Lumbar spine intervertebral disc desiccation is associated with medical comorbidities linked to systemic inflammation

Introduction: Symptomatic disc degeneration is a common cause of low back pain. Recently, the prevalence of low back pain has swiftly risen leading to increased patient disability and loss of work. The increase in back pain also coincides with a rapid rise in patient medical comorbidities. However, a comprehensive study evaluating a link between patient's medical comorbidities and their influence on lumbar intervertebral disc morphology is lacking in the literature.

Methods: Electronic medical records (EMR) were retrospectively reviewed to determine patient-specific medical characteristics. Magnetic resonance imaging (MRI) was evaluated for lumbar spine intervertebral disc desiccation and height loss according to the Griffith-modified Pfirrmann grading system. Bivariate and multivariable linear regression analyses assessed strength of associations between patient characteristics and lumbar spine Pfirrmann grade severity (Pfirrmann grade of the most affected lumbar spine intervertebral disc) and cumulative grades (summed Pfirrmann grades for all lumbar spine intervertebral discs).

Results: In total, 605 patients (304 diabetics and 301 non-diabetics) met inclusion criteria. Bivariate analysis identified older age, diabetes, American Society of Anesthesiologists (ASA) class, hypertension, chronic obstructive pulmonary disease (COPD), peripheral vascular disease, and hypothyroidism as being strongly associated with an increasing cumulative Pfirrmann grades. Multivariable models similarly found an association linking increased cumulative Pfirrmann grades with diabetes, hypothyroidism, and hypertension, while additionally identifying non-white race, heart disease, and previous lumbar surgery. Chronic pain, depression, and obstructive sleep apnea (OSA) were associated with increased Pfirrmann grades at the most affected level without an increase in cumulative Pfirrmann scores. Glucose control was not associated with increasing severity or cumulative Pfirrmann scores.

Conclusion: These findings provide specific targets for future studies to elucidate key mechanisms by which patient-specific medical characteristics contribute to the development and progression of lumbar spine disc desiccation and height loss.

Level of evidence: III (retrospective cohort).