O’Caoimh, R. et al. Prevalence of frailty in 62 countries across the world: a systematic review and meta-analysis of population-level studies. Age Ageing 50, 96–104 (2020).

Article  Google Scholar 

Hoogendijk, E. O. et al. Frailty: implications for clinical practice and public health. Lancet 394, 1365–1375 (2019).

Article  Google Scholar 

Clegg, A., Young, J., Iliffe, S., Rikkert, M. O. & Rockwood, K. Frailty in elderly people. Lancet 381, 752–762 (2013).

Article  Google Scholar 

Bone, A. E., Hepgul, N., Kon, S. & Maddocks, M. Sarcopenia and frailty in chronic respiratory disease. Chron. Respir. Dis. 14, 85–99 (2017).

Article  Google Scholar 

Marengoni, A. et al. The relationship between COPD and frailty: a systematic review and meta-analysis of observational studies. Chest 154, 21–40 (2018).

Article  Google Scholar 

Bousquet, J. et al. Should we use gait speed in COPD, FEV1 in frailty and dyspnoea in both? Eur. Respir. Soc. 48, 315–319 (2016).

Charbek, E., Espiritu, J. R., Nayak, R. & Morley, J. E. Frailty, comorbidity, and COPD. J. Nutr. Health Aging 22, 876–879 (2018).

Article  CAS  Google Scholar 

Hanlon, P. et al. Frailty in COPD: an analysis of prevalence and clinical impact using UK Biobank. BMJ Open Respir. Res. 9, e001314, https://doi.org/10.1136/bmjresp-2022-001314 (2022).

Article  Google Scholar 

Aguayo, G. A. et al. Agreement between 35 published frailty scores in the general population. Am. J. Epidemiol. 186, 420–434 (2017).

Article  Google Scholar 

Luo, J., Dai Zhang, W. T., Dou, L.-Y. & Sun, Y. Impact of frailty on the risk of exacerbations and all-cause mortality in elderly patients with stable chronic obstructive pulmonary disease. Clin. Interv. Aging 16, 593 (2021).

Article  Google Scholar 

Yee, N. et al. Frailty in chronic obstructive pulmonary disease and risk of exacerbations and hospitalizations. Int. J. COPD 15, 1967–1976 (2020).

Article  Google Scholar 

Page, M. J. et al. Updating guidance for reporting systematic reviews: development of the PRISMA 2020 statement. J. Clin. Epidemiol. 134, 103–112 (2021).

Article  Google Scholar 

Moher, D., Liberati, A., Tetzlaff, J., Altman, D. G. & Grp, P. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Int. J. Surg. 8, 336–341 (2010).

Article  Google Scholar 

Hanlon, P. et al. Frailty measurement, prevalence, incidence, and clinical implications in people with diabetes: a systematic review and study-level meta-analysis. Lancet Healthy Longev. 1, E106–E116 (2020).

Crowther, M., Avenell, A., MacLennan, G. & Mowatt, G. A further use for the Harvest plot: a novel method for the presentation of data synthesis. Res. Synth. Methods 2, 79–83 (2011).

Article  Google Scholar 

Ogilvie, D. et al. The harvest plot: a method for synthesising evidence about the differential effects of interventions. BMC Med. Res. Methodol. 8, 8 (2008).

Article  Google Scholar 

Akgun, K. M. et al. Association of chronic obstructive pulmonary disease with frailty measurements in HIV-infected and uninfected Veterans. AIDS 30, 2185–2193 (2016).

Article  Google Scholar 

Ambagtsheer, R. C., Beilby, J., Seiboth, C. & Dent, E. Prevalence and associations of frailty in residents of Australian aged care facilities: findings from a retrospective cohort study. Aging Clin. Exp. Res. 32, 1849–1856 (2020).

Avila-Funes, J. A. et al. Frailty among community-dwelling elderly people in France: the three-city study. J. Gerontol. Ser. A Biol. Sci. Med. Sci. 63, 1089–1096 (2008).

Article  Google Scholar 

Bernabeu-Mora, R. et al. Frailty is a predictive factor of readmission within 90 days of hospitalization for acute exacerbations of chronic obstructive pulmonary disease: a longitudinal study. Therapy 11, 383–392 (2017).

