Prevalence of severe irritable bowel syndrome among Italian adults. A meta-analysis

OBJECTIVE: To provide a summary estimate of the prevalence of irritable bowel syndrome (IBS) and IBS with severe symptomatology, stratified by gender and subtype, among Italian adults. MATERIALS AND METHODS: We searched MedLine and Scopus databases to identify surveys on IBS prevalence among Italian samples, and/or severe IBS prevalence among Caucasian populations, up to June 2017. Random-effect proportion meta-analyses were used to obtain summary estimates of IBS prevalence. Raw numbers of adults with IBS or severe IBS were computed multiplying pooled prevalence estimates by the current Italian adult population. For both IBS and severe IBS, several estimates were provided according to different scenarios, using the pooled estimates from meta-analyses, their highest and lowest 95% confidence intervals (CI), and the lowest prevalence among all individual studies. RESULTS: The pooled prevalence of IBS among Italian adults, resulting from a meta-analysis of 5 studies including 40,654 subjects, was 7.7% (95% CI: 6.0%-9.7%). The lowest published estimate was 5.4%. The overall number of Italian adults with IBS may thus range between a minimum of 2,736,700 (1,797,800 females; 65.7%) and 4,915,800. From a meta-analysis of 17 studies including 16,873 subjects, the pooled proportion of severe IBS was 23.5% (95% CI: 18.7%-28.7%), with a lowest published estimate of 8.4%. The overall number of Italian adults with severe IBS may thus range between 229,900 (86,600 with constipation-predominant subtype; 70,600 diarrhea-predominant; 72,600 mixed/alternating) and 1,410,800. In a standard, still conservative scenario, based upon the lowest 95% CIs from meta-analyses, the Italians with severe IBS would be 511,800. CONCLUSIONS: Using an extremely conservative, lowest plausible estimate, no less than 230,000 Italian adults are suffering from severe IBS, requiring appropriate treatment and recognition by healthcare providers. A standardized instrument to measure IBS severity is urgently required to support diagnostic and therapeutic processes, and improve the precision of epidemiological estimates.