Purpose: Platelet size has been demonstrated to reflect platelet activity and to predict poor clinical outcomes in patients with cardiovascular disease. However, the prognostic value of platelet size for mortality has not been studied in patients with acute kidney injury (AKI).
Materials and methods: A total of 349 patients who received continuous renal replacement therapy (CRRT) for AKI between August 2009 and October 2011 were divided into 2 groups based on the median mean platelet volume (MPV) at the time of CRRT initiation. Twenty-eight-day mortality rate was determined using Kaplan-Meier plots and time-dependent receiver operating characteristic curves were constructed. In addition, multivariate Cox analysis for mortality was used to evaluate the independent prognostic value of MPV.
Results: The mean age was 61.3 years, and 218 patients (62.5%) were male. At the initiation of CRRT, MPV level was inversely correlated with platelet count, whereas it was positively associated with Acute Physiology and Chronic Health Evaluation II scores. During the study period, 231 deaths (66.2%) occurred. Kaplan-Meier curve showed that 28-day all-cause mortality was significantly higher in patients with MPV≥10.2 fL compared with those with MPV<10.2 fL (P<.001). Moreover, Cox regression analysis revealed that MPV was an independent predictor for 28-day all-cause mortality after adjustment of age, age-adjusted Charlson Comorbidity Index, cause of AKI, platelet count, Acute Physiology and Chronic Health Evaluation II score, presence of malignancy, albumin, and C-reactive protein (hazard ratio, 1.080; 95% confidence interval, 1.010-1.155; P=.023).
Conclusion: Mean platelet volume at the time of CRRT initiation may be an inexpensive and useful predictor for 28-day all-cause mortality in patients with AKI requiring CRRT.
Keywords: Acute kidney injury; Continuous renal replacement therapy; Mean platelet volume; Mortality; Platelet.
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