Antibiotics Getting False Blame for Colitis, Study Finds

TOPLINE:

Antibiotic use does not appear to be associated with microscopic colitis (MC), despite presenting with similar symptoms of watery, non-bloody diarrhea. 

METHODOLOGY:

• MC, a change in the microbiome characterized by watery, non-bloody diarrhea, can significantly worsen a patient’s quality of life; antibiotic treatment may induce similar symptoms, but the association between MC and antibiotics is unknown.
• Researchers conducted a self-controlled case series study in 2393 adults in Sweden (age ≥ 65 years; 66.7% women) with a new prescription of antibiotics and biopsy-confirmed incident MC between 2srcsrc7 and 2src17.
• The primary outcome was the incidence of MC during the antibiotic treatment period and three posttreatment intervals (1-2 weeks, 2 weeks to 3 months, and 3-12 months) compared with nontreatment periods in the same individual.
• The patients received antibiotic treatment for a median of 1.6 weeks, most commonly phenoxymethylpenicillin (5src%) and doxycycline (35%).
• To test the association between antibiotic use and gastrointestinal workup, researchers used the same case-control design for a negative control outcome analysis of 19,src91 individuals on antibiotics whose biopsies showed normal mucosa instead of MC.

TAKEAWAY:

• The risk for MC increased during antibiotic treatment (adjusted incidence rate ratio [aIRR], 1.44; 95% CI, 1.13-1.84) and 3 months to 1 year posttreatment (aIRR, 1.19; 95% CI, 1.src7-1.32) compared with nontreatment periods.
• The negative control outcome analysis demonstrated similar but slightly higher risks for biopsy-confirmed normal mucosa after antibiotic treatment.
• The risk for MC was higher in women than in men and in people aged> 8src years than in those aged 65-79 years.
• The similar risk from antibiotics of MC and normal mucosa suggests the presence of detection bias from gastrointestinal side effects.

IN PRACTICE:

“Our findings suggest that physicians should not refrain from prescribing antibiotics due to concerns of patients developing MC. Nonetheless, cautious antibiotic prescribing should be standard care due to the increasing antimicrobial resistance and also the age-related alterations in pharmacokinetics and pharmacodynamics of antibiotics,” the authors wrote.

SOURCE:

This study was led by Máté Szilcz, Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. It was published online in Alimentary Pharmacology & Therapeutics.

LIMITATIONS:

Information regarding lifestyle factors such as body mass index and smoking was not available. The antibiotic exposure periods might not have accurately represented the actual consumption periods, and potential long-term effects beyond the 1-year posttreatment period could not be ruled out. This study was limited to individuals aged ≥ 65 years and comprised predominantly the northern European population, thus limiting generalizability.

DISCLOSURES:

This study was supported by funding from the Swedish Research Council for Health, Working Life and Welfare. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.