title: Anaesthetists' risk assessment of placebo nerve block studies using the SHAM (Serious Harm and Morbidity) scale.
abstract: The SHAM (Serious Harm and Morbidity) scale was developed to categorise the severity of potential complications of placebo control interventions in the context of local anaesthesia research. A convenience sample of 43 anaesthetists used the SHAM scale to grade ten published randomised controlled trials investigating local anaesthesia nerve blocks. The Fleiss κ statistic assessed agreement between these anaesthetists and probability of random agreement (Pr(e)) when using the SHAM scale; a κ > 0 shows concordance between assessors above random agreement. Overall κ was 0.50 (95% CI 0.49-0.51, p < 0.001), Pr(e) = 0.21. There was moderate agreement between assessors in determining whether studies were low-risk (SHAM score 0-2) or high-risk (SHAM score 3-4) (κ 0.60 (95% CI 0.58-0.62), Pr(e) = 0.51). Compared with anaesthetists given clinical examples of interventions when applying the SHAM score, anaesthetists who were not given examples showed significantly less inter-individual agreement (κ 0.76 (95% CI 0.72-0.81), Pr(e) = 0.5 vs 0.45 (95% CI 0.41-0.49), Pr(e) = 0.52, p < 0.0001). These results suggest that the SHAM score can be successfully used to grade the severity of potential complications of placebo-controlled interventions in local anaesthesia research and represent a first step towards the score's validation.
authors.affiliation: Department of Children's Anaesthesia, Women's and Children's Hospital, North Adelaide, South Australia, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Jarman
authors.forename: N
authors.initials: N
authors.lastname: Marks
authors.forename: C J
authors.initials: CJ
authors.lastname: Fahy
authors.forename: D
authors.initials: D
authors.lastname: Costi
authors.forename: A M
authors.initials: AM
authors.lastname: Cyna
mesh_terms: D000328:Adult; D000368:Aged; D000772:Anesthesia, Local; D000776:Anesthesiology; D001315:Australia; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000009:adverse effects* / Q000379:methods*; D015588:Observer Variation; D010919:Placebos / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D018570:Risk Assessment; D012720:Severity of Illness Index
chemical_list: D010919:Placebos