How Many People Really Have Chronic Constipation?

Chronic constipation is a common disorder. Estimatesof its prevalence, however, vary widelyaccording to the method used for diagnosis. In astudy reported in the March 2004 issue of the AmericanJournal of Epidemiology, Vicente Garrigues,MD, and colleagues examined the prevalence ofchronic constipation and evaluated the correlationbetween the Rome symptom criteria and self-reporteddefinitions of the disorder. A questionnaire comprising21 items was mailed to a random sample of489 Spanish adults (349 of whom responded).

Results showed that the prevalence of constipationwas 29.5% according to self-reported definitions,compared with 19.2% and 14.0% accordingto Rome I and Rome II symptom criteria, respectively.Agreement was good between self-reporteddefinitions and Rome I symptom criteria (kappa =.68) and between Rome I and Rome II symptom criteria(kappa = .71); agreement was moderatebetween self-reported definitions and Rome IIsymptom criteria (kappa = .55). The presence ofanal blockage, straining, and hard stools was correlatedwith higher constipation likelihood ratios. Theauthors conclude that the level of agreementbetween different diagnostic criteria is acceptabledespite varying prevalence estimates obtained witheach method.