ORIGINAL ARTICLEClinical Epidemiology of Ulcerative Colitis in Mexico A Single Hospital-based Study in a 20-year Period (1987-2006) Jesu´s K. Yamamoto-Furusho, MD, PhD, MSc Background: Ulcerative colitis (UC) is a chronic disease with a heterogeneous clinical evolution. The prevalence and incidence of UC vary widely and depend on multiple factors including ethnicity and geographic location. Goal: To determine the frequency of new cases of UC and their clinical characteristics in a large cohort from a referral hospital in Mexico City. Study: Patients with confirmed diagnosis of UC were included during a period between January 1987 and December 2006. Demographic and clinical data were collected from medical records. Results: A total of 848 new cases of UC were diagnosed during a 20-year period. All the patients had endoscopic and histologic confirmation. The mean of annual new UC cases increased from 28.8 in the first period (1987 to 1996) to 76.1 in the second period (1997 to 2006) (P<0.00008). The incidence of new cases increased 2.6-fold comparing both periods of time. This study consisted of 467 females and 382 males, with a mean age at diagnosis of 31.3 ± 12.3 years. The clinical manifestations were pancolitis (59.1%), and extraintestinal manifestations (41.5%). Most of the patients, 762 (89.8%) were taking sulfasalazine or 5-aminosalicylic acid, 282 (33.3%) used oral or systemic steroids, 237 (28%) were taking azathioprine. Conclusions: The frequency of new UC cases has increased significantly in the last 10 years in Mexico, largely due to the unique genetic make-up and the environmental factors (infectious diseases including parasites) not found in other countries. Key Words: UC, epidemiology, clinical, Mexico, Latin America (J Clin Gastroenterol 2009;43:221–224) I nflammatory bowel disease (IBD) is a group of chronic inflammatory disorders of unknown etiology involving the gastrointestinal tract and consists of 2 major groups: Ulcerative colitis (UC) and Crohn’s disease (CD) that are clinically characterized by recurrent inflammatory involvement resulting in a similar evolution. The prevalence and incidence of IBD vary widely and depend on multiple factors, including ethnic background Received for publication July 4, 2007; accepted April 7, 2008. From the Inflammatory Bowel Disease Clinic, Department of Gastroenterology, Instituto Nacional de Ciencias Me´dicas y Nutricio´n Salvador Zubira´n, Mexico City, Mexico. Acknowledgment of grants or financial support: None. Author does not have any conflict of interest. Reprints: Jesu´s K. Yamamoto-Furusho, MD, PhD, MSc, Department of Gastroenterology, Instituto Nacional de Ciencias Me´dicas y Nutricio´n Salvador Zubira´n, Vasco de Quiroga 15, Colonia Seccio´n XVI, Tlalpan, C.P. 14000, Mexico D.F., Mexico (e-mail: kazuofurusho@ hotmail.com). Copyright r 2009 by Lippincott Williams & Wilkins J Clin Gastroenterol Volume 43, Number 3, March 2009 and geographic location. The prevalence of IBD is 100 per 100,000 in the general population with 10,000 new cases diagnosed annually. The incidence of UC is stable with approximately 10 to 20 per 100,000 per year and a prevalence of 50 to 100 per 100,000 in the US population.1 Although both sexes are affected similarly,1 the peak onset of the disease varies with age typically presenting itself between ages 15 and 25 or between 55 and 65 (bimodal distribution). Although IBD occurs worldwide, the highest incidence is among whites, particularly the Ashkenazi Jewish population of Eastern Europe. Recently, increased rates of the disease have been reported in regions where the incidence of UC was thought to be low, such as Asia, Africa, and Latin America.2 The epidemiology of UC in Latin America, including Mexico, is still unknown; however, some reports have suggested a lower incidence and milder course of the disease in Latin America.3 The goal of this study was to determine the frequency of new cases and clinical characteristics of UC in a large cohort from a referral hospital in Mexico City. MATERIALS AND METHODS Data were collected from medical records during a 20year period from January 1, 1987 to December 31, 2006. A total of 1049 patients with possible diagnosis of UC were referred to the Instituto Nacional de Ciencias Me´dicas y Nutricio´n hospital. In the inclusion period, 848 new and confirmed cases of UC were identified. Two hundred and one cases were excluded for several reasons: incomplete medical records, no definitive diagnosis of UC, indeterminate colitis, colonic CD, and microscopic colitis. All of the patients on the list who were over 18 years of age were diagnosed and confirmed to have UC. This database covered both outpatient visits and hospitalizations. Diagnostic codes were based on the National Adaptation of the International Classification of Diseases (ICD) with separate