Background databases of electronic health records are powerful tools for dementia research, but data can be influenced by incomplete recording. We examined whether people with dementia recorded in a specialist database (from a mental health and dementia care service) differ from those recorded in primary care. Methods a retrospective cohort study of the population covered by Lambeth DataNet (primary care electronic records) between 2007 and 2019. Documentation of dementia diagnosis in primary care coded data and linked records in a specialist database (Clinical Records Interactive Search) were compared. Results 3,859 people had dementia documented in primary care codes and 4,266 in the specialist database, with 2,886/5,239 (55%) documented in both sources. Overall, 55% were labelled as having Alzheimer’s dementia and 29% were prescribed dementia medication, but these proportions were significantly higher in those documented in both sources. The cohort identified from the specialist database were less likely to live in a care home (prevalence ratio 0.73, 95% confidence interval 0.63–0.85), have multimorbidity (0.87, 0.77–0.98) or consult frequently (0.91, 0.88–0.95) than those identified through primary care codes, although mortality did not differ (0.98, 0.91–1.06). Discussion there is under-recording of dementia diagnoses in both primary care and specialist databases. This has implications for clinical care and for generalizability of research. Our results suggest that using a mental health database may under-represent those patients who have more frailty, reflecting differential referral to mental health services, and demonstrating how the patient pathways are an important consideration when undertaking database studies.

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记录的内容很重要：初级保健中的痴呆症记录与专业数据库的比较

电子健康记录的背景数据库是痴呆症研究的强大工具，但数据可能会受到不完整记录的影响。我们检查了专业数据库（来自心理健康和痴呆症护理服务）中记录的痴呆症患者是否与初级保健中记录的患者不同。方法对 2007 年至 2019 年兰贝斯数据网（初级保健电子记录）覆盖的人群进行回顾性队列研究。对初级保健编码数据中的痴呆诊断记录和专家数据库（临床记录交互式搜索）中的链接记录进行比较。结果 初级保健代码中记录了 3,859 人患有痴呆症，专家数据库中记录了 4,266 人患有痴呆症，其中 2,886 人/5,239 人 (55%) 在这两个来源中都有记录。总体而言，55% 的人被标记为患有阿尔茨海默氏痴呆症，29% 的人服用了痴呆症药物，但这些比例在两个来源中记录的比例均明显更高。从专家数据库中确定的队列与护理院相比，居住在疗养院的可能性较小（患病率 0.73，95% 置信区间 0.63–0.85），患有多种疾病（0.87，0.77–0.98）或经常就诊（0.91，0.88–0.95）。尽管死亡率没有差异（0.98，0.91-1.06），但通过初级保健代码确定的死亡率没有差异。讨论初级保健和专家数据库中的痴呆症诊断记录不足。这对临床护理和研究的普遍性具有影响。我们的结果表明，使用心理健康数据库可能无法代表那些更虚弱的患者，这反映了对心理健康服务的不同转诊，并证明了在进行数据库研究时患者途径如何成为一个重要的考虑因素。