
Cohorts of interest

S. aureus pneumonia vs No pneumonia

P. aeruginosa pneumonia vs No pneumonia


No pneumonia

S. aureus pneumonia

P. aeruginosa pneumonia

Odds Ratio/Difference^{a}

P Value^{a}

Odds Ratio/Difference^{b}

P Value^{b}


(95 % CI)

(95 % CI)


N = 201,394

N = 2275

N = 1007


Mean (SD) length of hospital stay per patient

7.2 (9.6)

37.9 (39.4)

55.4 (54.9)

30.69 (29.41, 32.00)

<.001

48.18 (45.43, 51.08)

<.001

Mean (SD) length of ICU/CCU stay per patient

1.1 (2.1)

6.9 (21.1)

14.8 (36.6)

5.75 (5.59, 5.91)

<.001

13.63 (13.21, 14.06)

<.001

No. (%) of patients with mechanical ventilation

14,960 (7.4)

1,425 (62.6)

627 (62.3)

20.89 (19.16, 22.78)

<.001

20.56 (18.08, 23.38)

<.001

 CI confidence interval, ICU intensive care unit
 ^{a}Odds ratio (OR) from Chisquare test is used for categorical variables, negative binomial models are used to test for differences between means for count variables (number of events and length of stay). Statistical comparisons are comparing Cohort 3 (pneumonia due to S. aureus) with Cohort 1 (no pneumonia, reference group); ie, Difference = mean (Cohort 3) − mean (Cohort 1) and OR = Odds (Cohort 3)/Odds (Cohort 1)
 ^{b}Odds ratio (OR) from Chisquare test is used for categorical variables, negative binomial models are used to test for differences between means for count variables (number of events and length of stay). Statistical comparisons are comparing Cohort 4 (pneumonia due to P. aeruginosa) to Cohort 1 (no pneumonia, reference group); ie, Difference = mean (Cohort 4) – mean (Cohort 1) and OR = Odds (Cohort 4)/Odds (Cohort 1)