Table 5. Quality of care as assessed by standardized mortality ratio (SMR) in the groups younger and older than 70 years.

Outcome	Age <70	Age ≥70	P-value
N (%)	1537 (64.9)	833 (35.1)
Observed mortality, n (%) (20)	71 (4.6 (3.6–5.6))	77 (9.2 (7.4–11.5))	<0.001
Expected mortality (%) *	6.83 (5.57–8.09)	13.49 (11.17–15.81)	<0.001
SMR (Observed / expected mortality) (20)	0.68 (0.53–0.85)	0.69 (0.54–0.85)	>0.05

The SMR between patients of 70 years and older and patients younger than 70 years is similar.

Abbreviation: SMR = Standardized mortality ratio = observed divided by expected mortality. An SMR <1 indicates ED management is better than expected.

The number between brackets indicates the amount of missing variables.

* Expected mortality is calculated at ED entrance (before ED treatment) with the PIRO-score, by means of the derivation cohort and the two validation cohorts in the PIRO study by Howell et al [13].