Intestinal Spirochetosis is Associated with Diarrhea, Weight Loss, and Abdominal Pain in Less Than Half of the Infected Subjects: A Study of 447 Patients and 1.2 Million Controls

Abstract

Purpose: Intestinal spirochetosis (IS) is a condition in which the colonic mucosa is colonized by anaerobic spirochetes, either Brachyspira aalborgi or Brachyspira pilosicoli. It is generally associated with immunocompromised states such as HIV infection, but can occur in patients with normal immune status. There is still debate whether it is a true pathogen or commensal organism. The purpose of this study was to determine its prevalence in subjects who have colonoscopies in the United States, and to compare the demographic and clinical characteristics of patients with and without spirochetosis. Methods: We used the Miraca Life Sciences database to extract histopathologic, demographic, and clinical information from all adult patients with colonic biopsies obtained between 1/2008 and 12/2012; those with lower GI cancer, colorectal surgery, or a history or diagnosis of inflammatory bowel disease were excluded. Cases were all patients with a histopathologic diagnosis of IS, in whose colonic biopsy specimens spirochetes were identified and confirmed by a silver stain; controls were all other patients. Correlations were evaluated by simple odds ratios (OR). Results: There were 457 patients with a diagnosis of spirochetosis (median age 55 years, range 18-90 years; 65.6% male) and 1,177,031 controls (median age 60 years, range 18-90 years; 49.0% male). Thus, the prevalence was approximately 1 in 2,600 colonoscopies. Patients with IS were younger (p<0.0001) and more likely to be male (OR 1.99; 95% CI 1.64-2.42; p<0.0001) than controls. Diarrhea was present in 30% of IS patients and 12% of the controls (OR 3.14; 95% CI 2.57-3.84; p<.0001), weight loss in 4.2% and 1.9%, respectively (OR 3.14; 95% CI 2.57-3.84; p<.001), and abdominal pain in 18% and 13%, respectively (OR 1.41; 95% CI 1.11-1.79; p<.005). Infection with the HIV was reported in four patients with IS (.9%) and in 275 controls (0.02%). Although this difference is significant, HIV infection was likely underreported in this population and, therefore, the power of this correlation may be underestimated. Conclusion: This is the largest clinicopathologic series of patients with documented spirochetosis. Diarrhea, abdominal pain, and weight loss were significantly more common in patients with IS than in controls. However, in aggregate, these symptoms affected only 40% of IS patients; the remaining 60% were detected incidentally as patients were undergoing screening for colorectal cancer or colonoscopy for manifestations (e.g., anemia) that were unrelated to the infection. We conclude that intestinal spirochetosis may be asymptomatic in more than half of the subjects infected.