Association of Karnofsky Performance Status with waitlist mortality among older and younger adults awaiting kidney transplantation

Patients with end-stage renal disease (ESRD) have impaired functional status compared with the general population. We sought to explore the association between Karnofsky Performance Status (KPS) and death/delisting from the kidney transplantation waitlist and whether this association differed by age. Patients listed for single-organ kidney transplantation in the United Network for Organ Sharing/Organ Procurement and Transplantation Network from January 1, 2015, to January 1, 2018, were included. We performed competing-risk regression analyses to determine the association between KPS (“Severely impaired”, “Moderately impaired”, “Non-impaired”) and death/delisting, with deceased-donor kidney transplantation as a competing risk. We tested for interactions between age and KPS on death/delisting. Of the 89,819 patients analyzed, 39% were impaired (KPS < 80) and 20% were aged ≥ 65 years. Older age and lower KPS were independently associated with higher risk of death/delisting (age 45-64 years, HR 1.97 [95% CI 1.73-2.24]; age ≥ 65 years, HR 3.62 [95% CI 3.33-3.92] compared with age < 45 years; moderately impaired, HR 1.68 [95% CI 1.45-1.95]; severely impaired, HR 4.80 [95% CI 3.71-6.21] compared with non-impaired). Lower KPS was associated with higher risk of death/delisting among all ages, but this effect was slightly less pronounced among individuals aged ≥ 65 years. Performance status should be used when counseling patients with ESRD on their risks for death/delisting.