Prevalence, Persistence, and Agreement of Physical Frailty Tools in Patients with Severe COPD Declining Pulmonary Rehabilitation: An Exploratory 1-Year Prospective Cohort Study

<b>Background:</b> Physical frailty is a prevalent and clinically important manifestation of COPD. While the ERS/ATS recommends the Short Physical Performance Battery (SPPB), handgrip strength (HGS), 30 s sit-to-stand (30secSTS), and Timed-Up-and-Go (TUG) as frailty screening tools, their agreement and predictive performance remain unclear. Furthermore, the trajectory of frailty is poorly understood in patients who decline pulmonary rehabilitation (PR). <b>Objective:</b> To assess the prevalence of and change in physical frailty and its association with 12-month all-cause hospitalizations and mortality. Secondarily, to assess the agreement and predictive value (positive; PPV/negative; NPV) of recommended screening tests in COPD patients declining PR. <b>Methods:</b> In this prospective cohort study, 102 patients with COPD (61 females, mean ± SD age 70 ± 9 years, FEV₁ 34 ± 11%, SPPB 8.0 ± 3.2 points, CAT 19 ± 7) underwent repeated frailty assessments at baseline and after 12 months using the SPPB (reference), TUG, 30secSTS, and HGS. <b>Results:</b> At baseline, 39% were physically frail (SPPB ≤ 7). Frailty persisted in 86%, and 23% had died at 12 months. Baseline age-adjusted physical frailty was not statistically associated with 12-month all-cause hospitalization (OR 1.79 [0.61-5.24]) or mortality (OR 3.54 [0.95-13.16]). Agreement with SPPB was moderate for TUG (κ = 0.53) and fair for 30secSTS (κ = 0.38) and HGS (κ = 0.26), with similar findings at 12 months. TUG had the highest PPV/NPV (0.85/0.71). <b>Conclusions:</b> Physical frailty is prevalent and persistent in patients with severe COPD who decline PR. ERS/ATS-recommended tools showed fair to moderate agreement and predictive value. TUG was the most robust proxy, though tool selection should be guided by clinical context and purpose.