Polish validation of the Simpler Modified Fried Frailty Scale for frailty screening in older inpatients

OBJECTIVES: This study aimed to translate and culturally adapt the Simpler Modified Fried Frailty Scale (SFS) into Polish and evaluate its psychometric performance against reference measures, with a focus on its potential as a brief frailty screening tool in inpatient settings. METHODS: The study was conducted in a geriatric inpatient setting in Poland and included 100 hospitalized adults aged ≥65 years who were able to ambulate and complete frailty assessments. Participants completed the SFS, the performance-based Modified Fried Frailty Scale (MFS), and the FRAIL scale. We assessed internal consistency, construct validity, item-level discrimination, diagnostic accuracy with positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR). RESULTS: Internal consistency was acceptable for a brief multidomain screener (α=0.61). Convergent correlations were strong with MFS and FRAIL (ρ=0.64 each; p<0.001). Agreement was fair-moderate (κ=0.38-0.46). Using the ≥3 cut-point, sensitivity was 70.8% (95% Confidence Interval (CI) 48.9-87.4), specificity 80.3% (69.5-88.5), PPV 53.1%, NPV 89.7%; LR⁺ 3.59, LR⁻ 0.36. Discrimination for MFS-defined frailty was good (the area under the curve =0.81, 95%CI 0.71-0.92). Items contributing most to discrimination were exhaustion/fatigue (Odds ratio (OR) =20.5), low activity (OR=8.1), and perceived slowness (OR=5.3), supporting the construct validity of self-reported phenotypic domains. . CONCLUSION: The Polish SFS showed good discrimination against MFS-defined frailty, acceptable internal consistency, and a high negative predictive value in this inpatient sample. These findings support its potential as a brief frailty screening tool, although further reliability testing and external validation across clinical settings are warranted.