Validity of the Questionnaire for Medical Checkup of <scp>Old‐Old</scp> (<scp>QMCOO</scp>) in screening for physical frailty in Japanese older outpatients

Abstract

Since April 2020, the Questionnaire for Medical Checkup of Old-Old (QMCOO, “Koki-Koreisha no shitsumon-hyou” in Japanese) had been adopted as the standard procedure in the medical checkup of older Japanese adults in the latter stages of life. The new 15-item questionnaire aims to evaluate the general health status of older adults aged ≥75 years in order to focus attention on frailty in older adults and to promote improvement in lifestyle.1 Frailty is a recognizable state of vulnerability associated with the cumulative decline in several physiological systems with increasing age. This cumulative decline depletes homoeostatic reserves, so that even minor stressor events could trigger health problems.2 A recent cross-sectional study of 223 community-dwelling residents aged ≥64 years showed a good correlation (r = 0.67, P < 0.001) between the QMCOO and the Kihon Checklist, which is the common frailty screening tool in Japan. The area under the curve of the QMCOO for estimating frailty based on the Kihon Checklist is 0.851.3 Limited evidence has been published regarding the validity of the QMCOO in estimating physical frailty based on Fried's phenotype model, which contains actual measurements of physical abilities. In our cross-sectional study, we analyzed 187 disability-free outpatients (95 men and 92 women) aged ≥65 years (mean age: 77.3 years; standard deviation: 5.7) enrolled from the frailty clinic to investigate the ability of the QMCOO to identify physical frailty. Physical frailty was measured using the 5-item Japanese version of the Cardiovascular Health Study (J-CHS) criteria.4 Briefly, physical frailty was defined as a situation in which three or more of the following characteristics were present: unintentional weight loss (≥2 kg within the past year), self-reported exhaustion, low grip strength, slow walking speed, and low physical activity. This study was approved by the Ethics Committee of Human Research at the National Center for Geriatrics and Gerontology, Japan (no. 881-7). Informed consent was obtained from all study participants. [Correction added on 7 September 2022, after first online publication: ‘(The frailty clinic in the hospital, National Center for Geriatrics and Gerontology)’ has been deleted from the first sentence in this paragraph.] Among the 187 outpatients, 21 were diagnosed with physical frailty. The QMCOO score was positively correlated with the number of frailty criteria met in the J-CHS, with a Spearman's rank correlation coefficient of 0.65 (P < 0.001). After adjusting for age and sex, the multivariable odds ratio (95% confidence interval) of one point increment in the QMCOO score for physical frailty was 2.07 (1.61–2.83). The receiver operating characteristic (ROC) curve for the QMCOO score is shown in Figure 1. The optimism-adjusted c-Statistic with 500 bootstrap samples was 0.93 (95% confidence interval, 0.89–0.96). The Hosmer–Lemeshow test showed an acceptable calibration when dividing outpatients into five groups (P = 0.27). The optimal screening threshold for the QMCOO score was determined by evaluating the maximal area under the ROC curve (i.e., c-Statistic) and the Youden index in the univariable logistic regression model (Table S1). The dichotomized level of the QMCOO score was used as an independent variable. A score of four points was observed as the optimal screening threshold for physical frailty, with a c-Statistic of 0.88 and a Youden index of 0.76. To the best of our knowledge, this is the first study to investigate the ability of the QMCOO to identify physical frailty using the J-CHS criteria, which are the standard criteria for diagnosing physical frailty. Actual measurements for walking speed and grip strength in the J-CHS criteria are precise and more valuable for diagnosing physical frailty. Our study confirms the findings of that previous study,3 and further expands the evidence regarding the screening ability of the QMCOO. However, it should be noted that the sample size was small (n = 187), which could suppress the statistical power and increase the inaccuracies in the estimated validation parameters of the ROC curve. Researchers and medical staff should consider this limitation when referencing our findings in their research and clinical practice. In conclusion, we observed that the QMCOO had good screening ability for physical frailty among older Japanese outpatients. We identified a preliminary optimal threshold for the QMCOO score, which could guide frailty screening during medical checkups for older Japanese adults in the latter stages of life. The author contributions were as follows: J.L. and S.S. – conceptualization; S.S. – resources; S.S. – funding acquisition; J.L. and S.S. – reviewing the literature; J.L. – writing a draft of the manuscript; S.S, K.M., M.T., Y.M. and H.A. – data acquisition; K.K. and M.T. – data curation; J.L. – data analysis; S.S. –supervision; all authors – data interpretation and critical revision. The authors would like to thank all study participants and staff of the Frailty Clinic in National Center for Geriatrics and Gerontology for their cooperation and contribution to this study. This study was supported in part by Research Funding for Longevity Sciences from the National Center for Geriatrics and Gerontology, Japan (grant nos 29-12, and 22-4). No grant provider played any role in the design, analysis, or writing of this article. The authors declare that they have no competing interests. This study was approved by the Ethics Committee of Human Research of the National Center for Geriatrics and Gerontology, Japan (no. 881-7). The study complied with the Declaration of Helsinki. Informed consent was obtained from all study participants. The authors elect not to share data. Table S1. The process used to explore the optimal threshold of the QMCOO for estimating physical frailty. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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