Time to clinical response and remission for therapeutics in inflammatory bowel diseases: What should the clinician expect, what should patients be told?

Table 3 Factors affecting time to response and response rates of therapies in inflammatory bowel disease

Variable	Parameter	Effect on time to response	Effect on response rate	Medications implicated	Level of evidence1	Ref.
Age	> 65 yr	↑	?	Anti-tumour necrosis factor-α (anti-TNF)	2b	Lobatón et al[143]
Increased body mass index	BMI > 25	-	↓	Azathioprine	2b	Holtmann et al[153]
	Weight > 82 kg	-	↓	Anti-TNF	1b	Reinisch et al[59]
Concomitant therapies		↓	↑	Immunomodulators with anti-TNF	1b	Colombel et al[50]
						Sandborn et al[69]
Smoking status	Current smoker	↑	↓	Anti-TNF	1b, 2b	Arnott et al[154]
						Sandborn et al[69]
Disease duration	> 2 yr	-	↓	Anti-TNF	1b	Colombel et al[155]
						Schreiber et al[156]
						D'Haens et al[157]

¹As per the Oxford level of evidence scoring; The available literature suggests a slower initial response but comparable long-term response rate; The use of “-“ denotes an absence of published data addressing this issue.