Table 5: Bivariate association between each predictor variable and total length of stay (369 observations).
| Independent variable | Mean difference of total LOS ± SD Days [95% CI: lower; upper]; Correlation rho | P value |
| Age | Spearman's rho: 0.116 day for every one year | 0.025 |
| Male | 0.75 ± 1.24 days [-1.68; 3.2] | 0.54 |
| Public Hospital | 2 ± 1.23 days [-0.42; 4.40] | 0.106 |
| ICU admission | 9 ± 1.35 days [6.64; 11.35] | < 0.001 |
| Sepsis | 4.92 ± 1.27 days [2.4; 7.43] | < 0.001 |
| Intubation | 8.53 ± 1.69 days [5.19; 11.88] | < 0.001 |
| Foley catheter insertion | 4.59 ± 1.32 days [1.97; 7.21] | < 0.001 |
| Central venous catheter insertion | 8.81 ± 1.59 days [11.97; 5.65] | < 0.001 |
| Surgical intervention | 3.79 ± 1.34 days [1.15; 6.44] | 0.005 |
| Co-morbidities | ||
| Coronary artery diseases | 3.07 ± 1.25 days [0.53; 5.60] | 0.018 |
| Atrial fibrillation | 7 ± 2.71 days [1.66; 12.33] | 0.01 |
| Site of infection | ||
| • Pneumonia | 4.96 ± 2.03 days [0.85; 8.95] | 0.018 |
| • Blood stream | 5.74 ± 2.52 days [0.67; 10.8] | 0.027 |
| • Surgical site | 6.10 ± 2.2 days [1.65; 10.54] | 0.008 |
| • Ventilator associated | 7.49 ± 2.48 days [2.60; 12.37] | 0.003 |
| Multi sensitive Bacteria | ||
| • Escherichia coli | -3.02 ± 1.44 days [-5.86; -0.019] | 0.036 |
| • Morganella morganii | 10.42 ± 4.86 days [0.848; 19.99] | 0.033 |
| • Stenotrophomonas maltophilia | 12.59 ± 5.31 days [2.13; 23.05] | 0.018 |
| MDR Bacteria | ||
| • Staphylococcus aureus | 9.56 ± 3.15 days [3.13; 15.99] | 0.005 |
| • Klebsiella pneumoniae | 13.20 ± 5.40 days [1.53; 24.88] | 0.029 |
| XDR Bacteria | ||
| - Acinetobacter baumannii | 9.12 ± 2.76 days [3.53; 14.71] | 0.002 |
| - Pseudomonas aeruginosa | 23.29 ± 13.18 days [-10.54; 57.14] | 0.137 |
| - Escherichia coli | 13.19 ± 6.86 days [-0.30; 26.69] | 0.055 |
| Polymicrobial infection* | 10.76 ± 1.9 days [6.98; 14.53] | < 0.001 |
| Developed nosocomial infection | 9.86 ± 1.19 days [7.51; 12.22] | < 0.001 |
*Polymicrobial infection: Involvement of ≥ 2 bacteria. Pearson chi-square test (to compare 2 qualitative variables), Pearson correlation coefficients in normal distribution and Spearman correlation coefficients for non-normal distribution (to compare 2 quantitative variables) and student t-test to compare (1 quantitative variable and 1 qualitative variable), Fisher's Exact Test was used when cell counts of less than 5 comprise 25% or more of a table.
Mean difference for gender was calculated by subtracting the mean LOS of male - mean LOS of female; mean difference for hospital was calculated by subtracting the mean LOS of hospital 1 (public) - mean LOS of hospital 2 (private). Mean differences of other variables (interventions, diseases, conditions, bacteria) were calculated by subtracting mean LOS of yes - mean LOS of no.
LOS: Length of Hospital Stay; ICU: Intensive Care Unit; MDR: Multi-Drug Resistant; XDR: Extensively-Drug Resistant.