Introduction: The clinical-epidemiological characteristics of patients who were diagnosed of spontaneous infectious spondylodiscitis (SIS) in our Internal Medicine Department are analyzed and the related factors associated with the increase of the incidence are evaluated.
Patients and methods: A cross-sectional, retrospective study of patients diagnosed of SIS from 1996 to 2005 was conducted. The study was divided in two periods: A (1996-2000) and B (2001-2005) and two main etiologic groups (pyogenic SIS and mycobacterial SIS) were compared.
Results: A total of 41 patients were diagnosed of SIS: 13 (31.7%) in period A and 28 (68.3%) in period B. Mean age was 58.5 +/- 17.6 years (range: 29-89). There were 73.2% men and all women presented in period B (0 vs 11, p = 0.008). Backgrounds were: 28 (68.3%) predisposing factors for SIS, 22 (53.6%), previous infections and 23 (56.1%) spinal diseases. There were not changes in the backgrounds during the study. The etiology of SIS was: 26 (63.4%) pyogenic, 12 (29.3%) mycobacterial and 3 (7.3%) brucellar. Patients with pyogenic SIS were older (63.6 +/- 3.2 vs 51.2 +/- 5.1 years, p = 0.035) and had less from onset of symptoms to diagnosis (62 +/- 12 vs 291 +/- 66 days, p = 0.0001) than patients with mycobacterial SIS. Total incidence of SIS and incidence of pyogenic SIS increased significantly during the study: (1.7/1000 admissions/year, p = 0.0057) and (1/1000 admissions/year, p = 0.0476). In the multivariate analysis, time from onset of symptoms to diagnosis was the only variable independently associated with the pyogenic etiological group (OR: 0.985, 95% CI: 0.975, 0.996, p = 0.005).
Conclusions: In our study, the increasing incidence of SIS was related to an increase in pyogenic SIS incidence. Although older age and some backgrounds could be orientative of SIS etiology, these factors did not increase during the study.