Investigation of gastrointestinal tolerability, treatment compliance and iron status markers in patients with iron deficiency anemia who received oral iron replacement therapy with versus without concomitant probiotic supplementation

A total of 295 patients, with newly diagnosed iron deficiency anemia (IDA) who were planned to receive routine oral IRT were included in this prospective randomized non-placebo, controlled 3-month follow-up study. Patients were randomly assigned via simple randomization method to receive either iron replacement therapy (IRT) alone or IRT plus L. plantarum 299v probiotic support . Adult (aged older than18 years) treatment-naïve patients diagnosed with newly diagnosed IDA without previous IRT were included in the study, while those with irritable bowel syndrome, previous IRT therapy or intolerance to IRT and those with a known chronic disease (i.e., inflammatory bowel disease (IBD), celiac disease) or untreated active menometrorrhagia and hemorrhoid were excluded from the study.

All patients received IRT with ferrous sulfate (Fe2 + ) preparation (100 mg, once daily) for 3 months, while those in the IRT-Pro group also received daily (10B CFU) L. plantarum 299v probiotic supplementation for 30 days starting from the first day of IRT.

Data on gastrointestinal intolerance symptoms (loss of appetite, nausea, vomiting, abdominal pain, diarrhea, constipation and bloating) were recorded at three time points including baseline, within the first 30 days of IRT and at any time during 3-month IRT.

Serum hemoglobin levels (g/dL) and serum iron status markers including ferritin (ng/mL), iron (µg/dL), total iron binding capacity (TIBC, µg/dL) and transferrin saturation (%) were recorded at baseline and at 3 rd month of IRT. Data on treatment discontinuation were also recorded in study groups along with comparison of study variables in patients with vs. without treatment discontinuation within the first 30 days of IRT.

At least 189 patients were calculated to be included via sample size estimation (G*Power 3.1.9 program) based on a power of 80 % at a type I error of 0.05, and an effect size (w=0.261) calculated using data from a previous study by Cekin et al. .

Given the high likelihood of missing data, a total of 200 patients were planned to be included in the study population with the use of 25% lost to follow up ratio. Statistical analysis was made using IBM SPSS Statistics for Windows, Version 22.0 (IBM Corp., Armonk, NY). Pearson chi-square test, Fisher's exact test and Mc-Nemar test were used for analysis of categorical variables. Mann-Whitney U test was used for analysis of non-normally distributed numerical data while independent sample t test was used for normally distributed data. The number needed to treat (NNT) analysis was performed to determine how many patients must receive IRT-Pro instead of IRT per se to prevent one additional treatment discontinuation. Data are expressed as mean ± standard deviation (SD), median, inter-quartile range (IQR), minimum-maximum and percent (%) where appropriate. p < 0.05 was considered statistically significant.

Inclusion Criteria:

• Treatment-naïve patients diagnosed with newly diagnosed iron deficiency anemia

Exclusion Criteria:

• Irritable bowel syndrome
• Celiac disease
• Untreated active menometrorrhagia
• Hemorrhoidal disease
• Previous iron replacement therapy