Table 2. Odds ratios (99.9% confidence interval) and model fit criteria from multiple logistic regression for occasional frequent users and persistent frequent users, based on the validation sample (n = 146,973).

Variable	Occasional frequent use n = 10,510	Persistent frequent use n = 1,859
Sex
Male	Reference
Female	1.02 (0.94–1.09)	1.14 (0.96–1.36)
Age category
18–34	1.42 (1.21–1.67)	1.57 (1.11–2.20)
35–54	1.11 (0.98–1.25)	1.20 (0.93–1.56)
55–64	Reference
65–74	0.97 (0.85–1.11)	0.96 (0.69–1.33)
75–84	1.10 (0.96–1.27)	1.04 (0.74–1.46)
≥85	1.14 (0.96–1.36)	0.76 (0.49–1.17)
PPDIP admissibility
Regular	1.11 (0.99–1.24)	1.09 (0.82–1.46)
≥65 years with GIS	1.36 (1.18–1.56)	1.65 (1.17–2.34)
Not admissible	Reference
Recipients of LRFA	1.76 (1.55–2)	2.73 (2.09–3.59)
Asthma	1.29 (1.16–1.43)	-
Chronic obstructive pulmonary disease	1.46 (1.33–1.59)	1.82 (1.52–2.17)
Coronary heart disease	1.11 (1.02–1.21)	1.17 (0.97–1.41)
Diabetes	1.2 (1.11–1.29)	1.37 (1.16–1.62)
Number of previous ED visits
≤1	Reference
2	2.53 (2.28–2.79)	3.75 (2.82–4.98)
3	3.78 (3.36–4.26)	7.26 (5.41–9.69)
4	5.63 (4.86–6.49)	12.58 (9.20–17.09)
≥5	12.47 (11.11–14)	37.07 (29.33–47.07)
Comorbidity index
0	Reference
1–2	1.32 (1.21–1.44)	1.40 (1.14–1.73)
3–4	1.48 (1.31–1.66)	1.38 (1.06–1.79)
≥5	1.39 (1.24–1.56)	1.28 (0.99–1.64)
Social deprivation
1	Reference
2	1.00 (0.87–1.14)	-
3	1.07 (0.94–1.22)	-
4	1.17 (1.03–1.33)	-
5	1.23 (1.08–1.4)	-
Material deprivation
1	Reference
2	1.04 (0.90–1.2)	-
3	1.10 (0.96–1.26)	-
4	1.14 (1.00–1.31)	-
5	1.16 (1.02–1.33)	-
Residential area
Metropolitan	Reference
Small town	1.16 (1.05–1.28)	-
Rural	1.29 (1.16–1.42)	-
Depression	1.30 (1.18–1.43)	1.34 (1.10–1.62)
Drug abuse	1.55 (1.29–1.85)	1.60 (1.20–2.13)
Area under the curve	0.76	0.89
R2	7%	28%
BIC	65,093	14,885

-: the variable was not selected during the variable selection process.