Bae Jong Bin, Han Ji Won, Kwak Kyung Phil, Kim Bong Jo, Kim Shin Gyeom, Kim Jeong Lan, Kim Tae Hui, Ryu Seung-Ho, Moon Seok Woo, Park Joon Hyuk, Youn Jong Chul, Lee Dong Young, Lee Dong Woo, Lee Seok Bum, Lee Jung Jae, Jhoo Jin Hyeong, Kim Ki Woong
1Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea.
2Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggido, Korea.
Aging Dis. 2019 Feb 1;10(1):1-11. doi: 10.14336/AD.2018.0123. eCollection 2019 Feb.
Dementia increases the risk of mortality (ROM) in the elderly and estimates of hazard ratio (HR) of dementia for mortality have ranged from 1.7 to 6.3. However, previous studies may have underestimated ROM of dementia due to length bias, which occurs when failing to include the persons with rapidly progressive diseases, who died before they could be included in the study. This population-based prospective cohort study conducted on 6,752 randomly sampled Koreans, aged 60 years or older (the Korean Longitudinal Study on Cognitive Aging and Dementia). Cognitive disorders were evaluated at baseline and 2-year follow-up using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD-K), and prevalent and incident cases of dementia were identified. The participants' deaths were confirmed through the National Mortality Database of Statistics Korea. We compared the ROM between prevalent and incident dementia, and estimated HR of dementia for mortality using Cox proportional hazards model. Of the 5,097 responders to the 2-year follow-up assessment, 150 participants had dementia from the baseline (prevalent dementia), and 95 participants developed dementia during the 2-year follow-up period (incident dementia). The ROM of participants with incident dementia was about 3 times higher than the ROM of those with prevalent dementia (HR = 3.04, 95% confidence interval [CI] = 1.34-6.91). Compared to cognitively normal participants at both the baseline and 2-year follow-up assessments, the ROM of those with incident dementia approximately 8 times higher (HR = 8.37, 95 % CI = 4.23-16.54). In conclusion, the ROM of dementia using prevalent cases was underestimated due to length bias, and dementia may be much more fatal than previously estimated. In clinical settings, the ROM of dementia warrants the attention of physicians, particularly in recently incident dementia cases.
痴呆症会增加老年人的死亡风险（ROM），痴呆症导致死亡的风险比（HR）估计值在1.7至6.3之间。然而，由于长度偏倚，先前的研究可能低估了痴呆症的ROM，长度偏倚是指在研究中未能纳入患有快速进展性疾病的人，这些人在能够被纳入研究之前就已经死亡。这项基于人群的前瞻性队列研究对6752名年龄在60岁及以上的韩国人进行了随机抽样（韩国认知衰老与痴呆纵向研究）。在基线和2年随访时使用韩国版阿尔茨海默病注册评估包（CERAD-K）对认知障碍进行评估，并确定痴呆症的现患和新发病例。通过韩国统计厅的国家死亡数据库确认参与者的死亡情况。我们比较了现患和新发痴呆症之间的ROM，并使用Cox比例风险模型估计痴呆症导致死亡的HR。在2年随访评估的5097名应答者中，150名参与者在基线时就患有痴呆症（现患痴呆症），95名参与者在2年随访期间患上痴呆症（新发痴呆症）。新发痴呆症参与者的ROM约为现患痴呆症参与者的3倍（HR = 3.04，95%置信区间[CI] = 1.34 - 6.91）。与在基线和2年随访评估时认知正常的参与者相比，新发痴呆症参与者的ROM大约高8倍（HR = 8.37，95%CI = 4.23 - 16.54）。总之，由于长度偏倚，使用现患病例估算的痴呆症ROM被低估了，痴呆症可能比之前估计的致命得多。在临床环境中，痴呆症的ROM值得医生关注，尤其是在最近新发的痴呆症病例中。
