Nearly every review of diverticular disease (DD) and some research papers begin with statistics about how many people have DD at different ages. Figures regularly quoted for Western countries are 5% of the population by the age of 40, 25% by the age of 60 and 65% at 85 years. Variations are also described such as 50% of the population over 60 years, or 1/3 to 1/2 of the population will get the disease. In England and Wales this works out at over 5 million people which would rise with the aging population.
Trying to find the sources of these figures by following references to them in articles can lead round in circles, when authors refer to each other saying the same thing. However, following these trails often leads back to a Belfast researcher called T G Parks (1) in the late 1960s. He investigated the incidence of DD in persons coming to autopsy and found 10% in 25 to 40 year olds, 30% in 50 year olds and about 50% in those aged between 75 to 85 years. In 200 autopsies in Australia in 1969, Hughes (2) found diverticula in 9% of 31 – 50 years, 36% of those between 51 and 70 years and 56% in those of 71 years or above.
POST MORTEM NUMBERS
Post-mortems (autopsies) are requested by coroners when deaths are sudden or of unknown cause. Severe complications of DD could fall into this category. Treatment of DD by surgery falls off after the age of 65 (3) and mortality starts to rise (4). Once diverticula are acquired then they are permanent so that the number of people with them will accumulate with age. For example, figures for diverticula at age 80 years will include all those who acquired the disease far earlier in life. This must be considered in the interpretation of the results. Hughes (2) described the lack of correlation between symptoms in life and post-mortem findings. The elderly can have a low sensitivity to the disease symptoms which can result in treatment delays, late hospitalisation and the duration of symptoms which are strongly related to adverse outcome of DD severe complications (5). Autopsy figures are biased by sample number towards the elderly and may not accurately reflect the relationship between diverticula, age and symptoms and even less accurately the number of people who have diverticula in the general population.
COLON EXAMINATIONS
Another source of data is the number of people who are found to have DD in examinations by sigmoidoscopy, colonoscopy, CT scans or barium enema X-ray. Such investigations are usually in response to abdominal symptoms and particularly after the age of 50 when colorectal cancer might be the cause. If cancer is not found but DD is, it can hardly be said that DD was found incidentally and was not the cause of the symptoms. A study (6) of 50,000 US male health professionals perhaps give an indication of the proportion of those with symptoms. In a 4 year period 382 (76.4%) were diagnosed because of symptoms and 118 (23.6%) were without symptoms and discovered during routine health screening. Pain is a common symptom of DD but whether patients are taking analgesics for DD or another complaint is not always reported if they are ‘symptomless’ The prevalence of DD in such examination results does vary in different places, different times and in comparison with the levels of other colon diseases. The type of patients and the reason for the examinations influences the findings which may be useful for comparisons but not for predicting levels of DD in the general population. (See Table)
The National Bowel Cancer Screening Programme could detect DD if colonoscopies are needed to investigate the presence of blood in faeces samples. Computerised national databases might be another source of information in the future. In Coventry (7) a survey of patients being treated for rectal bleeding found 24% had diverticulosis. According to AstraZeneca researchers, (8) patients with unspecified abdominal pain were 16 to 27 times more likely than controls to get a new diagnosis of DD in the following year. This information was obtained from the UK General Practice Research Database. Perhaps in the future this database might be used to show the impact of DD on patients at primary care level.
Accurate statistics about DD are available from the hospital situation. For example in 10 years to 2004 at Kings College Hospital, admissions have risen by 370% and recurrent admissions by 400%. Increases were found in younger patients and in emergency admissions and these changes were not related to the size or age of the catchment population (9). The cost of DD is rising significantly.
THE USE OF DATA
The true prevalence of DD may never be known. There are differences in time and place and the disease itself is so variable between and within individuals in its manifestations. The different sources of data described above each have their limitations and bias. Even a survey of the general population would rely on the source and selection of healthy people who would volunteer for an internal examination. Some researchers who assessed the available data concluded that the prevalence of DD is unknown (10). Others have used the post mortem findings of Parks and Hughes to represent the general populations of the Western world. For example, one group of researchers, (11) excluded people with a known history of complicated DD from the aged-matched control group, then assumed that 65% of the group would have undiagnosed, asymptomatic DD.
