CAR Associated With Endoscopic Activity in Ulcerative Colitis

ulcerative colitis
Researchers assessed the association between CRP-to-albumin ratio and ulcerative colitis regarding clinical remission, mucosal healing, and endoscopic disease severity.

C-reactive protein (CRP)-to-albumin ratio (CAR) is independently positively associated with moderate to severe endoscopic activity but not clinical remission or mucosal healing (MH) in patients with ulcerative colitis (UC), according to a study in BMC Gastroenterology.

Researchers assessed the association between CAR and UC regarding clinical remission, MH, and endoscopic disease severity. Clinical remission was defined as having no rectal bleeding and no abnormally high stool frequency (cutoff frequency: 3 times per day). MH and moderate to severe endoscopic activity were assessed with use of the Mayo endoscopic subscore (MES).

CARs were grouped into categories by thirds according to distribution of all participants. Tertiles were used to group patients into 3 categories: low CAR, ≤0.012 (reference); moderate CAR, 0.012-0.038; and high CAR, ≥0.038.

A total of 273 patients (mean age, 51.0±16.0 years; 59% men) with UC in Ehime Prefecture, Japan, were included from 2015 to 2019. Clinical remission, MH, and moderate to severe endoscopic activity rates were 57.9%, 26.0%, and 37.0%, respectively. Mean serum albumin, median CRP, and median CAR were 4.218 g/dL, 0.099 mg/dL, and 0.022, respectively.

High CAR was inversely associated with MH (crude odds ratio [OR], 0.48 [95% CI, 0.23-0.97]). This inverse association was no longer evident after adjustment for age, sex, body mass index, prednisolone use, antitumor necrosis factor α monoclonal antibody preparation, disease extent (proctitis/nonproctitis), and disease duration.

The study authors found a positive association between CAR and moderate to severe endoscopic activity (MES 2 or 3) (crude OR, 2.39 [95% CI, 1.31-4.43]). This association remained significant after adjustment (adjusted OR, 2.18 [95% CI, 1.11-4.35]; P for trend =.023).

High CAR was positively associated with moderate to severe endoscopic activity (crude OR, 2.41 [95% CI, 1.08-5.51] in the short-duration group (≤7 years). After adjustment, the association completely disappeared. In the long-duration group (>7 years), high CAR was independently associated with moderate to severe endoscopic activity, including after adjustment (adjusted OR, 2.95 [95% CI, 1.06- 8.79]; P for trend =.032). CAR was not associated with clinical remission or MH regardless of disease duration.

The researchers noted that their results are limited by the cross-sectional design, and many patients were receiving long-term treatment and had high clinical remission. Additionally, calprotectin data and other clinical scores, including the Clinical Activity Index, were unavailable, and selection bias may have affected the findings.

“In clinical settings, CAR can be used as a marker of disease activity but should not be used as a marker of remission, including MH, in patients with long UC duration,” study authors concluded.


Furukawa S, Yagi S, Shiraishi K, et al. Effect of disease duration on the association between C-reactive protein-albumin ratio and endoscopic activity in ulcerative colitis. BMC Gastroenterol. 2022;22(1):39. doi: 10.1186/s12876-022-02113-3