Higher accuracy of concurrent use of corrected QT interval and procalcitonin serum level to predict sepsis related mortality in ICU patients

Figures & data

Figure 1. CONSORT flow diagram

Figure 2. Comparison between the procalcitonin level (left) and the QTc (right) between the survivors and the non-survivor group

Table 1. Comparison according to ICU mortality

Characteristics		Total (N = 120)	Non survivor (N = 44)	Survivor (N = 76)	P value
Age (years)		56.5 ± 6.2	56.1 ± 6.9	56.7 ± 5.8	^0.621
Sex	Male (N/%)	77 (64.2%)	27.0 (61.4%)	50.0 (65.8%)	#0.626
	Female (N/%)	43 (35.8%)	17.0 (38.6%)	26.0 (34.2%)
Cause of admission	Cardiovascular (N/%)	61 (50.8%)	24.0 (54.5%)	37.0 (48.7%)	#0.536
	Neurological (N/%)	19 (15.8%)	5.0 (11.4%)	14.0 (18.4%)	#0.307
	Trauma (N/%)	30 (25.0%)	13.0 (29.5%)	17.0 (22.4%)	#0.382
	Others (N/%)	10 (8.3%)	2.0 (4.5%)	8.0 (10.5%)	§0.322
SOFA score mortality risk		52.6 ± 33.6	67.1 ± 33.4	44.3 ± 30.9	^<0.001*
APACHE II score mortality risk		67.3 ± 23.9	78.7 ± 17.5	60.7 ± 24.7	^<0.001*
Procalcitonin (ng/mL)		10.4 ± 4.5	13.4 ± 4.9	8.6 ± 3.1	^<0.001*
QTc (msec)		455.6 ± 48.3	493.1 ± 42.3	433.9 ± 37.0	^<0.001*
Prolonged QTc >470 (N)		45 (37.5%)	31.0 (70.5%)	14.0 (18.4%)	#<0.001*
Death day		–	9.8 ± 7.8	–	–

N = Number, ^ Independent t-test, # Chi-square test, § Fisher’s Exact test, * Significant

Table 2. Correlations of mortality day among died cases

Findings	R	P-value
Age	−0.073	0.637
SOFA mortality	−0.586	<0.001*
APACHE II mortality	−0.305	0.044*
Procalcitonin (ng/mL)	−0.430	0.004*
QTc	−0.431	0.003*

Total = 44. Pearson correlation. * Significant

Figure 3. ROC curve for different variables at day-1 in predicting death

Table 3. Diagnostic performance of different variables at day-1 in predicting death

Factors	AUC	SE	P	95% CI	Cut off
SOFA mortality	0.718	0.052	<0.001*	0.617–0.819	≥89.5
APACHE II mortality	0.697	0.048	<0.001*	0.603–0.791	≥67.0
Procalcitonin	0.823	0.037	<0.001*	0.751–0.895	≥8.4
QTc	0.847	0.036	<0.001*	0.776–0.918	≥469

Total = 120 AUC: Area under the curve, SE: Standard error, CI: Confidence interval, *significant

Table 4. Diagnostic characteristics of suggested cutoff points in predicting death

Characters	SOFA mortality ≥ 89.5	APACHE II mortality ≥ 67.0	Procalcitonin ≥8.4 ng/mL	QTc ≥469 ms
Sensitivity	54.5%	79.5%	97.7%	75.0%
Specificity	85.5%	60.5%	57.9%	81.6%
DA	74.2%	67.5%	72.5%	79.2%
YI	40.1%	40.1%	55.6%	56.6%
PPV	68.6%	53.8%	57.3%	70.2%
NPV	76.5%	83.6%	97.8%	84.9%
LR+	3.77	2.02	2.32	4.07
LR-	0.53	0.34	0.04	0.31
LR	7.09	5.96	59.13	13.29
Kappa	0.419	0.364	0.484	0.558

CI: Confidence interval, YI: Youden’s index, DA: Diagnostic accuracy, PPV: Positive Predictive Value, NPV: Negative Predictive Value, LR+: Positive likelihood ratio, LR-: Negative likelihood ratio, LR: Diagnostic odd ratio