Table 2

Univariate associations between independent variables and time to physician (tMD).

Parameter mean (min) 95% CI* **
Shift time of day
 Morning (0600–1400) Mean 35.6 31.7–39.5
 Evening (1400–2200) Mean 49.8 45.0–54.7
 Night (2200–0600) Mean 53.1 49.2–57.1
Number of on-duty physicians Mean 21.7 21.3–22.2 0.005
Shift weekday (Sunday = baseline)
 Sunday Mean 50.6 43.6–57.5 –
 Monday Mean 49.3 38.4–60.2 0.259
 Tuesday Mean 45.0 35.4–54.7 0.940
 Wednesday Mean 46.8 37.9–55.7 0.168
 Thursday Mean 48.5 38.8–58.1 0.436
 Friday Mean 38.2 30.9–45.5
 Saturday Mean 46.0 41.3–50.6 0.798
β-coefficient*** in regression vs.
Shift census proportion of:
 Patients from Qatar 1.1 0.48–1.8
 Females 0.82 0.21–1.4
 Patients arriving by ambulance 0.86  − 0.03–1.8
 Median age of patients in shift  − 4.0  − 5.7 to − 2.2
 Chief complaint (proportion in shift)
 Gastrointestinal  − 1.4  − 2.3 to − 0.6
 Soft tissue injury or infection  − 0.1  − 1.3 to 1.0 0.827
 Musculoskeletal pain  − 0.1  − 1.2 to 0.9 0.787
 Eye, ear, nose, or throat  − 0.7  − 2.0 to 0.6 0.317
 Neurologic or psychiatric  − 0.4  − 2.3 to 1.5 0.660
 Shock or trauma 1.5 0.4 to 2.7
 Chest complaints 0.1  − 1.7 to 1.9 0.936
 Fever 1.5  − 0.2 to 3.2 0.092

*CI: confidence interval.

**The value indicates the significance level of testing for association between and the parameter denoted in the first column.

***The β-coefficient indicates how strongly (indicated by an absolute value with zero as null value), and in which direction (indicated by the sign, with negative β meaning inverse correlation) the predictor variable influences the outcome of interest.14