“…Studies were mainly from the United States (n¼33) [10,, with other studies from Australia [54][55][56], Belgium [57], Brazil [58], Canada [59], Chile [60], England [61], Denmark [9,[62][63][64][65][66][67], Germany [68,69], India [70], Iran [71,72], Israel [73], Norway [74], Portugal [75], Spain [76], The Netherlands [77], and/or from multiple countries (France, Germany, Italy, Spain, the UK) [78]. Four studies were from middle-income countries [58,[70][71][72], and no studies were from low-income countries. Approximately half the studies (n¼31) were of specific chronic noncancer pain subpopulations, most commonly low back pain [10,25,28,31,32,35,38,46,48], followed by fibromyalgia [40,43,44,51,53,68], osteoarthritis…”