Validity and reliability of the Constipation Assessment Scale

Constipation is a significant problem in patients receiving neurotoxic chemotherapeutic agents, narcotic analgesics, antidepressants, tranquilizers, and muscle relaxants. Increasingly, as acute care moves into the community, nurses will need valid and reliable methods of assessing constipation in individuals with cancer. The purpose of this project was to study the validity and reliability of the Constipation Assessment Scale, a new tool designed to assess the presence and severity of constipation. The sample consisted of two groups: a control group of 32 working adults and a patient group of 32 adults at risk for constipation because of treatment with Vinca alkaloids or morphine. Consenting subjects were asked to complete the eight-item Constipation Assessment Scale (CAS). A significant difference in intensity of symptoms between the two groups (t = 6.32, p less than 0.0001) demonstrates the ability of the CAS to differentiate between subjects with and without constipation and thus provides evidence of construct validity of the scale. Further analysis of scores of the two subgroups in the patient group (subjects receiving morphine vs. Vinca alkaloids) revealed a significant difference (t = 2.54, p less than 0.01) in symptom intensity. This latter finding supports the ability of the CAS to differentiate between moderate and severe symptom intensity. Subjects completed the CAS in approximately 2 min. To study the test-retest reliability of the scale, a group of 16 apparently healthy working adults were asked to fill out the CAS twice with a 1-h delay. The two sets of scores were correlated (r = 0.98).(ABSTRACT TRUNCATED AT 250 WORDS)