Chronic constipation is a common disorder. Estimates of its prevalence, however, vary widely according to the method used for diagnosis. In a study reported in the March 2004 issue of the American Journal of Epidemiology, Vicente Garrigues, MD, and colleagues examined the prevalence of chronic constipation and evaluated the correlation between the Rome symptom criteria and self-reported definitions of the disorder. A questionnaire comprising 21 items was mailed to a random sample of 489 Spanish adults (349 of whom responded).
Results showed that the prevalence of constipation was 29.5% according to self-reported definitions, compared with 19.2% and 14.0% according to Rome I and Rome II symptom criteria, respectively. Agreement was good between self-reported definitions and Rome I symptom criteria (kappa = .68) and between Rome I and Rome II symptom criteria (kappa = .71); agreement was moderate between self-reported definitions and Rome II symptom criteria (kappa = .55). The presence of anal blockage, straining, and hard stools was correlated with higher constipation likelihood ratios. The authors conclude that the level of agreement between different diagnostic criteria is acceptable despite varying prevalence estimates obtained with each method.