Background Although initial treatments for pyogenic spondylitis include conservative approaches such as rest and antibiotics, some cases are refractory to conservative therapy.
Objectives The objective of this study was to clarify the predictors for achievement of C-reactive protein (CRP) normalization in pyogenic spondylitis.
Methods In the present study, we enrolled 83 patients (51 men and 32 women) with conservatively treated pyogenic spondylitis at Saitama Medical University from 2006 to 2015. We defined CRP normalization as a CRP level decrease to <0.25 mg/dl. A multiple logistic regression analysis was used to examine the association of achievement of CRP normalization with the number of infected vertebrae, bacterial strain, blood data, and the expansion of abscess to the epidural space by using functional magnetic resonance imaging. The blood data analysis included the following measurements: WBC, Hb, ALB, GOT, GPT, gamma GTP, BUN, Cr, UA, ALP, LDH, eGFR, TG, LDL, HDL, IP, and HbA1c levels.
Results Among 83 patients, 39 patients (47.0%) achieved the normalization of CRP levels. The average period from the onset to admission was 56.3 days. The average number of infected vertebrae was 2.19. Of the 83 patients, 81% had the following complications: diabetes (25 patients), high blood pressure (22 patients), heart disease (16 patients), urinary tract disease (9 patients), collagen disease (7 patients), dialysis (5 patients), malignant tumor (5 patients), hepatic dysfunction (4 patients), high uric acid (hyperuricemia, 3 patients). The pathogenic bacteria were MSSA (14 patients), MRSA (23 patients), others (5 patients), and unknown (41 patients). We found significant differences in the subjects with and without achievement of CRP normalization with respect to age (68.6 vs. 62.5 years), the number of affected vertebrae (1.9 vs. 2.6), ratio of resistant pathogenic bacteria (10% vs. 43%), ratio of expansion of abscess to the epidural space (27% vs.71%), and blood data such as Hb (12.0 vs. 10.6), ALB (3.1 vs. 2.8), eGFR (91.2 vs.71.8), Cr (0.9 vs. 1.9), and ALP (369 vs. 290) levels. After adjustment for age and sex, the number of infected vertebral bodies (≥3 vs. 2, odds ratio 1.03, 95% confidence interval: 1.00–1.07), resistant bacteria (7.7, 1.97–42.4), expansion of abscess to the epidural space (4.20, 1.63–11.5), and Hb level (1.31,1.04–1.69) showed significant associations with the normalization of CRP. In addition, to examine the variables independently associated with the normalization of CRP level, we used multiple logistic regression analysis with age, sex, number of infected vertebral bodies, resistant bacteria, expansion of abscess to the epidural space, and serum Hb level as explanatory variables, and found that expansion of the abscess to the epidural spaces was significantly associated with the normalization of CRP level (3.40, 1.11–10.7).
Conclusions The number of infected vertebral bodies, resistant strains of pathogenic bacteria, expansion of abscess to the epidural space, and serum Hb level predicts the prognosis of patients with pyogenic spondylitis. Particularly, expansion of abscess to the epidural spaces was strongly associated with the achievement of CRP normalization.
Disclosure of Interest None declared