Seasonal variation in hospital admissions for cardiorespiratory diseases in the Negev

Characteristics of patients admitted to the general medical wards of this hospital during the 21 months between January 1990 and September 1991 were analyzed. Cardiovascular and respiratory disease-related (CR) admissions accounted for 46.8% of the 18,774 admissions. Using a linear model, we examined the relationship between season and clinical characteristics of the patients admitted with CR diagnoses. They were admitted more often during the winter (December-February) than the summer (June-August). The ratio of CR admissions to other causes of admission was 0.75 in the summer, 0.93 in the spring, 1.01 in the winter, and 0.82 in the autumn (p < 0.0001). Seasonality affected more patients with coronary heart disease, noncoronary cardiac disease, and chronic pulmonary disease than those with pneumonia or other pulmonary diseases, or cerebrovascular events. Those admitted during the winter were older, had more than 1 CR condition, and their hospital stays were longer. This pattern of hospitalization partly explains the increase in admissions to medical wards in the winter with increase in work load.