Development and validation of the Kidney Transplantation and Quality of Life, a Korean questionnaire to assess the general quality of life and other health issues associated with medication change in kidney transplant recipients

Background: This study aimed to develop and validate the Kidney Transplantation and Quality of Life (KTQoL) questionnaire to evaluate the quality of life (QoL) in Korean kidney transplantation (KT) patients. During the validation, the KTQoL was used to compare the QoL of KT patients before and after conversion from twice-daily to a once-daily regimen of tacrolimus. Methods: Construct and content validity of the 24-item KTQoL was evaluated using factor analysis and a panel of experts, respectively. The questionnaire was validated in 50 KT patients, conducted before and after conversion from twice-daily to once-daily tacrolimus. Internal consistency was evaluated based on Cronbach's alpha coefficient. Results: The KTQoL showed high internal consistency (Cronbach's alpha 0.71 to 0.88). Besides the Concerns category, both the general and specific QoL of KT patients were relatively good (≥70% of positive responses) and did not change markedly after conversion to the once-daily regimen (42.9±8.8 vs. 43.6±8.6, P=0.740). After conversion, men scored better than women in total KTQoL, Specific QoL, and Symptoms, while employed patients had better Daily Life scores and showed greater improvement in Daily Life scores compared with unemployed patients. Conclusions: The KTQoL seems to be a reliable instrument to evaluate general and specific QoL in Korean KT patients. Most patients evaluated their QoL positively. Conversion to once-daily tacrolimus had no significant effect on QoL in the total sample of KT patients. The QoL of men and/or employed persons might improve more after conversion to once-daily tacrolimus.