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In‐hospital vs. 30‐day mortality in the critically ill – a 2‐year Swedish intensive care cohort analysis
Author(s) -
Rydenfelt K.,
Engerström L.,
Walther S.,
Sjöberg F.,
Strömberg U.,
Samuelsson C.
Publication year - 2015
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/aas.12554
Subject(s) - medicine , standardized mortality ratio , intensive care , intensive care unit , mortality rate , emergency medicine , saps ii , cohort study , cohort , retrospective cohort study , epidemiology , pediatrics , intensive care medicine , apache ii
Background Standardised mortality ratio ( SMR ) is a common quality indicator in critical care and is the ratio between observed mortality and expected mortality. Typically, in‐hospital mortality is used to derive SMR , but the use of a time‐fixed, more objective, end‐point has been advocated. This study aimed to determine the relationship between in‐hospital mortality and 30‐day mortality on a comprehensive Swedish intensive care cohort. Methods A retrospective study on patients >15 years old, from the Swedish Intensive Care Register ( SIR ), where intensive care unit ( ICU ) admissions in 2009–2010 were matched with the corresponding hospital admissions in the Swedish Hospital Discharge Register. Recalibrated SAPS (Simplified Acute Physiology Score) 3 models were developed to predict and compare in‐hospital and 30‐day mortality. SMR based on in‐hospital mortality and on 30‐day mortality were compared between ICU s and between groups with different case‐mixes, discharge destinations and length of hospital stays. Results Sixty‐five ICU s with 48861 patients, of which 35610 were SAPS 3 scored, were included. Thirty‐day mortality (17%) was higher than in‐hospital mortality (14%). The SMR based on 30‐day mortality and that based on in‐hospital mortality differed significantly in 7/53 ICU s, for patients with sepsis, for elective surgery‐admissions and in groups categorised according to discharge destination and hospital length of stay. Conclusion Choice of mortality end‐point influences SMR . The extent of the influence depends on hospital‐, ICU ‐ and patient cohort characteristics as well as inter‐hospital transfer rates, as all these factors influence the difference between SMR based on 30‐day mortality and SMR based on in‐hospital mortality.