Clinical rating of compliance in chronic hemodialysis patients

Objective: To develop a clinical rating scale of treatment compliance for u se in chronic hemodialysis patients and to test its reliability and validit y. Method: Forty-eight of 65 patients undergoing hemodialysis treatment at the Ottawa General Hospital during June 1994 met criteria for inclusion and co mpleted the study. Patients underwent a 10-15-minute interview, with 1 of 2 independent clinical interviewers, regarding diet, fluid intake, prescribe d medication usage, smoking, alcohol or drug use, and hemodialysis treatmen t attendance. Following each interview, a predesigned 3-point rating scale evaluating compliance in each of 6 domains (yielding an 18-point total scor e) to the treatment regimen was completed. Compliance ratings on 10 patient s assessed independently by both interviewers were used to establish scale reliability. Criterion validity was assessed by correlating compliance scal e scores with 3 biological measures (weight gain [kg], K+ [mmol/l], and PO4 [mmol/l]). Results: Reliability between clinical interviewers using the overall compli ance scale score (Intraclass correlation coefficient = 0.825) as well as co mponent subscales war; high (kappa values, 0.33-1.00). Biological measures of compliance correlated well with each other but poorly with clinical rati ngs (range 0.01-0.16). Biological measures identified compliance ar; being poorer than that found with the clinical interview scale. Conclusions: The Compliance Rating Scale (CRS) was shown to be reliable but was not well-validated against selected biological measures. Discrepancies between these 2 methods of assessing compliance may be due to differing un derlying compliance constructs or patient or interviewer biases. The CRS ha s value as a patient education tool in that it can be used to instruct pati ents regarding the benefits of adhering to the treatment regimen.