Recently, the Obstructed Defecation Syndrome score (ODS score) was developed and validated by Renzi to assess clinical staging and to allow evaluation and comparison of the efficacy of treatment of this disorder.
Our goal is to validate the Portuguese version of Renzi ODS score, according to the Consensus based Standards for the selection of the Health Measurement Instruments (COSMIN) checklist.
Following guidelines for cross-cultural validity, Renzi ODS score was translated into the Portuguese language. Then, a group of patients and healthy controls were invited to fill in the Renzi ODS score at baseline, after 2 weeks and 3 months, respectively. We assessed internal consistency, reliability and measurement error, content and construct validity, responsiveness and interpretability.
A total of 113 individuals (77 patients; 36 healthy controls) completed the questionnaire. Seventy and 30 patients repeated the Renzi ODS score after 2 weeks and 3 months respectively. Factor analysis confirmed the unidimensionality of the scale. Cronbach’s α coefficient of 0.77 supported item’s homogeneity. Weighted quadratic kappa of 0.89 established test-retest reliability. The smallest detectable change at the individual level was 2.66 and at the group level was 0.30. Renzi ODS score and the total (-0.32) and physical (-0.43) SF-36 scores correlated negatively. Patient and control’s groups significantly differed (11 points). The change score of Renzi ODS score between baseline and 3 months correlated negatively with the clinical evolution (-0.86). ROC analysis showed minimal important change of 2.00 with AUC 0.97. Neither floor nor ceiling effects were observed.
This work validated the Portuguese version of Renzi ODS score. We can now use this reliable, responsive, and interpretable (at the group level) tool to evaluate Portuguese ODS patients.
Constipation, classification; Defecation; Psychometrics; Surveys and questionnaires