Active Duty Service Members Newly Presenting With Low Back Pain in Fiscal Year 2017: Health Care Utilization, Access to Care, and Private Sector Costs Over 2-year Follow-up
Authors: Yuan Xiaoning , Pav Veronika , Colahan Courtney , Miller Matthew E , Hager Nelson A , Pasquina Paul F , Cohen Steven P , Isaacson Brad M 
Published: November 2022

ABSTRACT

Introduction
Low back pain (LBP) has accounted for the most medical encounters every year for the past decade among Active Duty Service Members (ADSMs) of the U.S. Armed Forces. The objectives of this retrospective, descriptive study were to classify LBP by clinical category (Axial, Radicular, and Other) and duration (Acute, Subacute, and Chronic) and examine the LBP-related health care utilization, access to care, and private sector costs for ADSMs over a 2-year follow-up period.

Materials and Methods
The Military Health System Data Repository was queried in fiscal year 2017 for all ADSMs (ages 18-62) with outpatient encounters documented with any of 67 ICD-10 diagnosis codes indicative of LBP. A 1-year clean period before the first (index) outpatient LBP encounter date was used to ensure no recent history of LBP care. Patients were eligible if continuously enrolled and on active duty for 1 year before and 2 years following the index visit. Patients were excluded for non-musculoskeletal causes for LBP, red flags, or acute trauma within 4 weeks of the index visit and/or systemic illness or pregnancy anytime during the clean or follow-up period.

Results
A total of 52,118 ADSMs met the inclusion criteria, and the cohort was classified by duration of LBP symptoms as Acute [17,916 (34.4%)], Subacute [4,119 (7.9%)], and Chronic [30,083 (57.7%)]. Over 2-year follow-up, 419,983 outpatient visits were recorded, with the majority occurring at MTFs [363,570 (86.6%)]. 13,237 (25.4%) of ADSMs in the total cohort were documented with no other LBP-related visits beyond their index encounter. In contrast, the Chronic cohort comprised the highest number of encounters [371,031 (89.2% of total encounters)], including 86% of imaging studies performed for LBP, and accounted for $9,986,606.17 (94.9%) of total private sector costs over the 2-year follow-up period. Interventional pain procedures ($2,983,767.50) and physical therapy ($2,298,779.07) represented the costliest categories in the private sector for the Chronic cohort, whereas Emergency Department ($283,307.43) and physical therapy ($137,035.54) encounters were the top contributors to private sector costs for the Acute and Subacute cohorts, respectively. Overall reliance on the private sector was highest for specialty care, including 10,721 (75.4%) interventional pain procedures and 306 (66.4%) spine surgeries.

Conclusions
Uncovering current trends in health care utilization and access to care for ADSMs newly presenting with LBP is vital for timely and accurate diagnosis, as well as early intervention to prevent progression to chronic LBP and to minimize its negative impact on military readiness and quality of life. This retrospective, descriptive study highlights the burden of chronic LBP on health care utilization and costs within the Military Health System, including reliance on the private sector care, amounting to $10,524,332.04 over the study period.