Native Platelet Function and Clinical Outcomes in Very Elderly Patients: A Retrospective Cohort Study

This study examined native platelet function in very elderly patients (≥80 years) not receiving antiplatelet or anticoagulant therapy, its correlation with routine laboratory parameters, and factors associated with poor 90-day outcomes.

This retrospective cohort study included 94 very elderly inpatients (80-89 years, n=50; ≥90 years, n=44). Patients on antiplatelet, anticoagulant, or glucocorticoid therapy within 7 days before admission were excluded. Baseline data, laboratory parameters-including ADP‑ and AA‑induced aggregation, platelet count, and 90‑day outcomes were collected. Adverse clinical outcomes occurred in 13 patients during this period. Spearman correlation and Firth penalized logistic regression were used.

No differences were found between age groups in platelet count or aggregation rates (all P > 0.05). Prothrombin time was longer in the ≥90 group (13.32±1.31 vs. 12.08±1.63 s, P < 0.001). Platelet function showed no meaningful correlation with white blood cell count, hemoglobin, or fibrinogen (|r| < 0.2, all P > 0.05). Among the 94 patients, 13 had poor outcomes. In Firth regression, neither age ≥90 years (OR=2.86, 95% CI: 0.85-9.62, P=0.090) nor coronary heart disease (OR=1.61, 95% CI: 0.50-5.21, P=0.424) reached statistical significance. The model's area under the ROC curve was 0.657 (bias‑corrected 0.640).

In this cohort of very elderly patients not on antiplatelet or anticoagulant therapy, native platelet function did not differ between octogenarians and nonagenarians and showed no correlation with routine hematological parameters. No statistically significant predictor of poor 90‑day outcomes was identified. The small number of outcome events (n=13) limits statistical power, so these findings should be considered exploratory. Larger prospective studies are needed to validate these findings.