OBJECTIVES:  Biologic therapies used to treat Crohn’s disease (CD) may lose their effect over time, requiring dose escalation. Practitioners and decision makers need such information, which is presently scarce. We summarized published rates of dose escalation in observational studies of CD in adults treated in the United Kingdom. METHODS:  Two independent reviewers searched Medline, Embase and proceedings from four major gastroenterology meetings from 1990-2015, hand searching references and relevant UK sites. We accepted full peer-reviewed articles, peer-reviewed abstracts of oral/poster presentations at scientific congresses, or audits. No restrictions were placed on publication date or language. Patients could be treated with any biologic with or without adjunctive therapy for any duration. Required data included number of patients treated, drug(s) used, treatment regimens, numbers or rates requiring dose escalation and proportions receiving co-medications. Data were tabulated and summarized descriptively. RESULTS: Thirteen publications were accepted for analysis, including ten full peer-reviewed articles, two poster abstracts and one audit. A total of 5,358 patients from across the UK were treated, mainly in referral centres; 51% were females and 49% males. Average age was 34.2 years; duration of CD was 6.4 years. Five publications (38%) reported on adalimumab, 3 (23%) on infliximab and 5 (38%) combined both drugs. No observational studies from the UK were found that examined vedolizumab. 73% of the patients analysed received therapy as first line biologic treatment, 15% second line and 12% did not report prior exposure. The overall rate of dose escalation was 12%; 19% in those treated with adalimumab and 8% with infliximab, after an average of 8.4 months. Doses were escalated in 7% of those receiving first line treatment (adalimumab 8%, infliximab 7%), and 22% for second line (all adalimumab); 59% of patients were administered co-medications. CONCLUSIONS: An appreciable proportion requires dose escalation, which increases by treatment line.