To which class of evidence does the use of probiotics during antibiotic therapy belong?

Evidence Classification for Probiotics During Antibiotic Therapy

Based on the most recent and highest quality evidence, the use of probiotics during antibiotic therapy belongs to Class B evidence (moderate quality evidence). 1

Understanding Evidence Classification for Probiotics

The evidence classification for probiotics during antibiotic therapy can be broken down as follows:

Class B Evidence for Prevention of Antibiotic-Associated Diarrhea (AAD)

• The American Gastroenterological Association (AGA) clinical practice guidelines from 2020 indicate that the use of certain probiotic strains for prevention of Clostridioides difficile infections in adults and children on antibiotics is supported by moderate quality evidence 1
• The AGA technical review specifically states that the overall quality of evidence for probiotics in preventing C. difficile-associated diarrhea (CDAD) is "Low" 1
• For specific strains and combinations, the evidence quality varies:
  • Saccharomyces boulardii shows Low quality evidence (RR, 0.41; 95% CI, 0.22–0.79) 1
  • The 2-strain combination of L. acidophilus CL1285 and L. casei LBC80R shows Low quality evidence (RR, 0.22; 95% CI, 0.11–0.42) 1
  • The 3-strain and 4-strain combinations also show Low quality evidence 1

Strain-Specific Considerations

• For pediatric AAD prevention, the evidence for high-dose probiotics (≥5 billion CFUs/day) is rated as moderate certainty evidence 2
• Specific strains like Lactobacillus rhamnosus GG and Saccharomyces boulardii have the strongest evidence base for preventing AAD 3, 4

Clinical Application of Evidence Classification

When applying this evidence classification in practice:

1. Patient Selection is Critical:

   • Probiotics may be most beneficial for patients at higher risk of developing CDAD (>15% baseline risk) 5
   • Avoid use in immunocompromised patients due to risk of fungemia 5

2. Strain Selection Based on Evidence:

   • Saccharomyces boulardii is the only single-strain probiotic demonstrating significant effect in reducing CDAD incidence 5
   • Lactobacillus rhamnosus has good evidence for AAD prevention in children and outpatient adults 3

3. Dosage Considerations:

   • Higher doses (≥5 billion CFUs/day) appear more effective than lower doses 2
   • Typical effective doses range from 10^10-10^11 CFU/day 5

Important Caveats and Limitations

• The AGA guidelines note that "the quality of evidence was low and the reporting of potential harms was not always consistent" 1
• For patients who place high value on avoiding potential harms, particularly those with severe illnesses or immunosuppression, it would be reasonable to not use probiotics 1
• Evidence is strain-specific - no general statement can be made about the efficacy of all probiotics in preventing AAD 3
• Despite the moderate evidence classification, significant knowledge gaps exist regarding optimal strains and dosages 1

In conclusion, while probiotics show promise in preventing antibiotic-associated diarrhea, the current evidence classification (Class B - moderate quality) reflects the need for additional high-quality research to further establish optimal strains, dosages, and patient populations.