The Endo-HRS Model: A Novel Endoscopic Score for Predicting Recurrence in Internal Hemorrhoid-A Prospective Multicenter Cohort

This prospective multicenter study introduces and validates the Endo-HRS model, a novel endoscopic scoring system based on hemorrhoid count, diameter, color, and patient sex, to effectively stratify recurrence risk and guide personalized management following foam sclerotherapy for grade I internal hemorrhoids.

The Gist

Imagine your body has a set of tiny, sensitive cushions near the exit (the anal canal) that help you control your bowel movements. Sometimes, these cushions get swollen, inflamed, or "leaky," causing bleeding and discomfort. This is what we call hemorrhoids.

For mild cases (Grade I), doctors often use a "foam injection" treatment. Think of it like a mechanic injecting a special foam into a leaky tire to seal the hole and stop the air from escaping. It's quick, minimally invasive, and usually works well.

But here's the problem: Sometimes, the "leak" comes back. The hemorrhoids return, and the bleeding starts again. Until now, doctors had to guess who was likely to have a recurrence. It was like trying to predict if a house will flood without looking at the weather forecast or the condition of the roof.

This paper introduces a new, smart tool called the Endo-HRS Model to solve that guessing game.

🌟 The "Hemorrhoid Weather Forecast" (The Endo-HRS Model)

The researchers looked at hundreds of patients who got the foam treatment and asked: "What did the hemorrhoids look like right before we treated them that made them come back?"

They found four specific "warning signs" that act like storm clouds on the horizon:

1. The Number of "Balloons": Did the patient have just one swollen cushion, or a whole cluster of them? (More cushions = higher risk).
2. The Size of the "Balloons": How big were they? (Bigger = higher risk).
3. The "Red Alert" Sign: When the doctor looked inside with a camera, were the cushions bright red and angry-looking, or just slightly pink? (Bright red, angry veins = higher risk).
4. The "Gender Factor": Interestingly, men seemed to have a slightly higher risk of recurrence than women in this study.

🛠️ How the New Tool Works

The team turned these four clues into a simple scorecard (the Endo-HRS).

• The Calculator: Imagine a digital app where a doctor types in the number of hemorrhoids, their size, and how red they look.
• The Result: The app instantly gives a score and puts the patient into one of three "Risk Buckets":
  • Bucket A (Low Risk): "Your roof looks solid. You probably won't need to check back for a long time (2–3 years)."
  • Bucket B (Medium Risk): "There are a few loose shingles. Let's check back in about a year."
  • Bucket C (High Risk): "This is a storm warning. The roof is weak. We need to monitor you closely and maybe intervene sooner."

🔬 The "Why" Behind the "What" (The Secret Sauce)

The researchers didn't just stop at the scorecard. They wanted to know why these specific patients had their hemorrhoids return. They took tiny samples (biopsies) from the high-risk patients and looked at them under a microscope.

They found two main culprits:

1. Clogged Pipes: The tiny blood vessels were swollen and congested (like a traffic jam in a small alley).
2. Bad Concrete: The tissue had too much "scar tissue" (collagen) built up in the wrong places. It was like trying to fix a leaky pipe with the wrong kind of cement—it didn't hold up well.

This discovery is huge because it tells us that recurrence isn't just bad luck; it's a biological issue with how the body's "plumbing" and "structural support" are built.

🏆 Why This Matters for You

Before this study, if you had mild hemorrhoids, the doctor would treat you and say, "Come back if you feel pain." It was a "wait and see" approach.

Now, thanks to this paper:

• Personalized Care: Your treatment plan is tailored to your specific risk.
• Better Planning: If you are "Low Risk," you save time and money on unnecessary check-ups. If you are "High Risk," you get the extra attention you need to prevent a relapse.
• A New Tool: Doctors now have a web-based calculator (like a weather app for hemorrhoids) to make these decisions instantly.

In short: This study turned a vague guess into a precise science. It's like moving from saying, "It might rain later," to having a radar that says, "It will rain in 20 minutes, so grab an umbrella." That's the power of the Endo-HRS model.

Technical Summary

1. Problem Statement

• Clinical Context: Internal hemorrhoids are a highly prevalent anorectal disorder. Endoscopic foam sclerotherapy using polidocanol is a minimally invasive treatment for Grade I hemorrhoids, offering rapid recovery and low adverse event rates.
• The Gap: Despite its efficacy, the primary limitation of this treatment is a high rate of recurrence (reported between 10–30% within the first year).
• Current Limitations: Existing classification systems (e.g., Goligher) rely on prolapse and subjective symptoms, failing to provide objective, quantifiable endoscopic markers for predicting recurrence. There is a lack of validated tools to stratify patients into risk categories for personalized follow-up and treatment planning.

2. Methodology

The study was a prospective, multicenter, observational cohort study conducted across four tertiary hospitals in China, adhering to the TRIPOD guidelines.

