Natl. J. Physiol. Pharm. Pharmacol. (2025), Vol. 15(1): 93–97

Research Article

10.5455/NJPPP.2025.v15.i1.16

Role of red cell distribution width in the evaluation of anemia in children aged less than 12 years

Shyamnath Athikkuzhiyil Viswanathan^1* and Anne Varghese²

¹Malankara Orthodox Syrian Church Medical College, Kolenchery, India

²Department of Physiology, Malankara Orthodox Syrian Church Medical College, Kolenchery, India

*Corresponding Author: Shyamnath Athikkuzhiyil Viswanathan. Malankara Orthodox Syrian Church Medical College, Kolenchery, India. Email: shyamnadhan [at] gmail.com

Submitted: 07/12/2024 Accepted: 28/12/2024 Published: 31/01/2025

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ABSTRACT

Background: From the viewpoint of healthcare, anemia is one of the major health problems in India. Early diagnosis and treatment of anemia are crucial for a healthier generation. Studies have shown that red cell distribution width (RDW) values have a potential relation with anemia.

Aim: To determine the association between RDW and anemia and to study the correlation between RDW and anemic status in different age groups.

Methods: Cross-sectional study design and standard statistical methods were used. Sensitivity, specificity, and receiver operating characteristics (ROC) were determined.

Results: Out of 245 children studied, The first category (up to 6 years) and the second category (6–12 years) include 132 children (54%) and 113 children (46%), respectively. Sensitivity and specificity were obtained using ROC curves with a cut-off RDW of 14.05% and 12.95% in the two age groups, respectively. Anemic status was categorized according to hemoglobin (Hb) levels in the two age groups. Patients with Hb levels below the WHO cutoff values are considered anemic. Pearson correlation coefficient calculation observed that there was a weak negative correlation (−0.24) between Hb and RDW (p=0.012). There was a moderate negative correlation (−0.3) between MCV and RDW (p=0.001).

Conclusion: As a diagnostic test, RDW alone was more specifically and sensitively associated with the detection of anemia in children aged 6 years compared with RDW in children aged 6–12 years. There was a weak negative correlation between Hb and RDW.

Keywords: RDW, Children, Anemia, Hemoglobin.

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Introduction

Anemia is one of the most common health problems in a developing country like India. Studies have shown that the prevalence of anemia in young children has been on a plateau of approximately 79% since more than 10 years and has declined due to active intervention from the administration. However, it persists as one of the most common medical conditions.

The most common cause of anemia is generally nutritional, but other factors like low birth weight, early cord clamping, other infections, maternal anemia, prevalence of malaria, Helicobacter pylori infection, helminthic infection, poverty, and poor access to iron-rich foods, also play an important role in the development of anemia. The critical stage of human development is during early life, and any physical or psychological damage during this period results in sustained effects on their stages of life (Schauer and Zlotkin 2003; Karimi et al., 2014; Anbaran et al., 2015; Khosravi Anbaran et al., 2016; Khadivzadeh et al., 2016). During early childhood, inaccurate feeding habits, mainly during weaning, increases the problem. Anemia occurs when breast milk is replaced by other foods that are low in vitamin B12, Iron, folic acid, and other nutrients (Santos et al., 2011). The consequence of anemia is mainly low oxygenation of brain tissue, which leads to decreased cognitive functions, impaired growth, developmental mile stones, and psychomotor development (Walter et al., 1989). Overall, the effect of anemia in children extends from impaired immunity at one end to scholastic and language development at the other end (Saroja et al., 2014). Studies show that red cell distribution width (RDW) values have a potential relation with anemia (Sazawal et al., 2014). Red cell distribution width is a laboratory determination of the anisocytosis of red cells, which is displayed by automated blood analyzers in modern laboratories. The RDW represents the coefficient of variation of the distribution of red blood cell volume. Anemia has become a major health problem in developing countries, and its prevalence has increased in many parts of India. In India, 89 million preschool children suffer from anemia (McLean et al., 2009).

