Monthly Archives: July 2011

Week 7 – Discussion points: Benefits of PCI in Stable Coronary Heart Disease

The points for this evening are as follows:

  1. Does the single-centre design mean that there are too few physicians being surveyed? Does it limit the range of viewpoints and practices that are examined?
  2. If most patients spoke to their doctor for at least five minutes about PCI, why did 88% still believe it would reduce their risk of MI?
  3. Why would 43% of cardiologists who identified no benefit in PCI in a hypothetical scenario proceed with it anyway?
  4. What can doctors do differently to communicate the benefits of treatment with their patients?
  5. With regards to the consent form, does this paper raise questions about the nature of informed consent?

Please note you can find the consent form and patient questionnaire online. (Thanks to @dean_jenkins for finding these).

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Week 7 – Introduction: Benefits of PCI in Stable Coronary Heart Disease

Percutaneous Coronary Intervention (PCI) is a surgery in which obstruction in a stenotic coronary artery is cleared either by balloon angioplasty or stenting. It is a very common procedure, with a 2006 American Heart Association report estimating 1.2 million procedures in 2003 in the US.

PCI is not generally effective in reducing numbers of myocardial infarctions (MI) or mortality in patients with chronic stable angina, but rather only improves quality of life. (This is according to a number of randomised trials and meta-analyses, most notably the highly-publicised COURAGE trial.) Conversely, PCI can be effective in reducing morbidity and mortality in unstable angina.

This study looked at 153 patients who were undergoing diagnostic cardiac catheterisation, but who had also signed consent form for PCI to be performed if it was deemed to be necessary by the interventional cardiologist. They were asked about demographic characteristics, history of angina, whether they felt they were adequately informed about the procedure, and what their expectations of its benefits were.

The study also looked at physicians’ responses to a similar survey. Ten interventional cardiologists and 17 referring cardiologists were asked about their beliefs on the benefits of PCI, and expected outcomes for various hypothetical patients. With interventional cardiologists, the authors also asked about beliefs for study patients undergoing surgery. From my perspective, the numbers here are strikingly small, though since this is a single-centre survey, this probably placed limits on the number of cardiologists who could be asked. It does, however, mean that some of the n numbers in the results section are very small.

The key finding of the paper is that, among patients, 88% believed PCI would reduce their risk of MI, and 82% believed it would reduce their risk of fatal MI; however, among physicians, only 17% believed PCI would reduce the risk of MI and 15% believed it would reduce fatal MI. Furthermore, there was little agreement between individual patients’ and their cardiologists’ responses.

Despite this disparity, most patients reported their doctor spending at least 5 minutes explaining the procedure to them, and over half received some written information on the matter. Furthermore, 96% believed they knew why they might undergo PCI, and more than half felt they had been actively involved in decision making. With patients on whom PCI was carried out, physicians were more likely than patients to believe that the patient had been involved in decision making (78% v 94%). Also of note: patients felt they were at greater risk of MI than their cardiologists did (according to a 5 point Likert scale). Perhaps bizarrely, patients who thought they knew why there were getting PCI were more likely to hold the inaccurate belief that PCI prevented MI though this did not reach significance (Odds ratio = 5.3, CI 0.82-34.53).

The physician responses to hypothetical scenarios also generated some interesting results, perhaps most significantly:

In the first 2 scenarios, 70% of cardiologists did not identify any bnefit associated with PCI, yet 43% of these indicated that they would proceed to PCI anyway

I can’t help but question why a doctor would go ahead with a procedure from which they could foresee no benefit. In addition, this recent study also showed that for non-acute indications, 12% of PCIs were classified as inappropriate. The majority of these procedures performed in patients with little to no angina or with low-risk ischemia on stress testing.

Patients overestimating the benefits of drugs is not limited to PCI and cardiology, but why is it that patients perceive benefit when there is none? Given that most patients in this study had a discussion with their cardiologist, why were they not better informed about the potential outcomes of PCI? Is it a failure to adequately distinguish between unstable and stable angina? It does follow logically that alleviating the symptoms of cardiovascular disease would alter some underlying mechanisms to reduce the risk of MI, but shouldn’t cardiologists be making it clear to patients that this is not the case? What can doctors do differently to communicate effectively with their patients?

~*~

If you have any other comments on the paper, please do raise them this evening. As usual, a bit before 8 o’clock this evening (UK time, so 7pm GMT) I’ll post the key points for discussion.

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Week 6 – Summary: Beta blockers and COPD

Please see the introduction for a summary of the paper itself.

Beta blockers are widely prescribed for a range of conditions and are now widely used in the management of cardiovascular disease. There has been concerns regarding the prescription  β-blockers in patients with COPD due to worries about the effect it may have on their respiratory function, particularly  inhibition of the bronchodilator response to beta agonists.

This BMJ paper examined the use of  β-blockers in patients with COPD to assess the effect on mortality, hospital admissions and exacerbations when used in combination with established therapy for COPD.

