Frailty was assessed with the Short Physical Performance Battery, which ranges from 0 to 12. Recipients with SPPB ≤ 7 were categorized as frail (white boxes), and those with SPPB >7 were categorized as not frail (gray boxes). HRQL was assessed by the SF12-Physical Component Score (generic-physical), the SF12-Mental Component Score (generic-mental), the Airway Questionnaire 20-Revised (respiratory specific), and the EuroQOL-5D (health utility).