Seasonal variations in hospital treatment periods and deaths among adult asthmatics

The purpose of this study was to examine possible seasonal variations in re lations between hospital treatment periods and in deaths (asthma-related an d other) among adult asthmatics. Out of a total of 364,871 asthma-induced hospitalization periods (diagnosis No. 493,international Classification of Diseases) recorded in the hospital discharge register maintained by the National Research and Development Cen tre for Welfare and Health during 1972-1992, all of those applying to perso ns aged >24 yrs during 1987-1992 were analysed here. The discharge file was linked to the register of deaths on the basis of the patients' serial secu rity numbers in order to analyse all deaths among the same patients during 1987-1993, A total of 81,243 asthma-related treatment periods were analysed. The month ly variation in the number of such periods showed a peak in January (18.2% above the mean number of monthly deaths in the study period) and a trough i n July (26.1% below the mean). Of the 7,622 hospitalized asthmatics who die d during the period examined here, 1,274 died of obstructive pulmonary dise ases, with asthma as the primary cause in 489 cases, The majority of the de aths acre? caused by cardiovascular diseases. Mortality was highest in Janu ary (+14.7%) and lowest in August (-123%). The similarity in the seasonal variation observed between the treatment per iods and deaths recorded for adult asthmatics may be taken to indicate a ge nuine need for treatment.