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Purpose: The toxicity index (TI) is a summary index that accounts for toxicity grades associated with cancer symptoms that is more sensitive than other toxicity systems to treatment differences. The TI can be used with patient-reported symptoms but requires that scores for different items represent equivalent severity. The purpose of this article is to provide an example of scoring patient-reported symptoms that satisfies the requirement of equivalent symptom severity., Methods: A sample of 1232 adults with rectal cancer from a Phase III clinical trial self-reported 18 symptoms on the European Organization for Research and Treatment of Cancer colorectal cancer measure using a 4-category response scale (not at all, a little bit, quite a bit, or very much). The participants were 22 to 85 years of age (mean age, 57 years), 30% were female, 85% were non-Hispanic white, 59% had stage II cancer, and 41% had stage III cancer. A recoded TI was created using item response theory category thresholds., Findings: The recoded TI had larger rank-order correlations than the original TI with Karnofsky performance status index, hemoglobin level, symptom bother, and other aspects of health-related quality of life., Implications: Recoding items based on category thresholds yielded a more valid TI score that can be used to summarize adverse events., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: The Kidney Disease Quality of Life Instrument (KDQOL) was developed to provide clinicians with a comprehensive assessment of the important domains of health-related quality of life (HRQOL) for patients with end-stage renal disease who are undergoing hemodialysis., Objective: The purpose of this study was to develop subscales from the 55 items comprising the Symptoms/Problems and Effects of Kidney Disease scales of the KDQOL and to measure the internal consistency reliability of these subscales., Methods: The 55 items from the Symptoms/Problems and Effects of Kidney Disease scales were arranged into substantively meaningful clusters using an affinity mapping procedure. The resulting subscales were assessed for internal consistency reliability using data from a sample of 165 individuals with kidney disease who had completed the KDQOL., Results: Eleven multi-item subscales were identified: pain, psychological dependency, cognitive functioning, social functioning, dialysis-related symptoms, cardiopulmonary symptoms, sleep, energy, cramps, diet, and appetite. Four items (clotting or other problems with access site, high blood pressure, numbness in hands or feet, and blurred vision) were not included in any of these subscales. Internal consistency reliability estimates for the 11 subscales ranged from 0.66 to 0.92. These subscales correlated with the scales from the 36-Item Short-Form Health Survey as hypothesized (ie, corresponding pain, energy, and social functioning scales had the highest correlations). In addition, several subscales were significantly associated, as hypothesized, with other variables such as the number of disability days., Conclusions: The results of this study further support the reliability and validity of the KDQOL. The 11 subscales identified yield more detailed information on the HRQOL of patients with kidney disease and provide a basis for specific improvements in the quality of care delivered to these patients.