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Table 3 Results of Poisson regression analysisa

From: Hospital characteristics related to the hospital length of stay among inpatients receiving invasive cervical discectomy due to road traffic accidents under automobile insurance in South Korea

Variables Length of stay
RRb 95% CI P-value
Inpatient-level variables
 Sex
  Male 1.000   -   
  Female 0.974 0.871 - 1.090 0.6480
Age 0.997 0.993 - 1.002 0.2906
 Principal diagnosis (ICD-10)
  Cervical disc disorders (M50) 1.000   -   
  Fracture of neck (S12) 1.261 1.040 - 1.528 0.0182
  Dislocation, sprain and strain of joints and ligaments at neck level (S13) 1.254 1.035 - 1.518 0.0207
  Injury of nerves and spinal cord at neck level (S14) 1.509 1.242 - 1.835 <.0001
  Others 1.642 1.352 - 1.995 <.0001
 Cervical spine surgery performed with cervical discectomy
  None 1.000   -   
  Arthrodesis 1.254 0.931 - 1.691 0.1367
  Corpectomy or corpectomy + arthrodesis 1.674 1.180 - 2.374 0.0039
 Charlson Comorbidity Index
  0 1.000   -   
  1 1.227 1.072 - 1.404 0.0030
  2 1.331 1.139 - 1.557 0.0003
   ≥ 3 1.543 1.285 - 1.853 <.0001
 Other surgical procedures during hospitalization
  Not received 1.000   -   
  Received 1.413 1.287 - 1.552 <.0001
 Study period
  2014, January-June 1.000   -   
  2014, July-December 0.912 0.811 - 1.027 0.1278
  2015, January-June 0.790 0.697 - 0.896 0.0002
  2015, July-December 0.768 0.671 - 0.879 0.0001
Hospital-level variables
 Proportion of inpatients with automobile insurance (%) 1.027 1.012 - 1.042 0.0005
 Volume of invasive cervical discectomy (per 10 case increase) 0.970 0.945 - 0.997 0.0224
 Bed turnover rate 0.988 0.979 - 0.997 0.0076
 Number of neurosurgeons or orthopedic specialists per 100 beds 0.930 0.876 - 0.987 0.0161
 Number of beds 0.977 0.964 - 0.990 0.0007
Types of hospital
 Hospital (N = 40) 1.000   -   
 General hospital (N = 118) 1.205 0.930 - 1.562 0.1585
Area
 Metropolitan (N = 107) 1.000   -   
 Non-metropolitan (N = 51) 0.997 0.895 - 1.110 0.9520
  1. ICD International classification of diseases, RR rate ratio, CI confidence interval
  2. aAll variables in the table were simultaneously adjusted
  3. bThe RRs (rate ratios) indicate the results of exponentiated coefficients and can be interpreted as percentage changes