“Developing a metric that covers the concepts and aspects of health that are most important to patients means to evaluate the efficacy of treatments, perform clinical trials and even compare efficacy of different treatments,” explains Bruce K. Tan, MD, MS. “To date, there has been no patient-reported measure that has been formally accepted by the FDA for use as an endpoint in clinical trials in the chronic rhinosinusitis (CRS) space. Metrics used to study CRS, like the Sinonasal Outcome Test-22 (SNOT-22), traditionally used patients with a variety of nasal conditions in their development and were also developed more than 20 years ago, when CRS definitions were not yet established.”
CRS-PRO Development & Examination
For a study published in The Journal of Allergy and Clinical Immunology: In Practice, Dr. Tan and colleagues developed and examined the initial reliability and validity of the CRS-PRO, a novel, patient-reported outcome (PRO) measure (PROM) of CRS. “We went about this in three rigorous phases,” notes Dr. Tan. “First, patients with CRS symptoms and objective evidence from CT or endoscopy were identified and interviewed individually or in focus groups by health psychologists to identify important health concepts. Transcripts of these interviews were qualitatively analyzed to identify the most important health concepts discussed by patients. We then utilized existing items from well-developed PROMs and wrote new questions if the concept raised did not correspond to a previously developed item and solicited feedback on these from patients with CRS. We were careful to include almost equal representation from CRS patients with and without nasal polyps to ensure that health concepts raised were common to both groups. We then tested a 21-item battery of questions on patients with stable symptoms not undergoing therapy and another group with symptoms expected to change after medical treatment.”
All patients completed the 21-item draft CRS-PRO, SNOT-22, and general quality-of-life measures from four patient-reported outcome measurement information system (PROMIS) short forms at baseline and at least 7 days later. Statistical analyses were then performed, including assessment of concurrent validity and performance by comparison with the SNOT-22 and PROMIS instruments.
To evaluate the average frequency among patients with CRS, baseline means of each item in the CRS-PRO were calculated (Table). “Although patients did bring up a multitude of symptoms or impairments that they felt were important to them in the focus groups, when we studied how these performed when patients with CRS were studied as a population, we found some were either: 1) so tightly correlated with each other they were essentially measuring the same thing; 2) reported as very mild; or 3) did not appear to change with treatment despite the objective improvements seen,” explains Dr. Tan.
Items with low mean scores, two impact items were removed from the instrument (items 20, 21), followed by items that were dyads of the concept of mucus in the nose (10) or the concept of sleep impairment (15) that had lower mean scores, as well as items from other dyads that had lower baseline symptom severity (2, 7) were selected for removal. Furthermore, items with high correlations like two psychosocial items (16, 18) were removed to reduce redundancy. “We found that the subset of 12 items could represent the health burden as well as the 21-item questionnaire,” says Dr. Tan. “It also demonstrated equivalent responsiveness to the SNOT-22 but is half the length and has clear evidence of development using input from patients with current definitions of CRS.” By utilizing CT and endoscopy, the study team also found corresponding objective changes that corresponded to the patient-reported changes experienced following therapy.
A Work in Progress
“CRS-PRO is now validated to evaluate health burden and treatment changes for patients with CRS,” Dr. Tan notes, adding that, “with all PROMs, full ‘validation’ is always a work in progress. Using the CRS-PRO to study the effects of a wider variety of treatments as well as translation and validation in different language and cultures remains needed.” In the meantime, the study team hopes for widespread implementation of CRS-PRO in clinical practice to measure treatment efficacy.
Development and Preliminary Validation of a New Patient-Reported Outcome Measure for Chronic Rhinosinusitis