Doctors Prescribe Antibiotics for Diverticulitis 97% of the Time Despite Guidelines
A VA study finds antibiotics are vastly overprescribed for uncomplicated diverticulitis, raising gut microbiome and resistance concerns.
Summary
A large study of over 33,000 VA patient visits found that doctors prescribed antibiotics for uncomplicated diverticulitis 96.6% of the time — even though current guidelines say most patients don't need them. This pattern held steady from 2015 to 2025, despite campaigns urging more selective use. Most patients in the study were otherwise healthy, without the warning signs that guidelines say actually justify antibiotics. Experts warn that unnecessary antibiotic use carries real harms, including disruption of gut microbiome, antibiotic resistance, and side effects. For health-conscious adults, this is a reminder to ask your doctor whether antibiotics are truly necessary if you're ever diagnosed with a mild case of diverticulitis.
Detailed Summary
Antibiotic overuse is a well-documented problem, but a new study reveals just how stubborn prescribing habits can be even when evidence clearly points the other way. Researchers analyzed over a decade of outpatient visits at Veterans Affairs facilities and found that antibiotics were prescribed for uncomplicated diverticulitis nearly 97% of the time — far exceeding what current clinical guidelines recommend.
The study, published in Annals of Internal Medicine, tracked 33,634 emergency department and urgent care visits across 120 VA facilities between 2015 and 2025. Despite guidelines from the American Gastroenterological Association stating that antibiotics can be used selectively rather than routinely in immunocompetent patients with mild cases, annual prescribing rates never dropped below 95.6%. Fluoroquinolones were the most common choice (46%), followed by amoxicillin-clavulanate (43%).
Most patients in the cohort were relatively healthy. The median Charlson Comorbidity Index score was zero, meaning most had few serious underlying conditions. The specific red flags that guidelines say should trigger antibiotic use — such as C-reactive protein above 140 mg/L or white blood cell counts above 15 billion cells per liter — were uncommon in this population.
For longevity-focused individuals, this matters beyond just antibiotic resistance. Unnecessary antibiotics can significantly disrupt the gut microbiome, which plays a central role in immune regulation, metabolic health, and inflammation — all key pillars of healthy aging. Fluoroquinolones in particular carry additional risks including tendon damage and neurological effects.
The researchers call for targeted interventions — likely clinical decision support tools or stewardship programs — to bring prescribing in line with evidence. The broader lesson: medical practice often lags behind science, and informed patients who ask whether antibiotics are truly necessary may protect both their gut health and long-term wellbeing.
Key Findings
- Antibiotics were prescribed in 96.6% of uncomplicated diverticulitis visits despite guidelines recommending selective use.
- Prescribing rates never fell below 95.6% annually across a 10-year window from 2015 to 2025.
- Most patients lacked the clinical markers that guidelines say justify antibiotic treatment.
- Fluoroquinolones were the most common regimen at 46%, carrying known risks including tendon and nerve damage.
- Unnecessary antibiotics may harm gut microbiome health, with downstream effects on immunity and inflammation.
Methodology
This is a news report summarizing a retrospective cohort study published in Annals of Internal Medicine, a high-credibility peer-reviewed journal. The study analyzed over 33,000 real-world outpatient visits across 120 VA facilities over 10 years, providing robust observational evidence. As a retrospective study, it cannot establish causation but offers strong descriptive insight into prescribing patterns.
Study Limitations
The study is limited to VA patients, who are predominantly older, male, and a specific demographic that may not represent the general population. Retrospective design means clinical nuance — such as undocumented symptoms — may have influenced prescribing decisions that the data cannot capture. Readers should consult the full Annals of Internal Medicine paper for complete methodology and subgroup analyses.
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