Risk Factors for Low Back Pain and Spine Surgery: A Retrospective Cohort Study in Soldiers.

Introduction: Musculoskeletal low back pain (LBP) is commonly treated symptomatically, with practice guidelines advocating reserving surgery for cases that fail conservative care. This study examined medical comorbidities and demographic variables as risk factors for chronic/recurrent LBP, spinal surgery, and time to surgery.

Methods: A 2015 retrospective cohort study was conducted in U.S. Army soldiers (N=1,092,420) from 2002 to 2011. Soldiers with medical encounters for LBP were identified using ICD-9 codes. Surgical treatment for LBP was identified according to Current Procedural Terminology codes. Comorbid medical conditions (psychological disorders, sleep disorders, tobacco use, alcohol use, obesity) and demographic variables were examined as risk factors for chronic/recurrent LBP within 1 year of the incident encounter, surgery for LBP, and time to surgery.

Results: Of 383,586 patients with incident LBP, 104,169 (27%) were treated for chronic/recurrent LBP and 7,446 (1.9%) had surgery. Comorbid variables showed increased risk of chronic/recurrent LBP ranging from 26% to 52%. Tobacco use increased risk for surgery by 33% (risk ratio, 1.33; 95% CI=1.24, 1.44). Comorbid variables showed 10%-42% shorter time to surgery (psychological disorders, time ratio [TR]=0.90, 95% CI=0.83, 0.98; sleep disorders, TR=0.68, 95% CI=0.60, 0.78; obesity, TR=0.88, 95% CI=0.79, 0.98; tobacco use, TR=0.58, 95% CI=0.54, 0.63; alcohol use, TR=0.85, 95% CI=0.70, 1.05). Women showed 20% increased risk of chronic/recurrent LBP than men but 42% less risk of surgery.

Conclusions: In the presence of comorbidities associated with mental health, sleep, obesity, tobacco use, and alcohol use, LBP shows increased risk of becoming chronic/recurrent and faster time to surgery.