Better health-related quality of life in kidney transplant patients compared to chronic kidney disease patients with similar renal function

Abstract

Renal functional deterioration is associated with physical and mental burdens for kidney transplant (KT) and chronic kidney disease (CKD) patients. However, the change in health-related quality of life (HRQOL) over time in KT patients compared to that of native CKD patients has not been evaluated. We addressed this issue using KT patients registered in the KNOW-KT cohort study and patients at CKD stage 1-3 registered in the KNOW-CKD cohort study. HRQOL scores were assessed using the Kidney Disease Quality of Life Short Form at baseline, 2-, and 4-years follow-up in 842 KT patients and at baseline and 5-year follow-up in 1,355 CKD patients. SF-36 scores declined at the 4-year follow-up, whereas CKD-targeted scores showed no change in the KT group. In contrast, CKD-targeted scores as well as SF-36 scores were decreased at the 5-year follow-up in CKD patients. When prognostic factors were analyzed for longitudinal HRQOL data over time, renal functions, diabetes, cardiovascular and cerebrovascular diseases, hemoglobin level, marital status, income, employment, and health care were significant prognostic factors. Furthermore, KT was an independent prognostic factor for better HRQOL. These results highlight that KT can offer a better HRQOL than that of CKD patients, even when renal function is similar.

Fig 1. Flow diagram of the study population.

(A) Among 1,080 KNOW-KT cohort participants, total 842 patients were analyzed after exclusion of 238 people. (B) Among 2,238 KNOW-CKD cohort participants, total 1,355 patients were analyzed after exclusion of 883 people. KNOW-KT, KoreaN cohort study for Outcome in patients With Kidney Transplantation; QOL, quality of life; KNOW-CKD, KoreaN cohort study for Outcome in patients With Chronic Kidney Disease.

Fig 2. Changes in SF-36 scores and CKD-targeted scores after kidney transplantation.

(A) HRQOL at baseline, 2- and 4-year follow-up was assessed by SF-36 scores in kidney transplant patients. (B-C) Physical component summary (PCS) score (B) and mental component summary (MCS) score (C) were also assessed. (D) Total CKD-targeted score was assessed by KDQOL-SF at baseline, 2- and 4-year follow-up. All values in panel a-d were displayed using Box and whisker plots. Top, middle, and bottom of boxes were the 75th, 50th, and 25th percentiles, respectively; whiskers illustrate the range. (E, F) Each domain covering PCS or MCS scores in SF-36 scores (E) and the CKD-targeted scores (F) was separately analyzed. Each value in panel e and f was displayed as the mean ± standard error of the mean. *P<0.05 and **P<0.01 compared to baseline (paired t-test). CKD, chronic kidney disease; HRQOL, health-related quality of life; KDQOL-SF, Kidney Disease Quality of Life Short Form; SF-36, Short Form-36 Health Survey (SF-36).

Fig 3. Comparison of changes in HRQOL between KT and CKD patients at the similar renal function according to CKD stage.

(A) SF-36 score at CKD stage 1–3. (B) PCS score at CKD stage 1–3. (C) MCS score at CKD stage 1–3. (D) CKD-targeted score at CKD stage 1–3. (E) SF-36 score at CKD stage 1–2. (F) SF-36 score at CKD stage 3. (G) CKD-targeted score at CKD stage 1–2. (H) CKD-targeted score at CKD stage 3 were compared between KT (solid lines) and CKD patients (dot lines). Each value was displayed as the mean ± standard error of the mean. Chronic kidney disease; MCS, mental component summary score; KT, kidney transplantation; PCS, Physical component summary score.