Development and Validation of a Primary Sclerosing Cholangitis-Specific Patient-Reported Outcomes Instrument: The PSC PRO

ABSTRACT

Background: PSC is a chronic liver disease associated with inflammation and biliary fibrosis that leads to cholangitis, cirrhosis, and impaired quality of life. Our objective was to develop and validate a PSC-specific PRO instrument.

Methods: We developed a 42-item PSC PRO instrument that contains 2 modules (Symptoms and Impact of Symptoms), and conducted external validation. Reliability and validity were evaluated using clinical data and a battery of other validated instruments. Test-retest reliability was assessed in a subgroup of patients who repeated the PSC PRO after the first administration.

Results: 102 PSC subjects (44±13 years, 32% male, 74% employed, 39% cirrhotic, 14% with history of decompensated cirrhosis, 38% history of depression, and 68% with inflammatory bowel disease (IBD) completed PSC PRO and other PRO instruments (SF-36, CLDQ, PBC-40, 5-D Itch). PSC PRO demonstrated excellent internal consistency (Cronbach alphas 0.84-0.94) and discriminant validity (41/42 items had the highest correlations with their own domains). There were good correlations between PSC PRO domains and relevant domains of SF-36, CLDQ, and PBC-40 (R=0.69-0.90; all p<0.0001), but lower (R=0.31-0.60, p<0.001) with 5-D Itch. Construct validity showed that PSC PRO can differentiate patients according to the presence and severity of cirrhosis and history of depression (p<0.05), but not by IBD (p>0.05). Test-retest reliability was assessed in 53 subjects who repeated PSC PRO within a median (IQR) of 37 (27-47) days. There was excellent reliability for most domains with intra-class correlations 0.71-0.88 (all p<0.001).

Conclusions: PSC PRO is a self-administered disease-specific instrument developed according to FDA guidelines. This preliminary validation study suggests good psychometric properties. Further validation of the instrument in larger and more diverse sample of PSC patients is needed. This article is protected by copyright. All rights reserved.

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