Devadas et al reported 2 scores for the prediction of colectomy for a patient with acute severe ulcerative colitis. One model is the CRAB score and the second is a logistic regression model. The authors are from Medical College Trivandrum and Nizam's Institute of Medical Sciences in India.
Patient selection: admission for acute severe ulcerative colitis
Parameters:
(1) serum CRP in mg/dL
(2) serum albumin in g/L
(3) hemoglobin in g/dL
CRAB score =
= (0.2 * (CRP)) - (0.26 * (albumin))
where:
• In Table 2 the titles of the 2 columns (colectomy, no colectomy) may be reversed.
• The units for serum albumin are mg/dL but the values are g/L.
• The values for serum CRP seem high for mg/dL.
Interpretation:
• A score > 0.4 has a sensitivity of 0.82 and specificity of 0.92 for colectomy within 24 months.
• The area under the ROC curve was 0.92.
The authors also reported a logistic regression model:
value of X =
= (0.203 * (CRP)) - (0.257 * (albumin)) - (0.075 * (hemoglobin)) + 0.134
probability of colectomy within 24 months =
= 1 / (1 + EXP((-1) * X))
