: 0.200).
Hemoglobin concentration performed poorly to detect iron deficiency anemia in women at term with high risk for iron deficiency and their newborns.
Anemia as a surgical risk factor
2013, Medicina Clinica
La anemia perioperatoria es frecuente en los pacientes quirúrgicos y se asocia a un aumento de la morbimortalidad y disminución de la calidad de vida. Las causas principales de anemia en el contexto perioperatorio son el déficit de hierro y la inflamación crónica.
En el postoperatorio, la anemia puede ser agravada por la pérdida sanguínea del intraoperatorio siendo la transfusión alogénica el método más habitual de tratamiento. Por otro lado, la transfusión de sangre no está exenta de riesgos, aumentando de nuevo la morbilidad y mortalidad de los pacientes. Dada la preocupación que esto genera, nos proponemos revisar la fisiopatología de estas anemias en el entorno quirúrgico así como su tratamiento mediante la ingesta de alimentos ricos en hierro, terapia con hierro oral e intravenoso (hierro sacarosa y carboximaltosa de hierro). En la anemia de tipo inflamatorio crónico utilizamos agentes estimulantes de la eritropoyesis (eritropoyetina alfa) y en casos de anemias mixtas la combinación de ambos tratamientos.
El objetivo siempre es reducir la necesidad de la transfusión perioperatoria y acelerar la recuperación de la anemia postoperatoria así como disminuir la tasa de morbimortalidad de los pacientes
Perioperative anemia is common in patients undergoing surgery and is associated with increased morbidity and mortality and a decreased quality of life. The main causes of anemia in the perioperative context are iron deficiency and chronic inflammation.
Anemia can be aggravated by blood loss during surgery, and is most commonly treated with allogeneic transfusion. Moreover, blood transfusions are not without risks, once again increasing patient morbidity and mortality. Given these concerns, we propose to review the pathophysiology of anemia in the surgical environment, as well as its treatment through the consumption of iron-rich foods and by oral or intravenous iron therapy (iron sucrose and iron carboxymaltose). In chronic inflammatory anemia, we use erythropoiesis-stimulating agents (erythropoietin alpha) and, in cases of mixed anemia, the combination of both treatments.
The objective is always to reduce the need for perioperative transfusions and speed the recovery from postoperative anemia, as well as decrease the patient morbidity and mortality rate.
Anemia - Prevalence and risk factors in pregnancy
2012, European Journal of Internal Medicine
Citation Excerpt :
Moreover, few data concern southern European countries, in which a high frequency of genetic disorders may be a confounding factor in assessment of the prevalence of iron deficiency anemia, when based only on determination of hemoglobin concentration [16]. The use of ferritin as the gold standard for iron stores examination has been extensively studied in the last decades, and in today's practice it is still considered the gold standard [28]. In women, medians of serum ferritin levels vary according to country, from 24 to 35 μg/l, corresponding to true levels of iron stores of 240 to 350 mg [29].
To assess the prevalence of decreased iron stores and anemia in pregnant women. To determine whether the risk factors: socio-demographic background, age, BMI, and parity are associated with abnormal hemoglobin concentrations and/or abnormal iron status.
A longitudinal study was carried out at the Department of Obstetrics, University Hospital of Zurich to establish the risk factors and prevalence of the decreased iron stores and anemia in early pregnancy. In order to determine the hematological parameters and ferritin levels, venous blood samples of 470 singleton pregnancies between 16 and 20 pregnancy weeks were collected. According to hemoglobin and iron status, the patients were divided into four groups: patients with iron deficiency anemia, patients with decreased iron stores, patients with anemia for other reasons and normal patients. The determinants socio-demographic background, age, BMI and parity were explored using multiple logistic regression analysis.
The prevalence of decreased iron stores (ferritin < 20 μg/l) was observed in 31.8% of subjects (149/470) and anemia (Hb < 110 g/l) in 18.5% (87/470). The prevalence of iron deficiency anemia was higher among women coming from former Yugoslavia and developing countries (p = 0.004 and p = 0.012). In patients coming from developing countries, a significant increase of anemia for other reasons was observed (p = 0.027) and in patients older than 30 years, a significant increase of decreased iron stores (p = 0.018).
In our study population with low parity, the prevalence of abnormal hemoglobin and abnormal iron status was 50.2% (236/470), and socio-demographic background was the most important risk factor of anemia.
Thalassemia and hemoglobinopathies rather than iron deficiency are major causes of pregnancy-related anemia in northeast Thailand
2006, Blood Cells, Molecules, and Diseases
A cross-sectional prevalence study of anemia was undertaken on 412 pregnant women in northeast Thailand during January 2003 to May 2004. With standardized diagnostic protocols and the CDC criteria of anemia [hemoglobin (Hb) <11 g/dl at ≤12 weeks of gestation and Hb <10.5 g/dl at ≤20 weeks of gestation], 71 (17.2%) subjects were anemic. Of these, 42 (59.2%) subjects had thalassemia, 5 (7.0%) had iron deficiency, 18 (25.4%) had combined thalassemia and iron deficiency and 6 (8.5%) had no thalassemia nor iron deficiency. Adjusted logistic regression analyses indicated that various thalassemia genotypes were significantly related to anemia, while homozygous Hb E had the highest risk with an odds ratio (OR) of 44.8 (95% CI 12.6–159.7). In comparison, iron deficiency demonstrated a much lower risk with OR of 3.1 (95% CI 1.4–6.8). This finding suggests that the contribution of iron deficiency to pregnancy associated anemia in this region is low.
The Nutritional Habits and Relationship Between The Antioxidant Activity and Iron Deficiency Anemia During Pregnancy
2022, Eastern Journal of Medicine
Factors associated with inadequate iron stores in women in the first trimester of pregnancy
2021, Revista Chilena de Nutricion

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General Obstetrics and Gynecology: ObstetricsDevelopment of a clinical prediction rule for iron deficiency anemia in pregnancy

Objective

Study design

Results

Conclusion

Section snippets

Material and methods

Results

Comment

Acknowledgments

J Nutr

Int J Gyn Ob

J Clin Epidemiol

Lancet

Lancet

Strategies of the Pan American Health Organization/World Health Organization fore the control of Iron deficiency in Latin America

Nutr Reviews

Effect of iron supplementation on serum ferritin levels during and after pregnancy

BJOG

Absorption of non-haem iron from food during normal pregnancy

BMJ

General Obstetrics and Gynecology: Obstetrics
Development of a clinical prediction rule for iron deficiency anemia in pregnancy