The incidence, providers involved, and patient factors associated with diagnosis of specific lumbar spine pathology subsequent an initial nonspecific low back pain diagnosis.

Background context: Low back pain (LBP) is an exceedingly common diagnosis with significant societal and healthcare burden. While nonspecific LBP diagnoses are frequently assigned and often resolve soon thereafter, some patients may subsequently be diagnosed with specific underlying lumbar spine pathology.

Purpose: To characterize the incidence, providers involved, and factors associated with specific pathology LBP (SP-LBP) diagnosed subsequent an initial nonspecific LBP (NS-LBP) diagnosis.

Study design: Retrospective cohort study.

Patient sample: Adult patients diagnosed with NS-LBP between 2010 - Q1 2022 were abstracted from a large national administrative database.

Outcome measurements: Incidence of subsequent SP-LBP diagnoses, providers involved, and factors associated with SP-LBP diagnoses in the 12-months following initial NS-LBP diagnosis.

Methods: Adult patients diagnosed with NS-LBP were identified based on International Classification of Disease (ICD) codes ICD-9-D-724.2 and ICD-10-D-M54.5. These patients diagnosed with new NS-LBP were reported based on incidence per 100,000 covered lives. Exclusion criteria included: patients less than 18 years old, those with any prior NS-LBP diagnosis, any prior SP-LBP diagnoses, and those with trauma, neoplasm, or infection diagnosed within 3-months prior to the initial NS-LBP diagnosis. Patients who subsequently received SP-LBP diagnoses within 12-months following initial NS-LBP were then identified. Patients were characterized based on age, sex, history of cancer, obesity, opioid use disorder, anxiety, and depression and then compared with patients receiving no additional LBP diagnosis by univariable and multivariable analysis. Provider specialties who initially diagnosed NS-LBP and those involved with subsequent SP-LBP diagnoses were identified.

Results: NS-LBP was identified for a robust cohort of 6,861,235 patients, yielding an incidence of 4,258 diagnoses per 100,000 covered lives. Subsequent SP-LBP diagnoses were identified for 562,982 (8.21%) within 12-months, of which 62.57% of these SP-LBP diagnoses occurred within 3-months. The most common of these subsequent diagnoses included radiculopathy (3.01% of the overall study population), disc degeneration (2.84%), and disc herniation (1.23%). Patients receiving a subsequent SP-LBP diagnosis were more likely older (per year increase, odds ratio [OR] 1.02), male (OR 1.10), had a history of cancer (OR 1.32), obesity (OR 1.30), opioid use disorder (OR 1.17), anxiety (OR 1.21), or depression (OR 1.17) (p<0.001 for all). NS-LBP was initially diagnosed predominantly by primary care providers (PCPs) in family medicine (44.09%) and internal medicine (27.49%). These PCP providers also contributed to the majority of SP-LBP diagnoses, while specialty providers contributed to a greater degree in SP-LBP diagnoses than NS-LBP.

Conclusion: NS-LBP is a common diagnosis that usually, 91.79% of the time, does not subsequently convert to a SP-LBP diagnosis within 12-months. This may reflect improvement of LBP symptoms and/or accurate initial triage, largely by PCPs. Of the minority of patients receiving a subsequent SP-LBP diagnosis, various patient factors were significantly associated, and a greater degree of specialty providers were involved, which highlights potential contributors to diagnostic difficulty of SP-LBP and the multidisciplinary nature of LBP management.