Table 2.
Factors associated with the incidence of hospital-acquired pneumonia
| Characteristics | Univariable | Multivariable |
|---|---|---|
| OR (95% CI) | Adjusted OR (95% CI) | |
| Age group | ||
| 20–29 | Reference | Reference |
| 30–39 | 1.25 (1.13–1.38) | 1.25 (1.13–1.39) |
| 40–49 | 1.42 (1.29–1.56) | 1.31 (1.19–1.45) |
| 50–59 | 1.91 (1.75–2.09) | 1.60 (1.47–1.75) |
| 60–69 | 2.91 (2.67–3.17) | 2.11 (1.93–2.31) |
| Over 70 | 6.22 (5.73–6.76) | 3.66 (3.36–3.99) |
| Sex (male) | 1.36 (1.32–1.39) | 1.35 (1.32–1.39) |
| Poverty (yes) | 1.45 (1.39–1.51) | 1.08 (1.04–1.13) |
| Asthma (yes) | 2.83 (2.73–2.93) | 1.73 (1.66–1.80) |
| COPD (yes) | 3.60 (3.44–3.77) | 1.62 (1.53–1.71) |
| Other chronic lower respiratory disease (yes) | 2.56 (2.48–2.64) | 1.79 (1.73–1.85) |
| CKD (yes) | 1.71 (1.62–1.81) | 1.07 (1.00–1.14)* |
| Anemia (yes) | 1.42 (1.36–1.48) | 1.04 (1.00–1.10)† |
| Tube feeding (yes) | 11.25 (10.82–11.71) | 3.32 (3.16–3.50) |
| Suction (yes) | 7.15 (6.89–7.42) | 2.34 (2.23–2.47) |
| Positioning (yes) | 4.71 (4.57–4.86) | 1.63 (1.55–1.72) |
| Surgery (no) | 2.76 (2.67–2.85) | 2.98 (2.87–3.09) |
| Mechanical ventilation (yes) | 11.40 (10.85–11.98) | 2.31 (2.15–2.47) |
| ICU admission (yes) | 4.22 (4.09–4.35) | 1.29 (1.22–1.36) |
| Location of hospital | ||
| Seoul metropolitan area | Reference | Reference |
| Other metropolitan area | 1.09 (1.05–1.14) | 1.16 (1.06–1.26) |
| Province | 1.40 (1.35–1.45) | 1.20 (1.11–1.31) |
| Type of hospital | ||
| Tertiary | Reference | Reference |
| General | 1.53 (1.37–1.69) | 1.54 (1.39–1.70) |
| Bed-to-nurse ratio‡ (n = 425,953) | ||
| Grade 1 | Reference | Reference |
| Grade 2 | 1.12 (1.03–1.23) | 1.16 (1.06–1.27) |
| Grade 3 | 1.36 (1.24–1.50) | 1.31 (1.19–1.44) |
| Grade 4 | 1.59 (1.42–1.78) | 1.42 (1.26–1.59) |
| Grade 5 | 1.62 (1.49–1.77) | 1.45 (1.32–1.59) |
| Type of hospital room (n = 504,279) | ||
| ≤ 3 beds | Reference | Reference |
| 4 beds | 5.38 (4.83–5.99) | 3.26 (2.92–3.64) |
| 5 beds | 6.08 (5.48–6.76) | 3.34 (3.00–3.72) |
| 6 beds | 5.10 (4.60–5.65) | 3.08 (2.77–3.42) |
| Ward with or without caregiver§ (n = 469,588) | ||
| With caregivers | 1.09 (1.03–1.14) | 1.19 (1.12–1.26) |
| Without caregivers | Reference | Reference |
The multivariable analysis included age, sex, poverty, asthma, COPD, other chronic lower respiratory diseases, CKD, anemia, tube feeding, suctioning, positioning, surgery, mechanical ventilation, ICU admission, year of hospitalization, location of the hospital, and type of hospital
CI confidence interval; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; HAP, hospital-acquired pneumonia; ICU, intensive care unit; OR, odds ratio
*p = 0.03
†p = 0.08
‡Bed-to-nurse ratio grading was defined as follows: tertiary hospitals were divided into the following grades: grade 1 (a bed-to-nurse ratio of less than 2.0), grade 2 (a bed-to-nurse ratio of 2.0–2.4), grade 3 (a bed-to-nurse ratio of 2.5–2.9), grade 4 (a bed-to-nurse ratio of 3.0–3.4), grade 5 (a bed-to-nurse ratio of 3.5–3.9), and grade 6 (a bed-to-nurse ratio of 4.0 or more). General hospitals are classified into the following grades: grade 1 (a bed-to-nurse ratio of less than 2.5), grade 2 (a bed-to-nurse ratio of 2.5–2.9), grade 3 (a bed-to-nurse ratio of 3.0–3.4), grade 4 (a bed-to-nurse ratio of 3.5–3.9), grade 5 (a bed-to-nurse ratio of 4.0–4.4), grade 6 (a bed-to-nurse ratio of 4.5–5.9), and grade 7 (a bed-to-nurse ratio of 6.0 or more)
§In wards without caregivers, only the nursing staff takes care of the patients, and caregivers do not stay at the bedside