Sleep apnoea and the risk of cardiovascular disease
Eur Resp J 2014; 43(2): 513-22
Obstructive sleep apnoea (OSA) is common, especially in older males, and has been associated with atherosclerosis and cardiovascular disease (CVD). Determining whether this atherosclerotic risk is directly related to hypoxia is difficult because patients with OSA tend to be overweight, itself a risk factor for CVD.
In this study, non-obese 20-week-old male mice were subjected to intermittent hypoxia, to imitate OSA, and after six weeks, were compared with mice kept in normal air.
The hypoxic group showed more severe dyslipidaemia, atherosclerosis and insulin resistance. They had remodelling of visceral white fat and increased inflammatory markers.
This study suggests that the hypoxia of OSA is a risk factor for CVD, independent of obesity levels.
Inhaled corticosteroids and paediatric growth
Arch Dis Child 2014; 99: 191-2
The data discussed in this article were from the Children's Asthma Management Program study.
The author acknowledges that the original study aims were unremarkable - comparing budesonide with nedocromil or placebo for the management of asthma in children aged five to 13 years.
When the study subjects were about 25 years old, 90% of the original cohort had their final adult height measured. Males lost 1.2cm off their final height and women 1.8cm compared to placebo.
It is worth noting that these children were on a very high dose of inhaled corticosteroid (ICS): 400 microgram per day of budesonide as a dry powder, with no spacer. They did not have the dose reduced with decreasing symptoms, as would be normal clinical practice. Therefore this represents the worse case scenario.
Atopy and asthma severity also affected height, indicating the disease process has some deleterious effect on height.
The author points out that losing a centimetre never killed anyone, but childhood asthma can.
Appropriate use of ICS should not be shied away from because of height fears, but discussed with parents.
Statins and the risk of diabetes
Am J Cardiol 2014; 113:631-6
Four years ago, a meta-analysis published in The Lancet found an increased incidence of new onset diabetes mellitus (NODM) in patients who were on statins. Post hoc analysis of trials suggested that the risk of developing diabetes outweighed the benefits of statins.
This study from Taiwan looked at the risk of developing diabetes and the risk of having an adverse cardiovascular event in prediabetic patients who were given a statin. They were compared with controls given no statin. The dose of the various statins was standardised to a simvastatin equivalent.
After an average of four years, the risk of developing NODM was 23.5% and 28.5% in statin non-users and users, respectively. The risk of having an adverse cardiac event was 16.7% and 12.9% respectively.
Statin use was associated with a higher risk of developing diabetes and a lower risk of having a cardiac event. The risk of each was dose dependent. The earlier the statin was started, the greater the risks and benefits. There were fewer hospitalisations in those started early.
The study authors concluded that the cardiovascular benefits of starting a statin in patients with prediabetes outweighed the risks of developing diabetes.
Silent stroke and AF
Am J Cardiol 2014; 113: 655-61
In the CHADS2 scoring system for assessing risk of stroke in patients with AF and whether they should be on an anticoagulant, previous stroke scores two points. A score of 2 or more would indicate the need for anticoagulation.
From postmortem studies and scanning, estimates of the incidence of silent stroke (no overt symptoms) have ranged from 8% to 28%. This would make a huge difference to CHADS2 scoring and treatment.
This study in South Korea looked at 1,200 brain MRIs performed for routine health check-ups in 400 patients with AF and 800 in sinus rhythm.
A silent stroke was found in 28.3% of patients in AF and 6.6% with sinus rhythm. Patients in AF were twice as likely to have had a silent stroke if they had hypertension or dyslipidaemia and three times as likely if they had valvular AF.
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- Dr Hunter is a GP in Bishop's Waltham, Hampshire, and a member of our team who regularly review the journals
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