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* = Presenting author

P391 Gender differences in adalimumab continuation rates: Results of a Crohn’s disease cohort

M. Lie*, J. Kreijne, J. van der Woude

Erasmus MC, Gastroenterology and Hepatology, Rotterdam, Netherlands

Background

Adalimumab (ADA), a humanised antibody against tumour necrosis factor alpha, is an effective treatment for Crohn’s disease (CD). Though ADA is widely used, long-term outcomes in clinical practice have been scarcely reported. As such, the aim of this study was to assess the long-term outcomes of ADA treatment in a prospective clinical cohort of CD patients.

Methods

A clinical cohort was formed of all CD patients starting ADA in a single tertiary Centre. Patients started ADA (160/80/40 mg every other week) between March 2006 and February 2011 and were followed-up to August 2015. Clinical outcomes were subdivided into primary non-response (ADA ceased within 6 months because of lack of effect), secondary non-response (ADA ceased after 6 months because of loss of effect), and treatment success (ongoing ADA usage). For patients stopping ADA, the reason was recorded. Ongoing ADA treatment was assessed using Kaplan–Meier analysis. Cox regression was used to assess factors affecting treatment outcomes.

Results

The cohort consisted of 188 patients, of which 107 (56.9%) were females. Follow-up duration was a median of 6.0 years (range 0.3–9.2). Primary non-response occurred in 13 patients (6.9%), and secondary non-response in 39 (20.7%).

In total, 49 patients (26.6%) of patients stopped ADA therapy because of intolerance, and 13 (6.9%) for other reasons (including 2 pregnancies). ADA treatment was ongoing in 82 patients (56.9%, including re-treated patients) at the end of follow-up.

Several gender differences were observed. Female patients report more side effects (81.3% vs 65.4%, Chi-squared p = 0.013) and stopped ADA more often because of side effects than male patients (35.4% vs 18.4%, Chi-squared p = 0.017) did, but no significant differences were seen regarding non-response.

In survival analysis (Figure 1), ADA-continuation rates were higher in male patients than in female patients (log rank, p = 0.006). In a multivariate Cox model, male gender (beta = 0.591, p = 0.020) and lower CDAI at start (beta = 0.003, p = 0.003) predicted longer ADA continuation (Table 1).

Figure 1. Kaplan–Meier survival curve, regarding ongoing adalimumab therapy.

Solid line represents females; dotted line males. The difference in curves is statistically significant (log-rank p = 0.006).

Table 1. Univariable and multivariable Cox proportional hazard analysis of patient factors influencing ADA co

VariableUnivariable (beta)Univariable (p-value)Multivariable (beta)Multivariable (p-value)
Gender0.5330.0070.5910.020
BMI*-0.0040.827
Age at start-0.0090.231
Active smoker-0.0390.853
CRP at start*0.0050.412
CDAI at start*0.004< 0.0010.0030.003
Previous anti-TNF-0.3160.101
Perianal disease0.0450.817
Immunomodulator use-0.0140.944

Conclusion

ADA treatment in CD patients has good long-term outcomes. Female patients report more side effects, and stop ADA more often because of side effects and, overall, are treated for shorter durations compared with male patients. In a Cox model, male gender and lower CDAI at start were predictive of continued ADA treatment.