Clinical significance of platelet-associated hematological parameters as an early supplementary diagnostic tool for sepsis in thrombocytopenic very-low-birth-weight infants

Platelet Indices: Universally Available Clinical Adjunct for Diagnosing Necrotizing Enterocolitis

OBJECTIVE

 Platelet function parameters can be predictive of several adult diseases and their severity. However, few studies report on the association between platelet indices and neonatal diseases, specifically necrotizing enterocolitis (NEC). The objective of this study is to investigate whether platelet indices are associated with NEC diagnosis and NEC-related mortality.

STUDY DESIGN

 We retrospectively examined records from infants admitted to the neonatal intensive care unit with a diagnosis of NEC, verified by the presence of pneumatosis on X-ray or pathology at surgery. We compared them with an age-matched group of prematures without NEC. We investigated platelet count, mean platelet volume (MPV), platelet distribution width and red cell distribution width to platelet ratio (RPR) and delta platelets from birth to the time of NEC diagnosis or day of life 14 in the control group.

RESULTS

 Sixty-nine infants with NEC and 78 control infants were studied. Basic sociodemographic data were similar in both groups. All platelet parameters measured-except for MPV-were significantly associated with NEC diagnosis. Although MPV was not associated with the diagnosis of NEC (p = 0.800), it was significantly associated with NEC-related mortality (p < 0.001). Only total platelet count and RPR were significantly associated with both NEC diagnosis (p < 0.0001) and mortality (p = 0.04 and 0.01, respectively). On multivariable analysis only the change in platelet count from birth to time of diagnosis remained significant.

CONCLUSION

 While not definitive, this study demonstrates that these routinely available, inexpensive, and easily calculated platelet indices can provide a clinical adjunct in the often-elusive attempts to definitively diagnose NEC in preterm neonates.

KEY POINTS

· Platelet indices were associated with NEC diagnosis.. · MPV was predictive of NEC-related mortality.. · Delta platelet count from birth was significantly related to NEC diagnosis..

Platelet Counts and Risk of Severe Retinopathy of Prematurity: A Bayesian Model-Averaged Meta-Analysis

BACKGROUND

We aimed to conduct a systematic review and Bayesian model-averaged meta-analysis (BMA) on the association between platelet counts and severe retinopathy of prematurity (ROP).

METHODS

We searched for studies reporting on platelet counts (continuous variable) or thrombocytopenia (categorical variable) and severe ROP or aggressive posterior ROP (APROP). The timing of platelet counts was divided into Phase 1 (<2 weeks) and Phase 2 (around ROP treatment). BMA was used to calculate Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (H1) over the probability of the data under the null hypothesis (H0).

RESULTS

We included 21 studies. BMA showed an association between low platelet counts and severe ROP. The evidence was strong (BF10 = 13.5, 7 studies) for phase 1 and very strong (BF10 = 51.0, 9 studies) for phase 2. Thrombocytopenia (<100 × 109/L) in phase 2 was associated with severe ROP (BF10 = 28.2, 4 studies). Following adjustment for publication bias, only the association of severe ROP with thrombocytopenia remained with moderate evidence in favor of H1 (BF10 = 4.30).

CONCLUSIONS

Thrombocytopenia is associated with severe ROP. However, the evidence for this association was tempered when results were adjusted for publication bias.

Platelet Counts and Patent Ductus Arteriosus in Preterm Infants: An Updated Systematic Review and Meta-Analysis

