Defining Pain That Does Not Interfere with Activities Among Rheumatoid Arthritis (RA) Patients

Yvonne C. Lee¹, Patricia Katz^2,3, Amanda Quebe⁴, Luna Sun⁴, Himanshu Patel⁴, Carol L. Gaich⁴, Natalie Boytsov⁴ and Kaleb Michaud^5,6, ¹Northwestern University Feinberg School of Medicine, Chicago, IL, ²Forward/National Data Bank for Rheumatic Diseases, Wichita, KS, ³University of California San Francisco, San Francisco, CA, ⁴Eli Lilly and Company, Indianapolis, IN, ⁵Rheumatology, University of Nebraska Medical Center, Omaha, NE, ⁶FORWARD, The National Databank for Rheumatic Diseases, Wichita, KS

Meeting: 2018 ACR/ARHP Annual Meeting

Keywords: activities of daily living (ADL), Fatigue, pain, Rheumatoid arthritis (RA) and work

Session Information

Date: Monday, October 22, 2018

Title: 4M103 ACR Abstract: Pain Mechanisms–Basic & Clinical Science (1917–1922)

Session Type: ACR Concurrent Abstract Session

Session Time: 4:30PM-6:00PM

Background/Purpose: RA patients differ in the degree to which pain interferes with function. To improve function, an understanding of this diversity is needed. Our objectives were to: (1) understand the degree to which pain interfered with specific activities, (2) characterize the distribution of pain intensity that does not interfere with activities (ie, non-interfering pain), and (3) identify characteristics associated with non-interfering pain.

Methods: Data were derived from subjects with rheumatologist-confirmed RA in FORWARD—The National Databank for Rheumatic Diseases. Subjects completed 8 items from the PROMIS Pain Interference Item Bank that asked the degree to which pain interfered with activities (from “not at all” to “very much”). If subjects reported any pain interference, they were asked, “At what level would pain no longer interfere with this activity?” Responses were collected using a 0-10 numeric rating scale (NRS; 10 = severe pain). Internal consistency of non-interfering pain items was assessed using Cronbach’s alpha and item-total correlations to determine if an overall mean of non-interfering pain could be calculated. Multiple linear regression analyses examined associations between non-interfering pain and the following characteristics: age, sex, disease duration, BMI, Rheumatic Disease Comorbidity Index, disability (Health Assessment Questionnaire), pain intensity NRS, fatigue NRS, self-reported current depression, sleep problems NRS, and fibromyalgianess (Polysymptomatic Distress Scale).

Results: As of April 2018, 1048 RA patients had completed questionnaires. Pain interference was most common for daily activities (70.1%) and least common for ability to concentrate (46.7%) (Table). The mean level at which pain no longer interfered with activities ranged from 2.7 ± 2.2 for ability to fall/stay asleep to 3.1 ± 2.1 for daily activities. Internal consistency across items was high (Cronbach’s alpha = 0.97). Overall, the mean threshold for non-interfering pain was 2.9 ± 2.0. Independent predictors of non-interfering pain were greater pain severity (β = 0.21, p < 0.0001) and lower fatigue (β = -0.11, p = 0.04). Other characteristics tested were not statistically significant at alpha = 0.05.

Conclusion: The mean pain level that did not interfere with activities was 3 (on a 0-10 scale) and did not vary depending on activity type. This may suggest that RA patients consider non-interfering pain to be a concept similar across different situations. Factors that may contribute to high non-interfering pain levels include pain and fatigue. Future studies are needed to determine if these associations, particularly that between pain intensity and non-interfering pain, reflect an artifact in rating (eg, patients who rate pain highly may also rate non-interfering pain highly) or underlying pathways that can be targeted to decrease the functional impact of pain.

Table. The proportion of RA patients who experience pain interference and the pain level at which pain does not interfere with activities (N = 1048)
Activity¹	PROMIS Pain Interference Questions	Pain Level That Would Not Interfere With Activity
Activity¹	% Experienced Pain Interference	Mean ± SD	Median (IQR)
Daily activities	70.1%	3.1 ± 2.1	3 (2,4)
Work around the house	69.2%	3.1 ± 2.1	3 (2,4)
Household chores	66.9%	3.0 ± 2.1	2 (2,4)
Ability to fall asleep/stay asleep	61.6%	2.7 ± 2.2	2 (1,4)
Ability to work	62.9%	2.9 ± 2.2	2 (1,4)
Enjoyment of life	57.8%	2.8 ± 2.3	2 (1,4)
Social activities	55.2%	3.1 ± 2.1	3 (2,4)
Ability to concentrate	46.7%	2.8 ± 2.1	2 (1,4)
Abbreviation: IQR, interquartile range. ¹Total number who responded to each question was 1047 for daily activities, 1046 for work around the house and household chores, 1044 for social activities, 1041 for ability to concentrate, 1040 for enjoyment of life, 1039 for fall asleep/stay asleep, and 458 for ability to work; 575 subjects did not answer the latter question because they were retired or otherwise not working.

Disclosure: Y. C. Lee, Pfizer, Inc., 2,Eli Lilly and Co., 6; P. Katz, None; A. Quebe, Eli Lilly and Company, 1, 3; L. Sun, Eli Lilly and Company, 1, 3; H. Patel, Lilly, 3; C. L. Gaich, Eli Lilly and Company, 1, 3; N. Boytsov, Lilly, 3; K. Michaud, None.

To cite this abstract in AMA style:

Lee YC, Katz P, Quebe A, Sun L, Patel H, Gaich CL, Boytsov N, Michaud K. Defining Pain That Does Not Interfere with Activities Among Rheumatoid Arthritis (RA) Patients [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 9). https://acrabstracts.org/abstract/defining-pain-that-does-not-interfere-with-activities-among-rheumatoid-arthritis-ra-patients/. Accessed .

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