The American Society of Hematology (ASH) defines Immune Thrombocytopenia Purpura (ITP) as isolated thrombocytopenia (platelet count less than 100,000/mm3) with normal white blood cells and hemoglobin with purpura rash. ITP was previously known as idiopathic thrombocytopenic purpura or immune thrombocytopenic purpura.¹

The severity of ITP is categorized into: mild (platelet count: >50,000/mm3), moderate (platelet count: 30,000 to 50,000/mm3), severe (platelet count: <30,000/mm3). In United States, the estimated prevalence of ITP is 9.5 per 100,000 people with a global prevalence of ITP of more than 200,000 people.² Severe bleeding (such as massive intracerebral hemorrhage and epistaxis) in newly diagnosed or chronic ITP is reported in 9.6% of adults and 20.2% of children.³

Platelet index is one of the parameters to evaluate platelet activity which is obtained from a complete blood test that includes Platelet Crit (PI), MPV, and PDW. MPV indicates platelet activity and is associated with thrombotic risk and various diseases while PDW reflects the variability of platelet size, indicating active platelet production and destruction. MPV and PDW levels are necessary in establishing the diagnosis of ITP.⁴ The study aims to determine the association between MPV and PDW with the severity of ITP.

This study was a cross-sectional study involving 100 ITP patients aged more than 18 years at Dr. Wahidin Sudirohusodo Hospital Makassar, Indonesia. The diagnosis of ITP was established by excluding all causes of thrombocytopenia. MPV and PDW values were obtained from the patient's complete blood test.

The inclusion criteria for this study include patients with Immune Thrombocytopenic Purpura (ITP) and aged 18 years. Exclusion criteria for this study include subjects with renal impairment, hepatitis b/c, pregnancy, malignancy (cancer), dengue hemorrhagic fever, severe infection (sepsis) and thrombocytopenia due to medication.

Ethical approval

All actions of this study will be carried out based on and on ethical approval given by the Health Research Ethics Committee (KEPK) Faculty of Medicine, Hasanuddin University, with number: 998/UN44.6.4.5.31/PP36/2024.

Statistical analysis

Data analysis was carried out using SPSS version 25. The analysis method consists of calculating descriptive statistics and frequency distribution. Descriptive methods aimed to obtain general information about the study sample. The statistical test used was Chi Square Test and multivariate analysis using Multiple logistic Regression. Statistical test results were considered significant if the test p value was <0.05.

This study consisted of 100 ITP patients, where the mean age of the study subjects was 41.8 + 15.5 years. The average platelet value was 28.6 + 25.2 ×103/µL. The average MPV value was 13.51 + 2.7 fL and the average PDW value was 19.71 + 5.3 fL (Table 1).

Table 1. Characteristics of the study

The study found that high MPV levels were significantly (p = <0.001) more common in severe ITP compared to mild and moderate (1.8% vs 17.5% vs 80.7%). This indicates that there is an association between high MPV values and severe ITP (Table 1). There were also high PDW levels which were significantly (p = <0.001) more common in severe ITP compared to mild and moderate (9.5% vs. 15.9% vs. 74.6%). This shows that there is an association between PDW values and severe ITP (Table 2).

Table 2. Association between MPV and PDW Values and the Severity of ITP

Analysis of the mean values of MPV and PDW with the severity of ITP found that the mean levels of MPV and PDW were consistently higher with the severity of ITP (p=<0.001), which means that there is an association between high mean levels of MPV and PDW levels and the severity of ITP (Table 3).

Table 3. Analysis of Mean MPV and PDW values with severity of ITP

Figure 1. Chart of the difference between mean MPV and the severity of ITP

Figure 2. Chart of the difference between mean PDW and the severity of ITP

Diagnostic test of MPV and PDW in predicting severe ITP found that the MPV value of 13.65 fL is predictive of severe ITP with a sensitivity 72.40% and specificity 83.30% (Table 4). PDW value of 18.8 fL is predictive of severe ITP with a sensitivity 79.30% and specificity 76.20%.(Table 5).

