Platelet indices in critically ill septic patients as a predictor of mortality

Figures & data

Figure 1. Flowchart of the enrolled patients.

Table 1. Comparison between the two studied groups according to patients’ characteristics and causes of infection of the studied groups.

		Non-Survivors (n = 19)	Survivors (n = 35)	P value
Sex	Male	11(57.9%)	20(57.1%)	0.957
	Female	8(42.1%)	15(42.9%)
Age (years)		54.37 ± 9.30	40.54 ± 9.56	<0.001*
BMI (kg/m^2)		29.33 ± 5.28	29.72 ± 5.85	0.810
SOFA score at admission		10.0(10.0–12.0)	6.0(5.0–7.0)	<0.001*
WBCs (*10^3/dl) at admission		22.43 ± 4.71	20.05 ± 5.71	0.128
Causes of infection
Intra-abdominal infection		6(31.6%)	10(28.6%)	0.615
Chest infection		6(31.6%)	7(20%)
C.N.S infection		4(21.1%)	5(14.3%)
Surgical wound infection		3(15.8%)	7(20%)
Urinary tract infection		0(0%)	3(8.6%)
Bed sores & central line infection		0(0%)	3(8.6%)

Data are presented as mean ± SD, frequency (%) or median (IQR), BMI: Body mass index, WBCs: white blood cells, C.N.S: Central nervous system, *: significant P value

Table 2. Comparison between the two studied groups according to platelet count, plateletcrit and mean platelet volume.

	N	Non-survivors (n = 19)	N	Survivors (n = 35)	P value
Platelet count (*10^3/dl)
Day 1	19	183.05 ± 34.31	35	209.89 ± 41.72	0.020*
Day 3	13	178.92 ± 19.60	34	252.47 ± 42.81	<0.001*
Day 7	4	164.25 ± 16.50	26	283.50 ± 48.29	<0.001*
Day 14	0	-	7	331.86 ± 29.05	-
Day 21	0	-	1	392.0	-
Day 28	0	-	1	395.0	-
PCT (%)
Day 1	19	0.18 ± 0.04	35	0.20 ± 0.05	0.259
Day 3	13	0.16 ± 0.03	34	0.25 ± 0.05	<0.001*
Day 7	4	0.15 ± 0.05	26	0.27 ± 0.05	<0.001*
Day 14	0	-	7	0.32 ± 0.02	-
Day 21	0	-	1	0.39	-
Day 28	0	-	1	0.39	-
MPV (fl)
Day 1	19	11.47 ± 0.97	35	10.57 ± 0.45	0.001*
Day 3	13	11.37 ± .38	34	10.07 ± 0.59	<0.001*
Day 7	4	11.45 ± 0.44	26	9.30 ± 0.70	<0.001*
Day 14	0	-	7	8.64 ± 0.56	-
Day 21	0	-	1	8.0	-
Day 28	0	-	1	8.0	-
PDW (%)
Day 1	19	15.49 ± 1.35	35	13.34 ± 1.34	<0.001*
Day 3	13	16.19 ± 0.71	34	11.81 ± 1.35	<0.001*
Day 7	4	16.63 ± 0.80	26	10.69 ± 1.01	<0.001*
Day 14	0	-	7	10.09 ± 0.65	-
Day 21	0	-	1	9.30	-
Day 28	0	-	1	9.0	-
Procalcitonin (ng/dl)
Day 1	19	13.68 ± 6.44	35	4.06 ± 2.09	6.331*
Day 3	13	14.80 ± 6.60	34	1.66 ± 1.25	7.128*
Day 7	4	15.45 ± 10.11	26	0.60 ± 0.54	2.937*
Day 14	0	-	7	0.34 ± 0.15	-
Day 21	0	-	1	0.10	-
Day 28	0	-	1	0.10	-

Data are presented as mean ± SD, *: significant P value ≤ 0.05, PCT: Plateletcrit, MPV, Mean platelet volume, PDW: platelet distribution width

Figure 2. ROC curve of different parameters to discriminate non-survivor’s from survivors’ groups.

Table 3. Validity (AUC, sensitivity, specificity) for different parameters to predict mortality.

	AUC	p	95% C. I	Youden Index J	Cut-Off^#	Sensitivity	Specificity	PPV	NPV
Procalcitonin	0.919	<0.001*	0.822–1.016	0.805	>5.6	94.74	85.71	78.3	96.8
MPV	0.868	<0.001*	0.743–0.993	0.684	>10.9	84.21	80.00	69.6	90.3
PDW	0.856	<0.001*	0.756–0.957	0.561	>14	78.95	74.29	62.5	86.7
CRP	0.850	<0.001*	0.749–0.951	0.605	>50	63.16	74.29	57.1	78.8
PLT	0.672	0.038*	0.520–0.824	0.317	≤183	57.89	71.43	52.4	75.8
PCT	0.593	0.261	0.428–0.758	0.197	≤0.17	52.63	57.14	40.0	69.0

*: Significant P value ≤ 0.05. PDW: platelet distribution width, MPV, Mean platelet volume, PLT: Platelet, CRP: C-reactive protein, PCT: Plateletcrit, NPV: Negative predictive value, PPV: Positive predictive value. CI: Confidence Intervals.

Table 4. Univariate and multivariate logistic regression analysis for the parameters affecting mortality.

	Univariate		^#Multivariate
	p	OR (95%C.I)	p	OR (95%C.I)
Procalcitonin	0.003*	1.786(1.220–2.615)	0.009*	1.701(1.145–2.528)
MPV	<0.001*	7.970(2.621–24.238)	0.007*	2.290(1.254–3.544)
PDW	<0.001*	3.141(1.706–5.781)	0.035*	4.837(1.117–2.094)
PLT	0.027*	0.980(0.962–0.998)	0.544	1.010(0.978–1.042)

OR: Odd’s ratio, C.I: Confidence interval, LL: Lower limit, UL: Upper Limit, #: All variables with p < 0.05 was included in the multivariate, PDW: platelet distribution width, MPV, Mean platelet volume, PLT: Platelets, *: Statistically significant at p ≤ 0.05.

Table 5. Correlation between Procalcitonin and SOFA score with different parameters.

	Non-Survivors (n = 19)		Survivors (n = 35)
	r	p	r	p
Procalcitonin
PLT-	−0.551*	0.014*	−0.396*	0.019*
PCT-	−0.523*	0.022*	−0.355*	0.036*
MPV+	0.626*	0.004*	0.549*	0.001*
CRP+	0.744*	<0.001*	0.682*	<0.001*
PDW+	0.476*	0.039*	0.607	<0.001*
Age+	0.639*	0.003*	0.517	0.001*
SOFA score+	0.525*	0.021*	0.585	<0.001*
SOFA score
PLT-	−0.492*	0.018*	−0.371*	0.024*
PCT-	−0.437*	0.041*	−0.352*	0.038*
MPV+	0.592*	0.007*	0.634*	<0.001*
PDW+	0.492*	0.013*	0.687	<0.001*

PDW: platelet distribution width, CRP: C reactive protein, PLT: Platelet, PCT: Plateletcrit, MPV, Mean platelet volume, r: Pearson coefficient, *: Statistically significant at p ≤ 0.05