Validity and reliability of the Modified Manchester Health Questionnaire in assessing patients with fecal incontinence

Abstract

Purpose: To date, no measures of fecal incontinence severity or its impact on quality of life have been validated for telephone interview. This study was designed to 1) compare responses of a self-administered and a telephone-administered Fecal Incontinence Severity Index; 2) compare a self-administered Fecal Incontinence Quality of Life Scale to the Manchester Health Questionnaire after modifying the latter for telephone administration and American English (Modified Manchester Health Questionnaire); 3) assess test-retest reliability of the telephone-administered Modified Manchester Health Questionnaire; and 4) assess the internal consistency of the Modified Manchester Health Questionnaire subscales.

Methods: Consecutive, English-speaking, nonpregnant females known to have fecal incontinence were invited to participate. Two validated paper questionnaires accompanied the letter informing them of the study: Fecal Incontinence Severity Index and Fecal Incontinence Quality of Life Scale. Consenting patients were contacted for the initial telephone administration of the Modified Manchester Health Questionnaire, and patients who agreed to continue the study were contacted for a repeat telephone administration of the Modified Manchester Health Questionnaire two to four weeks after completing the first interview.

Results: Fifty-one females were invited to participate in the study; however, 13 declined or were ineligible. Thirty females, aged 49.3 +/- 10.3 years, returned self-administered questionnaires and completed the first telephone interview, and 21 completed a second telephone interview after an average interval of 23 days. The telephone-administered Fecal Incontinence Severity Index scores were significantly lower than those yielded by the self-administered Fecal Incontinence Severity Index, (6.19 vs. 9.85; P < 0.001), but the telephone and written administrations were significantly correlated (r = 0.5; P < 0.02). Correlations between the Modified Manchester Health Questionnaire quality of life subscales and the paper Fecal Incontinence Quality of Life subscales ranged from 0.6 to 0.9 (median, r = 0.81). The correlation between the total score for the Fecal Incontinence Quality of Life and the total score for the Modified Manchester Health Questionnaire quality of life scales was 0.93 (P < 0.001). Test-retest reliability for the eight Modified Manchester Health Questionnaire subscales ranged from 0.55 to 0.98 (median, r = 0.83), and test-retest reliability for the two telephone administrations of the Fecal Incontinence Severity Index was r = 0.75. Cronbach's alpha for the eight Modified Manchester Health Questionnaire subscales ranged from 0.79 to 0.92 (median, alpha = 0.85).

Conclusions: Telephone-administered versions of the Modified Manchester Health Questionnaire showed good-to-excellent validity, internal consistency, and test-retest reliability. The telephone-administered Fecal Incontinence Severity Index yielded lower severity scores than the written Fecal Incontinence Severity Index; however, the difference (3.66 units) was not clinically significant.