According to the World Bank data, the prevalence of anemia among children under 5 years old in India was 57% in 2016 (Prevalence of anemia among children (% of children under 5). According to National Family Health Survey data, the prevalence of anemia among children aged 6–59 months who are anemic (Hb<11 g/dl) was 35.7% (National Family Health Survey). Various studies conducted in European countries have shown that RDW can be a screening tool for iron deficiency anemia and thalassemia. Studies have also reported increased RDW values in hemolytic anemia (Qurtom et al., 1989; Kotwal et al., 1999).

Some studies have revealed the high sensitivity of RDW for the screening of anemia (96%–100%) (Das Gupta et al., 1994). Along with other blood parameters like serum iron, serum ferritin, total iron binding capacity, hemoglobin (Hb), electrophoresis, RDW can be used to confirm anemia (Aulakh et al., 2009; Choudhary et al., 2015). International studies have shown the cost effectiveness of RDW in the early diagnosis of anemia, especially iron deficiency anemia, with appropriate accuracy and minimum testing methods (Aulakh et al., 2009; Nadeem et al., 2012).

On the threshold of this background, the attempt here is to study the utility of RDW in screening and categorizing anemia in children aged 12 years for better follow-up and case management.

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Materials and Methods

The cross-sectional study was conducted over a period of 2 months in 2018 involving children aged up to 12 years. Children aged below 12 years with congenital and cardiac disorders were excluded from the study. All data were maintained confidential. Approval to use medical records and waiver of informed consent were obtained. The sample size was calculated using the following formula:

4PQ/L2

P=62%, prevalence (Behera and Bulliyya 2016)

Q=100-p

L=10% of p (allowable error).

245 children up to 12 years old who satisfied the inclusion and exclusion criteria were included. Data on RDW, Hb (fluorescent flow cytometry), MCV Values, hospital number, age, and other relevant data were collected from the automated blood analyzer (SYSMEX XN 550) and from medical records. After data collection, statistical analysis was performed. Children were categorized into two age groups (Group 1; up to 6 years, Group 2; 6–12 years). Patients with Hb levels less than WHO standards for age were categorized as anemic (WHO 2001). (Table 1).

The severity of anemia was categorized based on Hb values. Receiver operating characteristic analysis was performed to determine the efficacy of RDW in predicting anemic status separately for different age groups. As data follows normality, the Pearson correlation coefficient method was performed and the correlation between Hb and RDW and between MCV and RDW were analyzed. R SOFTWARE was used for the statistical analysis.

Table 1. Haemoglobin concentration (g/dl) for the diagnosis of anemia and severity assessment according to WHO/UNICEF/UNU.

Fig. 1. Group 1 (up to 6 years).

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Results

The 245 children were categorized into two age groups. The first Group (up to 6 years) included 132 children (54%), and the second Group (6–12 years) included 113 children (46%). To find the association between RDW and anemia, we used the ROC curve analysis (Figs. 1 and 2), from this, the area under the curve for the RDW value for Group 1 was 84.1% with a sensitivity and specificity of 77% and 75%, respectively, and the optimum cut-off value of RDW was 14.05%. The area under the curve for Group 2 was 60%, with sensitivity and specificity of 60% and 54%, respectively, and the optimum cut-off value of RDW was 12.95% (Table 2).

Patients with Hb levels below the WHO cutoff values were considered anemic in the two age groups. In Group 1, 30 children (out of 132) were anemic and in Group 2, 20 children (out of 113) were anemic (Table 3). The severity of anemia was further evaluated. Moderate anemia was found to be more frequent in Group 1 than in Group 2 (Fig. 3).

From Pearson correlation coefficient calculation, it was observed that there was a weak negative correlation (−0.24) between Hb and RDW (p=0.012). It was also observed that there was a moderate negative correlation (−0.3) between MCV and RDW (p=0.001).

