Journals Watch - Sleep apnoea, asthma and COPD

A review of this week's medical research. By GP Dr Simon Hunter

CPAP for sleep apnoea can reduce the risk of hypertension (Photograph: SPL)
CPAP for sleep apnoea can reduce the risk of hypertension (Photograph: SPL)

Sleep apnoea as a risk factor for hypertension
JAMA 2012; 307(20): 2169-76

Obstructive sleep apnoea (OSA) affects 17% of Americans (and only 3-7% of Spaniards, as another paper in this journal informs us). Several studies have suggested a connection between OSA and hypertension.

This prospective cohort study of nearly 1,900 patients sets out to confirm this and examines whether treating OSA with continuous positive airway pressure (CPAP) reduces the risk of hypertension.

Patients were followed for an average of 12 years. Incidence of hypertension in controls was 2.19 per 100 patient-years, 3.34 in patients with OSA who were ineligible for CPAP, 5.84 in patients eligible for CPAP but who declined it, 5.12 in those who were non-adherent to CPAP and 3.06 in those who used CPAP.

The authors conclude OSA is an independent risk factor for hypertension and treating it with CPAP can reduce this risk.

Risk of anaphylaxis after childhood immunisation
Arch Dis Child 2012; 97(6): 487-90

Anaphylaxis after immunisation is rare and unlikely to be picked up in pre-licence trials. Previous studies have been hampered by poor reporting.

Paediatricians were asked to report confirmed and suspected anaphylaxis after immunisation through the British Paediatric Surveillance Unit. Reported symptoms were assessed against a standard definition of anaphylaxis.

Over the 13-month study, 15 reports were made, of which seven were deemed to be genuine anaphylaxis. In three, onset was within 15 minutes, but four began after 30 minutes, with one starting two hours later.

Two cases were from single-dose measles (incidence of 12 reactions per 100,000 doses); three were associated with the HPV vaccine Cervarix (1.4 reactions per million doses). Other vaccines implicated were MenC, school leaver (tetanus/polio), Typhim, ACWY and Havrix. No anaphylactic reactions to infant or preschool boosters were reported.

Care plans in COPD
Ann Intern Med 2012; 156(10): 673-83

This study set out to show how a comprehensive care management programme for COPD could improve outcomes.

Patients in the intervention arm had group and individual education, booklets, proactive telephone calls and guidance for their doctors.

They were compared with controls in terms of exacerbations, hospitalisations, mortality and disease knowledge. All of the patients had been hospitalised in the past year.

The study was stopped by the data monitoring committee when less than half of the planned total of 960 patients had been recruited.

Hospitalisation was 27% in the programme group and 24% among controls; there were 28 deaths from all causes in the programme compared with 10 in the control group, with 10 versus three deaths from COPD in each group, respectively.

The lack of improvement in self-management was disappointing and the increased mortality inexplicable, but it does show that what appears to be common sense will not always work.

Sexual activity after acute MI
Am J Cardiol 2012; 109(10): 1439-44

This US study looked at sexual activity in men and women in the first year after acute MI and at factors influencing this.

A third of women and nearly half of men received advice on resuming sexual activity, although unmarried men and women were less likely to receive advice than their married counterparts, even if they were sexually active.

About half of patients who were sexually active before MI reported a drop in activity after it, while a tenth of patients reported no sexual activity.

In men, significant predictors for not resuming sexual activity were no discharge instructions, no discussion with their doctor and poor physical functioning before their MI.

In women, the only predictor was lack of discharge instructions. Those who resumed sexual activity experienced no more MI than those who did not resume, which is reassuring.

Dummies and nebulised therapy masks
Arch Dis Child 2012; 97(6): 497-501

Giving nebulised therapy to infants can be difficult because the mask can upset them, making them squirm and cry, reducing its effectiveness.

A dummy (or pacifier as the study calls it) will calm many babies, but means they have to breathe through their nose.

This study in Canada compared lung deposition using a conventional mask against a mask with a built-in dummy. Particles labelled with a gamma radiation-emitting marker were nebulised through the mask. Lung deposition was found to be similar for both masks.

This was a small pilot study, but letting a baby have its dummy might be worthwhile if a mask cannot be tolerated.

Changes in prescribing for paediatric asthma
Arch Dis Child 2012; 97(6): 521-5

The British Thoracic Society asthma guideline has been updated regularly since it was first published in 1990.

In 2003 the recommended maximum dose of inhaled corticosteroids (ICS) for children was reduced from 800 to 400 microgram beclometasone. This study assessed patterns of asthma prescribing in children before and after this change, from 2001 to 2006.

The number of children prescribed an ICS inhaler fell, while the number prescribed an ICS/long-acting beta-agonist (LABA) combination device increased. The number of under-12s on high-dose ICS fell, indicating that guidelines were being adopted.

One fly in the ointment was that 24% of children on ICS/LABA had gone straight to this without trying ICS alone, but overall it looks as if the guidelines are changing practice.

Reflect on this article and add notes to your CPD Organiser on MIMS Learning

  • Dr Hunter is a GP in Bishop's Waltham, Hampshire, and a member of our team who regularly review the journals

These further action points may allow you to earn more credits by increasing the time spent and the impact achieved.

  • Ensure practice nurses are aware that although childhood immunisations are very safe, anaphylactic reactions can occur, sometimes after the child has left the building.
  • Add advice on sexual function to the cardiac clinic protocol.
  • Audit all asthmatic children at your practice to see if any have gone straight on to a combination device without first trying inhaled corticosteroids on their own.

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