[Burden of diverticular disease: an observational analysis based on Italian real-world data.]

Diverticular disease (DD) represent a wide variety of conditions associated with the presence of diverticula in the colon. The most serious form is an acute episode of diverticulitis which can lead to hospitalization and surgery with various types of consequences. The main aim of this study was to evaluate, from both cross-sectional and longitudinal perspective, the economic burden of diverticulitis in the real practice.

A deterministic linkage was performed at individual user level between the different administrative sources of the Marche Region through anonymised ID number for a period of analysis between 1 January 2008 and 31 December 2014. We enrolled all patients with at least one hospitalization for "diverticulitis of the colon without mention of haemorrhage" (ICD-9-CM code 562.11) or "diverticulitis of the colon with haemorrhage" (ICD-9-CM code 562.13) as primary or secondary diagnosis. Cost and outcome were analysed considering transversally (for contemporaneous) and longitudinal (for cohort) perspective. Hospital mortality at one year after discharge was evaluated by mortality rates and Kaplan-Meier curve considering the surgery performed (or not performed) during the index hospitalization.

Considering the cross-sectional perspective, 427 patients per year were estimated (about 35 patients per 100,000 adult residents) with an average number of hospitalization equal to 1.14. The direct healthcare costs incurred by the Marche region for episodes of diverticulitis in 2008-2014 amounted to approximately € 11.4 million (€ 1.6 million a year), of which € 10.9 million (95.5%) for the hospitalizations, € 246,000 (2.1%) for pharmaceutical treatment and € 270,000 (2.4%) for specialist outpatient services. The cohort analysis estimates an intra-hospital mortality rate equal to 5.9 per 100 patients' year (5.5 for non-surgery patients and 8.9 for surgery patients - P<0.05). Kaplan-Meier curve demonstrate that there were no differences between intra-hospital mortality due to surgery during index hospitalization.

Our study is the first analysis in Italy to use real-world data to measure the burden of DD with a cross-sectional and longitudinal perspective. This study could be useful for decision maker that could quantify the economic and epidemiological burden of DD in hospital.