It appears that accurate hospital data on the numbers being treated there are being compared with the old post-mortem data to represent the whole population and the difference between these is asymptomatic DD. As one gastroenterologist has explained “given that 2/3 of the population in the UK have diverticulosis by the age of 65 we can conclude that most are indeed asymptomatic or have very little symptoms since certainly 2/3 of the population do not consult gastroenterologists”. There are disabling symptoms before, after and irrespective of the complications of DD which get hospital attention. These are dealt with at primary care level where little data is available. This level is also a selective and variable gateway to seeing a hospital consultant and an area where NHS savings might be made (12). Many patients with diverticulosis, suffering from chronic abdominal pain, are labelled as having IBS (13) and are unlikely to be referred to a consultant. If the prevalence of DD is in doubt, then statements commonly made about the disease are unsubstantiated –
“most patients are asymptomatic”
“90% of DD is identified incidentally as it is frequently asymptomatic in nature”
“only between 10% and 25% of those affected develop symptoms”
Such views influence the approach to DD by health care professionals, pharmaceutical companies, committees awarding research grants or even government thinking on benefits.
Some researchers are not complacent about the increasing load on hospitals. The current methods of management of DD do not appear to be cost effective and there should be protocols for evidence-based, cost-effective management. More research should be done on prevention of complications and management in the community (14). Recurrent admissions are associated with symptomatic DD (15). The identification of risk factors for colon perforation would allow primary public health prevention, secondary risk factor modification, and early prophylactic surgery to be aimed at people at high risk (16)
Most patients would agree with the hospital accountants about more research on basic treatment and prevention of complications because it might also improve their quality of life (17, 18). Hopefully those who see the need for this research will not be discouraged by dubious statistics.
© M Griffiths 2008
REFERENCES
(1) Parks T G. Natural history of diverticular disease of the colon. Clinics in Gastroenterology. 1975 ,4, 53.
(2) Hughes L E. Postmortem survey of diverticular disease of the colon. 1. diverticulosis and diverticulitis. Gut, 1969, 10, 336.
(3) Rodkey G V. Diverticular disease: diverticulitis, bleeding and fistula. In Oxford Textbook of Surgery, Oxford University Press, 1994.
(4) Twentieth Century Mortality. CD Rom, Office for National Statistics, 2003.
(5) Pisanu A et al. Surgical treatment of perforated diverticular disease: evaluation of factors predicting prognosis in the elderly. Int Surg, 2004,89,35.
(6) Aldoori W H. et al. A prospective study of alcohol, smoking, caffeine, and the risk of symptomatic diverticular disease in men. Ann Epidemiol. 1995 ,5, 221.
(7) Agaba A E. et al. One stop rectal bleeding clinic: the Coventry experience. Int Surg. 2006, 91, 288.
(8) Wallander M A. Unspecified abdominal pain in primary care: the role of gastrointestinal morbidity. Int J Clin Pract. 2007, 61, 1663.
(9) Jeyarajah S. et al. Diverticular disease increases and affects younger ages: an epidemiological study of 10 year trends. Int J Colorectal Dis. 2008, 23, 619.
(10) Kang J Y. et al. Diverticular disease of the colon – on the rise: a study of hospital admissions in England between 1989/1990 and 1999/2000. Aliment Pharmacol Ther. 2003, 17, 1189.
(11) Morris C R. et al. Do calcium channel blockers and antimuscarinics protect against perforated colonic diverticular disease? A case control study. Gut. 2003, 52, 1734.
(12) Hawkes N. Care rationing plan ‘a panic measure to solve cash crisis’ The Times, April 8 2006.
(13) Anish A. et al. Diverticular disease and diverticulitis. Am J Gastroenterol 2008, 103, 1550.
(14) Papagrigoriadis S. et al. Impact of diverticular disease on hospital costs and activity. Colorectal Dis. 2004, 6, 81.
(15) John S K. et al. A prospective study of acute admissions in a surgical unit due to diverticular disease. Dig Surg 2007, 24, 186.
(16) Morris C R. et al. Epidemiology of perforated colonic diverticular disease. Postgrad Med J. 2002, 78, 654.
(17) Koo V. et al. Young patients with diverticular disease: a preliminary quality of life study. Int J Surg. 2007, 5, 244.
