Hospitals' star ratings and clinical outcomes: ecological study
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《英国医生杂志》
1 Intensive Care National Audit and Research Centre, London WC1H 9HR, 2 London School of Hygiene and Tropical Medicine, London WC1E 7HT
Correspondence to: N Black nick.black@lshtm.ac.uk
Introduction
We compared the 2001-2 rating of 102 acute hospital trusts for which we had validated data for that year. We calculated each patient's predicted risk of death before discharge from hospital4 and compared it with actual mortality for all admissions in 2001-2 for each unit.
We compared rating with crude mortality at the patient level rather than aggregated by hospital; our sample of hospitals with all hospitals; and university with non-university hospitals using 2 tests for trend. We compared rating with size of intensive care unit and mean age of patients, using Spearman's . We calculated confidence intervals for mortality adjusted for risk, using logistic regression of mortality on rating and predicted log odds of mortality. We tested rating and adjusted mortality using the likelihood ratio test.
The distribution of ratings for the 102 acute hospital trusts was similar to that for all 166 trusts (2 = 1.7; P = 0.19). Rating was associated with teaching status (university hospitals had more stars than non-university hospitals—52% v 29% had three, 38% v 45% had two, 5% v 19% had one, 5% v 7% had zero; 2 = 3.9; P = 0.05) but not size of its critical care unit (Spearman's = 0.09; P = 0.34).
Rating and crude mortality for critical care admissions were significantly associated (2 = 4.1; df = 1; P = 0.04) (figure): mortality in trusts with three stars was about 4% lower than in trusts with zero stars. However, case mix of critical care admissions also differed considerably. Rating was inversely associated with the mean age of critical care admissions ( = -0.19; P = 0.04). The association between rating and hospital mortality was no longer significant when case mix differences were taken into account (P = 0.4) (figure).
Odds ratio for crude case mix and for case mix adjusted for risk hospital mortality by star rating of acute hospital trust
Comment
Department of Health. NHS performance ratings: acute trusts, specialist trusts, ambulance trusts, mental health trusts 2001/02. London: DoH, 2002.
Gill K, Black SA, Clarke P, Corbett CRR. Misleading mortality data in league tables. Ann R Coll Surg Engl 2003;85(suppl): S244-7.
Rowan K, Black N. A bottom-up approach to performance indicators through clinician networks. Health Care UK 2000 Spring: 42-6.
Rowan KM. Outcome comparisons of intensive care units in Great Britain and Ireland using the APACHE II method . Oxford: University of Oxford, 1993.
Black N, Payne M. Directory of clinical databases: improving and promoting their use. Qual Saf Health Care 2003;12: 348-52.(Kathy Rowan, director1, D)
Correspondence to: N Black nick.black@lshtm.ac.uk
Introduction
We compared the 2001-2 rating of 102 acute hospital trusts for which we had validated data for that year. We calculated each patient's predicted risk of death before discharge from hospital4 and compared it with actual mortality for all admissions in 2001-2 for each unit.
We compared rating with crude mortality at the patient level rather than aggregated by hospital; our sample of hospitals with all hospitals; and university with non-university hospitals using 2 tests for trend. We compared rating with size of intensive care unit and mean age of patients, using Spearman's . We calculated confidence intervals for mortality adjusted for risk, using logistic regression of mortality on rating and predicted log odds of mortality. We tested rating and adjusted mortality using the likelihood ratio test.
The distribution of ratings for the 102 acute hospital trusts was similar to that for all 166 trusts (2 = 1.7; P = 0.19). Rating was associated with teaching status (university hospitals had more stars than non-university hospitals—52% v 29% had three, 38% v 45% had two, 5% v 19% had one, 5% v 7% had zero; 2 = 3.9; P = 0.05) but not size of its critical care unit (Spearman's = 0.09; P = 0.34).
Rating and crude mortality for critical care admissions were significantly associated (2 = 4.1; df = 1; P = 0.04) (figure): mortality in trusts with three stars was about 4% lower than in trusts with zero stars. However, case mix of critical care admissions also differed considerably. Rating was inversely associated with the mean age of critical care admissions ( = -0.19; P = 0.04). The association between rating and hospital mortality was no longer significant when case mix differences were taken into account (P = 0.4) (figure).
Odds ratio for crude case mix and for case mix adjusted for risk hospital mortality by star rating of acute hospital trust
Comment
Department of Health. NHS performance ratings: acute trusts, specialist trusts, ambulance trusts, mental health trusts 2001/02. London: DoH, 2002.
Gill K, Black SA, Clarke P, Corbett CRR. Misleading mortality data in league tables. Ann R Coll Surg Engl 2003;85(suppl): S244-7.
Rowan K, Black N. A bottom-up approach to performance indicators through clinician networks. Health Care UK 2000 Spring: 42-6.
Rowan KM. Outcome comparisons of intensive care units in Great Britain and Ireland using the APACHE II method . Oxford: University of Oxford, 1993.
Black N, Payne M. Directory of clinical databases: improving and promoting their use. Qual Saf Health Care 2003;12: 348-52.(Kathy Rowan, director1, D)