Effect of eradicating hydrogen-forming small intestinal bacterial overgrowth with rifaximin on body weight change

Abstract

Hydrogen formed by small intestinal bacterial overgrowth in patients with non-constipated irritable bowel syndrome has an inverse relationship with obesity. However, the effect of eradicating small intestinal hydrogen-producing bacterial overgrowth on the body weight of these patients has not yet been reported. The aim of this study was to investigate body weight changes after eradicating small intestinal bacterial overgrowth with rifaximin treatment in patients with non-constipated irritable bowel syndrome.We reviewed the charts of patients with non-constipated irritable bowel syndrome who showed abdominal symptoms with documented lactulose hydrogen breath test results in order to diagnose small intestinal bacterial overgrowth. A total of 153 patients were enrolled in the study and divided into quartiles according to body mass index (BMI) and body weight.In the lowest body weight quartile, the BMI and body weight were significantly increased (0.4 kg/m, P = .038; 0.6 kg, P = .010, respectively) in patients with negative lactulose hydrogen breath tests after rifaximin treatment. However, there was no significant change in body weight in the other quartiles. Despite treatment with rifaximin for 12 weeks, there was no change in BMI or body weight in any group of patients with consistently positive lactulose hydrogen breath tests.Eradication of hydrogen formed by small intestinal bacterial overgrowth does not cause clinically significant changes in body weight.

Figure 1

Flow chart of study patients. LHBT = lactulose hydrogen breath test.

Figure 2

Body mass index (BMI) and body weight changes after treatment with rifaximin in patient groups by pretreatment BMI or body weight quartile. (a and b) The BMI and body weight changes according to quartiles of BMI or body weight in patients with negative LHBTs after rifaximin treatment (n = 83). (c and d) BMI and body weight changes according to the BMI or body weight quartile in patients who had sustained positive LHBT results after 12 wk of rifaximin treatment (n = 70). Mean differences: (a) Q1, +0.40 ± 0.62; Q2, +0.26 ± 0.84; Q3, +0.17 ± 0.81; Q4, −0.28 ± 0.61. (b) Q1, +0.6 ± 1.1; Q2, +0.2 ± 2.7; Q3, +0.6 ± 2.4; Q4, −0.3 ± 1.4. (c) +0.17 ± 0.42; Q2, +0.00 ± 0.57; Q3, +0.21 ± 0.51; Q4, −0.20 ± 0.84. (d) +0.5 ± 0.9; Q2, −0.4 ± 0.6; Q3, −0.6 ± 2.2; Q4, +0.1 ± 1.1. Mean differences are expressed as mean ± standard deviation. P-value was calculated using the paired t-test. BMI = body mass index, LHBT(−) = negative lactulose hydrogen breath test, LHBT(+) = positive lactulose hydrogen breath test, Q1 = 1st quartile, Q2 = 2nd quartile, Q3 = 3rd quartile, Q4 = 4th quartile.

Figure 2 (Continued)

Body mass index (BMI) and body weight changes after treatment with rifaximin in patient groups by pretreatment BMI or body weight quartile. (a and b) The BMI and body weight changes according to quartiles of BMI or body weight in patients with negative LHBTs after rifaximin treatment (n = 83). (c and d) BMI and body weight changes according to the BMI or body weight quartile in patients who had sustained positive LHBT results after 12 wk of rifaximin treatment (n = 70). Mean differences: (a) Q1, +0.40 ± 0.62; Q2, +0.26 ± 0.84; Q3, +0.17 ± 0.81; Q4, −0.28 ± 0.61. (b) Q1, +0.6 ± 1.1; Q2, +0.2 ± 2.7; Q3, +0.6 ± 2.4; Q4, −0.3 ± 1.4. (c) +0.17 ± 0.42; Q2, +0.00 ± 0.57; Q3, +0.21 ± 0.51; Q4, −0.20 ± 0.84. (d) +0.5 ± 0.9; Q2, −0.4 ± 0.6; Q3, −0.6 ± 2.2; Q4, +0.1 ± 1.1. Mean differences are expressed as mean ± standard deviation. P-value was calculated using the paired t-test. BMI = body mass index, LHBT(−) = negative lactulose hydrogen breath test, LHBT(+) = positive lactulose hydrogen breath test, Q1 = 1st quartile, Q2 = 2nd quartile, Q3 = 3rd quartile, Q4 = 4th quartile.

Figure 2 (Continued)

Body mass index (BMI) and body weight changes after treatment with rifaximin in patient groups by pretreatment BMI or body weight quartile. (a and b) The BMI and body weight changes according to quartiles of BMI or body weight in patients with negative LHBTs after rifaximin treatment (n = 83). (c and d) BMI and body weight changes according to the BMI or body weight quartile in patients who had sustained positive LHBT results after 12 wk of rifaximin treatment (n = 70). Mean differences: (a) Q1, +0.40 ± 0.62; Q2, +0.26 ± 0.84; Q3, +0.17 ± 0.81; Q4, −0.28 ± 0.61. (b) Q1, +0.6 ± 1.1; Q2, +0.2 ± 2.7; Q3, +0.6 ± 2.4; Q4, −0.3 ± 1.4. (c) +0.17 ± 0.42; Q2, +0.00 ± 0.57; Q3, +0.21 ± 0.51; Q4, −0.20 ± 0.84. (d) +0.5 ± 0.9; Q2, −0.4 ± 0.6; Q3, −0.6 ± 2.2; Q4, +0.1 ± 1.1. Mean differences are expressed as mean ± standard deviation. P-value was calculated using the paired t-test. BMI = body mass index, LHBT(−) = negative lactulose hydrogen breath test, LHBT(+) = positive lactulose hydrogen breath test, Q1 = 1st quartile, Q2 = 2nd quartile, Q3 = 3rd quartile, Q4 = 4th quartile.

Figure 2 (Continued)

Body mass index (BMI) and body weight changes after treatment with rifaximin in patient groups by pretreatment BMI or body weight quartile. (a and b) The BMI and body weight changes according to quartiles of BMI or body weight in patients with negative LHBTs after rifaximin treatment (n = 83). (c and d) BMI and body weight changes according to the BMI or body weight quartile in patients who had sustained positive LHBT results after 12 wk of rifaximin treatment (n = 70). Mean differences: (a) Q1, +0.40 ± 0.62; Q2, +0.26 ± 0.84; Q3, +0.17 ± 0.81; Q4, −0.28 ± 0.61. (b) Q1, +0.6 ± 1.1; Q2, +0.2 ± 2.7; Q3, +0.6 ± 2.4; Q4, −0.3 ± 1.4. (c) +0.17 ± 0.42; Q2, +0.00 ± 0.57; Q3, +0.21 ± 0.51; Q4, −0.20 ± 0.84. (d) +0.5 ± 0.9; Q2, −0.4 ± 0.6; Q3, −0.6 ± 2.2; Q4, +0.1 ± 1.1. Mean differences are expressed as mean ± standard deviation. P-value was calculated using the paired t-test. BMI = body mass index, LHBT(−) = negative lactulose hydrogen breath test, LHBT(+) = positive lactulose hydrogen breath test, Q1 = 1st quartile, Q2 = 2nd quartile, Q3 = 3rd quartile, Q4 = 4th quartile.