(18) Bolster L T. et al. Diverticular disease has an impact on quality of life – results of a preliminary study. Colorectal Dis. 2003, 5, 320.
TABLE
COMPARISON OF LEVELS OF DIVERTICULAR DISEASE WITH OTHER BOWEL DISEASES IN DIFFERENT TIMES, COUNTRIES AND TEST METHOD
| REF | COUNTRY | YEAR | NUMBER
OF PATIENTS |
METHOD OF EXAM. | PERCENTAGE OF PATIENTS WITH | PATIENT CRITERIA | |||
| DD | POLYPS | CANCER | IBD | ||||||
| 1 | Finland | 2006 | 532 | BE | 42 | 4.8 | 3.8 | – | All patients examined |
| 2 | USA | 2005 | 124 | CT | 18 | – | 8 | – | Patients over 60 years |
| 3 | USA | 2005 | 360 | BE | 6.5 | – | – | – | Patients with abdominal pain |
| 4 | Netherlands | 2005 | 10836 | C | 21 to 37 | 9 to 16 | 4 to 6 | 9 to 15 | All patients in 11 year period |
| 5 | Greece | 2004 | 176 | C | 11.4 | 8.5 | – | – | Patients with positive faecal blood test |
| 6 | Kenya | 1980 | 183 | BE | 10.9 | – | 6.5 | – | All patients in a I year period |
| 7 | Brazil | 2005 | 2567 | C | 12.9 | 15.5 | 10.2 | 11.9 | All tests between 1984 and 2002 |
| 8 | Portugal | 2006 | 1245 | C | 16.4 | 40.3 | 4.8 | 3.5 | All patients in 11 day period in 31 hospitals |
| 9 | UK | 2006 | 250 | C | 24 | 14.4 | 1.6 | 3.2 | Patients with rectal bleeding |
| 10 | Crete | 2001 | 502 | PM | 22.9 | 21.1 | – | – | Age range 16 to 93 |
| 11 | Sweden | 2007 | 2222 | CT | 8.2 | – | 1.5 | 0.6 | Patients with acute abdominal pain |
| 12 | UK | 2004 | 9223 | C | 14.9 | 22.5 | 3.8 | 13.9 | Patients in 3 NHS regions in 4 months |
| 13 | UK | 2007 | 3956 | S | 15 | 10.7 | 3.4 | 7.1 | Patients with bowel symptoms over 5 years |
| 14 | Netherlands | 2008 | 4241 | C | 27 | 30 | 9 | – | All C tests in 3 months at 18 hospitals |
ABBREVIATIONS
DD = diverticular disease IBD = inflammatory bowel disease – = no data available
METHODS OF EXAMINATION
BE = Barium enema x-ray CT = CT scan C = Colonoscopy PM = Post mortem S = Sigmoidoscopy
REFERENCES
1. Vehmas, Clin Radiol, 2006, 61, 270
2. Husty et al. Am J Emerg Med, 2005, 23, 259
3. Lewis et al. J Gerontol A Biol Sci Med Sci, 2005, 60, 1071
4. Loffeld et al. Eur J Intern Med, 2005, 16, 37
5. Chrissidis et al. Tech Coloproctol, 2004, 8 Suppl 1, s193
6. Calder et al. Diagn Imaging, 1980, 49, 23
7. Nahas et al. Arq Gastroenterol, 2005, 42, 77
8. Cremers et al. Dig Liver Dis, 2006, 38, 912
9. Agaba et al. Int Surg, 2006, 91, 288
10. Paspatis et al. Int J Colorectal Dis, 2001, 16, 257
11. Stromberg et al. World J Surg, 2007, 31, 2347
12. Bowles et al. Gut, 2004, 53, 277
13. Kelly et al. Colorectal Dis, 2008, 10, 390
14. Meurs-Szojda et al. Int J Colorectal Dis, 2008, Jul 2, (Epub ahead of print)
Data from abstracts on PubMed
© M Griffiths 2008
Note This article was adapted for inclusion in the Autumn 2008 issue of the Journal of the Bladder and Bowel Foundation, and is available in the professional resources section of their website. The Table was not used.
Tags: Diagnosis, Hospitals, Statistics, Symptoms