Atypical aetiology in patients hospitalised with community-acquired pneumonia is associated with age, gender and season; a data-analysis on four Dutch cohorts

Table 4 Three multivariable logistic regression sensitivity analyses: 1) Excluding viral pathogens; 2) Cases with unknown aetiology being indicated as not atypical; and 3) Cases with unknown aetiology being indicated as atypical

	1) Atypical vs. other (viral cases excluded)		2) Atypical vs. other and unknown		3) Atypical and unknown vs. other
Parameter	OR	95 % CI	OR	95 % CI	OR	95 % CI
Non-respiratory season	4.2	2.58–6.72**	3.0	1.95–4.47**	2.0	1.47–2.76**
Age <60 years	2.7	1.69–4.36**	3.0	1.97–4.59**	1.0	0.75–1.35
Male gender	1.7	1.09–2.81*	1.6	1.02–2.41*	1.2	0.91–1.56
COPD^a	0.2	0.11–0.48**	0.3	0.15–0.65*	0.5	0.37–0.70**

Abbreviations: OR odds ratio, CI confidence interval, COPD chronic obstructive pulmonary disease
*Indicates a p-value <0.05; **Indicates a p-value < 0.001
^aIndicates four missing values

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