Comparing hospital mortality – how to count does matter for patients hospitalized for acute myocardial infarction (AMI), stroke and hip fracture

Table 1 How the three different 30-day mortality measures (W30D, S30D and IH30D) account for deaths when place and time of death varies

		W30D^†	S30D^‡	IH30D^§
Place of death	In-hospital, during initial admission	Yes	Yes	Yes
	In-hospital during a subsequent admission	Yes	No	Yes
	Outside hospital	Yes	Yes	No
Start for counting number of days	From Day 0 at the initial hospital	Yes	Yes	No
	From Day 0 at each hospital in the chain of admission	No	No	Yes
Weight attributed to each hospital	(Days at hospital)/ total hospital days)	Yes	No	No
	Unweighted	No	Yes	Yes
Transferred patients included	Yes	Yes	No	Yes

‘Yes’ indicate that the actual place or time of death are included.
^†W30D: In-and-out-of-hospital mortality within 30 days, attributing the outcome to all hospitals by fraction of time spent in each hospital for transferred patients.
^‡S30D: In-and-out-of-hospital mortality within 30 days, patients treated at one hospital only.
^§IH30D: In-hospital mortality within 30 days, for each hospital admission.

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