Increase in admission threshold explains stable asthma hospitalization rates

Background. Asthma morbidity and mortality has increased substantially in r ecent years, but asthma hospitalization rates among many geographic and soc iodemographic groups have remained stable. Observations on asthma hospitali zation rates and severity of acute episodes might provide valuable insight into the functioning of the health care system during this period of health care reform. Objective. To analyze changes between 1991 and 1995 in childhood asthma hos pitalization rates and severity of acute episodes. Design and Methods. All 29 329 hospitalizations, including 2028 for asthma, for the 198 893 children (< 19 years of age) in Monroe County (Rochester), New York, were studied during this 5-year period. Severity was determined by hospital record review on a 22% random sample. Using the worst oxygen sa turation (Sao(2)) during the first 24 hours of hospitalization as the prima ry index of severity, episodes were categorized as mild (0 to greater than or equal to 95), moderate (90 to 94), or severe (< 90). Results. Hospitalization rates are expressed as hospitalizations per 1000 c hild-years. The overall asthma hospitalization rate was 2.04 (95% confidenc e interval, 1.95-2.13). The overall annual asthma hospitalization rate rema ined relatively stable from 1991 (1.90) to 1995 (2.31), whereas the hospita lization rates for severe asthma rose 270%-from 0.57 to 1.55-during this pe riod. Simultaneously, the hospitalization rates for mild asthma decreased f rom 0.26 to 0.12. As a proportion of all asthma hospitalizations between 19 91 and 1995, severe episodes increased from 31.5% to 60.4%; conversely, mil d episodes decreased from 14.1% to 4.7%. Conclusions. Severity increased significantly among children hospitalized f or asthma while the overall asthma hospitalization rate remained stable. It seems that the health care system in this community has responded to an in crease in severity of asthma by raising the severity threshold for admissio n.