Airwaves
STROKE AND SLEEP APNOEA
There has been much interest recently in the precise relationship between stroke and sleep apnoea. There is some evidence
that there is an increased risk of stroke in sleep apnoea and a high prevalence of sleep disordered breathing can also be
found after stroke. In this issue of Thorax Turkington and colleagues report a study of patients with stroke admitted to hospital in whom sleep studies were performed
within 24 hours of admission. The authors show that upper airway obstruction in the first 24 hours after admission with stroke
is associated with a worse functional outcome and an increased chance of death and dependency at 6 months. Longer respiratory
events were also associated with a worse outcome after stroke. In the accompanying editorial Gibson discusses some of the
reasons why patients with sleep apnoea may have an adverse outcome with stroke. He also discusses the implications of these
findings and the difficulties of treating stroke patients with nasal CPAP therapy at a very early stage after development
of the stroke. However, if compliance is satisfactory, CPAP may have an important role in selected patients with stroke and
sleep apnoea.
See pages 361 and 367
Kaplan-Meier survival plot. Stroke patients with a respiratory disturbance index (RDI) <10 had significantly longer survival times than those with RDI >10 (p<0.04).
DOES FARMING CAUSE ASTHMA?
There has been some evidence that growing up on a farm may protect against asthma in children and young adults, although whether
this effect also occurs in adult farmers is less clear. Eduard and colleagues report a study in adult Norwegian farmers in
whom exposure to various factors including dust, fungal spores, endotoxin and ammonia were assessed with exposure measurements.
Current asthma was most common in cattle and pig farmers, with non-atopic asthma being more common in pig farmers and in those
with two or more types of livestock, while atopic asthma was less common. Exposure measurements were positively associated
with non-atopic asthma and negatively with atopic asthma. Thus, farm exposures may protect against atopic asthma but cause
non-atopic asthma in farmers.
See page 381
MORE ON FREQUENT EXACERBATORS AND HEALTH STATUS
As COPD exacerbation frequency has a close relationship with health status, it is now regarded as one of the most important
outcome measures in COPD and a target for new treatments. Miravitlles and colleagues confirm that there are significant differences
in health status between patients with frequent and infrequent exacerbations, both at baseline and after follow up for 2 years
when the differences observed were even greater. Seasonal changes were also found and were related to a higher exacerbation
frequency in the winter. Hospital admissions also had an adverse effect on the health status. However, a surprising result
was that the health status scores did not worsen with time; the authors explain this as the effect of study inclusion, with
treatment being optimised and support given to these patients, helping them to cope better with their disability. The results
also emphasise the need to perform longer term follow up studies in COPD with an appropriate placebo.
See page 387
ASTHMA AND SOCIOECONOMIC STATUS
There has been much interest in the association between asthma and socioeconomic status, although overall the studies have
been cross sectional in nature and have provided conflicting conclusions. In this month’s Thorax we publish a paper by Hancox and colleagues describing the follow up from birth to age 26 of the Dunedin, New Zealand cohort.
In this study, in which detailed follow up was conducted, the authors found no association between childhood or adult socioeconomic
status and asthma prevalence, airway responsiveness, or lung function. It is possible that these findings may not apply to
some other countries, but any further studies planned on this topic should take note of the methodology developed in this
study.
See page 376
TREATMENT OF SARS
In this month’s Thorax we publish a paper by Sung and colleagues from Hong Kong which describes the outcome of treatment for SARS. High dose steroid
therapy (with methylprednisolone) was used in a large proportion of patients who had not responded to a combination of the
antiviral agent ribavarin and low dose steroids, 88.8% of whom showed a response to treatment. The overall mortality was around
11% and these patients had significant co-morbidities. However, the protocol was uncontrolled and, although the results are
encouraging, high dose steroids can be a problem in an infectious disorder. Any future SARS outbreak must include randomised
controlled studies of the effect of high dose steroid therapy on outcome.
See page 414
