Diagnostic predictive value of platelet indices for discriminating hypo productive versus immune thrombocytopenia purpura in patients attending a tertiary care teaching hospital in Addis Ababa, Ethiopia

Abstract

BackgroundBone marrow examination may be required to discriminate causes of thrombocytopenia as hypoproductive or hyperdestructive. However, this procedure is invasive and time consuming. This study assessed the diagnostic value of Mean Platelet Volume (MPV), Platelet Distribution Width (PDW) and Platelet Large Cell-Ratio (P-LCR) in discriminating causes of thrombocytopenia as hypoproductive or hyperdestructive (Immune thrombocytopenia purpura).MethodA prospective cross-sectional study was conducted on 83 thrombocytopenic patients (Plt < 150 × 109/L). From these, 50 patients had hypoproductive and the rest 33 Immune Thrombocytopenia Purpura (ITP). Age and sex matched 42 healthy controls were included as a comparative group. Hematological analysis was carried out using Sysmex XT 2000i 5 part diff analyzer. SPSS Version16 was used for data analysis. A two by two table and receiver operating characteristic (ROC) curve was used to calculate sensitivity, specificity, positive and negative predictive values, for a given platelet indices (MPV, PDW and P-LCR). Student t test and Mann Whitney U test were used to compare means and medians, respectively. Correlation test was used to determine associations between continuous variables.ResultsAll Platelet indices were significantly higher in ITP patients (n = 33) than in hypoproductive thrombocytopenic patients (n = 50) (p < 0.0001). In particular MPV and P-LCR have larger area under ROC curve (0.876 and 0.816, respectively), indicating a better predictive capacity, sensitivity and specificity in discriminating the two causes of thrombocytopenia. The indices were still significantly higher in ITP patients compared to 42 healthy controls (p < 0.0001). A significant negative correlation was observed between platelet count and platelet indices in ITP patients, (p < 0.001).ConclusionMPV, PDW and P-LCR help in predicting thrombocytopenic patients as having ITP or hypoproductive thrombocytopenia. If these indices are used in line with other laboratory and clinical information, they may help in delaying/ avoiding unnecessary bone marrow aspiration in ITP patients or supplement a request for bone morrow aspiration or biopsy in hypoproductive thrombocytopenic patients.

Low Serum Vitamin D Levels in Egyptian Adults With Chronic Primary Immune Thrombocytopenia: A Single Center Study.

“…[15] ;Negash et al [16] who found that the MPV is significantly elevated in ITP patients than in patients with hypoproductive thrombocytopenia. In disagreement with this result, a study conducted by Borkataky et al [17] who found no significant difference in the MPV between the destructive thrombocytopenia groups and the control group.…”

Mean platelet volume and response to the first line therapy in newly diagnosed adult immune thrombocytopenia patients: a retrospective study

“…A few previous studies have investigated the relationship between the MPV and ITP. MPV was found higher in ITP than aplastic anaemia [3], chemotherapyrelated myelosuppression [4], myelodysplastic syndrome [8] and other hypoproductive thrombocytopenia [6]. MPV was also found higher in ITP than healthy controls [6,12].…”

“…So, it is assumed that MPV is high in the ITP patients. The previous studies indicated that MPV may be used to differentiate between hypo and hyper productive thrombocytopenia and ITP patients have higher MPV than the hypoproductive thrombocytopenia (aplastic anaemia, myelodysplasia) [3][4][5][6][7][8]. However, different mechanisms may be dominant in different patients and this may cause different MPV values in patients.…”

“…A power calculation (GPower 3.1 software) indicated the need for 30 patients to have 80% power to detect a 2 fL difference in MPV (for example, 10 fL in one group and 12 in the other, with the standard deviation of 3). Difference and standard deviation were chosen according to ITP and healthy population values in the previous studies [6,12].…”

“…Mean platelet volume (MPV), which is easily available in clinical practice, is a marker of platelet function [2]. Several studies have investigated the MPV value in the diagnosis and differential diagnosis of the ITP and hypoproliferative thrombocytopenia [3][4][5][6][7][8], relapse of the ITP [9,10] and thrombocytosis [11]. Although these studies have revealed important aspects of the MPV and ITP, they have not investigated the relationship between the MPV and short-term treatment response to the first line therapy.…”