Content Validity of Sjögren's Syndrome Symptom Diary and Functional Assessment of Chronic Illness Therapy-Fatigue in Patients with Sjögren's.
Rheumatol Ther 2022;
9:1559-1574. [PMID:
36152275 PMCID:
PMC9561476 DOI:
10.1007/s40744-022-00489-y]
[Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/17/2022] [Indexed: 12/03/2022] Open
Abstract
Introduction
Sjögren’s Syndrome Symptom Diary (SSSD) and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) are patient-reported outcome (PRO) instruments assessing Sjögren’s symptoms. Original SSSD items have demonstrated content validity, however qualitative evidence supporting the updated ‘tiredness’ item and two new supplementary items is lacking. Although well established and validated in other rheumatic diseases, there is no qualitative evidence supporting content validity of FACIT-F in Sjögren’s. This study addressed these evidence gaps to support use of SSSD and FACIT-F as clinical trial endpoints, in clinical practice and in other research settings.
Methods
Qualitative, semi-structured telephone interviews were conducted with patients with Sjögren’s (n = 12) and expert Sjögren’s physicians (n = 10). Patient interviews explored content validity (e.g., understanding and relevance) of the new and updated SSSD items, perceptions of item and total score meaningful change on SSSD, and understanding and relevance of FACIT-F items. Physician interviews explored opinions on various SSSD scoring approaches.
Results
The new and updated SSSD items and FACIT-F demonstrated good content validity. Most patients considered a two-point improvement on most SSSD items meaningful, as well as a one- or two-point total score improvement. Most physicians reported tracking changes in patient responses to individual items as the most appropriate SSSD scoring approach.
Conclusions
SSSD and FACIT-F are content valid in a Sjögren’s population, meeting an important criterion to support their use as clinical trial endpoints, but also their use in clinical practice and other research settings. Qualitative data exploring meaningful change will be valuable in supporting psychometrically derived responder definitions.
Sjögren’s Syndrome Symptom Diary (SSSD) and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) are questionnaires completed by individuals with Sjögren’s to assess the severity of their symptoms. It is important to show that these questionnaires are well understood and relevant to the individuals who complete them. Therefore, interviews were conducted with individuals with Sjögren’s to explore their understanding and relevance of new and updated SSSD questions. Similarly, the interviews explored whether the FACIT-F questionnaire was well understood and relevant to individuals with Sjögren’s, as this has not been explored before. Interviews were also conducted with expert Sjögren’s physicians to explore the best approach to scoring SSSD (e.g., calculating a total score or looking at scores on individual items). The new and updated SSSD questions and the FACIT-F questionnaire were well understood and considered relevant by most individuals with Sjögren’s. This suggests these questionnaires are appropriate for use in Sjögren’s clinical trials, clinical practice, and other research settings. Most individuals with Sjögren’s considered an improvement of two points on individual SSSD questions to be important, as well as a one- or two-point improvement in their total SSSD score. Most physicians agreed on the best approach to scoring SSSD.
Collapse