Table 3. Clinical characteristics of fasting H2 based subgroups (post-hoc).
| Mean (SD) | Low H2 (n = 71) | High H2 (n = 35) | P value |
|---|---|---|---|
| age | 36.0 (10.5) | 34.5 (12.1) | 0.67 |
| gender F/M (%) | 64.8 / 35.2 | 51.4 / 48.6 | 0.19 |
| BMI | 23. 4 (3.9) | 23.1 (3.0) | 0.67 |
| IBS-SSS | 281.2 (100.0) | 278.1 (116.0) | 0.90 |
| HAD anxiety | 8.3 (4.5) | 7.4 (4.3) | 0.56 |
| HAD depression | 5.4 (3.4) | 4.1 (2.5) | 0.44 |
| PHQ-15 | 13.2 (4.9) | 12.2 (5.5) | 0.56 |
| IBS-C, n (%) | 15 (21.1) | 5 (14.3) | 0.83 |
| IBS-D, n (%) | 21 (29.6) | 12 (34.3) | |
| IBS-M, n (%) | 25 (35.2) | 12 (34.3) | |
| IBS-U, n (%) | 10 (14.1) | 6 (17.1) | |
| OATT (days) | 1.5 (1.2) | 1.3 (0.8) | 0.56 |
| Energy from diet (kcal) | 2198.7 (598.7) | 2037.0 (554.0) | 0.56 |
| %Carbohydrates | 44.2 (8.5) | 45.2 (8.3) | 0.67 |
| %Protein | 16.7(3.6) | 17.2 (4.4) | 0.67 |
| %Fat | 36.1 (6.8) | 34.4 (7.9) | 0.60 |
| FODMAPs (g) | 16.3 (10.0) | 14.1 (8.3) | 0.56 |
SD: Standard Deviation; High H2: fasting H2 level≥10ppm; Low H2: fasting H2 level<10ppm; BMI: body mass index; IBS-SSS: IBS Severity Scoring System; HAD: hospital anxiety and depression scale; PHQ-15: patient health questionnaire 15; IBS-C: irritable bowel syndrome with constipation; IBS-D: irritable bowel syndrome with diarrhea; IBS-M: irritable bowel syndrome with mixed pattern; IBS-U: irritable bowel syndrome unsubtyped; OATT: oroanal transit time; FODMAP: fermentable, oligo-, di-, mono-saccharides and polyols; all questionnaires are expressed as mean total scores; Statistical significance is determined by Oneway ANOVA for quantitative parameters. Multiple testing strategy consisted in Benjamini Hochberg adjustment for quantitative parameters and two-sided Chi2 test for qualitative parameters.