Design of a frailty index among community living middle-aged and older people: The Rotterdam study. (March 2017)

• Record Type: Journal Article
• Authors: Schoufour, Josje D.; Erler, Nicole S.; Jaspers, Loes; Kiefte-de Jong, Jessica C.; Voortman, Trudy; Ziere, Gijsbertus; 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.
• Is Part Of: Maturitas. Volume 97(2017)
• Page Start: 14
• Page End: 20
• Publication Date: 2017-03
• Subjects: FI frailty index -- FI-score frailty index score -- RS rotterdam study -- ROC receiver operating curve -- AUC area under the curve; Mortality -- Frailty index -- Missing data -- Construct validity -- Criterion validity; Climacteric -- Periodicals; Menopause -- Periodicals; Climacteric -- Periodicals; Geriatrics -- Periodicals; Menopause -- Periodicals; Middle Aged -- Periodicals; Climatère -- Périodiques; Ménopause -- Périodiques; Climacterium; Climacteric; Menopause; Electronic journals; Periodicals; 612.66
• DOI: 10.1016/j.maturitas.2016.12.002
• Languages: English
• ISSNs: 0378-5122

Abstract

Highlights: We developed a frailty index for community-living older people. The frailty index showed construct and criterion validity. Frailty is associated with all-cause mortality. We advise the use of at least 30 deficits to construct a frailty index. If 20 deficits are known, multiple imputation of missing values can increase precision. Abstract: 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 FI-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 FI-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 FI if data are not imputed. Future research should use the continuous nature of the FI to monitor trajectories in frailty and find preventive strategies.