This was a retrospective cohort study: it identified cases from a disease-specific database in Tayside which is used by GPs and secondary care respiratory physicians. During the discussion, some concerns were raised over the observational nature of the study, and it was felt that while observational studies can be very useful, we need to be aware of their limitations.

@alasdairforrest also commented on the practicality of such a study versus a prospective study:

The Regional Ethics Committee may have preferred a retrospective study to a therapeutic trial. Or 1/5 paperwork?

The key issue was the balance between simplicity, reduced costs and increased patient numbers usually associated with an observational study, and the difficult with being as “controlled” as a prospective study. @silv24 also added that observational studies take less time to carry out.

The consensus reached was that while observational studies have their limitations, such as the need to consider randomisation problems and confounding factors, they “can also lead to more definitive questions and enable better RCTs in the future” (@mgtmccartney).

As for whether observational studies can be used to change clinical practice, again the responses were mixed. Some agreed that they could be used, but that it was dependent on the strength of the evidence. Alternatively, observational studies could act as a good starting point for other research. Others felt that observational studies alone were inadequate, but that they can add the evidence in favour of a particular practice. As @drgandalf52 pointed out, “to convince the bulk of GPs [we] need to convince NICE”.

An important issue raised with the paper was the lack of information on the patient:

  • “we don’t actually know why any of these patients were on beta blockers for one thing!” (@silv24)
  • “Although database sounds comprehensive, past history of patients is unknown and no record of indication for starting BBs” (@northern_doctor)
  • “the biggest bias might have been that beta blockers were only prescribed to less seriously ill [patients] in [the] first place” (@amcunningham)
The discussion then moved onto whether the end-points used in the study were robust enough to show that beta blockers are safe in COPD in this patient population. @alasdairforrest felt that “hazard ratio for emergency steroids is a good endpoint”, and @northern_doctor pointed out that this shows there was no adverse effect of beta-blockers on airway. Furthermore, @silv24 “found the data on reductions in hospital admissions and emergency oral corticosteroid use very interesting”.
I think @northern_doctor neatly summed the issue up:
I think authors were very thorough with statistical and subgroup analysis to anticipate possible limitations - Couldn’t have done more with data that was available
The paper only considers one geographical area, so did this affect the application of the results to other populations? There was a bit of debate over whether the population studied was representative of the wider population in the UK, but @citylivindundee, first author of the paper, clarified that:
database covers tayside, population >200,000. we believe it to be typical of general population
We discussed the possibility of a nationwide database for patient details, either specific for a study, or as a general NHS database. @northern_doctor pointed out the pre-existing SITS-MOST data for stroke thrombolysis, which perhaps shows the idea would be feasible for a study such as this, although there would need to be a reason for collating this data (for example a study) due to costs.Some felt that the paper, on its own, did not provide adequate evidence for using beta blockers in COPD patients, and that further studies, such as RCTs, would be necessary to confirm the findings. However others felt that since this paper contributed to a pre-existing body of research into the safety of beta-blockers in COPD (such as this Cochrane Review via @mgtmccartney), it may not be ethical to conduct an RCT.

Overall, it was felt that while this paper has its flaws and needs to be considered in context, it provides further evidence towards the idea that all patients with cardiovascular disease can be prescribed beta-blockers, regardless of co-existing COPD.
~*~
We would like to thank Phil Short (@citylivindundee), first author of the paper, for contributing to the discussion.

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Week 6 – Discussion points: Beta-Blockers and COPD

The discussion points for this week are as follows:

1. This paper is a retrospective cohort study – what is the place of observational studies in influencing or changing clinical practice?

2. Endpoints measured – where they robust enough to show that beta blockers are safe in COPD in this patient population?

3. The paper used a database of patients in one geographical area. Should we be trying to build up the links needed to produce this kind of data across the UK more generally?

4. Is there a need for prospective research into whether beta blockers are safe in patients with COPD?

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Week 6 – Introduction: Beta-Blockers and COPD

Beta blockers are widely prescribed for a range of conditions and are now widely used in the management of cardiovascular disease. Patients with chronic obstructive pulmonary disease (COPD) often have concurrent co-morbidities including cardiovascular disease. However there has been concerns regarding the prescription  β-blockers in these patients due to worries about the effect it may have on their respiratory function:

  • evidence that the use of  β-blockers in patients with COPD may lead to a reduction in their lung function (by reducing their FEV1 - Forced expiratory volume in one second)
  • β-blockers may increase airway hyperresponsiveness

One of the mainstays of treatment of COPD is the use of beta-agonists and there have been concerns that  β-blockers may lead to inhibition of the bronchodilator response to these drugs.

As such there has been some reluctance to prescribe  β-blockers in these patients. This paper published in the BMJ looked at the use of  β-blockers in patients with COPD to assess the effect on mortality, hospital admissions and exacerbations when used in combination with established therapy for COPD.

This was a retrospective cohort study which identified cases from a disease-specific database in Tayside which is used by GPs and secondary care respiratory physicians. All patients fulfil the GOLD guidelines for diagnosis of COPD and data on these patients was collected by respiratory nurses at yearly visits. The authors then identified patients who had an admission to hospital due to COPD and also gathered data on the prescription of respiratory and cardiovascular drugs and on deaths from the general register.

