Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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![[Read Rapid Response]](/icons/misc/sectionDOWN.gif)
Howler in "This Week in the BMJ"
- Hugh Tunstall-Pedoe (15 March 2004)
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Survival after Surgery or theraputic catherisation for congenital heart disease
- Fiona M Woollard (17 March 2004)
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Type II error in analysis of CCAD children's cardiac surgery survival?
- Anthony P Roberts (18 March 2004)
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Adjustment for procedure mix
- Paul Aylin (6 April 2004)
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Hugh Tunstall-Pedoe, Director of Cardiovascular Epidemiology Unit University of Dundee, Scotland UK
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The paragraph on this article for "This Week in the BMJ" headed "Children treated for heart conditions survive equally well across UK" contains the statement: "Survival at one year was double that at 30 days, and may be a better descriptor of overall outcome." This implies resurrection and is obvious nonsense, and funny use of English. The article itself says mortality at one year was twice that at 30 days. There is a tendency in Newspeak to use the antithesis for the real word (eg healthcare for disease care) and the BMJ would not be the first to confuse survival and mortality. But it is a bad precedent. Competing interests: None declared |
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Fiona M Woollard, Personal Assistant YO24 1EP
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I read with interest Dr Gibbs et al’s paper regarding congenital heart disease survival rates in the UK. Whilst I broadly welcome the paper that Dr John Gibbs and his colleagues supplied. There are a number of important features of this report which require addressing: - Namely that the report is based during the period 2000/2001 and does not take into account of any surgeries undertaken in previous years. - It does not take into account multiple heart defects such as my son who had interrupted aortic arch, ASD, VSD, PDA, isolated right sub-clavian arteries operated in 1992. I wonder where he would fit in your categories? - Later he went on to develop aortic stenosis, sub-aortic stenosis and left ventricular hypertrophy. There are no such categories for these patients albeit a rare defect. - It does not take into account deaths that are over a year – he survived 8 years. - It does not take into account how my son died and what of, for example, he died of complications of endocarditis – congestive heart failure. He could have died, for instance, crossing the road – he would have come under other. The other factors need to be addressed so as to improve the standards. - It does not take into account that he may have died in another hospital other than the tertiary centre. - There is a risk of benchmarking in that surgeons may not wish to do complex surgery like my son’s for procedures such as Ross Procedure, Ross- Konno Procedure and other complex heart surgery where the risk of failure is extremely high. Thereby the patient misses out and dies. Surgery should be dependent on the clinical need of the patient and not just benchmarking and success. I note too that the mortality figure at one year is 91.2% making a total of 8.8% deaths, approximately 1 in 10 of the cohort chosen. This is still high. The tables too are interesting certain hospitals have a better performance rate than others. Clarification should be sought as to why this is the case. It would also be clarification for parents who have difficult decisions to make about treatment choices and where they can be treated. Second opinions should always be offered where the surgery is complex and difficult decisions need to be made. The differences in the figures may be the case that proper communication has not taken place; poor note keeping; a lack of understanding about congenital heart disease and congestive heart failure is not high within certain paediatric units. In which case, it needs addressing and identifying. There is also a lack of knowledge of the role of genetics particularly in relation to VCFS/DiGeorge syndrome and these should be addressed. Genetics should be offered at the outset in order to plan treatment and therapy. Please note that the views expressed within this rapid response are my personal views and not those of any medical member of my family. Competing interests:
Parent of a child with complex congenital heart disease operated in 1992 in the UK
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Anthony P Roberts, Clinical Effectiveness Advisor South Tees Hospitals NHS Trust, The James Cook University Hospital, Middlesbrough, UK, TS4 3BW
