Longitudinal Associations of PROMIS-29 Anxiety and Depression Symptoms With Low Back Pain Impact in a Sample of U.S. Military Service Members

Published in: Military Medicine (2021). doi: 10.1093/milmed/usab339

Posted on RAND.org on November 19, 2021

by Michael Stephen Dunbar, Anthony Rodriguez, Maria Orlando Edelen, Ron D. Hays, Ian D. Coulter, Daniel Siconolfi, Patricia M. Herman

Read More

Access further information on this document at Oxford Academic

This article was published outside of RAND. The full text of the article can be found at the link above.


The Impact Stratification Score (ISS) is a measure of the impact of chronic low back pain (LBP) consisting of nine Patient-Reported Outcomes Measurement Information System (PROMIS-29) items, but no studies have examined the ISS or its association with psychological symptoms in military samples. This study examines longitudinal associations between psychological symptoms and the ISS among military service members.

Material and Methods

The study involved secondary data analysis of a sample of active duty U.S. military service members aged 18-50 years with LBP (n = 733). Participants completed the PROMIS-29 at three time points during treatment: baseline (time 1, T1), week 6 of treatment (time 2, T2), and week 12 of treatment (time 3, T3). The impact of LBP was quantified using the ISS (ranging from 8 = least impact to 50 = greatest impact). Psychological symptoms were assessed as PROMIS-29 anxiety and depression scores. Separate autoregressive cross-lagged models examined reciprocal associations of ISSs with anxiety, depression, and emotional distress scores from T1 to T3.


Within each time point, the ISS was significantly and positively correlated with anxiety and depression. In autoregressive cross-lagged models, anxiety and depression predicted the ISS at the next time point and associations were similar in magnitude (e.g., anxiety T2 to ISS T3: ß= 0.12, P < .001; depression T2 to ISS T3: ß= 0.12, P <.001). The ISS did not predict future depression or emotional distress scores at any time point, but the ISS at T2 was significantly, positively associated with anxiety scores at T3 (ß= 0.07, P = .04).


Psychological symptoms consistently and prospectively predict the impact of LBP as measured by the ISS among service members undergoing pain treatment. The ISS may also be associated with future anxiety but not depression. PROMIS-29 anxiety and depression items may be useful adjunctive measures to consider when using the ISS to support LBP treatment planning and monitoring with service members.

Research conducted by

This report is part of the RAND Corporation External publication series. Many RAND studies are published in peer-reviewed scholarly journals, as chapters in commercial books, or as documents published by other organizations.

Our mission to help improve policy and decisionmaking through research and analysis is enabled through our core values of quality and objectivity and our unwavering commitment to the highest level of integrity and ethical behavior. To help ensure our research and analysis are rigorous, objective, and nonpartisan, we subject our research publications to a robust and exacting quality-assurance process; avoid both the appearance and reality of financial and other conflicts of interest through staff training, project screening, and a policy of mandatory disclosure; and pursue transparency in our research engagements through our commitment to the open publication of our research findings and recommendations, disclosure of the source of funding of published research, and policies to ensure intellectual independence. For more information, visit www.rand.org/about/principles.

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.