Vital signs of the systemic inflammatory response syndrome in adult patients with acute infections presenting in out-of-hours primary care: A cross-sectional study

Figures & data

Figure 1. Flowchart of included patients.

Table 1. Patient characteristics of the total study population and divided by contact type and by hospital referral.

Patient characteristic	All patients (n = 558)	Clinic consultations			Home visits
		Not referred to hospital (n = 334)	Referred to hospital (n = 75)	Total (n = 409)	Not referred to hospital (n = 104)	Referred to hospital (n = 45)	Total (n = 149)
Background characteristics
Age, median (IQR^a), year	50 (31–71)	41 (27–55)	44 (27–61)	41 (27–56)	79 (68–84)	75(59–84)	78 (67–84)
Female, N (%)	315 (56.5)	196 (58.7)	40 (53.3)	236 (57.7)	57 (52.8)	22 (48.9)	79 (53.0)
Source of infection, N (%)
Lower respiratory tract infection	102 (18.3)	47 (14.1)	3 (4.0)	50 (12.2)	36 (34.6)	16 (35.6)	52 (34.9)
Upper respiratory tract infection	78 (14.0)	65 (19.5)	7 (9.3)	72 (17.6)	6 (5.8)	0 (0.0)	6 (4.0)
Urogenital infection	107 (19.2)	73 (21.9)	3 (4.0)	76 (18.6)	26 (25.0)	5 (11.1)	31 (20.8)
Abdominal infection	95 (17.0)	38 (11.4)	39 (52.2)	77 (18.8)	8 (7.7)	9 (20.0)	18 (12.1)
Skin or soft tissue infection	103 (6.9)	89 (26.6)	5 (6.7)	94 (23.0)	8 (7.7)	1 (2.2)	9 (6.0)
Fever of unknown origin	48 (8.6)	8 (2.4)	14 (18.7)	22 (5.4)	16 (15.4)	10 (22.2)	26 (17.4)
Other	25 (4.5)	14 (4.2)	4 (5.3)	18 (4.4)	3 (2.9)	4 (8.9)	7 (4.7)
Vital signs of SIRS
Body temperature measurement, N (%)	471 (84.4)	275 (82.3)	61 (81.3)	336 (82.2)	92 (88.5)	43 (95.6)	135 (90.7)
Body temperature, mean (SD^b), °C	37.5 (0.9)	37.2 (0.7)	37.8 (1.0)	37.3 (0.8)	37.7 (1.0)	38.3 (1.1)	37.9 (1.1)
Respiratory rate measurement, N (%)	279 (50.0)	142 (42.5)	35 (46.7)	177 (43.3)	63 (60.6)	39 (88.7)	102 (68.5)
Respiratory rate, mean (SD), breaths/min	20 (6.9)	17 (4.7)	19 (6.0)	17 (5.1)	22 (6.5)	27 (7.5)	24 (7.3)
Heart rate measurement, N (%)	368 (65.9)	186 (55.7)	45 (60.0)	231 (56.5)	92 (88.5)	45 (100)	137 (91.9)
Heart rate, mean (SD), beats/min	87 (18.3)	83 (16.6)	91 (19.1)	85 (17.4)	87 (16.7)	100 (20.9)	92 (19.1)
≥2 SIRS vital sign abnormalities,^c N (%)	95 (17.0)	22 (6.6)	13 (17.3)	35 (8.6)	28 (26.9)	32 (71.1)	60 (40.3)
Antibiotics, N (%)	244 (43.7)	177 (53.0)	0 (0.0)	177 (43.3)	67 (64.4)	0 (0.0)	67 (45.0)
30-day mortality, N (%)	5 (0.9)	0 (0.0)	0 (0.0)	0 (0.0)	3 (2.9)	2 (4.4)	5 (3.4)

^aInterquartile range.

^bStandard deviation.

^cDefined as body temperature <36 or >38 °C; tachycardia >90/min; tachypnoea >20/min.

Table 2. Differences in patient characteristics between referred patients and patients not referred to the hospital.

Patient characteristic	Referred (n = 120)	Not referred (n = 438)
Age, median (IQR^a), year	55 (35–75)	48 (31–69)
Vital signs of SIRS, N (%)
Temperature <36 or >38 °C	48 (40)	66 (15)
Respiratory rate >20/min	44 (37)	55 (13)
Heart rate >90/min	50 (42)	81 (18)
Number of SIRS vital sign abnormalities, N (%)
0 (n = 343)	46 (38)	297 (68)
1 (n = 120)	29 (24)	91 (21)
2 (n = 61)	22 (18)	39 (9)
3 (n = 34)	23 (19)	11 (3)
Other clinical signs and symptoms, N (%)
Hypotension^b	10 (8)	6 (1)
Peripheral oxygen saturation <94%	27 (23)	18 (4)
Shivering	37 (31)	68 (16)
Unable to walk normally	18 (15)	28 (6)
Rapid progression of illness	62 (52)	77 (18)
Altered mental status	9 (8)	12 (3)

^aInterquartile range.

^bDefined as systolic blood pressure ≤100 mmHg.

Table 3. Logistic regression analyses for association of patient characteristics with hospital referral: univariable and multivariable analyses.

	Univariable analyses		Multivariable analyses
Patient characteristic	Odds ratio (95% CI^a)	p-Value	Odds ratio (95% CI)	p-Value
Age (per year)	1.01 (1.00–1.02)	0.04	0.99 (0.98–1.00)	0.09
Vital signs of SIRS
Temperature <36 or >38 °C	3.76 (2.40–5.89)	<0.001	1.68 (0.94–2.99)	0.08
Respiratory rate >20/min	4.03 (2.53–6.43)	<0.001	1.76 (0.94–3.30)	0.08
Heart rate >90/min	3.15 (2.04–4.87)	<0.001	1.36 (0.78–2.37)	0.3
Other clinical signs and symptoms (yes/no)
Hypotension^b	6.54 (2.33–18.4)	<0.001	4.07 (1.16–14.3)	0.03
Peripheral oxygen saturation <94%	6.77 (3.58–12.8)	<0.001	5.23 (2.40–11.4)	<0.001
Shivering	2.43 (1.52–3.87)	<0.001	1.12 (0.62–2.06)	0.7
Unable to walk normally	2.58 (1.38–4.96)	0.003	1.03 (0.46–2.28)	0.9
Rapid progression of illness	5.0 (3.25–7.74)	<0.001	3.75 (2.26–6.20)	<0.001
Altered mental status	2.88 (1.18–7.00)	0.02	1.50 (0.48–4.70)	0.5

^a Confidence interval; ^bDefined as systolic blood pressure >100 mmHg.