Table 4. MPV sensitivity and specificity test on severe ITP

Table 5. PDW sensitivity and specificity test on severe ITP

Figure 3. MPV ROC curve

Figure 4. PDW ROC curve

Thrombocytopenia is a clinical manifestation that commonly occurs in various diseases and is one of the potentially life-threatening conditions. Thrombocytopenia can be divided into two main causes, namely hypo-productive due to failure of the bone marrow to produce platelets and hyper-destructive due to increased platelet destruction. Hyper-destructive thrombocytopenia mainly occurs due to autoimmune diseases. ITP is an autoimmune disease where there is impaired maturation of megakaryocytes in the bone marrow and increased platelet destruction in the peripheral blood..5

ITP patients often present with severe thrombocytopenia or even bleeding. In some cases, this is an extremely serious emergency, as there is a high risk of serious bleeding complications such as intracranial or gastrointestinal bleeding. In a few hours, the diagnosis of ITP should be made based on history taking, physical examination, complete blood test and peripheral blood smear examination.5

The diagnosis of ITP can be made through history taking, physical examination, complete blood test, and peripheral blood smear examination. However, the diagnosis is a diagnosis of exclusion. There are no tests available for the diagnosis of ITP. Platelet indices (MPV and PDW) have been shown to be clinically useful in differentiating ITP from thrombocytopenia caused by insufficient platelet production.6 This study aimed to determine the association of mean MPV and PDW involving 100 ITP patient, where the mean age of the study subjects was 41.8 + 15.5 years. The mean platelet count was 28.6 + 25.2 ×103/µL. The mean MPV value was 13.51 + 2.7 fL and the mean PDW value was 19.71 + 5.3 fL.

Mean Platelet Volume (MPV) is a method to measuring platelet volume and identifying progenitor cells (megakaryocytes) in the bone marrow. When platelet production is reduced, young platelets become enlarged and more active, causing an increase in MPV levels, indicating that the diameter of the platelets increases. It can be used as an indicator of the rate and activation of platelets. PDW is one of the platelet index that can be used to diagnose thrombocytosis, including in patients with ITP. In the study, PDW in ITP patients was higher compared to healthy people.  In ITP patients with platelet counts less than 45 × 103 per µL, MPV and PDW levels tend to be higher.7

In this study, the MPV and PDW values were significantly higher in severe ITP. This shows that there is a relationship between the MPV and PDW values and the severity of ITP. Previous studies by Ntaios et al on MPV and PDW in 134 ITP patients showed that there was an increase in the mean values of MPV and PDW among ITP patients.5 Similar results were also reported by Kaito et al who compared MPV and PDW values in aplastic anemia and ITP patients, where the mean MPV and PDW values were significantly higher in ITP patients than aplastic anemia patients.8

A study by Lee et al comparing MPV and PDW levels in patients with ITP and essential thrombocytosis (ET) found that in the ITP group, MPV and PDW were higher compared to healthy subjects. In the ET group, MPV was lower compared to the ITP group and healthy subjects, and PDW was lower compared to the ITP group. When the ITP group was subdivided (PLT count < 45 × 103/μL vs ≥ 45 × 103/μL), MPV and PDW tended to be higher in patients with PLT count < 45 × 103 per μL.9

In this study, MPV and PDW diagnostic tests were carried out in predicting severe ITP. It was found that the MPV value of 13.65 fL is a value that can predict severe ITP with a sensitivity of 72.40% and a specificity of 83.30%. PDW value of 18.8 fL is a value that can predict severe ITP with a sensitivity of 79.30% and specificity of 76.20%. Previously, Negash et al. found that MPV values greater than 11.05 fL and PDW values greater than 14.25 fL were predictive of ITP with a sensitivity of 67% and specificity of 95% for MPV and a sensitivity of 61% and specificity of 62% for PDW.10

Previous studies have shown that there is an increase in MPV and PDW values in ITP patients. This can be a modality for the diagnosis of ITP, given the absence of a definitive standard examination, although the history of the disease, physical examination and other complementary examinations also need to be considered in establishing the diagnosis of ITP.

This study has several limitations that need to be considered. First, the sample size was limited to 100 ITP patients. Secondly, this study did not explore other factors such as comorbid conditions, current therapy, and additional clinical variables that may influence MPV and PDW values.

In this study, it can be concluded that high value of MPV and PDW were found more in patients with severe ITP. In addition, the mean MPV and PDW values were also found to be higher along with the severity of the ITP degree.

Funding

Not applicable.

Author contribution

FA (Concept, Design, Sources, Materials, Data Collection and Processing, Analysis and Interpretation, Literature Search, Manuscript Writing). SS (Concept, Design, Supervision, Analysis and Interpretation, Literature Search). SA (Concept, Design, Supervision, Analysis and Interpretation, Literature Search). SB (Concept, Design, Supervision, Analysis and Interpretation, Literature Search). FS (Concept, Design, Supervision, Analysis and Interpretation, Literature Search). AAZ (Concept, Design, Analysis and Interpretation, Critical Review).

Acknowledgements

This research was supported by the Department of Internal Medicine, Faculty of Medicine, Hasanuddin University, Makassar, South Sulawesi, Indonesia.

Conflicts of interests

The authors declare no conflict of interest

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