Symptoms of Constipation: Relationship Between Questionnaires and Diaries and Impact on Quality of Life.

Background & aims: Widely used to identify constipation in clinical trials and epidemiologic studies, bowel questionnaires have not been adequately validated vs the gold standard approach, diaries. Constipation is associated with poor quality-of-life (QoL). However, the contribution of individual symptoms to QoL is unknown.

Methods: Bowel symptoms (questionnaires and 2-week bowel diaries), somatic symptom scores (range, 0-4), and bowel symptom-related QoL were evaluated in healthy women and women with constipation in the community and clinic.

Results: The bowel variables were significantly correlated and not significantly different between the first and second weeks of the diary. Agreement between bowel symptoms assessed with questionnaires and diaries was significant (P < .001) but varied among symptoms. Of 73 participants who reported 0 to 2 stools/week on questionnaires, 63 (86%) recorded more frequent stools in a diary. Among participants with frequent (≥25% of the time) hard stools, straining, and incomplete evacuation on a questionnaire, respectively 32%, 49%, and 23% recorded these symptoms less frequently in a diary. Only 116 of 222 participants (52%) satisfied constipation criteria by questionnaires and diaries; the remainder satisfied either questionnaire or diary criteria. Stool form, excessive straining, incomplete evacuation, and somatic symptoms were independently associated with poor QoL. Each unit increase in the somatic symptom score was associated with an increased odds of poor QoL (odds ratio, 5.31; 95% confidence interval, 4.54-6.08).

Conclusions: Disparities exist between bowel symptoms recorded with questionnaires and diaries. Bowel diaries characterize constipation symptoms in a refined manner; only 52% of participants satisfied constipation symptom criteria on both instruments. Somatic symptoms overshadow the contribution of bowel symptoms to QoL.