The test-retest reliability of fecal incontinence severity and quality-of-life assessment tools.

Background: The St. Mark's score and Cleveland Clinic score are widely used for assessing the severity of fecal incontinence, whereas the Rockwood quality of life scale is used to evaluate the impact on the quality of life of patients.

Objective: The aim of this study was to determine the intra- and interobserver reliability of these assessment tools.

Design: All patients were recruited prospectively. To assess intraobserver reliability each patient was asked to complete 4 assessments (the St. Mark's and Cleveland Clinic scores, the Rockwood scale, and a visual analog scale) at 2 time points: initially at recruitment (P1) and then 6 weeks later (P2). No alteration to medications or treatment occurred during this interval. For interobserver reliability, the St. Mark's and Cleveland Clinic scores were also completed by a physician (time point P1) and a nurse (time point P2).

Outcome Measures: Intra- and interobserver reliability were determined by using an intraclass correlation coefficient. An intraclass correlation coefficient value of less than 0.40 indicates poor reliability, values in the range 0.40 to 0.75 indicate fair to good reliability, and a value of greater than 0.75 shows excellent reliability.

Results: Thirty-nine patients (34 female) with a median age of 65 years were studied. The intraclass correlation coefficient for intraobserver reliability for the Cleveland Clinic score at time points P1 and P2 was 0.858 (95% CI, 0.611-0.940); and for St. Mark's score, the intraclass correlation coefficient was 0.823 (95% CI, 0.556-0.922). The intraclass correlation coefficients for the quality-of-life domains ranged between 0.864 and 0.938, whereas the intraclass correlation coefficient for the visual analog scale was 0.958 (95% CI, 0.906-0.982). The interobserver reliability ranged from 0.795 to 0.945 for the Cleveland Clinic score and from 0.793 to 0.939 for the St. Mark's score.

Limitations: Of the 39 patients recruited, only 31 patients completed the second assessment at time point P2. This increases the risk of nonresponse error in this study, which is a recognized limitation of mail-mode surveys.

Conclusion: Current assessment tools for the severity of fecal incontinence and its impact on quality of life have an excellent intra- and interobserver reliability and remain a good objective measure of patients' symptoms (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A135).