Does Intolerance of Uncertainty Affect the Magnitude of Limitations or Pain Intensity?
Authors: Donthula Deepanjli , Kortlever Joost T. P. , Ring David , Donovan Erin , Reichel Lee M. , Vagner Gregg A. 
Published: November 2019

Abstract

Background
Intolerance of uncertainty—the tendency to overestimate the chance of and be unwilling to accept potential, but unlikely, negative outcomes in uncertain situations—is a cognitive construct that has been shown to affect symptoms and limitations for patients with traumatic and nontraumatic upper-extremity conditions. Cognitive flexibility and tolerance of uncertainty can be trained and practiced, with the potential to increase musculoskeletal health. However, to our knowledge, the degree to which intolerance of uncertainty might be associated with symptom intensity and the magnitude of limitations in adults with upper-extremity problems has not been characterized.

Questions/purposes
After accounting for personal and social factors, is intolerance of uncertainty independently associated with (1) the magnitude of physical limitations and (2) pain intensity?

Methods
In this cross-sectional, observational study, 139 new and returning patients presenting to one of four orthopaedic offices in a large urban area completed the Intolerance of Uncertainty Scale (a validated measure of the level of comfort with uncertain situations), the Patient-reported Outcomes Measurement Information System—Physical Function Upper Extremity computer adaptive test (to measure the magnitude of limitations), and an 11-point ordinal measure of pain intensity. The mean age of the 139 participants was 51 years ± 16 years and 55% (76 of 139) were men. Participants presented to the clinics with a wide variety of upper-extremity conditions, such as trigger finger, distal radius fractures, lateral epicondylitis, or non-specific shoulder pain. We also assessed sex, race, marital status, education level, income, public versus private insurance, area deprivation index, and the participant’s self-perception of their healthcare experience through a multiple-choice question (answer choices: none, some, a little, and a lot of experience). The following patient characteristics were more common in our study participants: white, employed, part of a married or unmarried couple, and private insurance coverage. We created two multivariable linear regression models to assess factors independently associated with the magnitude of limitations and pain intensity.

Results
After controlling for potentially confounding variables including sex, insurance, area deprivation index, and type of visit, we found that fewer physical limitations were associated with a greater intolerance of uncertainty (regression coefficient [β] -0.30; 95% confidence interval, -0.50 to -0.10; p = 0.003; semi-partial r2 = 0.07; adjusted r2 for the full model = 0.16), as was being a man (β 3.2; 95% CI, 0.08-6.3; p = 0.045; semi-partial r2 = 0.03) and having private insurance coverage (β 5.2; 95% CI, 2.1-8.2; p = 0.001; semi-partial r2 = 0.08). After controlling for one important potentially confounding variable, the level of education, greater pain intensity was associated with a greater intolerance of uncertainty (β 0.08; 95% CI, 0.02-0.14; p = 0.009; semi-partial r2 = 0.05; adjusted r2 for the full model = 0.08).

Conclusions
Intolerance of uncertainty—a byproduct of cognitive bias and error, which are elements of the normal functioning of the human mind—increases limitations and pain intensity across diagnoses, independent of demographic and social factors. Future studies can address the effect of strategies that incorporate mindset training (for example, cognitive behavioral therapy and its derivatives) on musculoskeletal symptoms and limitations.

Level of Evidence
Level II, prognostic study.