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Retrospective cohort study of false alarm rates associated with a series of heart operations: the case for hospital mortality monitoring groups

Poloniecki, Jan, Sismanidis, Charalambos, Bland, Martin (orcid.org/0000-0002-9525-5334) and Jones, Paul (2004) Retrospective cohort study of false alarm rates associated with a series of heart operations: the case for hospital mortality monitoring groups. BMJ. pp. 375-379. ISSN 1756-1833

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OBJECTIVE: To examine the efficacy of different methods of detecting a high death rate and determining whether an increase in deaths after heart transplantation could be explained by chance. DESIGN:Retrospective analysis of deaths after heart transplantation. Seven methods were used: mortality above national average, mortality excessively above national average, test of moving average mortality, test of number of consecutive deaths, sequential probability ratio test (SPRT), cusum graph with v-mask, and CRAM chart. The national average mortality was not available and a rate of 15% was used instead as the benchmark. SETTING: Regional cardiothoracic unit. PARTICIPANTS: All 371 patients who received a heart transplant in the programme, 1986-2000. MAIN OUTCOME MEASURES: 30 day survival after transplantation. RESULTS: All methods provided evidence that the 30 day mortality had been high at some stage. The probability that the finding was a false positive depended on which test was used. At the end of the series the average mortality, sequential probability ratio, and cusum tests indicated a level of deaths higher than the benchmark while the remaining four tests yielded negative results. CONCLUSIONS:If the decision to test for outlying mortality is made retrospectively, in the light of the data, it is not possible to determine the false positive rate. Prospective on-site mortality monitoring with the CRAM chart is recommended as this method can quantify the death rate and identify periods when an audit of cases is indicated, even when data from other institutions are not available. A hospital mortality monitoring group can routinely monitor all deaths in the hospital, by specialty, using hospital episode statistics (HES) data and appropriate statistical methods.

Item Type: Article
Copyright, Publisher and Additional Information: © 2004 BMJ Publishing Group Ltd
Institution: The University of York
Academic Units: The University of York > Health Sciences (York)
The University of York > Biology (York)
Depositing User: Repository Officer
Date Deposited: 25 Aug 2004
Last Modified: 12 Jul 2016 07:16
Published Version: http://dx.doi.org/10.1136/bmj.37956.520567.44
Status: Published
Refereed: Yes
URI: http://eprints.whiterose.ac.uk/id/eprint/40

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