[Nocturnal enuresis. A frequent problem with a difficult estimation of its prevalence]. / La enuresis nocturna. Un trastorno frecuente con una prevalencia difícil de estimar.

INTRODUCTION: Nocturnal enuresis is a disorder with a maintained historical interest. Not only the multifactorial etiopathology, also its prevalence. OBJECTIVE: We consider reviewing the literature for knowing the problematic in the calculation of the prevalence of this disease. MATERIAL AND METHOD: We searched in Pubmed database with Mesh terms: "Enuresis", "Nocturnal Enuresis", we added in the search box terms bedwetting and epidemiology or prevalence. We included manuscripts in English and Spanish with more than 1000 patients as sample, we also included review papers. We analyzed the methodology and the prevalence, when it was possible, we stratified results in age, sex and the frequency of wet nights. RESULTS: The analyzed study's methodology is heterogeneous. Therefore comparisons are difficult. Due to the difficulty within the interpretation of the overall frequency, the results are not interesting unless methodology, age range of the sample and diagnosis criteria are previously detailed. CONCLUSIONS: An own epidemiology study is necessary in order to solve our problematic.