Neurogenic bowel dysfunction affects the majority of persons with spinal cord injuries (SCIs).  Yet, there are few patient-reported outcome measures (PROMs) to assess its severity, let alone determine its impact on bowel related quality of life (QOL).  
The Irritable Bowel Syndrome-Quality of Life (IBS-QOL) questionnaire evaluates the impact of bowel dysfunction on several aspects of QOL, although this questionnaire has not been validated for the SCI population. To address the current gap, we sought to validate the Irritable Bowel Syndrome-QOL (IBS-QOL) questionnaire by assessing its face validity in the SCI population.

Content and face validity are often considered the most important properties of a PROM which need to be assessed prior to its use in research and practice. Content and face validity were assessed using semi-structured one-on-one interviews via telecommunication. English and Spanish-speaking patients with chronic SCIs, as well as care providers at a large safety net hospital were enrolled. Using semi-structured one-on-one interviews, the participants were asked to review the IBS-QOL survey and express their opinion about this measure (all items together) in terms of comprehensiveness and relevance to the construct of bowel-related QOL in SCI population. In addition, the experts rated the relevance of each item, and the patients were asked about the comprehensibility of the questionnaire. Interviews were conducted via telecommunication and transcribed to extrapolate common themes.

Experts who participated in face validation included five physicians (four physiatrists and one gastroenterologist) and one nurse practitioner who had been in practice for an average of 19 years (range: 3-29) and provided care for an estimated average of 242 SCI patients annually (range: 95-500). Item-level analysis of expert responses showed that for 97% (33/34) of questions, at least 4/6, agreed that questions were relevant for the construct and population of interest. Some experts highlighted body image items that were less frequently encountered in their practice, suggesting that such items were likely more appropriate for IBS patients.

Twelve patients participated in the study. Both Spanish- (n=5) and English-speaking patients (n=7) unanimously agreed that the IBS-QOL was easy to understand, without any grammatical or spelling errors, questions made sense, and had adequate instructions. All but one English-speaking patient agreed that the questionnaire was clear in its aim, while the remaining patient did not elaborate on the topic. All but one Spanish-speaking patient found the questionnaire to be easy to read, while the remaining patient felt the questionnaire was challenging to read but offered no suggestion on how to make it more readable. As a common theme, the patients expressed that detailed assessment of bowel-QOL as part of their routine care was of great interest.

Using both patient and expert interviews, we demonstrated that the IBS-QOL has sufficient content and face validity for assessment of bowel-related QOL after SCI.

Additional studies are needed to assess the reliability of this measure, while longitudinal designs can be utilized to assess its ability in capturing the meaningful changes in QOL in response to bowel rehabilitation.