Table 3 Results from the logistic regression considering the variables known about the patient when entering the PED as independent variables and “avoidable visit” as the dependent variable, the reference is “not avoidable” (the results are presented in odds ratio, confidence interval and p-value)

Year

2014

—

—

2015

0.94

0.92, 0.96

< 0.001

2016

0.98

0.96, 1.00

0.10

2017

0.91

0.89, 0.93

< 0.001

2018

0.90

0.88, 0.91

< 0.001

2019

0.81

0.79, 0.83

< 0.001

2020

0.72

0.69, 0.75

< 0.001

—

—

Age (years)

[6...8]

—

—

—

—

[0...2]

1.03

1.01, 1.05

0.010

0.92

0.84, 0.99

0.035

[3...5]

1.23

1.20, 1.26

< 0.001

1.23

1.12, 1.34

< 0.001

[9...11]

0.67

0.66, 0.69

< 0.001

0.85

0.77, 0.94

0.001

[12...14]

0.56

0.55, 0.58

< 0.001

0.76

0.69, 0.84

< 0.001

[15...17]

0.60

0.58, 0.61

< 0.001

0.77

0.70, 0.85

< 0.001

Sex

Female

—

—

—

—

Male

1.03

1.02, 1.04

< 0.001

1.07

1.02, 1.13

0.004

Season

Fall

—

—

—

—

Spring

1.05

1.03, 1.07

< 0.001

2.68

2.51, 2.85

< 0.001

Summer

1.15

1.13, 1.17

< 0.001

2.04

1.93, 2.16

< 0.001

Winter

1.05

1.04, 1.07

< 0.001

1.32

1.17, 1.47

< 0.001

Weekend

No

—

—

—

—

Yes

1.06

1.04, 1.07

< 0.001

0.99

0.94, 1.05

0.75

Time of day

[12...15]

—

—

—

—

[0...3]

0.93

0.91, 0.96

< 0.001

1.08

0.97, 1.19

0.15

[4...7]

0.74

0.72, 0.77

< 0.001

0.75

0.65, 0.87

< 0.001

[8...11]

0.96

0.94, 0.97

< 0.001

0.95

0.88, 1.02

0.18

[16...19]

1.05

1.03, 1.07

< 0.001

1.04

0.97, 1.12

0.26

[20...23]

1.10

1.08, 1.12

< 0.001

1.19

1.12, 1.28

< 0.001

Residence municipality

Porto

—

—

—

—

Maia

0.95

0.93, 0.97

< 0.001

0.95

0.87, 1.03

0.19

Matosinhos

0.97

0.95, 0.99

< 0.001

1.03

0.95, 1.11

0.51

Gondomar

1.00

0.98, 1.02

0.81

1.00

0.93, 1.08

0.94

Valongo

0.94

0.92, 0.96

< 0.001

0.92

0.85, 1.01

0.073

Other

1.06

1.04, 1.08

< 0.001

1.10

1.02, 1.19

0.010

Referral

No

—

—

—

—

Yes

0.73

0.72, 0.75

< 0.001

0.80

0.76, 0.84

< 0.001

Made a return visit 72 h prior

No

—

—

—

—

Yes

0.80

0.78, 0.83

< 0.001

1.12

1.00, 1.26

0.040

Visit by frequent attender

No

—

—

—

—

Yes

1.01

1.00, 1.03

0.11

0.90

0.83, 0.97

0.007