Design of a frailty index among community living middle-aged and older people: The Rotterdam study

作者：Schoufour Josje D; Erler Nicole S; Jaspers Loes; Kiefte de Jong Jessica C; Voortman Trudy; Ziere Gij**ertus; Lindemans Jan; Klaver Caroline C; Tiemeier Henning; Stricker Bruno; Ikram Arfan M; Laven Joop S E; Brusselle Guy G O; Rivadeneira Fernando; Franco Oscar H

来源：Maturitas, 2017, 97: 14-20.

DOI：10.1016/j.maturitas.2016.12.002

• Mortality
• Frailty index
• Missing data
• Construct validity
• Criterion validity

Objectives: To design a frailty index (FI) and evaluate three methods to handle missing data. Furthermore, we evaluated its construct (i.e., skewed distribution, correlation with age and sub-maximum score) and criterion validity (based on mortality risk).
Study design: We included 11,539 participants (45 years) from a population-based cohort in the Netherlands. Frailty was measured with a FI, which we constructed based on the accumulation of 45 health-related variables, related to mood, cognition, functional status, diseases and conditions, biomarkers, and nutritional status. A total Fl-score was calculated by averaging the scores of the deficits, resulting in a score between 0 and 1, with higher scores indicating increasing frailty. Mean imputation, single- and multiple imputation were applied.
Main outcome measure: Mortality data were obtained by notification from the municipal administration. Median follow-up time was 9.5 years, during which 3902 (34%) participants died.
Results: The median FI for the full population was 0.16 (IQR=0.11-0.23). The distribution of the FI was slightly right-skewed, the absolute maximum score was 0.78 and there was a strong correlation with age (Pearson correlation= 0.52;95% CI = 0.51-0.54). The adjusted HR per unit increase in Fl-score on mortality was 1.05 (95% CI = 1.05-1.06). Multiple imputation seemed to provide more robust results than mean imputation.
Conclusion: Based on our results we advise to the use of at least 30 deficits from different health domains to construct a Fl if data are not imputed. Future research should use the continuous nature of the FI to monitor trajectories in frailty and find preventive strategies.

• 出版日期2017-3