The multidimensional kidney transplant self-management scale : development and psychometric testing

Abstract

Poor long-term kidney transplant outcomes are a significant problem in the U.S. Interventions must focus on preserving allograft function by managing modifiable risk factors. An instrument capable of identifying problems with post-kidney transplant self-management behaviors may enable the design and testing of self-management interventions. This study’s purpose was to test the psychometric properties of the new Kidney Transplant Self-Management Scale (KT–SM). The Zimmerman framework adapted for kidney transplant self-management guided the cross-sectional study. A total of 153 kidney recipients recruited from Facebook® completed the Self-Efficacy for Managing Chronic Disease (SEMCD), Patient Activation Measure (PAM), Kidney Transplant Questionnaire (KTQ), and KT–SM Scale instruments via a REDCap® survey. Most participants were female (65%), White (81.7%), and middle-aged (M = 46.7; SD = 12.4 years) with a history of dialysis (73%) and received a kidney transplant an average of 6.58 years previous (SD = 6.7). Exploratory factor analysis results supported the 16-item KT–SM Scale as a multidimensional scale with five domains with loadings ranging between .39 and .89: medication adherence, protecting kidney, cardiovascular risk reduction, ownership, and skin cancer prevention. Internal consistency reliability for the total scale (Cronbach’s α = .84) and five domains ranged from .71 to .83. The total and domains were positively correlated, ranging from r = .51 to .76, p = .01. Criterion-related validity was evidenced by significant correlations of KT–SM and domains with SEMCD (r =.22 to .53, p = .01), PAM (r = .31 to .52, p = .01), and the overall KTQ (r = .20 to .32, p = .01) except for one KT–SM domain: protecting kidney. Construct validity was evaluated using multivariate regression analysis. The linear combination of age, patient activation, and self-efficacy explained 45% of the variance in KT–SM behaviors; 47% of the variance in KTQ (measuring quality of life) was predicted by age, comorbidity, and self-efficacy. These findings provide beginning evidence of reliability and validity for the newly developed KT–SM scale. Instruments like this may provide a means to capture the self-management behaviors of the kidney transplant population, which is critical for future work on interventions.