Comparison of the seasonal patterns of asthma identified in general practitioner episodes, hospital admissions, and deaths

Abstract

Background-Seasonal variations in asthma are widely recognised. This study was undertaken to investigate the relative diVerences in seasonal patterns by age as they impact on episodes of care in general practice, hospital admissions, and deaths. Methods-General practice episode data from the Weekly Returns Service of the Royal College of General Practitioners, hospital admissions for asthma in England, and deaths registered as due to asthma in England and Wales over the years 1990-7 were examined. Age specific weekly rates of new episodes of asthma presenting to general practitioners, numbers of hospital admissions and deaths were analysed by the multiplicative decomposition method to separate secular from seasonal trends. The seasonal indices thereby obtained were plotted as three week moving averages. Results-In children aged 0-4 and 5-14 years general practice episodes and admissions to hospital were strikingly congruent in timing and in magnitude, except in September when particularly high rates of admission (absolute and relative to general practice episodes) occurred. In the 15-44 age group there were marked mid summer peaks of general practice episodes and deaths but admissions to hospital were at about the annual average; in September/ October there were peaks of episodes and admissions whereas deaths peaked in November. In the 45-64 age group a peak in general practice episodes of asthma was evident in mid summer when admissions were about average and deaths were at a minimum; all three measures tended to increase gradually with the approach of winter. Finally, in those age over 65 years, general practice episodes of asthma, admissions to hospital, and deaths followed similar 'U' shaped patterns with substantial peaks in mid winter. Conclusions-The seasonal pattern of asthma evolves with age. There are important diVerences in the seasonal pattern of general practice episodes, admissions to hospital, and deaths. Individual seasonal histories are important for the management of asthma. The combined analysis of these three data sets provides a new perspective on the epidemiology of asthma. (Thorax 2000;55:662-665)

Relationships between the seasonality of temperature and ischaemic heart disease mortality: implications for climate based health forecasting

“…Apart from their weather sensitivity (McGregor 2001), a characteristic of these diseases is the strong seasonality displayed. For example, strong winter peaks of asthma can be identified in general practitioner episodes, hospital admissions and deaths in England, Malta and areas covered by the European Community Respiratory Health Survey (Fleming et al 2000, Verlato et al 2000, Grech et al 2002. Eccles (2002) and Law et al (2002) have further noted that acute upper and lower respiratory tract viral infections also display clear winter peaks.…”

Objective Airway Monitoring Improves Asthma Control in the Cold and Flu Season

“…The CUE intervention had a positive effect on asthma health outcomes and a protective effect during periods of seasonal vulnerability, especially winter and spring. It has been previously reported that adverse asthma outcomes in middle age and elderly patient cohorts reach peak levels in the winter season, 17 driven largely by viral exacerbations. Similarly, the control group in this study, with a mean age of 50 years, experienced a marked increase in periods of worsening symptoms, oral steroid use, and urgent care use in the winter season.…”

Hospital Admissions for Childhood Asthma After Smoke-Free Legislation in England

“…16 Figure 1 also compares the predicted estimate with the actual counts using the full model. The close approximation of the actually and predicted value demonstrates that the model provides an accurate fit of the time series data.…”