The treatment for functional constipation (FC) generally relies on the classification by clinical symptoms, but whether the classification by clinical symptoms is consistent with that by colorectal and anal function examinations still remains unclear.

To examine the consistency between FC classification by clinical symptoms and colorectal and anal functional examinations.

Forty FC outpatients and inpatients completing colorectal and anal functional examinations in Department of Gastroenterology, Hebei General Hospital from January 2018 to August 2021 were enrolled in this retrospective study. Symptoms were acquired for classifying FC by use of a questionnaire survey, including the frequency of spontaneous defecation per week, shape and type of stool assessed using the Bristol Stool Scale, difficulty in defecation, sense of anorectal blockage during defecation, requirement for manual assistance in defecation, and the frequency and degree of feeling of incomplete evacuation. And the results detected by examinations, including anorectal manometry (ARM) , defecography and gastrointestinal transit time (GITT) were also used for FC classification. The consistency of FC classification by symptoms and the three examinations was assessed.

The FC classification by symptoms was as follows: slow transit constipation (STC) 〔27.5% (11/40) 〕, defecation disorder constipation〔20.0% (8/40) 〕, mixed constipation〔37.5% (15/40) 〕, and normal-transit constipation (NTC) 〔15.0% (6/40) 〕. FC classified by ARM included defecation disorder constipation〔80.0% (32/40) 〕and NTC〔20.0% (8/40) 〕, and by defecography also only included defecation disorder constipation〔67.5% (27/40) 〕 and NTC 〔32.5% (13/40) 〕. By GITT, FC classification contained three types: STC〔20.0% (8/40) 〕, defecation disorder constipation 〔15.0% (6/40) 〕, and NTC〔65.0% (26/40) 〕. The weighted Kappa test indicated that the FC classification by symptoms was not consistent with that by ARM, defecography or GITT (Kappa=-0.123, P=0.502; Kappa=-0.040, P=0.794; Kappa=-0.140, P=0.215) , and there was no overall consistency between FC classification by symptoms and the three examinations (Kappa=-0.005, P=0.944) .

Mixed constipation was the major type of FC classified by symptoms, while defecation disorder constipation was the major type of FC classified by the three examinations. As there are differences between clinical symptom classification and examination classification, FC should be diagnosed based on both clinical symptoms and examination results, accompanied with the individualized analysis.