Table 4.
Predictors of subsequent frailty in lung transplant recipients
| Model | Time-dependent predictor* | Change in SPPB frailty (95% CI) |
Odds Ratio frail versus not frail (95% CI) |
|
|---|---|---|---|---|
| 1 | Sarcopenia Component | Per 1.0 kg decrease in grip strength | −0.08 (−0.10, −0.06) | 1.27 (1.12, 1.43) |
| 2 | Weak grip ¶ | −0.88 (−1.20, −0.56) | 7.14 (2.20, 23.18) | |
| 3 | Body Composition | Underweight (BMI <18.5 kg/m2) | −1.35 (−2.08, −0.61) | 11.53 (0.90, 148.30) |
| Obesity (BMI ≥ 30 kg/m2) | −0.17 (−0.56, 0.23) | 4.33 (1.42, 13.18) | ||
| 4 | Malnutrition | Per 1.0 g/dl decrease in albumin | −0.63 (−0.90, −0.36) | 1.92 (0.90, 4.09) |
| 5 | Albumin <3.5 g/dl ¶ | −0.70 (−1.04, −0.36) | 2.82 (0.99, 8.06) | |
| 6 | Renal dysfunction | Per 10-mL/min/1.73m2 decrease in eGFR | −0.18 (−0.27, −0.10) | 1.54 (1.18, 2.00) |
| 7 | CKD Stage 3 versus Stage 1 or 2 | −0.27 (−0.62, 0.08) | 3.80 (1.05, 13.72) | |
| CKD Stage 4 or 5 versus Stage 1 or 2 | −0.90 (−1.38, −0.42) | 6.20 (1.46, 26.32) | ||
Generalized linear mixed effects model with sarcopenia, body composition, malnutrition, and renal dysfunction as a time-dependent predictors and frailty as the “lagged” outcome.
Measures of frailty were obtained at study visits at 3-, 6-, 12-, 18-, 24-, 30-, and 36-months after lung transplantation. Measures of body composition, sarcopenia, nutrition, and renal function in the 3–6-month time period preceding each study visit were collected and used as time-dependent predictors of the subsequent, or “lagged” outcome of frailty.
Frailty was quantified using the Short Physical Performance Battery (SPPB), which ranges from 0–12 (minimal important difference = 1); lower scores denote worse frailty. Frailty was defined as a continuous measure and as a binary outcome (frail = SPPB ≤7).
Body composition was determined by the most extreme body mass index (BMI) in the interval prior to visit. Underweight and obesity were compared to a reference BMI of 18.5 to <30 kg/m2.
Grip strength was used as a proxy for sarcopenia. A weak grip was defined as proposed by the European Working Group on Sarcopenia in Older People27.
Malnutrition determined by the lowest serum albumin in the interval prior to visit, both as a continuous and a binary predictor.
Measures of renal function were calculated as the lowest estimated glomerular filtration rate (eGFR) and the worst chronic kidney disease (CKD) stage in the time period preceding each study visit. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.29
Models 1–5 were adjusted for study visit, age, sex, and race. Models 6 and 7 were adjusted for study visit.
Results represent the effect of sarcopenia, body composition, malnutrition, and renal dysfunction on SPPB score and odds ratio for frailty; 95% confidence intervals are noted in parenthesis.
Denotes that predictor is binary.