code for UC (K51.9). The diagnosis of UC was carried out by the presence of the following criteria: a history of diarrhea or blood in stools, macroscopic appearance by endoscopy and biopsy compatible with UC, no suspicion of CD on the small bowel radiograph, ileocolonoscopy, and biopsy. The Montreal classification of disease extent of UC was used in all patients.4 All patients were recruited from several urban areas or cities (Mexico City, Veracruz, Puebla, Morelia, Toluca, Campeche, La Paz, Pachuca, Quere´rato, Guanajuato, and Villahermosa) and rural areas. Relevant clinical and demographic information in all UC patients were collected from medical records: sex, age at diagnosis, familial aggregation, smoking history, previous appendectomy, disease evolution, extension, extraintestinal manifestations, medical or surgical treatment, 221 The frequency of new cases with UC increased over the time (Fig. 222 FIGURE 3.1%) of the UC patients underwent proctocolectomy. toxic megacolon (5. 492 (59. New cases of ulcerative colitis diagnosed during the 20-year period of study in Mexico. and 130 (15.3%) as shown in Figure 2.9%).35%). The data analysis was performed with SSPS version 14. routine evaluations were performed for different pathogens such as bacteria.9%). The most common causes of colectomy were: failed to medical treatment (89. Distribution of extent of ulcerative colitis in Mexican patients.4%) had proctitis (E1) as shown in Figure 3. and fever (5%). perforation (3. The age-group distribution of the patients were as follows: 21 to 30 years (37. magnetic resonance imaging) or histologic criteria. respectively after diagnosis of their disease. Forty-three patients underwent colectomy in their first 5 years since diagnosis.3%) patients were nonsmokers and 73 (8. The diagnosis of primary sclerosing cholangitis (PSC) was made based on radiologic (endoscopic retrograde cholangiopancreatography.3 ± 12.5%) had extraintestinal manifestations that included: arthritis 100 80 Pancolitis (E3) 60 Year 06 Year 05 Year 03 Year 04 Year 01 Year 02 Year 99 Year 00 Year 97 Year 98 Year 96 Year 90 Year 88 Year 89 Year 87 0 Year 94 Proctitis (E1) Year 95 20 Year 93 Left-sided colitis (E2) Year 91 40 Year 92 Number of New cases 120 FIGURE 1. r 2009 Lippincott Williams & Wilkins .6%).8 in the first period (1987 to 1996) to 76. 7 cases with second-degree relatives affected by UC). further progression to left-sided colitis was observed in 13 patients (10%) in a period of 5 ± 3 years.6-fold comparing both periods of time. Clostridium difficile. 41 to 50 years (10. 216 (25. Extent of the Disease The extent of the disease was evaluated by using total colonoscopy and biopsies were taken from different segments of colon in all cases.1%) had pancolitis (E3). Four patients developed dysplasia or colorectal cancer 15 years after the initial diagnosis. 216 patients with initial left-sided colitis. During the follow-up.5%) had left-sided colitis (E2). Surgery During this period.2%) and over 60 years of age (1. The mean age at diagnosis was 31.5%). The incidence increased 2. All of the patients with pancolitis and distal colitis underwent routine cancer surveillance and a biopsy was taken from 4 different segments of the colon every 10 cm. cancer (0. 250 200 150 100 50 0 < 10 10 to 20 21 to 30 31 to 40 41 to 50 51 to 60 > 60 Age at diagnosis FIGURE 2. 84 patients had pancolitis and only 2 cases had left-sided colitis.6%). this was performed after 8 and 15 years.3 years. the male to female ratio (0.6%) patients were exsmokers. Extraintestinal Manifestations Three hundred fifty-two UC patients (41. During the whole study period (1987 to 2006).5%). mucoid diarrhea (45%). March 2009 350 300 Number of cases and clinical course of disease. The P value was 2-tailed and less than 0.J Clin Gastroenterol Yamamoto-Furusho Statistical Analysis Descriptive statistics are expressed as mean and standard deviation. 1). Number 3. 31 to 40 years (25. Other causes of colitis including infectious were excluded. Of the 848 UC patients. 467 female and 382 male patients with UC were analyzed. 51 to 60 years (12.9:1.00008).1%). The year 1987 was selected as the starting point because the coverage of the hospital register was incomplete for earlier periods.3%). Data were analyzed by Student t test for numerical variables and w2 test for nominal variables. During the follow-up.1 in the second period (1997 to 2006) (P<0. The duration of follow-up was at least 5 months since the patient was diagnosed with UC and all patients had several histologic examinations.0) was equal. A prior history of appendectomy was revealed in 20 cases (2. The predominant clinical features of UC patients were: bloody diarrhea (90%).7%). Most of the patients are residing in urban areas (91. and parasites. RESULTS A total of 848 patients were diagnosed with UC between 1987 and 2006 at this hospital.05 was considered statistically significant. All cases with unconfirmed or wrong diagnosis were excluded from the study. abdominal pain (39%). rectal symptoms (28%). Number of ulcerative colitis patients according to the age at diagnosis.4%) and a total of 775 (91. and massive hemorrhage (0. In patients with proctitis. weight loss (21%). The Montreal classification was used to define the extent of UC.0 for Windows. the UC had progressed to pancolitis in 54 (15%) in a period of 7 ± 2 years. The mean of new UC cases increased annually from 28. Familial aggregation was present in 57 (6. 