Supplementary Material for: Incidence and prevalence of dementia: A 2015-2020 population-based study in the Campania Region of Italy

Objective: To provide population-based estimates of prevalence and incidence of any dementia and Alzheimer’s dementia in the Campania Region (South Italy), and to validate towards a clinical registry. Methods: Population-based study, using routinely collected healthcare data of individuals living in the Campania Region (South Italy) from 2015 to 2020. We included individuals aged ≥65 years alive at the prevalence day (1 January 2021) who had at least one administrative record for dementia and/or Alzheimer's dementia from 2015 to 2020. Age-and sex-standardised prevalence rates were calculated using direct standardisation method (European population in 2020 as reference population). To estimate incidence, we tested three possible algorithms, which differed for the duration of the time interval between study baseline (Jan 1, 2015) and index date (first record for dementia and/or Alzheimer's dementia in administrative databases). We employed a clinical database for the validation of our algorithms towards neuropsychological test results. Results: Among individuals aged over 65, 80,392 had dementia, of which 35,748 had Alzheimer's dementia. The age- and sex-standardized prevalence rates per 1,000 individuals for any dementia and Alzheimer's dementia were 77.64 (95%CI = 77.57; 77.68) and 34.05 (95%CI = 34.01; 34.09), respectively. There were 82.10 incident of any dementia cases per 100,000 per year (0.79 sensitivity and 0.62 specificity), and 59.89 incident cases of any dementia per 100,000 per year (0.80 sensitivity and 0.59 specificity). The capture-recapture method showed very low number of undetected cases (1.7% for any dementia and 3.0% for Alzheimer’s dementia). Our algorithms showed acceptable performance with AUC ranging from 0.59 to 0.72, and double likelihood ratio of correctly identifying individuals above and below MMSE standard cut-offs (24 and 26). Conclusions: Prevalence and incidence of any dementia and Alzheimer's dementia in the Campania Region (South Italy) from 2015 to 2020 are in line with previous estimates from other countries. Our algorithm, integrating administrative and clinical data, holds potential for assessing dementia's epidemiological burden, identifying risk factors, planning healthcare access, and developing prevention strategies.

研究目的：为获取意大利南部坎帕尼亚大区任意痴呆及阿尔茨海默病痴呆的人群患病率与发病率估计值，并针对临床登记系统开展算法验证。
研究方法：本研究为基于人群的流行病学研究，采用2015年至2020年意大利南部坎帕尼亚大区常住居民的常规医疗健康数据。纳入标准为：在患病率统计基准日（2021年1月1日）仍存活、且2015至2020年间至少存有1条痴呆和/或阿尔茨海默病痴呆的行政医疗记录、年龄≥65岁的个体。采用直接标准化法（以2020年欧洲人群作为参考人群）计算年龄及性别标准化患病率。为估算发病率，本研究测试了3种不同算法，其核心差异在于研究基线（2015年1月1日）与索引日期（行政数据库中首次出现痴呆和/或阿尔茨海默病痴呆记录的日期）之间的时间间隔时长。本研究使用临床数据库，结合神经心理学测试结果对所提出的算法进行验证。
研究结果：在65岁以上人群中，共计80392例确诊痴呆，其中35748例为阿尔茨海默病痴呆。任意痴呆及阿尔茨海默病痴呆的年龄-性别标准化患病率（每千人）分别为77.64（95%CI = 77.57; 77.68）与34.05（95%CI = 34.01; 34.09）。每10万人年的任意痴呆新发病例数为82.10例（灵敏度0.79，特异度0.62），另一组算法下的任意痴呆新发病例数为59.89例/10万人年（灵敏度0.80，特异度0.59）。捕获-再捕获法显示未被检出的病例占比极低（任意痴呆为1.7%，阿尔茨海默病痴呆为3.0%）。本研究所用算法表现可接受，受试者工作特征曲线下面积（Area Under the Receiver Operating Characteristic Curve, AUC）介于0.59至0.72之间，且正确识别简易精神状态检查表（Mini-Mental State Examination, MMSE）标准分界值（24与26分）上下人群的似然比翻倍。
研究结论：2015至2020年意大利南部坎帕尼亚大区任意痴呆及阿尔茨海默病痴呆的患病率与发病率，与其他国家既往的流行病学估计结果相符。本研究整合行政与临床数据的算法，在评估痴呆流行病学负担、识别危险因素、规划医疗服务可及性以及制定预防策略方面具备应用潜力。