The main outcome measures were hazard ratios from all cause mortality, emergency oral corticosteriod use (use to treat exacerbations of COPD) and respiratory related hospital admissions. In these patients 88% of the β-blockers used were cardioselective.

The results – this paper showed a 22% reduction in all cause mortality in patients prescribed  β-blockers. There was a reduction in the adjusted hazard ratio for patients prescribed β-blockers with standard treatment for COPD compared to those who weren’t (0.28 vs 0.43). The paper also showed a reduction in oral corticosteriod use and hospital admission. There was no adverse effect on lung function detected at all stages of the stepwise treatment approach to COPD.

The authors of this paper concluded that:

 β blockers may reduce mortality and COPD exacerbations when added to established inhaled stepwise therapy for COPD, independently of overt cardiovascular disease and cardiac drugs, and without adverse effects on pulmonary function

A list of discussion points will be posted shortly. Thank you to @amcunningham for suggesting this paper.

Posted in Introductions, Week 6 | 1 Comment

Week 5 – Summary: Safer Surgery Checklist

Apologies for the delay in posting the summary of last Sunday’s discussion. A week of nights on call in A&E didn’t leave much time for anything but sleeping.  The summary will be posted as soon as possible and I will tweet a link as soon as I do this. Thank you all for continuing to join in the journal club discussions and I am looking forward to tomorrow night’s discussion already.

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Week 5 – Discussion points: Safer Surgery Checklist

The NEJM paper published in 2009 has had an impact worldwide with the introduction of surgical checklists in over 3000 hospitals. This paper highlighted an important patient safety issue and aimed to tackle this with a relatively simple intervention. The discussion points below are meant to be a broad starting point for the evening, I hope that in particular the methodology of the paper will be discussed in detail.

1. This study ran for less than a year in eight healthcare settings and there have been many criticisms made of the methodology of the paper (see this blogpost & this letters page for examples of the criticisms). Is this adequate enough to support the widespread implementation of the checklist purely based on this paper?

 2. In the discussion of the paper the authors mention the Hawthorn effect as a possible mechanism of improvement, i.e. an improvement in performance due to the subject’s knowledge of being observed. However this has also been raised as a flaw in the study, the fact that the participants knew they were in a trial could have lead to the improvements shown rather than it being due to the checklist. Does this reduce the validity of the study and its findings?

 3. The checklist is a relatively simple intervention, is there a risk that this could become a tick-box exercise rather than being given due care and attention?

 4. In a letter responding to the paper members of NCEPOD stated that they supported the initiative but were concerned that the implied decrease in the perioperative rate of death was unlikely to be as great in the UK as reported in the paper. Does this make the study any less relevant to practice in developed countries?

If there is time I would also like to discuss how the paper is relevant to practice in less developed countries. Thank you to @fidouglas, @amcunningham & @assidens for their help

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Week 5 – Introduction: Safer Surgery Checklist

A Surgical Safety Checklist to Reduce Morbidity and Mortality in a Global Population – Haynes et al for the WHO Safe Surgery Saves Lives Study Group

The paper chosen for this week’s journal club has had an impact on patient safety worldwide: As an F1 during my colorectal surgery job (on the rare occasions I went to theatre) I saw how this paper has changed practice with the implementation of the WHO safe surgery checklist.

In the surgical setting it has been estimated that almost half of all complications are unavoidable. This is a huge patient safety issue. In 2008, the WHO published guidelines to ensure the safety of surgical patients. From this, the authors of the NEJM paper designed a 19 item checklist with the with the aim of reducing surgical complications and its subsequent morbidity and mortality.

The surgical safety checklist is a simple intervention, a checklist that is followed at three key points with the whole surgical team present – before the induction of anaesthesia, before skin incision and before the patient leaves the operating theatre. The primary endpoint of the study was the occurrence of any major complication, including death, during a period of postoperative hospitalisation, up to 30 days (complications were defined as outlined in the American College of Surgeons’ National Surgical Quality Improvement Program).

The trial was run at eight sites in a range of healthcare settings worldwide. Before the checklist was implemented at the trial sites, baseline data, including complication rates, were reported for 3,733 patients at all trial sites. The checklist was then implemented, consecutively enrolling patients over the age of 16 years undergoing non-cardiac surgery. During the pre-checklist period the rate of any complication at all sites was 11%. After the implementation of the checklist this fell to 7% (P<0.001). The total in-hospital rate of death fell from 1.5% to 0.8% (P=0.003). The authors of the paper concluded that:

 Applied on a global basis, this checklist program has the potential to prevent large numbers of deaths and disabling complications, although further study is needed to determine the precise mechanism and durability of the effect in specific settings.

According to the WHO over 3000 hospitals worldwide have now implemented the surgical safety checklist, an impressive figure that shows how research can translate into a world-wide change in practice. Tonight night at 8.00pm BST we will be discussing this paper – a list of discussion points will be posted shortly. I look forward to another interesting and lively debate.

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