Stroke hospitalization and case-fatality in the United States, 1988–1997
Age-adjusted stroke mortality in the US has declined in recent decades. However, little is known about stroke morbidity. Using the National Hospital Discharge Survey data from 1988 to 1997, we examined the change in stroke hospitalization and case-fatality in the US. During the 10 years, age-adjusted stroke hospitalization rate increased 22% (from 381 to 463/100,000, p=0.048). By regions, stroke hospitalization rates overall were 641, 600, 562 and 438 for the South, Midwest, Northeast, and West respectively (p<0.05), and were increased in all regions during the 10 years. Overall, 58% of stroke hospitalizations were due to ischemic stroke, 13% due to hemorrhagic stroke, and 29% were classified as other stroke. The hospitalization rates were 74.8 and 332.4 per 100,000 respectively for hemorrhagic and ischemic strokes and the increase rate in 10 years were 13.5% (p=0.214) and 31.5% (p=0.044) respectively. During 10 years, stroke patients with diabetes, hypertension and congestive heart failure increased 17.4% (p=0.17), 34% (p=0.05), and 31% (p=0.091) respectively. The average length of hospital stay reduced from 11.1 to 6.2 days (decrease of 44.1%), with an average annual percentage decrease of 6.1% (p=0.012). Although the total number of patients hospitalized for stroke increased during this period, the total person-days in hospital decreased 22% (p=006). In-hospital death among stroke decreased steadily from 12.7% to 7.6% (decrease of 40%, p=0.04). In-hospital case-fatality was estimated by stratifying patients on age, gender, region, type of stroke, and other co-morbidity. Case-fatality rate was substantially higher among patients with hemorrhagic than ischemic stroke (28.0% vs 5.8%, p<0.01); among patients with congestive heart failure than those without (17.9% vs 8.5%). In addition, patients of old age (≥75 years), men, those living in the Northeast had higher case-fatality rates than those younger, women and living in elsewhere. In conclusion, the declining of age-adjusted stroke mortality in the US has not been found to be related to the decrease in incidence. However, the observed reduction in hospital case-fatality might contribute to the decline of stroke mortality.