• Study Population:
  • Development Cohort: 483 patients with Goligher Grade I internal hemorrhoids treated with 1% polidocanol foam sclerotherapy.
  • External Validation Cohort: 279 independent patients from separate centers.
  • Multi-modal Verification Cohort: A subset of 40 patients for histopathological correlation.
• Intervention: Standardized foam sclerotherapy (1% polidocanol) administered via endoscopy.
• Data Collection & Variables:
  • Two blinded endoscopists recorded objective endoscopic variables: number of hemorrhoids, maximum diameter, red color sign (RCS) grade (0–3), mucosal erosion, and dentate line injury.
  • Follow-up involved scheduled colonoscopies every 6 months for up to 36 months.
  • Outcome: Recurrence was defined as the endoscopic reappearance of hemorrhoids with bleeding or vascular abnormalities.
• Statistical Modeling:
  • Model Development: Univariable Cox proportional hazards regression screened candidates ($P < 0.10$), followed by backward stepwise multivariable selection.
  • Scoring System: The Endoscopic Hemorrhoid Recurrence Score (Endo-HRS) was constructed by assigning weighted points based on regression coefficients.
  • Validation: Internal validation via 1,000 bootstrap resamples; external validation on the independent cohort.
  • Performance Metrics: Harrell's C-index, time-dependent ROC curves (AUC), and calibration plots.
  • Pathological Analysis: Tissue biopsies were analyzed using H&E and Masson's trichrome staining to quantify microvascular density and collagen proportionate area (CPA).

3. Key Contributions

1. Novel Predictive Model (Endo-HRS): The first endoscopic scoring system specifically designed to predict recurrence after foam sclerotherapy for Grade I hemorrhoids.
2. Objective Endoscopic Markers: Shifted focus from subjective symptoms to quantifiable endoscopic features (hemorrhoid count, diameter, and vascular congestion signs).
3. Multi-Modal Validation: Uniquely combined clinical data, external cohort validation, endoscopic imaging, and histopathological analysis to link clinical risk scores with underlying biological mechanisms.
4. Clinical Implementation Tool: Developed a web-based calculator and a simplified three-tier risk stratification system (Groups A, B, C) for point-of-care use.
5. Pathophysiological Insight: Provided evidence linking recurrence to specific histological changes (vascular congestion and aberrant collagen deposition).

4. Key Results

• Recurrence Rates: Cumulative recurrence rates were 0.62% (6 months), 2.48% (12 months), 10.1% (24 months), and 20.0% (36 months).
• Independent Predictors: Four factors were identified as independent predictors of recurrence:
  1. Number of hemorrhoids (HR ~3.39 for higher counts).
  2. Maximum hemorrhoid diameter (HR ~22.94 for larger sizes).
  3. Red Color Sign (RCS) grade (HR ~1.67 for higher grades).
  4. Male Sex (Retained for clinical relevance despite $P=0.08$).
• Model Performance:
  • Discrimination: The model showed excellent discrimination with a C-index of 0.82 in the development cohort and 0.90 in the external validation cohort. Time-dependent AUCs exceeded 0.80–0.90 at 24, 36, and 48 months.
  • Stratification: Patients were divided into three risk groups based on Youden-optimized cutoffs:
    • Group A (Low Risk): Score < 18.2
    • Group B (Moderate Risk): Score 18.2 – 27.4
    • Group C (High Risk): Score ≥ 27.4
  • Group C patients had significantly shorter recurrence-free intervals compared to Groups A and B ($P < 0.00001$).
• Pathological Correlation:
  • High-risk patients (Group C) exhibited marked submucosal venule dilation/congestion.
  • Collagen Proportionate Area (CPA) was 14.6-fold higher in Group C compared to Group A and 2.6-fold higher than Group B, suggesting that excessive collagen deposition and ECM remodeling drive recurrence.

5. Significance and Implications

• Personalized Medicine: The Endo-HRS model enables clinicians to move from a "one-size-fits-all" follow-up approach to risk-stratified management. Low-risk patients may avoid frequent invasive surveillance, while high-risk patients can be monitored closely or considered for earlier re-intervention.
• Mechanistic Understanding: The study bridges the gap between clinical endoscopic appearance and histopathology, suggesting that recurrence is not just a mechanical failure but is driven by abnormal extracellular matrix (ECM) remodeling and vascular hyperplasia.
• Clinical Utility: The availability of a web-based calculator facilitates immediate risk assessment during endoscopy, improving workflow efficiency.
• Limitations: The study notes that the model was developed exclusively in a Chinese population with Grade I hemorrhoids treated with 1% polidocanol, limiting generalizability to other grades, populations, or sclerosing agents without recalibration. Inter-observer variability in endoscopic scoring remains a potential challenge.

Conclusion: The Endo-HRS model represents a significant advancement in the management of internal hemorrhoids, providing a validated, objective, and biologically grounded tool to predict recurrence and guide personalized treatment strategies.