Pain Catastrophizing and Its Association with Military Medical Disability Among US Active Duty Service Members with Chronic Predominately Musculoskeletal Pain: A Retrospective Cohort Analysis

Abstract

Context

Pain catastrophizing is characterized by negative emotional and cognitive responses to pain and is a predictor of work-related disability. Its association with military medical disability has not been studied.

Objective

To (1) identify the pain catastrophizing scale (PCS) score cut point most strongly associated with military medical disability, (2) measure the difference in rate of disability between service members with baseline PCS scores above versus below the cut point, and (3) determine if improvement in PCS score during pain specialty care is associated with decreased likelihood of disability.

Methods

This was a retrospective cohort analysis comparing PCS scores collected from US Army active duty service members at time of initial visit to an interdisciplinary pain management center and periodically during pain treatment. Outcome was determination during the following year of a military service-disqualifying disability.

Results

Receiver operating characteristic (ROC) curves determined that a PCS score of 20 was the single cut point most closely associated with subsequent disability. Kaplan–Meier curves showed significantly higher disability rate during the following year among those with baseline PCS scores ≥20 (52%) compared to those with lower scores (26%). Scheffe-adjusted contrasts showed that service members with PCS scores ≥20 whose scores improved to <20 at follow-up were significantly less likely to have a medical disability (42.6%; 95% CI, 0.07–0.58) than those whose PCS score remained ≥20 (76.3%; 95% CI, 68.0%–84.7%).

Conclusion

A PCS score cut point of 20 distinguishes between high versus low likelihood of disability among service members. Those with high baseline PCS score had twice the likelihood of disability than those with low scores. Service members who decreased their PCS score from high to low during pain specialty care had lower likelihood of disability. Prospective research is needed to determine if treatments that lower pain catastrophizing yield reduced likelihood of subsequent disability.

Plain Language Summary

Pain catastrophizing is a persistent tendency to have distressing thoughts and emotions related to pain and worsens work-related outcomes. This study examined the association between pain catastrophizing and military medical disability in a population of active duty US Army service members. The pain catastrophizing scale (PCS) scale is a 13-item questionnaire with a range of 0 (lowest catastrophizing) to 52 (highest catastrophizing). The aims of the study were to (1) identify the PCS score cut point most strongly associated with later military medical disability, (2) measure the difference in rate of disability between service members with baseline PCS scores above versus below the cut point, and (3) determine if improvement in PCS score during pain specialty care is associated with a decreased likelihood of disability. The study found that service members with high PCS scores were twice as likely to have medical disability than those with low scores. Additionally, those who reduced their PCS score were less likely to be medically disabled later. This study showed that PCS score may help to identify service members at increased risk of disability so that they may be offered therapies that reduce pain catastrophizing. The main limitation of this study is its retrospective design; we cannot be certain if improvement in PCS resulted in lower disability rates or if inherently more disabling conditions resulted in greater catastrophizing.

Keywords:

• pain catastrophizing
• chronic pain
• interdisciplinary
• disability
• military

Abbreviations

AUC, area under the curve; CBT, cognitive behavioral therapy; IDES, Integrated Disability Evaluation System; IPMC, interdisciplinary pain management center; MAMC, Madigan Army Medical Center; MCID, minimal clinically important difference; NIH, National Institutes of Health; PCS, Pain catastrophizing scale; PROMIS, Patient reported outcomes measurement information system; ROC, receiver operating characteristic; US, United States.

Data Sharing Statement

The data sharing agreement with the Defense Health Agency who provided data for this analysis to the research team does not authorize release of data used for this analysis. Requests for data access may be directed to the corresponding author, who will request authorization of release from the Defense Health Agency.

Ethics Approval and Informed Consent

The study protocol was determined to meet the revised Common Rule by the MAMC Human Research Protections Office, complies with the Declaration of Helsinki, and was approved by the MAMC Institutional Review Board, protocol number 218052. The study involved retrospective analysis of de-identified data; therefore, informed consent was waived.

Acknowledgments

The authors wish to extend their appreciation to Norma Bowling of Kennell and Associates in support of the Defense Health Agency Enterprise Intelligence and Data Solutions Program Management Office for her data management support. Tandem Editing LLC provided professional editing support.

The views expressed are those of the authors and do not reflect the policy or position of the Department of the Army, Department of Defense, the NIH or its HEAL Initiative or the US Government. The content is solely the responsibility of the authors. The investigators adhered to the policies for protection of human subjects as prescribed in 45 CFR 46. No nonhuman animal species were used in the conduct of this research.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

All the authors report no financial relationships or other conflicts of interests related to this work.

Additional information

Funding

This work was supported by the National Institutes of Health (NIH) through the NIH HEAL Initiative under award number K24AT011995.