Lanska D J, Kryscio R
Department of Neurology, University of Kentucky, Lexington 40536-0084.
Neurology. 1994 Aug;44(8):1541-50. doi: 10.1212/wnl.44.8.1541.
We analyzed state-specific stroke-hospitalization, case-fatality, and mortality rates for the US Medicare population for 1989, using national data resources of the Health Care Financing Administration (HCFA), the National Center for Health Statistics, and the Bureau of the Census. State-specific hospital admission rates for stroke ranged from 0.66 to 1.26%, compared with the national value of 0.94%. Both hospital-usage rates and deviations of observed rates from predicted values (based on statistical models of the HCFA) showed significant spatial autocorrelation, with high rates clustered in the southeastern United States and low rates clustered in the Mountain census division of the West and also somewhat in the Northeast. Case-fatality rates increased nationally from 14.9% at 15 days after hospital admission to 31.2% at 180 days after hospital admission. State-level case-fatality rates showed relatively little interstate variation and no clear or consistent spatial pattern, although there was statistically significant spatial autocorrelation at several intervals after hospital admission. Admission rates and case-fatality rates were not significantly associated at any interval after admission to 180 days, suggesting that variation in case-fatality rates was not simply a result of differences in severity-of-illness thresholds for hospital admission. State-specific stroke-mortality rates ranged from 294.5 to 523.5 per 100,000 population, compared with the national value of 415.3 per 100,000 population. State-specific mortality rates for stroke showed significant spatial autocorrelation, with high rates clustered in the South and low rates clustered in the Northeast and the Mountain census division of the West. The spatial distribution of stroke-mortality rates strongly resembled the spatial distribution of hospitalization rates but did not resemble the spatial distribution of case-fatality rates at any interval from 15 to 180 days after hospital admission. Indeed, in univariate spatial-regression models fitted to the data using a maximum likelihood procedure and weighted for non-constant variances, the best predictor of state-level stroke-mortality rates was the hospital-utilization rate for stroke; attempts to improve the model by including case fatality at various intervals and interaction terms did not yield a significant improvement. These data suggest that factors determining stroke occurrence and hospital utilization are more important than factors determining case fatality in terms of explaining the long-standing distribution of stroke mortality in the United States. Factors affecting only case fatality but not hospitalization, such as the quality of medical care provided in the hospital, cannot explain the geographic distribution of stroke mortality in the United States.
我们利用医疗保健财务管理局（HCFA）、国家卫生统计中心和人口普查局的全国数据资源，分析了1989年美国医疗保险人群中各州特定的中风住院率、病死率和死亡率。各州特定的中风住院率在0.66%至1.26%之间，而全国值为0.94%。医院使用率以及观察到的比率与预测值（基于HCFA的统计模型）的偏差均显示出显著的空间自相关性，高比率集中在美国东南部，低比率集中在西部的山区人口普查区以及东北部的部分地区。全国病死率从入院后15天的14.9%上升至入院后180天的31.2%。各州层面的病死率在州际间变化相对较小，且没有明显或一致的空间模式，尽管在入院后的几个时间段存在统计学上显著的空间自相关性。入院率和病死率在入院至180天的任何时间段均无显著关联，这表明病死率的差异并非仅仅是由于入院时疾病严重程度阈值的不同所致。各州特定的中风死亡率在每10万人294.5至523.5之间，而全国值为每10万人415.3。各州特定的中风死亡率显示出显著的空间自相关性，高比率集中在南部，低比率集中在东北部和西部的山区人口普查区。中风死亡率的空间分布与住院率的空间分布非常相似，但与入院后15至180天任何时间段的病死率空间分布均不相似。实际上，在使用最大似然法对数据进行拟合并针对非恒定方差进行加权的单变量空间回归模型中，州层面中风死亡率的最佳预测指标是中风的医院利用率；通过纳入不同时间段的病死率和交互项来改进模型的尝试并未带来显著改善。这些数据表明，就解释美国中风死亡率的长期分布而言，决定中风发生和医院利用的因素比决定病死率的因素更为重要。仅影响病死率而不影响住院率的因素，如医院提供的医疗护理质量，无法解释美国中风死亡率的地理分布。
