Analysis of the Epidemiological Trends on Inpatient Diverticulosis Admissions in the US: A Longitudinal Analysis From 1997-2018

Background Diverticulosis of the colon is characterized by outpouchings of mucosa and serosa through the muscular layer of the large intestinal wall. It is classically associated with increasing age with older individuals having a higher prevalence and greater density of diverticula secondary to its progressive disease nature. Also, diverticular disease is associated with dietary habits, low fiber intake in western society as well as obesity. The aim of this study was to investigate the epidemiological trends associated with diverticular disease in the United States in a 21-year interval from 1997 to 2018. Methods Using the Nationwide Inpatient Sample, all hospitalizations between 1997 and 2018 were analyzed. We examined annual data for hospitalization rate, the average length of stay (LOS), mean age and interval age groups, and hospital charges for inpatient admissions for diverticular disease (diverticulitis and diverticulosis). Results Between 1997 and 2018, the number of hospitalizations for patients with a primary discharge diagnosis of diverticular disease (diverticulosis and diverticulitis) increased 32% from 220,896 to 293,530 with 89.7 discharges per 100,000 persons in 2018 versus 81.0 discharges per 100,000 persons in 1997. Overall, the average age of patients decreased from 67.55 ± 0.15 years in 1997 to 64.59 ±0.08 in 2018, [t-value (t) 12.56, degrees of freedom (df) 514424, 95% confidence interval (CI) 2.497-3.423, P<0.0001]. On further evaluation, the mean average age in males decreased from 63.16±0.21 years in 1997 to 61.31±0.12 years in 2018, (t 8.16, df 217981, 95% CI 1.404-2.295 P<0.0001), while in females it decreased from 70.53±0.14 years to 67.15±0.10 years, (t 20.13, df 296422, 95% CI 3.050-3.709 P<0.0001), in the same interval time. While evaluating different subgroups of age in this time interval, the prevalence rate of diverticular disease diagnosis per 100,000 persons increased in the interval age between 18-44 years from 20.1 to 29.8, [relative risk (RR) 0.848, CI 95% 0.834-0.863, P< 0.0001) and 45-64 years from 107.1 to 125.3, (RR 0.761, CI 95% 0.754-0.769 P<0.0001) while it decreased in the interval age between 65-84 years from 357.6 to 259.7, (RR 1.211, CI 95% 1.206-1.226, P<0.0001) as well as > 85 years from 746.2 to 523.6, (RR 1.130, CI 95% 1.112-1.147, P<0.0001) The length of stay (LOS) mean average in days decreased from 5.8 ± 0.04 days in 1997 to 4.4±0.021 days in 2018, (t 33.08 df 514424, 95%CI 1.316-1.483, P< 0.0001). Hospital Inpatient National Statistics data over hospital mean charges, available from the period between 1997 to 2015, shows that the mean hospital charges in US dollars increased over 100%, from $19,735.17 in 1997 to $39,575 in 2015 (P<0.001) even after adjusting values to 2015 inflation. Conclusion There is an overall trend of decreased mean age of patients admitted with diverticular disease in the US over the past 21 years with a respective significant increased rate of disease in younger age groups. We postulate that these changes may be associated with poor dietary habits and obesity epidemics worsened in the last two decades in the US. In addition, despite the decreased length of stay over the same time period, the mean hospital charges more than double likely reflecting the increased access to expensive diagnostic methods such as computed tomography and colonoscopies.