Multidimensional Frailty Assessment and Post-Transplant Outcomes in Liver Transplant Candidates

Liver Frailty Index (LFI)

Frailty will be assessed using the Liver Frailty Index (LFI), which is calculated from three standardized physical performance tests: grip strength (kg, average of three trials), chair stands (seconds to complete five repetitions), and balance test (seconds, up to 10 seconds in three positions). LFI score will be calculated according to the standard LFI formula. Frailty severity will be categorized as: ≥4.5: Severe frailty 3.2-4.4: Moderate frailty \<3.2: Not frail Unit of Measure: LFI score (continuous) Direction: Higher scores indicate greater frailty (worse outcome).

6-Minute Walk Test (6MWT) Distance

The 6-minute walk test (6MWT) will be conducted according to European Respiratory Society and American Thoracic Society guidelines along a 30-meter corridor. Participants will be instructed to walk as far as possible in six minutes. Distance walked will be recorded in meters and rounded to the nearest meter. Oxygen saturation, heart rate, blood pressure, and fatigue (Modified Borg Scale) will be recorded before and after the test, with continuous SpO₂ and heart rate monitoring during the walk. Frailty classification will be based on the following thresholds: \<250 m (severe frailty), 250-350 m (moderate frailty), \>350 m (not frail). Unit of Measure: Meters (continuous) Direction: Higher walking distance indicates lower frailty (better outcome).

Karnofsky Performance Status (KPS)

The Karnofsky Performance Status (KPS) is a subjective measure of frailty, originally developed for oncology and subsequently applied in cirrhosis. The scale ranges from 0% (death) to 100% (normal; no complaints; no evidence of disease), scored in 10-point increments. Applicable to both hospitalized and ambulatory patients. Frailty classification will be based on the following thresholds: 0-40% = Severe frailty 50-70% = Moderate frailty ≥80% = Not frail Unit of Measure: Percentage (%) Direction: Higher KPS score indicates lower frailty (better outcome).

Activities of Daily Living (ADL)

The Activities of Daily Living (ADL) scale is a subjective measure of frailty, developed to assess functional status in aging populations. It evaluates six functions: bathing, dressing, toileting, continence, transferring, and feeding. The scale is self-reported and scored from 0 (dependent) to 6 (independent). Frailty classification will be based on the following thresholds: ≥2 difficulties (severe frailty), 1 difficulty (moderate frailty), and 0 difficulties (not frail). Unit of Measure: Score (0-6) Direction: Higher scores indicate lower frailty (better outcome).

Nutritional Risk Index (NRI)

Nutritional status will be assessed using the Nutritional Risk Index (NRI). The NRI score will be calculated using serum albumin level (g/dL), current body weight (kg), and usual body weight (kg) according to the following formula: NRI = (15.19 × serum albumin \[g/dL\]) + (41.7 × current weight / usual weight) Nutritional status will be categorized as follows: NRI ≥ 100: No malnutrition 97.5 ≤ NRI \< 100: Mild malnutrition 83.5 ≤ NRI \< 97.5: Moderate malnutrition NRI \< 83.5: Severe malnutrition Unit of Measure: NRI score Direction: Higher NRI values indicate better nutritional status.

Phase Angle Measured by Bioelectrical Impedance Analysis (BIA)

Phase angle will be measured using bioelectrical impedance analysis (BIA) as an indicator of cellular integrity and nutritional status. Measurements will be performed according to standard BIA procedures at the time of hospital admission. Phase angle values will be categorized according to predefined study criteria as follows: \<4.4 degrees: Abnormal 4.4-5.4 degrees: Borderline ≥5.4 degrees: Normal Unit of Measure: Degrees Direction: Higher phase angle values indicate better cellular health and nutritional status.

Sarcopenia Diagnosis According to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) Criteria

Sarcopenia will be assessed according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Evaluation will include assessment of muscle strength, muscle mass, and physical performance using standardized measurement procedures at hospital admission. Sarcopenia will be classified as: Probable sarcopenia: Low muscle strength Sarcopenia: Low muscle strength and low muscle mass Severe sarcopenia: Low muscle strength, low muscle mass, and low physical performance Unit of Measure: Categorical classification (probable sarcopenia, sarcopenia, severe sarcopenia) Direction: Lower sarcopenia severity indicates better muscle status.

Handgrip Strength (HGS)

Handgrip strength will be measured using a hand dynamometer in the dominant hand following a standardized protocol (patient seated, elbow at 90 degrees, three trials, best value recorded). Low muscle strength will be defined according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria as \<27 kg for men and \<16 kg for women. Unit of Measure: Kilograms (kg) Direction: Higher handgrip strength indicates better muscle strength and physical status.