Amid speculation that total blood counts may be associated with heart failure prognosis, researchers find that higher levels of platelet distribution width could be used to predict a worse prognosis for heart failure.
High platelet distribution width (PDW) was found to be a predictor of worse prognosis in patients with heart failure (HF), according to findings of a recent study published in PLoS One.
The researchers wrote that this is the first study to report an association between high PDW and adverse prognosis for HF. “These findings are pivotal for clinical practice because complete blood count is performed in almost all patients with HF, and PDW is reported routinely and automatically,” wrote the investigators.
PDW, a biomarker for platelet activation, is defined as the distribution width at 20% of the total height of the distribution curve for platelet size. Researchers noted that increased PDW levels may be associated with atherosclerosis, coronary artery disease, cerebrovascular disease, and systemic inflammatory disease. PDW can also be a predictor for cardiac death, infarction recurrence, and another revascularization in patients with acute myocardial infarction.
The investigators noted that the usefulness of complete blood count, outside of analyzing hemoglobin and hematocrit, in predicting prognosis has not yet been fully evaluated. More researchers are directing their attention to red blood cell distribution to see whether it can be a prognostic marker in patients with cardiovascular disease. Prior research has found that higher red blood cell distribution width independently contributed to all-cause death in patients with HF.
The study included patients who were hospitalized at Fukushima Medical University Hospital in Fukushima, Japan, for acute decompensated HF between October 2009 and September 2019 and had their PDW measured. A total of 2450 patients met the inclusion criteria, and after excluding 704 patients who had received maintenance dialysis and/or had a history of cancer, 1746 patients were enrolled.
Patients were sectioned into 3 tertiles based on their PDW levels. A total of 586 patients with the lowest PDW levels (PDW < 15.9 fL) were placed into the first tertile (33.6%). Patients in the second tertile (n = 617) had a PDW level between 15.9 and 16.8 fL (35.3%). The third tertile included 543 patients with a PDW level of at least 16.9 fL (31.1%).
Researchers gathered laboratory and echocardiographic data from patients within 1 week prior to discharge when they were in stable condition. The PDW levels in the groups were 13.4 fL in the first tertile (12.2-14.2), 16.5 (16.2-16.7) fL in the second tertile, and 17.3 (17.0-17.7) fL in the third tertile (P <.001).
The study had primary end points of all-cause death, cardiac death, and cardiac event. Cardiac deaths were defined as deaths as a result of worsened HF, ventricular fibrillation, or acute coronary syndrome, of which there were 212 in the study during hospital discharge follow-up period, which was a median of 1352 days.
A total of 480 cardiac events, which was defined as a cardiac death (n = 81) or an unplanned hospitalization for HF (n = 399), occurred during the follow-up period. There were also 391 all-cause deaths. The rates of all primary end points were the highest among the third tertile (P < .001).
Additionally, the prevalence of chronic kidney disease was the higher for patients in the third tertile compared with the second and first tertiles (57.5%, 49.3%, and 49.0%, respectively; P = .005).
The third tertile was the only group associated with adverse prognosis, the investigators concluded using a multivariate analysis.
PDW tertiles demonstrated U- or J-shaped associations with HF severity and prognosis, which investigators noted could signal that there may be a threshold of usefulness for PDW levels for identifying patients with HF who are at high risk.
Investigators said that further studies are needed to further demonstrate whether PFW has any clinical significance in patients with HF. Future studies should include a larger patient cohort and should analyze the underlying mechanisms that could contribute to altered PDW levels.
Sato Y, Yoshihisa A, Watanabe K, et al. Association between platelet distribution width and prognosis in patients with heart failure. PLoS One. 2020;15(12):e0244608. doi:10.1371/journal.pone.0244608