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Discussion

The prevalence of anemia in our study is low compared to other states and regions of India, which can be attributed to the grass roots implementation of health policies in Kerala. The majority of anemic patients were found to have mild anemia (in both groups). Only one patient was severely anemic (in Group 1).

Despite having a low per capita income, Kerala has a reasonably strong primary health care system, and its social development indicators are at par with those of many developed countries (Rakesh 2017)

Fig. 2. Group 2 (6—12 years).

Table 2. Area with sensitivity, specificity, and cutoff value of RDW in the two age groups.

A study conducted by Sazawal et al. (2014) in India in 2014 (Sazawal et al., 2014) concluded that RDW alone was a less sensitive and specific test (RDW cut-off of 18% showed a sensitivity of 76.5% and specificity of 73.1%. The RDW cutoff of 16.4% had a sensitivity of 94%, and at a cutoff of 21%, the specificity was 95%) compared with a combination of Hb ≤ 10 g/dl and RDW >15%, which yielded a sensitivity of 99% and specificity of 90%. These findings corroborate with our study, where the cutoff value of RDW for Group 1 was 14.05%, with sensitivity and specificity of 77% and 75%, respectively, and Group 2 was 12.95%, with sensitivity and specificity of 60% and 54%, respectively.

In a study conducted by Thompson et al. (1988) on 247 hospitalized anemic patients, there was limited sensitivity and specificity for RDW alone in detecting iron deficiency anemia (RDW value >15% has a sensitivity of 71% and specificity of 54%). In another study, conducted by Viswanath et al. (2001) on 100 anemic children in India, they showed that RDW had a sensitivity and specificity of 92.1% and 90.9%, respectively, in the detection of iron deficiency anemia compared with peripheral smear.

In developed countries for early detection of iron deficiency anemia, RDW is generally performed along with routine blood examination. In a developing country like India, RDW, which is displayed by all recent automated cell counters, can be used as a cheap, time-efficient, and reliable early indicator for anemia as well as to distinguish between iron deficiency anemia and other causes of microcytosis. Compared with peripheral smear, which requires technical experts for accurate reporting and assessment of RDW, does the same diagnostic evaluation is less expensive and time-efficient.

There are numerous health programs initiated in India to prevent major problems caused by anemia, including the National Nutritional Anemia Control Program, National Nutritional Anemia Prophylaxis Program, Adolescent Girls Anemia Control Programme, WIFS [Weekly Iron Folic Acid Supplementation], Iron Plus Initiative (Vir et al., 2008; Dongre et al., 2011; Aguayo et al., 2013), which can be a reason for the low prevalence of anemia in Kerala.

The main limitation of our study is that the sample size was small compared with the prevalence of anemia in the community. As this was a hospital-based study, the findings and conclusions are not necessarily reflective of the community status.

Table 3. Presents the anemic and non-anemic children between the two groups.

Fig. 3. Anemic status categorizing as mild, moderate, and severe.

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Conclusion

As a diagnostic test, RDW alone was more specifically and sensitively associated with the detection of anemia in children aged 6 years than RDW in children aged 6–12 years. There was a weak negative correlation between Hb and RDW, which is significant. This study will help in the early detection of anemia in the pediatric age group, especially in children less than 6 years, cost-effectively so that prompt treatment can be initiated. This study has helped me in gaining insights into the management of anemia and to learn good research methodology skills.

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Acknowledgment

Department of Physiology for their encouragement; ICMR for granting STS Award and studentship; Department of Biostatistics for statistical help; Medical College Administration for permission for conducting the study.

Conflict of interest

The authors declare no Conflict of Interest.

Funding

Nil.

Authors’ contributions

Dr. Shyamnath Athikkuzhiyil Viswanathan: Concepts, Design, Definition of intellectual content, Literature search, Clinical studies, Data analysis, Manuscript preparation, Manuscript editing, and review.

Dr. Anne Varghese: Concepts, Design, Definition of intellectual content, Literature search, Clinical studies, Data analysis, Manuscript preparation, manuscript editing, and review

Data availability

Yes.

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