Incidence and Predictors of Multimorbidity in the Elderly: A Population-Based Longitudinal Study

Background
We aimed to calculate 3-year incidence of multimorbidity, defined as the development of two or more chronic diseases in a population of older people free from multimorbidity at baseline. Secondly, we aimed to identify predictors of incident multimorbidity amongst life-style related indicators, medical conditions and biomarkers.
Methods
Data were gathered from 418 participants in the first follow up of the Kungsholmen Project (Stockholm, Sweden, 1991–1993, 78+ years old) who were not affected by multimorbidity (149 had none disease and 269 one disease), including a social interview, a neuropsychological battery and a medical examination.
Results
After 3 years, 33.6% of participants who were without disease and 66.4% of those with one disease at baseline, developed multimorbidity: the incidence rate was 12.6 per 100 person-years (95% CI: 9.2–16.7) and 32.9 per 100 person-years (95% CI: 28.1–38.3), respectively. After adjustments, worse cognitive function (OR, 95% CI, for 1 point lower Mini-Mental State Examination: 1.22, 1.00–1.48) was associated with increased risk of multimorbidity among subjects with no disease at baseline. Higher age was the only predictor of multimorbidity in persons with one disease at baseline.
Conclusions
Multimorbidity has a high incidence at old age. Mental health-related symptoms are likely predictors of multimorbidity, suggesting a strong impact of mental disorders on the health of older people.

研究背景：本研究旨在计算老年人群的3年共病（multimorbidity）发病率，共病定义为基线无共病的老年群体中出现两种及以上慢性疾病的情况。其次，本研究旨在从生活方式相关指标、基础疾病状况与生物标志物中筛选出新发共病的预测因素。
研究方法：数据来源于瑞典斯德哥尔摩孔斯霍尔姆研究（Kungsholmen Project）1991-1993年的首次随访队列中的418名78岁及以上老年参与者，这些参与者基线均无共病（其中149名无基础疾病，269名患有1种基础疾病），研究采集了社会访谈、神经心理测试组合与体格检查相关数据。
研究结果：随访3年后，基线无基础疾病的参与者中有33.6%、基线患1种基础疾病的参与者中有66.4%新发共病；对应的发病率分别为12.6/100人年（95%置信区间：9.2~16.7）与32.9/100人年（95%置信区间：28.1~38.3）。经校正后，在基线无基础疾病的参与者中，认知功能更差（简易精神状态检查表（Mini-Mental State Examination）得分每降低1分的比值比（OR）及95%置信区间为1.22、1.00~1.48）与共病发病风险升高显著相关。在基线患1种基础疾病的参与者中，年龄更高是新发共病的唯一预测因素。
研究结论：老年群体中共病发病率较高。与心理健康相关的症状可能是共病的预测因素，这提示精神障碍对老年人健康存在显著影响。