Google Scholar 

Bernabeu-Mora, R. et al. Frailty transitions and associated clinical outcomes in patients with stable COPD: a longitudinal study. PLoS ONE 15, e0230116 (2020).

Blaum, C. S., Xue, Q. L., Michelon, E., Semba, R. D. & Fried, L. P. The association between obesity and the frailty syndrome in older women: the Women’s Health and Aging Studies. J. Am. Geriatr. Soc. 53, 927–934 (2005).

Article  Google Scholar 

Castellana, F. et al. Physical frailty, multimorbidity, and all-cause mortality in an older population from Southern Italy: results from the Salus in Apulia Study. J. Am. Med. Dir. Assoc. 22, 598–605 (2021).

Article  Google Scholar 

Chen, C.-Y., Wu, S.-C., Chen, L.-J. & Lue, B.-H. The prevalence of subjective frailty and factors associated with frailty in Taiwan. Arch. Gerontol. Geriatr. 50, S43–S47 (2010).

Article  Google Scholar 

Chen, P. J., Yang, K. Y., Perng, W. C., Lin, K. C. & Wang, K. Y. Effect of dyspnea on frailty stages and related factors in Taiwanese men with COPD. Int. J. COPD 13, 2463–2469 (2018).

Article  CAS  Google Scholar 

Cheong, C. Y. et al. Risk factors of progression to frailty: findings from the Singapore Longitudinal Ageing Study. J. Nutr. Health Aging 24, 98–106 (2020).

Chin, M., Voduc, N., Huang, S., Forster, A. & Mulpuru, S. Practical lessons in implementing frailty assessments for hospitalised patients with COPD. BMJ Open Qual. 9, 01 (2020).

Article  Google Scholar 

Crow, R. S. et al. Mortality risk along the frailty spectrum: data from the National Health and Nutrition Examination Survey 1999 to 2004. J. Am. Geriatr. Soc. 66, 496–502 (2018).

Article  Google Scholar 

de Albuquerque Sousa, A. C. P., Dias, R. C., Maciel, Á. C. C. & Guerra, R. O. Frailty syndrome and associated factors in community-dwelling elderly in Northeast Brazil. Arch. Gerontol. Geriatr. 54, e95–e101 (2012).

Article  Google Scholar 

Dias, L. D., Ferreira, A. C. G., da Silva, J. L. R., Conte, M. B. & Rabahi, M. F. Prevalence of frailty and evaluation of associated variables among COPD patients. Int. J. Chron. Obstruct. Pulm. Dis. 15, 1349–1356 (2020).

Article  Google Scholar 

Fragoso, C. A. V., Enright, P. L., McAvay, G., Van Ness, P. H. & Gill, T. M. Frailty and respiratory impairment in older persons. Am. J. Med. 125, 79–86 (2012).

Article  Google Scholar 

Fried, L. P. et al. Frailty in older adults: evidence for a phenotype. J. Gerontol. Ser. A Biol. Sci. Med. Sci. 56, M146–M157 (2001).

Article  CAS  Google Scholar 

Gale, N. S. et al. Frailty: a global measure of the multisystem impact of COPD. Chron. Respir. Dis. 15, 347–355 (2018).

Article  Google Scholar 

Galizia, G. et al. Role of clinical frailty on long-term mortality of elderly subjects with and without chronic obstructive pulmonary disease. Aging Clin. Exp. Res. 23, 118–125 (2011).

Article  Google Scholar 

Gephine, S., Grosbois, J. M., Saey, D., Maltais, F. & Mucci, P. Effects of home-based pulmonary rehabilitation on physical frailty in people with COPD and chronic respiratory failure. Eur. Respir. J. 56(Supplement 64), 888 (2020).

Gu, J.-J., Liu, Q. & Zheng, L.-J. A frailty assessment tool to predict in-hospital mortality in patients with acute exacerbations of chronic obstructive pulmonary disease. Int. J. Chron. Obstruct. Pulm. Dis. 16, 1093 (2021).

Article  CAS  Google Scholar 

Hanlon, P. et al. Frailty and pre-frailty in middle-aged and older adults and its association with multimorbidity and mortality: a prospective analysis of 493 737 UK Biobank participants. Lancet Public Health 3, e323–e332 (2018).

