This calculator estimates the risk of hepatocellular carcinoma (HCC) in individuals with chronic hepatitis B using the REACH-B model. Inputs include categorical data regarding the patient's sex, age, ALT levels, HBeAg status, and hepatitis B virus DNA level. Each category is assigned a unique numeric score based on predefined criteria.

The calculator includes the following components for scoring:

1. Sex: Female (0 points), Male (2 points)
2. Age Years:
   - 30-34 (0 points)
   - 35-39 (1 point)
   - 40-44 (2 points)
   - 45-49 (3 points)
   - 50-54 (4 points)
   - 55-59 (5 points)
   - 60-65 (6 points)
3. ALT, U/L:
   - < 15 (0 points)
   - 15-44 (1 point)
   - >= 45 (2 points)
4. HBeAg: Negative (0 points), Positive (2 points)
5. Hepatitis B Virus DNA Level, copies/mL:
   - < 300 undetectable (0 points)
   - 300-9,999 (0 points)
   - 10,000-99,999 (3 points)
   - 100,000-999,999 (5 points)
   - >= 1,000,000 (4 points)

The total score is determined by adding the points assigned to each input. Based on this score, the model provides an interpretation of the patient's risk of developing hepatocellular carcinoma over different periods (3, 5, and 10 years).

Interpretations based on score:

- Score 0: Risk is 0.0% in 10 years, 5 years, and 3 years.
- Score 1: Risk is 0.1% in 10 years, 0.0% in 5 and 3 years.
- Score 2: Risk is 0.1% in 10 years, 0.0% in 5 and 3 years.
- Score 3: Risk is 0.2% in 10 years, 0.1% in 5 years, 0.0% in 3 years.
- Score 4: Risk is 0.3% in 10 years, 0.1% in 5 years, 0.0% in 3 years.
- Score 5: Risk is 0.5% in 10 years, 0.2% in 5 years, 0.1% in 3 years.
- Score 6: Risk is 0.7% in 10 years, 0.3% in 5 years, 0.1% in 3 years.
- Score 7: Risk is 1.2% in 10 years, 0.5% in 5 years, 0.2% in 3 years.
- Score 8: Risk is 2.0% in 10 years, 0.8% in 5 years, 0.3% in 3 years.
- Score 9: Risk is 3.2% in 10 years, 1.2% in 5 years, 0.5% in 3 years.
- Score 10: Risk is 5.2% in 10 years, 2.0% in 5 years, 0.9% in 3 years.
- Score 11: Risk is 8.4% in 10 years, 3.3% in 5 years, 1.4% in 3 years.
- Score 12: Risk is 13.4% in 10 years, 5.3% in 5 years, 2.3% in 3 years.
- Score 13: Risk is 21.0% in 10 years, 8.5% in 5 years, 3.7% in 3 years.
- Score 14: Risk is 32.0% in 10 years, 13.6% in 5 years, 6.0% in 3 years.
- Score 15: Risk is 46.8% in 10 years, 21.3% in 5 years, 9.6% in 3 years.
- Score 16: Risk is 64.4% in 10 years, 32.4% in 5 years, 15.2% in 3 years.
- Score 17: Risk is 81.6% in 10 years, 47.4% in 5 years, 23.6% in 3 years.

The final score, ranging from 0 to 17, offers a specific and easy-to-understand percentage that predicts the likelihood of developing HCC within specified timeframes.

The Risk Estimation for Hepatocellular Carcinoma in Chronic Hepatitis B (REACH-B) is a risk stratification model designed to predict the probability of hepatocellular carcinoma in patients with chronic hepatitis B. The clinical purpose of the REACH-B model is to aid in the identification of high-risk patients who may benefit from closer monitoring or early intervention. The intended patient population for this model includes individuals with chronic hepatitis B infection.

The key components or inputs used in the REACH-B model include the patient's sex, age, alanine aminotransferase (ALT) levels, hepatitis B e-antigen (HBeAg) status, and hepatitis B virus (HBV) DNA levels. The model assigns different risk scores based on these variables. For instance, males are assigned a higher risk score than females. Age is also considered, with increasing age associated with a higher risk score. ALT levels are categorized into three groups, with higher levels associated with a higher risk score. The presence of HBeAg and higher HBV DNA levels also contribute to an increased risk score.

Risk estimation for hepatocellular carcinoma in chronic hepatitis B (REACH-B)