Extent of misclassification of death from Creutzfeldt-Jakob disease in England 1979-96: retrospective examination of clinical records

OBJECTIVE: To investigate the extent to which deaths from Creutzfeldt-Jakob disease were misclassified during 1979-96. DESIGN: Structured review of clinical records based on predetermined criteria to determine whether death could have been due to sporadic or variant Creutzfeldt-Jakob disease. SETTING: 100 health authorities and 275 NHS trusts in England. SUBJECTS: 1485 people who died aged 15-44 years from selected neurological disorders in England during 1979-96. MAIN OUTCOME MEASURE: Cause of death. RESULTS: The clinical records of 705 (48%) subjects were successfully traced. Tracing of clinical records was highest in subjects who died during 1990-6. There was sufficient information in the records of 640 (91%) of the 705 subjects to exclude Creutzfeldt-Jakob disease as a cause of death. In 61 (9%) subjects, there was insufficient information to reach any conclusion about the validity of the cause of death recorded on the death certificate. The clinical records of four subjects were examined further by the National Creutzfeldt-Jakob Disease Surveillance Unit; none was thought to have died from Creutzfeldt-Jakob disease. CONCLUSIONS: No new cases of sporadic or variant Creutzfeldt-Jakob disease were detected in a sample of deaths most likely to have included misclassified cases. This suggests that the surveillance system is unlikely to have missed a significant number of cases among people aged 15-44 years. Hence, any rapid increase in the number of cases of variant Creutzfeldt-Jakob disease in this age group is likely to be real not artefactual.

研究目的：探究1979年至1996年间，克雅氏病（Creutzfeldt-Jakob disease）死亡病例的错判程度。
研究设计：基于预设标准对临床病历开展结构化回顾，以判定死亡原因是否可能为散发性或变异型克雅氏病。
研究场景：英格兰境内的100个卫生当局及275家国民保健（NHS）信托机构。
研究对象：1979年至1996年间，英格兰境内1485名15至44岁因选定神经系统疾病死亡的受试者。
主要结局指标：死亡原因。
结果：成功追溯到705名（48%）受试者的临床病历。病历追溯成功率在1990年至1996年期间死亡的受试者中最高。在705名受试者中，有640名（91%）的病历具备足够信息，可排除克雅氏病作为死亡诱因。另有61名（9%）受试者的病历信息不足，无法判定死亡证明上记录的死因是否有效。英国国家克雅氏病监测中心（National Creutzfeldt-Jakob Disease Surveillance Unit）对4名受试者的病历进行了进一步审查，均未认定其死于克雅氏病。
结论：在本次最可能涵盖错判病例的死亡样本中，未检测到散发性或变异型克雅氏病新增病例。这提示该监测系统不太可能在15至44岁人群中遗漏大量病例。因此，该年龄组变异型克雅氏病病例数的任何快速增长，均应为真实情况，而非人为假象。