P578. C-reactive protein levels at first month of adalimumab treatment as predictive of nonresponse in Crohn's disease patients
E. Rodrigues-Pinto1, F. Magro1, F. Vilas-Boas1, J. Santos-Antunes1, A. Nunes1, S. Lopes1, C. Dias2, G. Macedo1, 1Centro Hospitalar São João, Faculdade Medicina Universidade Porto, Gastroenterology department, Porto, Portugal, 2Faculdade Medicina Universidade Porto, Health Decision and Information Science Department, Porto, Portugal
Adalimumab (ADA) is effective in treating Crohn's disease (CD) and C-reactive protein (CRP) is a useful biomarker in assessing inflammatory activity. Our aim is to correlate CRP levels and CRP variations during the first year of treatment with ADA in patients who started it due to luminal disease.
Cross sectional study of CD patients who started treatment with ADA due to luminal disease (patients with perianal disease or post-operative recurrence as an indication for treatment were excluded). Seventy-three patients with CD were evaluated (6.5 CRP measurements per patient). Primary nonresponse (PNR) was defined as no symptomatic improvement and CRP persistently elevated; sustained response (SR) as symptomatic improvement for at least 1 year without therapeutic adjustment; response after therapeutic adjustment (RTA) as analytic and clinical response but requiring IFX dose/frequency adjustment or association with another drug.
Non-stenosing and non-penetrating behaviour was statistically significant associated with sustained response (p = 0.044). Previous Infliximab treatment did not influence CRP response (p = 0.230), as well, as previous surgery (p = 0.095), however, there was a tendency towards SR when no surgery was performed. Baseline CRP levels were higher in PNR compared with SR (32 mg/L vs 21.4 mg/L) and RTA (32 mg/L vs 26.5 mg/L), however no significance was reached (p = 0.076). CRP levels were statistically significant at 1st, 4th, 5th, 6th, 11th and 12th month, being significantly higher in PNR compared to SR and RTA, however no differences were found between SR and RTA. During first year of treatment, CRP levels were in median 30.23 mg/L higher in PNR regarding SR ([11.204;49.251], p = 0.002) and 24.55 mg/L regarding RTA ([4.766;44.338], p = 0.015). CRP levels were 5.67 mg/L lower in SR regarding RTA, but no significance was found ([−12.13; 0.78], p = 0.085). In all groups there was a median 0.015 CRP decrease, measurement to measurement ([−0.767; 0.738], p = 0.969), but not statistically significant.
CRP levels correlate with the pattern of response to ADA in CD. High inflammatory burden during ADA treatment is correlated with a worse response. First month is an important timepoint in evaluating who won't response to ADA.