Key points are not available for this paper at this time.
Diverticula occur as a result of mucosa and submucosa herniation through the muscular layer of the colonic wall. Diverticulosis refers to the presence of one or more diverticula, and the disease has a clinical spectrum from asymptomatic to symptomatic disease with potentially lethal complications (Figure 1). Diverticula may be distributed throughout the colon but are most frequently located in the sigmoid colon, i. e. the distal loop of the colon approximately 20–60 cm from the anal verge. Endoscopic and radiological aspects of colonic diverticulosis. Symptomatic diverticular disease may include patients with chronic abdominal pain and diverticulosis, without evident infection or inflammation. The most common and significant complications include both diverticular bleeding and diverticulitis, the latter being responsible for the occurrence of peritonitis, fistulae and abscesses. It may also be responsible for colonic strictures. Although colonic diverticulosis is a very frequent condition, complications occur in a limited subset of patients. Diverticular disease is commonly found in developed countries, slightly more frequently in the USA than in Europe, and is a rare condition in Africa (Table 1). The prevalence is largely age-dependent and is uncommon (a prevalence of 5%) in those under the age of 40 years, increasing up to 65% in those aged 65 years or more. 1, 2 In a French study published in 1986 that was based on barium enemas, the prevalence of colonic diverticulosis increased regularly with age, and progression appeared to be more rapid after the age of 60 years, although it must be pointed out that the number of patients in these older age groups was larger than in younger groups (Figure 2). 2 Progression of colonic diverticulosis prevalence according to age. The true prevalence of diverticulosis is difficult to define as most individuals are asymptomatic. Necropsy series may overestimate the frequency of diverticula as they are performed in older age groups. Barium radiological studies and more recently, endoscopic series could also overestimate their frequency, as included subjects may have been referred because of gastrointestinal symptoms. Studies performed in western European countries are shown in Table 2. Prevalence appears to be quite homogenous throughout Europe, without a geographical gradient. Discrepancies between the studies reviewed here are mainly explained by differences in methodology and sampling size. They all concur that increasing age and European nationality are associated with increasing prevalence. Moreover, some indication is available that the prevalence of colonic diverticulosis is increasing over time throughout the world. The earliest autopsy and barium enema series date from the 1920s to 1940s, and report rates of 0. 6–15%, while more recent studies describe a rate of up to 40–60% in those over the age of 70 years. Whether this is due to increased numbers of older individuals in the population, increased screening or a true rise in the prevalence is not known. 11–13 Although diverticulosis increases with age, there seems to be no clear progression of the extent of colon affected or acceleration from asymptomatic to symptomatic disease over time. In a radiological study, Horner did not show any progression of the disease over a 4–5-year interval in 183 patients. 16 Furthermore, uncomplicated diverticular disease is not associated with any specific symptoms and may coexist with undiagnosed functional bowel disorders. 17 Few studies have evaluated the progression from uncomplicated to complicated diverticular disease. Lower gastrointestinal bleeding (occurring in about 5–15% of patients with colonic diverticula) and infection, resulting in abcesses, peritonitis and perforation, (occurring in about 15–20%), are the most frequent complications. Complications tend to appear more frequently in elderly patients, and represent a large portion of those admitted for diverticular disease. In an American survey, the rate of admissions correlated with increasing age, from 238/100 000 in patients aged 65–69 years to 631/100 000 for those aged > 85 years. 18 In a recently published British study, the yearly incidence of perforation of colonic diverticula was 4/100 000, with a slightly higher rate in men than in women. 19 The use of nonsteroidal anti-inflammatory drugs was frequently associated with the occurrence of a perforation. The outcomes in patients admitted for a complication of colonic diverticular disease has been examined in a British study; 76. 3% had diverticulitis and 13. 3% had lower gastrointestinal bleeding. 20 The overall mortality rate was 11. 3%, and 90% of bleeding cases and 75% of infectious complications were treated nonoperatively. Five-year follow-up on approximately half of the surviving patients revealed that 1% died from recurrent diverticular disease and one-third remained symptomatic. 21 In another British study, 31. 7% of patients admitted with complicated diverticular disease required surgery, with a post-operative mortality rate of 12%. 22 In a series of 296 consecutive patients admitted with diverticulitis documented with computed tomography, 29% were operated on during their first episode and recurrence occurred in 20% during a 5-year follow-up. 23 Diverticular disease has been increasingly recognized as a clinical entity over the last century and, as the population ages, it appears to be increasing in both asymptomatic and symptomatic presentations. Europe, like other industrialized areas in the world, is characterized by a high prevalence of the disease, which increases with age and represents a significant risk to health with subsequent indications for healthcare expenditure in the elderly population. No statistics are currently available on the clinical and financial burden of the condition in European countries. However, referring to a mathematical model used in the 1980s in the USA, where the prevalence of the disease is similar to Europe, it is possible to compile the available epidemiological data and calculate the possible burden of diverticular diseases in Europe (Table 3). 24 In the US survey published in 1980, diverticulosis affected 30 million Americans, annually bringing 200 000 to the hospital and incurring healthcare costs of US300 million per annum. The differences in healthcare systems across European countries preclude such an estimate for the European Union as a whole. Nevertheless, the impressive figures in Table 3 demonstrate that diverticular disease is the source of significant healthcare costs because its complications occur more frequently in elderly patients, and that it deserves a higher priority than it has received to date. Epidemiological studies and the geographical distribution of the disease both suggest that a high fibre intake could play a protective role. In a study comparing a group of vegetarians and controls, fibre intake was double in vegetarians (41. 5 ± 12. 6 g/day) than in controls (21. 4 ± 8. 2 g/day). The prevalence of diverticulosis was significantly lower in vegetarians (12%) than in controls (33%). 25 In a prospective cohort study of 43 881 American male health professionals, the intake of the insoluble component of fibre was significantly correlated with a decreased risk of symptomatic diverticular disease (relative risk 0. 63; confidence interval 0. 44–0. 9), and this inverse correlation was particularly strong for cellulose. 26 The question may thus be posed: may we not prevent diverticular disease with a high-fibre diet? There are many factors that interfere in epidemiological and nutritional studies, so that a high-bulk diet cannot be recommended for everyone. Moreover, as shown by the study in US professionals, the type of fibre is of importance. However, in symptomatic uncomplicated diverticular disease, several studies demonstrated that a high-fibre diet is beneficial. Furthermore, a British study suggests that among those who already have diverticula, complications and recurrences of diverticulitis are reduced on such a diet. 27 It does seem reasonable therefore to recommend a high-fibre diet to those who have symptomatic uncomplicated diverticular disease or those who have suffered a complication in the past. Healthcare costs are higher in these groups of patients and justify the use of intervention. Diverticulosis is extremely prevalent across Europe. Symptomatic disease and complications associated with the condition increase with increasing age. The ageing population in the European Union may account for the apparent increase in prevalence observed in recent times. However, additional factors such as diet may be involved. As with most diseases, prevention is better than cure. There is evidence to show that increasing the proportion of insoluble fibre in diets may prevent disease development and its complications, which account for significant morbidity in European populations.
Michel Delvaux (Mon,) studied this question.