Table 2.
Association of intensive care unit admission and longer hospital stay with age and virus type among children aged <2 years hospitalised with acute lower respiratory infection in Auckland, New Zealand 2012–2015
| Adjusted Models | ICU admission | Prolonged hospital stay | ||||
|---|---|---|---|---|---|---|
| RR | (95% CI) | P-value | RR | (95% CI) | P-value | |
| Main effects | ||||||
| Demographics | ||||||
| Age in months | 0.95 | (0.92–0.99) | 0.016 | 0.97 | (0.96–0.97) | 0.000 |
| European/ Asian/ Other | 1.00 | (ref) | 1.00 | (ref) | ||
| Maori | 1.34 | (0.95–1.89) | 0.095 | 1.04 | (0.94–1.16) | 0.467 |
| Pacific | 1.01 | (0.70–1.45) | 0.957 | 0.99 | (0.89–1.10) | 0.857 |
| NZDep2013 1–6a (Least deprived) | 0.85 | (0.59–1.22) | 0.388 | 1.04 | (0.92–1.17) | 0.539 |
| NZDep2013 7–8 | 1.00 | (ref) | 1.00 | (ref) | ||
| NZDep2013 9–10 (Most deprived) | 0.53 | (0.38–0.72) | 0.000 | 0.95 | (0.86–1.05) | 0.307 |
| Underlying conditions | ||||||
| Respiratory (asthma, other lung disease, and/or prior respiratory hospitalisation) | 1.80 | (1.40–2.33) | 0.000 | 1.20 | (1.11–1.30) | 0.000 |
| Other underlying conditions (Congenital cardiovascular, immune, renal, hepatic) | 2.05 | (1.36–3.09) | 0.001 | 1.68 | (1.39–2.04) | 0.000 |
| Premature birth and/or low birth weightb | 1.78 | (1.36–2.33) | 0.000 | 1.15 | (1.05–1.27) | 0.002 |
| Viral Infection | ||||||
| Influenza | 0.33 | (0.12–0.89) | 0.028 | 0.78 | (0.64–0.95) | 0.014 |
| RSV | 1.55 | (1.00–2.39) | 0.051 | 1.02 | (0.94–1.11) | 0.591 |
| Rhinovirus | 0.86 | (0.65–1.14) | 0.306 | 0.85 | (0.78–0.93) | 0.000 |
| Adenovirus | 1.53 | (1.12–2.09) | 0.007 | 0.98 | (0.78–1.23) | 0.861 |
| Interactive effects (scale) | ||||||
| Influenza and age in months (multiplicative) | 1.07 | (0.98–1.16) | 0.135 | 1.03 | (1.02–1.06) | 0.001 |
| Influenza and age in months (additive [RERI]) | 0.05 | (0.01–0.09) | 0.012 | |||
| RSV and age in months (multiplicative) | 0.91 | (0.86–0.97) | 0.003 | |||
| RSV and age in months (additive [RERI]) | −0.15 | (−0.3–0.01) | 0.042 | |||
| Adenovirus and age in months (multiplicative) | 1.02 | (1.01–1.05) | 0.036 | |||
| Adenovirus and age in months (additive [RERI]) | ||||||
ICU, intensive care unit; RR, risk ratio; RERI, relative excess risk owing to interaction; RSV, respiratory syncytial virus.
aSmall area-level measure of household deprivation derived from variables collected at the 2013 national census (NZDep2013 Index of Deprivation) [24].
bPreterm birth defined as <37 weeks of gestational age. Low birth weight defined as birth weight <2500 g.