Small intestinal bacterial overgrowth--an incidental finding?

To assess the prevalence of typical clinical features and need for treatment of small intestinal bacterial overgrowth (SIBO) in the elderly.

Random selection of patients, regardless of their nutritional status.

Acute admissions ward in the Dept. of Medicine for the Elderly.

Thirty elderly patients between 68 and 90 years of age.

Active clinical problems, including the presence of recent weight loss and diarrhea, were recorded. Routine blood tests, including serum vitamin B12, red cell folate, albumin and calcium, and qualitative small bowel bacteriology results, were analyzed. The effect of age on all variables was studied.

Twenty of the 30 small bowel aspirates had proven SIBO, and strict anaerobes were isolated in 15. The mean blood test values did not differ significantly between culture-positive and culture-negative patients. There was no significant correlation between those variables and the total bacterial counts. Of the 20 proven SIBO cases, eight had anemia, five had hypoalbuminemia, five had diarrhea, four complained of recent weight loss, and none had B12 deficiency. Alternative causes other than SIBO were identified for many of these abnormalities. Advancing age correlated significantly with rising counts of small bowel strict anaerobes.

These data suggest that age may be a predisposing factor in the development of anaerobic overgrowth but that SIBO is a benign entity in the elderly. Contrary to previous recommendations, treatment of this condition is not routinely indicated.