The Ostomy-Q: Development and Psychometric Validation of an Instrument to Evaluate Outcomes Associated with Ostomy Appliances.

Using an ostomy appliance can affect many aspects of a person's health-related quality of life (HRQL). A 2-part, descrip- tive study was designed to develop and validate an instrument to assess quality-of-life outcomes related to ostomy ap- pliance use. Study inclusion/exclusion criteria stipulated participants should be 18 to 85 years of age, have an ileostomy or colostomy, used an appliance for a minimum of 3 months without assistance, and able to complete an online survey. All participants provided sociodemographic and clinical information. In phase 1, a literature search was conducted and existing instruments used to measure HRQL in persons with an ostomy were assessed. Subsequently, the Ostomy-Q, a 23-item, Likert-response type questionnaire, divided into 4 domains (Discreetness, Comfort, Confidence, and Social Life), was developed based on published evidence and existing ostomy-related HRQL tools. Seven (7) participants re- cruited from a manufacturer user panel took part in exploratory/cognitive qualitative interviews to refine the new quality- of-life questionnaire. In phase 2, the instrument was tested to assess item variability and conceptual structure, item-total correlation, internal consistency, test-retest reliability, sensitivity, and minimal important difference (MID) in an online validation study among 200 participants from the manufacturer's user panel (equally divided by gender, 125 [62.5%] >50 years old, 128 [64%] with an ileostomy). This exercise also included completion of the Stoma Quality of Life Question- naire and 2 domains from the Ostomy Adjustment Inventory-23 to assess convergent validity. Eighty-two (82) participants recompleted these study instruments 2 weeks later to assess test-retest reliability. Sociodemographic and clinical data were assessed using descriptive statistics; Cronbach's alpha was used for internal consistency (minimum 0.70), principle component analysis for item variability/conceptual structure, and item-total correlation; intraclass correlation coefficient was used for test-retest reliability; and standard error of measurement was applied to MID. All domains demonstrated good internal consistency (between 0.69 and 0.78). All scales showed stability, with a minimum intraclass correlation coefficient of 0.743 (P <.001). The Ostomy-Q showed good convergent validity with other instruments to which it was compared (P <.01). In this study, the Ostomy-Q was found to be a reliable and valid outcome measure that can enhance understanding of the impact of ostomy appliances on users. Some items for social relationships and discreetness may need more exploring in the future with other patient groups.