title: Genetic polymorphisms and their association with the prevalence and severity of chronic postsurgical pain: a systematic review.
abstract: BACKGROUND
  Although several patient characteristic, clinical, and psychological risk factors for chronic postsurgical pain (CPSP) have been identified, genetic variants including single nucleotide polymorphisms have also become of interest as potential risk factors for the development of CPSP. The aim of this review is to summarize the current evidence on genetic polymorphisms associated with the prevalence and severity of CPSP in adult patients.
  
  
  METHODS
  A systematic review of the literature was performed, and additional literature was obtained by reference tracking. The primary outcome was CPSP, defined as pain at least 2 months after the surgery. Studies performed exclusively in animals were excluded.
  
  
  RESULTS
  Out of the 1001 identified studies, 14 studies were selected for inclusion. These studies described 5269 participants in 17 cohorts. A meta-analysis was not possible because of heterogeneity of data and data analysis. Associations with the prevalence or severity of CPSP were reported for genetic variants in the COMT gene, OPRM1, potassium channel genes, GCH1, CACNG, CHRNA6, P2X7R, cytokine-associated genes, human leucocyte antigens, DRD2, and ATXN1 CONCLUSIONS: Research on the topic of genetic variants associated with CPSP is still in its initial phase. Hypothesis-free, genome-wide association studies on large cohorts are needed in this field. In addition, future studies may also integrate genetic risk factors and patient characteristic, clinical, and psychological predictors for CPSP.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands d.hoofwijk@mumc.nl.
authors.forename: D M N
authors.initials: DM
authors.lastname: Hoofwijk
authors.affiliation: School for Mental Health and Neuroscience (MHeNs), Faculty of Health, Medicine and Life Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: R R I
authors.initials: RR
authors.lastname: van Reij
authors.affiliation: School for Mental Health and Neuroscience (MHeNs), Faculty of Health, Medicine and Life Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: B P
authors.initials: BP
authors.lastname: Rutten
authors.affiliation: School for Mental Health and Neuroscience (MHeNs), Faculty of Health, Medicine and Life Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Kenis
authors.affiliation: Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands.
authors.forename: W F
authors.initials: WF
authors.lastname: Buhre
authors.affiliation: Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands.|School for Mental Health and Neuroscience (MHeNs), Faculty of Health, Medicine and Life Sciences, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: E A
authors.initials: EA
authors.lastname: Joosten
mesh_terms: D059350:Chronic Pain / Q000453:epidemiology* / Q000503:physiopathology*; D006801:Humans; D010149:Postoperative Pain / Q000453:epidemiology* / Q000503:physiopathology*; D011110:Polymorphism, Genetic / Q000502:physiology*; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: chronic pain; pain; polymorphism, genetic; postoperative