Use of simple clinical and laboratory predictors to differentiate influenza from dengue and other febrile illnesses in the emergency room

Table 2 Symptoms/signs and laboratory characteristics of patients with influenza, dengue, and other febrile illnesses

Variable	Influenza (n = 526)	Dengue (n = 148)	Other febrile illnesses (n = 175)	P ^a	P ^b
Symptom/sign^c (n [%])
Rhinorrhea	333 (63.3)	0	73 (41.7)	<0.001	<0.001
Cough	356 (67.6)	38 (25.7)	112 (64)	<0.001	0.396
Sore throat	207 (39.3)	24 (16.2)	43 (24.6)	<0.001	<0.001
Malaise	183 (34.8)	95 (64.2)	21 (12)	<0.001	<0.001
Headache	149 (28.3)	62 (41.9)	33 (18.9)	0.001	0.015
Vomiting/nausea	116 (22.1)	43 (29.1)	37 (21.1)	0.076	0.801
Diarrhea	57 (10.8)	15 (10.1)	26 (14.9)	0.807	0.154
Abdominal pain	40 (7.6)	31 (20.9)	18 (10.3)	<0.001	0.265
Joint pain	26 (4.9)	74 (50)	10 (5.7)	<0.001	0.539
Orbital pain	0	17 (11.5)	2 (1.1)	<0.001	0.062
Rashes	5 (0.9)	88 (59.5)	0	<0.001	0.196
Dyspnea	41 (7.8)	3 (2)	1 (0.6)	0.008	<0.001
Drowsiness	13 (2.5)	0	0	0.083	0.036
Seizures	8 (1.5)	0	0	0.211	0.211
Laboratory characteristics
Leukopenia (WBC <3.0 × 10⁹ cells/L) (n/N [%])	9/283 (3.2)	82/146 (56)	4/152 (2.6)	<0.001	0.749
Platelet count 149-100 × 10⁹ cells/L (n/N [%])	38/238 (15.9)	27/146 (18.5)	5/133 (3.7)	0.522	0.003
Platelet count <100 × 10⁹ cells/L (n/N [%])	7/238 (2.9)	109/146 (74.6)	3/133 (2.3)	<0.001	0.696

WBC = white blood cell count; n/N = number of patients/total number of patients with data available.
^aInfluenza vs. dengue.
^bInfluenza vs. other febrile illnesses.
^cAn individual patient might have more than one symptom/sign.

ISSN: 1471-2334