Validation of an updated patient-reported outcomes questionnaire for sacral tumors.

Abstract

Background context: Assessing functional outcomes and quality of life is crucial in evaluating patient and disease management. Sacral tumors are rare and present with complex oncologic backgrounds and diverse symptoms, complicating the development of a clinically relevant and generalizable tool. A previous validation study refined an initial attempt to create a tool specific to sacral tumor patients. This study is the first independent validation of the revised shorter outcome tool.

Purpose: To validate a revised patient-reported outcomes questionnaire specific to patients with sacral tumors. Secondarily, to assess the functional outcomes of patients with sacral tumors.

Study design/setting: A survey study from a tertiary care multidisciplinary clinic was used for this study.

Patient sample: This study included 70 patients with sacral tumors who presented to our institution between October 2017 and June 2022.

Outcome measures: The following eight questionnaires included in the revised sacral tumor survey were evaluated: the Patient Reported Outcomes Measurement Information System (PROMIS) Global Health short form v1.1, PROMIS Pain Intensity 3a v1.0, PROMIS Gastrointestinal Bowel Incontinence 4a v1.0, PROMIS Gastrointestinal Constipation 9a v1.0, PROMIS Sexual Function and Satisfaction v1.0 Male and Female, Urogenital Distress Inventory (UDI-6), and PROMIS Ability to Participate in Social Roles and Activities v2.0.

Methods: Reliability, validity, and instrument coverage were evaluated by determining item completion rate, median score with interquartile range (IQR), and floor and ceiling effects. Internal consistency was measured using Cronbach's alpha. Bias-corrected bootstrapping (1,000 resamples) was applied to calculate the standard error and 95% confidence intervals. Spearman rank correlation coefficients were used to assess the extent of questionnaire convergence and divergence.

Results: Our analysis demonstrates moderate to significant floor and ceiling effects among PROMIS Gastrointestinal Symptoms Scale, PROMIS Sexual Function, and Urinary Distress Inventory (16%-61%) with predominantly more ceiling effects. Floor effects were notable for male interest (27%), female interest (29%), and female orgasm (38%). Moderate floor effects were noted for male satisfaction (11%), male orgasm (10%), and lubrication (14%). When controlling for patients with a colostomy, floor effects generally decreased, while ceiling effects showed variable changes. The revised questionnaire demonstrated strong internal consistency, with Cronbach's alpha values exceeding the threshold of 0.7 for all assessments except lubrication. GI bowel incontinence, male satisfaction, female satisfaction, and female interest were potentially redundant with a Cronbach's alpha above 0.9. In convergent validity, we found no significant trend in correlations between scores. Secondarily, when compared to patients with chronic diseases, our population reported similar levels of impaired physical health.

Conclusions: Substantial floor and ceiling effects, along with poor convergence, were observed for many of the bowel, bladder, and sexual function questionnaires. Some metrics improved when accounting for patients with colostomies; however, the significant floor and ceiling effects identified in the bowel, bladder, and sexual function surveys must be considered in future research using the modified sacral tumor survey. PROMIS instruments effectively capture the profound impact of sacral tumors and their treatment on patients' physical and mental well-being.