Opioid response in paediatric cancer patients and the Val158Met polymorphism of the human catechol-O-methyltransferase (COMT) gene: an Italian study on 87 cancer children and a systematic review

Table 4 Characteristics of five studies (nine papers) investigating the association between COMT gene and opioid response and/or side effects included in the systematic review

Study name, [ref]	Study design	Patients characteristics	Opioid administered	Data			M/F	Mean Age (years)
Study name, [ref]	Study design	Patients characteristics	Opioid administered	Opioid dose	Pain	Side effects	M/F	Mean Age (years)
EPOS study	European observational study	Cancer pain patients	Morphine, methadone, fentanyl, hydromprphone, buprenorphine, ketobemidone, oxycodone
[18] (Klepstad, 2011)		2201 Caucasians		X			1154/1047	62.4
[19] (Barratt, 2014)^a		667 subjects treated with transdermal fentanyl					334/342	Median: 64
[20] (Barratt, 2015)^b		468 Caucasian subjects treated with transdermal fentanyl			X	X	218/250	Median: 64
[21] (Laugsand, 2011)		1579 subjects not receiving chemotherapy and with information on nausea and vomiting				X	850/729	61.9
[22] Matsuoka, 2012	Japanese observational study	48 Opioid-treatment-naïve cancer patients	Morphine	X			25/23	69.0
[23, 24] Rakvåg, 2005–2008	Norwegian observational study	207 Cancer pain Caucasian patients	Morphine	X	X	X	117/90	63.2
[28] Ross, 2008	United Kingdom case-control study	228 Cancer pain patients	Morphine, Oxycodone, fentanyl, methadone		X	X	106/122	57.2
[26] Chatti, 2016	Tunisian observational study	129 Cancer pain patients	Morphine	X			63/66	Number of patients for each age group: 17-25 yrs.: 12 26-45 yrs.: 50 46-65 yrs.: 67

^aBarratt, 2014 [19] was a subgroup analysis of Klepstad, 2011 [18] (i.e. 676 subjects treated with transdermal fentanyl)
^bBarratt, 2015 [20] was a subgroup analysis of Barratt, 2014 [19] (i.e. 468 Caucasian subjects treated only with transdermal fentanyl)

ISSN: 1471-2407