Background: A meta-analysis published in 2015 showed a significant association between low platelet counts in the first day(s) of life and risk of patent ductus arteriosus (PDA). The meta-analysis pooled data from 11 studies cohorts (3,479 preterm infants). Objective: To update the meta-analysis by adding new studies on the topic and including other platelet parameters different from platelet counts. Methods: PubMed/Medline and Embase databases were searched. Random-effects risk ratios (RR) and differences in means (DM) and 95% confidence intervals (CI) were calculated. Results: We included 31 studies (7,638 infants). Meta-analysis showed that the risk of developing any PDA was significantly associated with platelet counts<150 × 109/L (11 studies, RR 1.58, 95% CI 1.28 to 1.95), and <100 x 109/L (7 studies, RR 1.61, 95% CI 1.14 to 2.28), but not <50 x 109/L (4 studies, RR 1.34, 95% CI 0.77 to 2.32). Risk of developing hemodynamically significant PDA (hsPDA) was significantly associated with platelet counts<150 x 109/L (12 studies, RR 1.33, 95% CI 1.09 to 1.63), and <100 x 109/L (7 studies, RR 1.39, 95% CI 1.06 to 1.82), but not <50 x 109/L (6 studies, RR 1.24, 95% CI 0.86 to 1.79). Infants with hsPDA had significantly lower mean platelet counts (19 studies, DM 22.0 x 109, 95% CI 14.9 to 29.1) and platelet mass (11 studies, DM 214.4, 95% CI 131.2 to 297.5) and significantly higher platelet distribution width (PDW, 9 studies, DM -0.53, 95% CI -1.01 to -0.05) than infants without hsPDA. Meta-analysis could not demonstrate significant differences in mean platelet volume (MPV). Conclusion: Compared to the previous analysis, this updated meta-analysis included 21 additional studies that provide stronger evidence of the association between low platelet counts and PDA/hsPDA. Other platelet parameters such as platelet mass and PDW are also associated with hsPDA risk. However, the low number of platelets may be an epiphenomenon associated with the maturity and clinical stability of preterm infants rather than a contributing factor in the pathogenesis of PDA.

Perinatal factors affecting platelet parameters in late preterm and term neonates

Platelets parameters including platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV) and platelet distribution width (PDW) are associated with various physiological and pathological functions in various disease. However, few studies have addressed whether perinatal factors may be associated with platelet parameters at birth in a large cohort of late preterm and term neonates. The aim of this study to investigate perinatal factors affecting platelet parameters in late preterm and term neonates. We retrospectively investigated platelet parameters including PLT, PCT, MPV, and PDW on the first day of life in 142 late preterm and 258 term neonates admitted to our NICU from 2006 through 2020. PLT, MPV, PCT, PDW on Day 0 did not significantly differ between the two groups. In term neonates, multivariate analysis revealed that PCT correlated with being small for gestational age (SGA) (β = -0.168, P = 0.006), pregnancy induced hypertension (PIH) (β = -0.135, P = 0.026) and male sex (β = -0.185, P = 0.002). PLT was associated with SGA (β = -0.186, P = 0.002), PIH (β = -0.137, P = 0.024) and male sex (β = -0.166, P = 0.006). In late preterm neonates, multivariate analysis revealed that PLT were associated with PIH, whereas no factors associated with PDW and MPV were found. In all patients studied, chorioamnionitis (CAM) was significantly associated with MPV (CAM = 10.3 fL vs. no CAM = 9.7 fL, P<0.001). Multivariate analysis showed that SGA, male sex and PIH were associated with PCT and PLT. This study demonstrates that different maternal and neonatal complications affect platelet parameters in late preterm and term neonates.

Intraventricular Hemorrhage and Platelet Indices in Extremely Premature Neonates

Intraventricular hemorrhage (IVH) is a multifactorial disorder, the most important risk factors of which are prematurity and low birth weight. Disturbances in cerebral blood flow, inherent fragility of the germinal matrix vasculature, and platelet/coagulation disturbances are the 3 major pathogenic mechanisms. In this context, we investigated the role of platelet indices and several maternal and neonatal characteristics in the development of IVH through a retrospective cohort analysis of 130 extremely premature neonates, 24% of whom presented with severe IVH. There was a significant difference in platelet counts between the IVH and the control group on the first day of life (P=0.046). Presence of IVH was linked with lower birth weight (P=0.006) and lower gestational age (P=0.001). Platelet count on the first day of life was positively correlated with survival (P=0.001) and, along with platelet mass, was indicative of the worst IVH grade recorded for each neonate (P=0.002 and 0.007, respectively). Prolonged prothrombin time was also correlated with IVH (P<0.001), but factor analysis supported no prominent role. Maternal medications seem to play a minor role as well. In conclusion, IVH in extremely premature infants cannot be solely explained by platelet parameters, and further studies are required to determine the relationships between IVH, platelet indices, and outcomes.