Platelet count-to-platelet distribution width ratio and other platelet indices as cost-effective markers of preeclampsia: a case control study

Abstract Background Platelet indices, like platelet count (PC), plateletcrite, mean platelet volume (MPV) and platelet distribution width (PDW), and their ratios have shown to be a cost-effective and better predictors of preeclampsia (PE). However, the PC/PDW ratio was not studied. Thus, this study aimed to compare platelet indices and their ratios between pregnant women with and without PE. Methods An analytical, comparative, case-control study was conducted. Pregnant women of 20 weeks gestation or more were categorized into either case (with PE) or control (without PE) group. The differences between cases and controls were compared using Student’s t-test and Mann‒Whitney U-test for the continuous variables and chi-square tests and Fisher’s exact test for categorical variables. Multivariable linear regression analysis for hematological parameters was performed to assess the effect of gestational age. Logistic regression was performed to calculate the odds ratio. A receiver operating characteristic curve was used to analyze the sensitivity and specificity of the tests and to find significant cutoff values to predict the presence of PE. The level of significance (α) was set at 0.05. Results A total of 24 cases and 72 controls were enrolled. There was a statistically significant reduction in the values of PC (p=0.004), plateletcrit (p=0.012), PC/MPV ratio (p=0.002), and PC/PDW ratio (p= <0.001) among the pregnant women with PE compared to the control study group, while a significant increase was noticed in the values of PDW (p= <0.001) and MPV (p=0.021). PC/PDW had the highest area under the curve (AUC) of 0.767, followed by PDW (AUC=0.752). At the cutoff value of 15.1 (p<0.001) for PC/PDW, the sensitivity was 70.8%, and the specificity was 81.9%. The odds of diagnosing true positive cases of PE was 11.02 (95% CI =3.79-31.99, p=<0.001) times higher compared to values below it at this cutoff point. Conclusions The present study suggests that platelet indices are economical tests that can act as indicators of risk of PE. Among all the parameters, PC/PDW has the highest sensitivity and specificity in the detection of PE at the cutoff of 15.1 and has emerged as a better predictor of PE.