Iezzoni L I, Shwartz M, Ash A S, Mackiernan Y D
Division of General Medicine and Primary Care, Beth Israel Hospital, Boston, MA, USA.
J Health Serv Res Policy. 1996 Apr;1(2):65-76. doi: 10.1177/135581969600100204.
In the USA, the role of patient severity in determining hospital resource use has been questioned since Medicare adopted prospective hospital payment based on diagnosis-related groups (DRGs). Exactly how to measure severity, however, remains unclear. We examined whether assessments of severity-adjusted hospital lengths of stay (LOS) varied when different measures were used for severity adjustment.
The complete study sample included 18,016 patients receiving medical treatment for pneumonia at 105 acute care hospitals. We studied 11 severity measures, nine based on patient demographic and diagnosis and procedure code information and two derived from clinical findings from the medical record. For each severity measure, LOS was regressed on patient age, sex, DRG, and severity score. Analyses were performed on trimmed and untrimmed data. Trimming eliminated cases with LOS more than three standard deviations from the mean on a log scale.
The trimmed data set contained 17,976 admissions with a mean (S.D.) LOS of 8.9 (6.1) days. Average LOS ranged from 5.0-11.8 days among the 105 hospitals. Using trimmed data, the 11 severity measures produced R-squared values ranging from 0.098-0.169 for explaining LOS for individual patients. Across all severity measures, predicted average hospital LOS varied much less than the observed LOS, with predicted mean hospital LOS ranging from about 8.4-9.8 days.
No severity measure explained the two-fold differences among hospitals in average LOS. Other patient characteristics, practice patterns, or institutional factors may cause the wide differences across hospitals in LOS.
在美国，自医疗保险采用基于诊断相关分组（DRG）的前瞻性医院支付方式以来，患者病情严重程度在决定医院资源使用方面的作用一直受到质疑。然而，究竟如何衡量病情严重程度仍不明确。我们研究了在使用不同的病情严重程度调整方法时，病情严重程度调整后的住院时长（LOS）评估是否会有所不同。
完整的研究样本包括在105家急性护理医院接受肺炎治疗的18016名患者。我们研究了11种病情严重程度衡量方法，其中9种基于患者人口统计学、诊断和手术编码信息，另外2种源自病历中的临床发现。对于每种病情严重程度衡量方法，将住院时长对患者年龄、性别、DRG和病情严重程度评分进行回归分析。分析分别在经过截尾处理和未经过截尾处理的数据上进行。截尾处理消除了对数尺度上住院时长超过均值三个标准差的病例。
经过截尾处理的数据集包含17976例入院病例，平均（标准差）住院时长为8.9（6.1）天。105家医院的平均住院时长在5.0 - 11.8天之间。使用经过截尾处理的数据，11种病情严重程度衡量方法在解释个体患者住院时长方面的决定系数（R平方值）范围为0.098 - 0.169。在所有病情严重程度衡量方法中，预测的平均医院住院时长的差异远小于观察到的住院时长差异，预测的平均医院住院时长范围约为8.4 - 9.8天。
没有一种病情严重程度衡量方法能够解释医院之间平均住院时长的两倍差异。其他患者特征、医疗实践模式或机构因素可能导致医院之间住院时长存在巨大差异。
