GPs have been urged to use β-blockers more often in patients with COPD and comorbid heart problems after the largest study to date showed they improved survival after MI in these patients.
Experts said the study, reported in the BMJ, provides the strongest evidence to date the drugs are beneficial in COPD patients with cardiovascular disease – and supported the authors’ call for wider use of the drugs, especially the cardioselective ones such as atenolol, bisoprolol or metoprolol.
Historically, use of β-blockers has been low in patients with COPD because of concerns the drugs may provoke bronchospasm in these patients and the Joint British Societies’ JBS2 guidance recommended the drugs be avoided in COPD. However, more recently the 2010 NICE heart failure guideline recommended β-blocker use in patients with heart failure and COPD without significant airways reversibility.
Using data from the Myocardial Ischaemia National Audit Project (MINAP) linked to the General Practice Research Database, researchers analysed how β-blocker use impacted on the outcomes of 1,063 patients with COPD who had a first MI between January 2003 and the end of December 2008.
Patients started on a β-blocker during the hospital admission for MI - and those who were already being treated with one before they had the MI - had significantly improved survival compared with those not receiving the drugs.
However, just 23% of patients were prescribed a β-blocker before the MI and 22% during the hospital admission, while 55% were never prescribed one of the drugs throughout the study.
Patients treated with β-blockers tended to be younger with less cardiovascular comorbidity and fewer COPD exacerbations than those not receiving them.
But even after adjusting for these differences, β-blocker use during hospital admission was associated with a 50% reduction in mortality over the median three-year follow-up compared with no use, while use of a β-blocker before the MI was associated with a 40% reduction in mortality.
The researchers concluded: ‘Use of β-blockers remains limited in patients with COPD, and this lack of prescribing might be contributing to the increase in mortality in these patients after MI.’
Dr Rupert Jones, a GPSI in respiratory medicine from the Respiratory Research Unit at Peninsula Medical School in Plymouth, said β-blockers have probably become more frequently prescribed since the study ended, but supported the call for wider use.
Dr Jones said: ‘Historically there has been a problem and GPs may fear making the bronchospasm worse and if the patient has comorbid asthma care is needed - somewhere around 15% of patients have comorbid and asthma and GPs may worry they have got the diagnosis right.’
‘But β-blockers should be prescribed unless there is a clear reason why not and that should be incumbent both on the hospital to initiate and on the GPs reviewing them thereafter – for heart failure as well as heart attack and ischemic heart disease.’
‘We have to be very clear β-blockers have survival advantages and should be used, unless there is a clear contraindication – and comorbid asthma does need to be considered carefully.’
Dr Kevin Gruffydd-Jones, a member of the steering committee of the General Practice Airways Group and a GP in Box, Wiltshire, said the study gave further weight to the evidence that the drugs are beneficial and safe in COPD.
He said: ‘Firstly, unless there is a very strong suggestion of comorbidity with asthma, or other contra-indications, then β-blockers are safe to use in COPD.
‘Secondly, there’s a strong association between COPD with other cardiovascular diseases, so therefore should have a low threshold for using this drugs – COPD should not be a contraindication.’
He added: ‘This study provides further evidence in a prospective cohort study that this is a good thing.’