Assessment of patient-reported symptoms and distress in IgG4-related disease (IgG4-RD): Development, clinical validation, and content validation of the IgG4-RD Symptom Severity Index

Zachary S Wallace; Grace A McMahon; Buuthien Hang; Xiaoqing Fu; Tyler Harkness; Karen Donelan; Ana Fernandes; Claire Cook; Guy Katz; Cory Perugino; John H Stone

doi:10.1016/j.semarthrit.2023.152253

Assessment of patient-reported symptoms and distress in IgG4-related disease (IgG4-RD): Development, clinical validation, and content validation of the IgG4-RD Symptom Severity Index

Semin Arthritis Rheum. 2023 Dec:63:152253. doi: 10.1016/j.semarthrit.2023.152253. Epub 2023 Aug 18.

Authors

Affiliations

¹ Clinical Epidemiology Program, Mongan Institute, Massachusetts General Hospital, USA; Rheumatology Unit, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, USA; Harvard Medical School, USA. Electronic address: zswallace@mgh.harvard.edu.
² Clinical Epidemiology Program, Mongan Institute, Massachusetts General Hospital, USA; Rheumatology Unit, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, USA.
³ Clinical Epidemiology Program, Mongan Institute, Massachusetts General Hospital, USA.
⁴ Health Policy Research Center, Mongan Institute, Massachusetts General Hospital, USA; Harvard Medical School, USA.
⁵ Rheumatology Unit, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, USA.
⁶ Rheumatology Unit, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, USA; Harvard Medical School, USA.

PMID: 37619485
PMCID: PMC11004491 (available on 2024-12-01)
DOI: 10.1016/j.semarthrit.2023.152253

Abstract

Objective: IgG4-related disease (IgG4-RD), a multi-organ autoimmune disease, causes diverse manifestations that can lead to symptoms and distress. We developed and validated the Symptom Severity Index (SSI) to assess symptom burden.

Methods: A pilot SSI was tested in n = 5; several gaps were identified. Twenty semi-structured qualitative interviews were performed to expand the item set and identify missing symptoms. Subsequent changes resulted in the current SSI; it was administered with quality of life (QOL) measures to n = 136. We assessed symptom burden and the construct validity of the SSI. A distress score for each symptom is calculated by multiplying symptom frequency ("Never" [0 points] to "Every Day" [3 points]) by associated distress ("None" [0 points] to "Very Much" [4 points]). Each distress score is summed to calculate a total SSI score.

Results: The SSI assesses the frequency and distress of 24 symptoms. Among n = 136 with ≥ 1 SSI, 90% experienced ≥ 1 symptom and 88% had distress. The median SSI score was 6.5 (IQR 3.0, 18.0). Fear of more severe disease was observed in 49%. The SSI inversely correlated with the SF-36 (r= - 0.51, p<0.001), the feeling thermometer (r= - 0.28, p<0.001), and the EQ-5D (r= - 0.28, p<0.001). The median SSI score was higher during active vs non-active disease among n = 52 who completed >1 SSI (15 [6, 26] vs. 3 [2, 14], p = 0.008).

Conclusions: Symptoms and distress are common in IgG4-RD and associated with worse health-related QOL. The SSI has face, content, and construct validity; it corresponds with QOL measures.

Keywords: IgG4-related disease; Patient reported outcomes; Symptom burden.

MeSH terms

Autoimmune Diseases* / diagnosis
Humans
Immunoglobulin G4-Related Disease*
Patient Reported Outcome Measures
Quality of Life

Abstract

MeSH terms

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