Pickle L W, White A A
Centers for Disease Control, National Center for Health Statistics, Hyattsville, MD 20782, USA.
Stat Med. 1995;14(5-7):615-27. doi: 10.1002/sim.4780140519.
Maps of morbidity or mortality rates, whether considered individually or as a layer in a geographic information system application, invite multiple comparisons of area rates. However, comparisons of rates across different populations require standardization of the age-specific rates to account for differences in population age structures. The indirect standardization method, or equivalently the standardized mortality ratio (SMR), has been recommended for small areas where age-specific rates can be quite variable. Although theoretically equivalent to directly adjusted rates under the assumption of independent age and area effects, indirect summary measures are not comparable across areas when this assumption is violated. We tested the validity of this assumption for the 10 most common causes of death in the United States during 1980-84 and examined the geographic clustering apparent when categorized death rates, adjusted by different methods, are presented as thematic maps. Although overall agreement between the methods was good (rank correlation coefficient > 82 per cent for each cause), when the adjusted rates were classified into quintiles 18 per cent of the states fell into different categories depending on the method of adjustment. Using an internal standard for the indirect method reduced this discrepancy to 4.9 per cent. However, both traditional chi-square tests and a generalized logistic spline model identified significant interactions between age and area for each cause of death, a violation of the assumption required for equivalence of the methods. Potential variation in geographic inferences is illustrated by maps of direct and indirect rates and an empirical Bayes posterior mean, which is a function of these traditionally adjusted rates. Based on these results, we recommend the direct age-adjustment method for rate maps.
发病率或死亡率地图，无论是单独考虑还是作为地理信息系统应用中的一个图层，都需要对地区发病率进行多次比较。然而，比较不同人群的发病率需要对年龄别发病率进行标准化，以考虑人口年龄结构的差异。对于年龄别发病率变化较大的小区域，推荐使用间接标准化方法，即标准化死亡率（SMR）。尽管在年龄和地区效应独立的假设下，理论上间接标准化方法等同于直接调整后的发病率，但当该假设不成立时，间接汇总指标在不同地区之间是不可比的。我们检验了1980 - 1984年美国10种最常见死因这一假设的有效性，并研究了将不同方法调整后的分类死亡率以专题地图形式呈现时明显的地理聚集情况。尽管两种方法之间的总体一致性较好（每种死因的秩相关系数>82%），但当将调整后的发病率分为五等份时，18%的州根据调整方法落入不同类别。使用间接方法的内部标准可将这种差异降至4.9%。然而，传统的卡方检验和广义逻辑样条模型都表明，每种死因的年龄和地区之间存在显著的交互作用，这违反了方法等效所需的假设。直接和间接发病率地图以及经验贝叶斯后验均值（它是这些传统调整发病率的函数）说明了地理推断中潜在的变化。基于这些结果，我们推荐在绘制发病率地图时使用直接年龄调整方法。