Article  Google Scholar 

Hirai, K. et al. Comparison of three frailty models and a sarcopenia model in elderly patients with chronic obstructive pulmonary disease. Geriatr. Gerontol. Int. 19, 896–901 (2019).

Article  Google Scholar 

Ierodiakonou, D. et al. Determinants of frailty in primary care patients with COPD: the Greek UNLOCK study. BMC Pulm. Med. 19, 63 (2019).

Article  Google Scholar 

Kennedy, C. C. et al. Frailty and clinical outcomes in chronic obstructive pulmonary disease. Ann. Am. Thorac. Soc. 16, 217–224 (2019).

Article  Google Scholar 

Kim, S., Jung, H. W. & Won, C. W. What are the illnesses associated with frailty in community-dwelling older adults: the Korean frailty and aging cohort study. Korean J. Intern. Med. 35, 1004–1013 (2020).

Article  Google Scholar 

Kusunose, M., Oga, T., Nakamura, S., Hasegawa, Y. & Nishimura, K. Frailty and patient-reported outcomes in subjects with chronic obstructive pulmonary disease: are they independent entities? BMJ Open Respir. Res. 4, e000196 (2017).

Lahousse, L. et al. Adverse outcomes of frailty in the elderly: the Rotterdam Study. Eur. J. Epidemiol. 29, 419–427 (2014).

Article  Google Scholar 

Lahousse, L. et al. Risk of frailty in elderly with COPD: a population-based study. J. Gerontol. A Biol. Sci. Med. Sci. 71, 689–695 (2016).

Article  CAS  Google Scholar 

Lai, H. Y., Chang, H. T., Lee, Y. L. & Hwang, S. J. Association between inflammatory markers and frailty in institutionalized older men. Maturitas 79, 329–333 (2014).

Article  CAS  Google Scholar 

Lee, J. S. W., Auyeung, T. W., Leung, J., Kwok, T. & Woo, J. Transitions in frailty states among community-living older adults and their associated factors. J. Am. Med. Dir. Assoc. 15, 281–286 (2014).

Article  Google Scholar 

Limpawattana, P. et al. Frailty syndrome in ambulatory patients with COPD. Int. J. COPD 12, 1193–1198 (2017).

Article  Google Scholar 

Liotta, G. et al. Assessment of frailty in community-dwelling older adults residents in the Lazio region (Italy): a model to plan regional community-based services. Arch. Gerontol. Geriatr. 68, 1–7 (2017).

Article  Google Scholar 

Ma, L. et al. Prevalence of frailty and associated factors in the community-dwelling population of China. J. Am. Geriatr. Soc. 66, 559–564 (2018).

Article  Google Scholar 

Maddocks, M. et al. Physical frailty and pulmonary rehabilitation in COPD: a prospective cohort study. Thorax 71, 988–995 (2016).

Article  Google Scholar 

Medina-Mirapeix, F. et al. Patterns, trajectories, and predictors of functional decline after hospitalization for acute exacerbations in men with moderate to severe chronic obstructive pulmonary disease: a longitudinal study. PLoS ONE 11, e0157377 (2016).

Medina-Mirapeix, F. et al. Physical frailty characteristics have a differential impact on symptoms as measured by the CAT score: an observational study. Health Qual. Life Outcomes 16, 140 (2018).

Article  Google Scholar 

Motokawa, K. et al. Frailty severity and dietary variety in Japanese older persons: a cross-sectional study. J. Nutr. Health Aging 22, 451–456 (2018).

Article  CAS  Google Scholar 

Nagorni-Obradovic, L. M. & Vukovic, D. S. The prevalence of COPD co-morbidities in Serbia: results of a national survey. NPJ Prim. Care Respir. Med. 24, 14008 (2014).

Article  Google Scholar 

Oishi, K. et al. A new dyspnea evaluation system focusing on patients’ perceptions of dyspnea and their living disabilities: the linkage between copd and frailty. J. Clin. Med. 9, 1–13 (2020).

Article  Google Scholar 

Park, S. K., Richardson, C. R., Holleman, R. G. & Larson, J. L. Frailty in people with COPD, using the National Health and Nutrition Evaluation Survey dataset (2003-2006). Heart Lung 42, 163–170 (2013).

Article  Google Scholar