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The data analysed by Gibbs et al of CCAD data is of enormous importance in terms of the reassurance of the public and yet it requires considerable effort to understand the presentation of results 1. Even Professor Treasure admits "Apparently insignificant sporadic deaths dispersed amongst these sets … cannot be seen as a pattern." 2. This is in part because of the analysis method chosen by the authors. A simpler and more visually powerful method would simply scatter the % survival against the number of cases (the denominator) 3. As a visual aid, to assess the degree of scatter, the mean and a line representing the lower 2.66 SD (or 99%) limit can be overlaid. The 1 year survival results for the CCAD data looks like this (Gibbs et al published enough data for re-analysis to be possible, to their credit):
Overall survival Chart
The other advantage of this method is that it reduces the type II error rate to credible proportions. Gibb's method requires a unit to experience sufficient deaths to be 2.66 SDs from 2.66 SD of the mean - a tall order indeed. The simpler method proposed here produces 2.66 SD limits for the set as a whole. The results for 1 year survival following repair of coarctation looks like this. Coartation survival chart
The BMJ is publishing more and more data from real clinical practice, in more and more formats, in order to explore variation in outcomes 4. It is time that the BMJ lead a debate about the tools needed to do this, so that an agreed set of methods may be used for reporting in this area. 1. John L Gibbs, James L Munroe, David Cunningham, Anthony Rickards. Survival after surgery or therapeutic catherisation for congenital heart disease in children in the United Kingdom: analysis of the central cardiac audit database for 2000-1. BMJ 2004;328:611-5 2. Tom Treasure. Congenital heart disease: Monitoring interventions after Bristol. BMJ 2004;328:594-5 3. Paris P Tekkis, Peter McCulloch, Adrian C Steger, Irving S Benjamin, and Jan D Poloniecki. Mortality control charts for comparing performance of surgical units: validation study using hospital mortality data. BMJ 2003; 326:786 - 788. 4. Brian Jarman, Paul Aylin, Alex Bottle. Acute stroke units and early CT scans are linked to lower in-hospital mortality rates. BMJ 2004;328:369 Competing interests: I em employed by an NHS hospital Trust and an NHS Primary Care Trust to advise on the interpretation of performance data |
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Paul Aylin, Clinical Senior lecturer in Epidemiology and Public Health Department of Epidemiology & Public Health, Imperial College London, Norfolk Place, London W2 1PG
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I welcome the published analysis of survival following surgery for congenital heart disease in children, and in particular the linkage of records to ONS mortality data to allow validation of fact of death and the analysis of longer term survival. However, it is not surprising that the authors failed to find significant differences between centres, given that their analysis was limited to only one year of data, and their centre comparisons were based on only six procedures. A reanalysis of the Hospital Episode Statistics made available to the Bristol Inquiry[1] and using as far as possible, the same six pooled benchmark procedures for 30 day in-hospital mortality for single years between 1991 to 1995, reveals that even with the extremely divergent performance observed at Bristol, it might very well have been missed using these criteria, with mortality reaching only borderline significance in just one year, 1993/4 (11.7%, 99%CI 5%-23%, compared to a national average of 4.7%). In the original analysis (commissioned by the Bristol Inquiry), analyses were published by centre for open and closed surgery. For open procedures in children under one year, adjustment was made for 11 different procedures using a logistic regression model, providing an alternative to stratification, and thus maintaining enough numbers to demonstrate any outliers. If stratification is merited, it would seem to be more natural to stratify by age. To further maximise statistical power, several years of data were combined. Why have the authors limited their analysis to only one year of data? Hospital Episode Statistics data will shortly be made available, linked to ONS mortality, allowing 1 year survival to be determined using routinely collected data. It will be interesting to compare results. [1] Aylin P, Alves B, Best N, Cook A, Elliott P, Evans SJW, Lawrence AE, Murray GD, Pollock J, Spiegelhalter D, Comparison of UK paediatric cardiac surgical performance by analysis of routinely collected data 1984- 96: was Bristol an outlier? Lancet 2001;358:181-87 Competing interests: Expert witness to the Bristol Inquiry, Deputy Director of Dr Foster Unit at Imperial |
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