Intra- and inter-observer agreement in the classification of dyssynergic defecation on high-resolution anorectal manometry using water-perfusion system

Background and Aims Dyssynergic defecation (DD) classified on anorectal manometry is based on variations in anal sphincter pressures and rectal pressure generated during bearing down. There is a paucity of data on intra- and inter-observer agreement in the classification of DD on high-resolution anorectal manometry (HRAM) using a water-perfusion system. Methods This cross-sectional observational study was conducted between June 2014 and May 2016 on 70 adult patients with DD. Observer 1 did the baseline analysis and reanalyzed the readings at least 6 months later, blinded to the initial analysis results (intra-observer variability). Four other blinded observers (5–25 years in anorectal manometry and minimum 5 years of experience in HRAM) then individually analyzed the manometry data (inter-observer variability). Results Intra-observer agreement was excellent (kappa 0.862) for classifying DD. Agreement between the six observations (i.e. two from observer 1 and four from independent observers) was also good (kappa 0.632). The highest agreement was for type 4 DD (kappa 0.738), followed by type 1 (0.680), type 2 (0.664), and type 3 (0.537). Cronbach’s alpha value was 0.93, suggesting excellent internal consistency. Conclusion The diagnosis of the types of DD on anorectal manometry using a water-perfusion system has excellent intra-observer and good inter-observer agreement .