Abstract
OBJECTIVE: To determine the association between patient-reported spinal morning stiffness and lumbar disc degeneration (LDD) and systemic inflammation, as measured by C-reactive protein (CRP), in older patients with non-specific back pain. The ultimate objective is to help shape a future definition of spinal osteoarthritis (OA). DESIGN: Baseline data from the Dutch "Back Complaints in the Older Adults" (BACE) study was used. The relationship between the severity and duration of patient-reported spinal morning stiffness, LDD (i.e., multilevel disc space narrowing and multilevel osteophytes), and CRP was assessed. Regression models adjusted for confounding variables were performed. RESULTS: Six hundred and seventy-five patients were included. The mean age was 66.52 years (SD 7.69), with a mean CRP of 3.20 mg/L (SD 7.61). The severity of spinal morning stiffness was associated with multilevel disc space narrowing: OR 2.89 (95 % CI: 1.24 to 6.74) for 'mild', OR 2.97 (95 % CI: 1.18 to 7.44) for 'moderate', OR 3.23 (95 % CI: 1.17 to 8.90) for 'severe', and OR 5.62 (95 % CI: 1.70 to 18.60) for 'extreme' morning stiffness severity. However, spinal morning stiffness severity was not associated with multilevel osteophytes, and both multilevel features of LDD showed no associations with the duration of spinal morning stiffness. No associations were found between spinal morning stiffness severity or duration, and CRP levels. CONCLUSIONS: Our results suggest that the severity of patient-reported spinal morning stiffness might be considered in future definitions of symptomatic spinal OA and that spinal morning stiffness is probably a symptom of a degenerative process in the spine rather than a symptom of systemic inflammation in patients with back pain.