Association between anemia and lumbar disc degeneration in patients with low back pain: an observational retrospective study.

ABSTRACT

OBJECTIVE: The goal of this study was to evaluate the possible associations between anemia and morphologic features of lumbar disc degeneration (LDD) in subjects with low back pain. MATERIALS AND METHODS: A total of 131 patients with normocytic or microcytic anemia (mean age 41.0 ± 6.4 yrs, BMI 24.8 ± 3.3 kg/m2, 12.2% men) and a matched control group of 131 patients without anemia (mean age 41.0 ± 6.4 yrs, BMI 24.9 ± 3.1 kg/m2, 12.2% men) were evaluated for LDD according to the Pfirrmann scoring system. The primary outcome was the difference of radiological features of LDD between two groups. The second outcome was the correlation between the hemoglobin (Hb) value and disc degeneration (DD). Statistical associations were assessed by Student's t-test, Chi-square test, and Spearman correlation. RESULTS: Anemic patients had a significantly higher number of degenerated discs than non-anemic patients in the level of L2/3 and L3/4 (p < 0.05). We also found that the severe DD occurred more frequently in the level of L2/3, L3/4 and L5/S1 among anemic patients (p < 0.05). In addition, we noticed that the incidence of multilevel LDD happened much more frequently in patients with anemia (p < 0.05). The Hb value showed a borderline negative correlation with the total score of DD (p = 0.056). CONCLUSION: The results suggested that patients with anemia, and those without are radiologically different with varying patterns of DD. Patients with back pain and anemia were more likely to have extensive and severe DD. Although relevant mechanisms are not yet well understood, this study improved our understandings of the pathophysiology for LDD.