SOP Udates – 30 April 2025 – Diverticulitis

Updates from 2020 to 2025

2020 Amendments

In 2020, the amendments (No. 35 for RH and No. 36 for BoP) made the following changes:

• Added Factor: Introduced a new factor linking the use of immunosuppressive drugs within 30 days before the clinical onset of diverticular perforation, abscess, or fistula.
• Revised Factor: Replaced an existing factor with one linking immunosuppressive drugs within 30 days before clinical worsening.
• Definitions: Added a definition for “immunosuppressive drug” (e.g., corticosteroids, chemotherapeutic agents) and removed the prior definition of “being treated with an immunosuppressive drug.”

These changes were relatively narrow, focusing solely on immunosuppressive drugs.

2025 SOPs

The 2025 SOPs (No. 51 for RH and No. 52 for BoP) repealed the previous versions and introduced comprehensive updates, significantly expanding the list of factors that may connect diverticular disease of the colon to service. The updates include:

Common New Factors (Present in Both RH and BoP)

1. Body Mass Index (BMI): Links higher BMI to onset or worsening (thresholds differ; see differences below).
2. Diabetes Mellitus: Associated with onset or worsening of diverticular bleeding.
3. Physical Inactivity: Inability to perform activity >3 METs for at least 5 years before onset or worsening.
4. Chronic Renal Failure: Linked to onset or worsening, defined by low glomerular filtration rate or dialysis.
5. Solid Organ Transplant: Associated with worsening (excludes corneal transplants).
6. Immunosuppressive Medications: Retained from 2020, linked to onset (for perforation, abscess, fistula) and worsening within 30 days.
7. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Use for at least 4 weeks before onset or worsening of bleeding, perforation, abscess, or fistula.
8. Antiplatelet Medications: Linked to onset or worsening of diverticular bleeding within 7 days of last dose.
9. Opioids: Use for at least 4 weeks before worsening.
10. Smoking: At least 10 pack-years before onset or worsening, with conditions on cessation timing.
11. Low Fiber Intake: Inability to consume ≥30g/day of fiber for 5 consecutive years within 10 years before onset.
12. Foreign Object Contact: Contact with foreign material (e.g., bones, stents) at the affected site at worsening.
13. Inadequate Clinical Management: Inability to obtain appropriate care before worsening.

Additional Factors in Reasonable Hypothesis (RH) Only

The 2025 RH SOP (No. 51) includes the following factors not present in the BoP SOP:

1. Systemic Sclerosis: Linked to onset.
2. Menopausal Hormone Therapy: Use for at least 1 year before onset.
3. Alcohol Consumption: ≥180 kg within 10 years before onset.
4. Red Meat Consumption: ≥200 g/day for at least 5 years before onset.

These updates reflect a broader scope of risk factors compared to the 2020 focus on immunosuppressive drugs alone.

Differences Between Reasonable Hypothesis (RH) and Balance of Probabilities (BoP) in 2025

The RH and BoP SOPs differ in their standards of proof, with RH being a lower threshold (used for operational service) and BoP being more stringent (used for non-operational service). This is reflected in the 2025 SOPs as follows:

Key Differences

1. BMI Threshold
   • RH: BMI ≥25 (overweight) for at least 5 years before onset or worsening.
   • BoP: BMI ≥30 (obese) for at least 5 years before onset or worsening.
   • Explanation: The lower threshold in RH makes it easier to establish a connection, aligning with its less stringent standard.
2. Additional Factors in RHThe following factors are included in RH (No. 51) but absent in BoP (No. 52):
   • Systemic Sclerosis: Before clinical onset.
   • Menopausal Hormone Therapy: At least 1 year before onset.
   • Alcohol Consumption: ≥180 kg within 10 years before onset.
   • Red Meat Consumption: ≥200 g/day for at least 5 years before onset.
   • Explanation: These additional factors broaden the scope for RH, facilitating claims under its lower standard of proof.
3. Shared Factors
   • All other factors (e.g., diabetes, NSAIDs, smoking) are identical in wording and conditions between RH and BoP, including timeframes and specific conditions (e.g., 30 days for immunosuppressive drugs, 4 weeks for NSAIDs).

Basis of Determination

• RH: Based on “sound medical-scientific evidence that indicates” a connection to service.
• BoP: Based on it being “more probable than not” that a connection exists.
• This reflects the differing evidentiary burdens, with RH requiring a plausible link and BoP requiring a higher likelihood.

Summary

• Updates: The 2025 SOPs expand significantly from the 2020 amendments, adding numerous factors like BMI, diabetes, and lifestyle factors, beyond just immunosuppressive drugs.
• Differences: RH has a lower BMI threshold (≥25 vs. ≥30) and includes four additional factors (systemic sclerosis, hormone therapy, alcohol, red meat) not in BoP, consistent with RH’s lower standard of proof.

These changes provide a more detailed framework for assessing service-related diverticular disease, with RH offering a broader and less stringent set of criteria compared to BoP.