86 (10. ova. under 20 years (13.78%) cases (50 patients with first-degree relatives and Volume 43. New cases of UC were reported yearly as frequency. IL-13].2%). and colectomy.22 In contrast.24 The high frequency of pancolitis and PSC was found at this hospital population can be explained by referral bias used to admit patients and because it is the biggest specialized medical center in whole country. Some reports have suggested a lower incidence and milder course of UC in Latin America. In contrast.1%) as shown in Figure 4.1%) populations with UC. colorectal cancer.3 However. Medical Treatment Used in UC Mexican Patients Sulfasalazine 5-aminosalycilic acid (5-ASA) Oral and systemic glucocorticosteroids Azathioprine 6-mercaptopurine Infliximab Budesonide UC indicates ulcerative colitis. The number of new cases has increased significantly in the last decade in Mexico. In the developing world. IL-5.5%) of PSC was found in the Mexican population compared with the European and North American studies. DISCUSSION To the best of our knowledge. and clinical features of UC in different ethnic populations. and Lebanon. 762 (89.5% 64.23 In addition. Romania.4%). true populationbased registries are hard to find. the highest frequency reported up to now. whereas a low familial aggregation and high prevalence of infectious diseases (including parasites) in Mexico could affect the clinical course of the disease. Sulfasalazine or 5-ASA was used over the course of the follow-up.6–8 The present study identified some different clinical characteristics of UC to that reported in white and Asian populations.19. Variable incidence and prevalence rates. This mechanism would explain the protective role of helminthes in TH1-driven disorders such as intestinal inflammation. where helminth carriage has steadily declined.3%).3. (24.9.5%.78%) of familial aggregation of UC found in the Mexican population compared with a high proportion of familial aggregation of UC (13.18 but higher rates of colorectal cancer have been reported in white populations. Oral and systemic glucocorticosteroids at different points in time and azathioprine was added during the course of disease (Table 1).17% 0.21. this is the first Latin America study that reports the clinical epidemiology in a large cohort of Mexican patients with UC. a high frequency (10. In the present study. PSC (10.10 There are clinical manifestations that may act differently among the different ethnic groups.11 Korea (30.12 Iran (18.4%). In relation to demographic characteristics. The diverse clinical patterns of UC in several geographic regions are influenced by genetic and environmental factors. Medical Treatment Most of the patients. 237 (28%) were taking azathioprine and other treatments (0. which is consistent with that reported in Western countries between 21% and 41%21 and Indian population. the frequency of extraintestinal manifestations was 41. the frequency of pancolitis was lower in other populations such as China (7. dysplasia and colorectal cancer was noted in 4 UC patients (0. confirming this tendency in the world including Latin American countries.11. Topical medication was used in 110 patients with proctitis (13%) based on 5-ASA. and ankylosing spondylitis (1.6% Clinical Epidemiology of Ulcerative Colitis in Mexico incidence may be a westernized lifestyle. However.5 There is increasing evidence to indicate that helminth carriage might protect the host from immunologic disorders. r 2009 Lippincott Williams & Wilkins 25.5% of the UC patients had been colectomized during the 5-year period16 but differs from other European studies where the cumulative risk for colectomy was 20% after 5 years of evolution of the disease. pyoderma gangrenosum (2. and also improving the diagnostic modalities and a lower prevalence of infectious diseases by worm parasites.1% showed pancolitis. March 2009 30 Frequency 25 20 15 10 Ankylosing spondilitis Uveitis Pyoderma Sacroiliitis Erythema nodosum PSC 0 Arthropathy 5 FIGURE 4. anterior uveitis (2. 59. low rates were reported in Chinese (6.1%). erythema nodosum (4.J Clin Gastroenterol Volume 43.17 On the other hand. may provide insight into the pathophysiology of UC.3% 33. Number 3.8%) were taking sulfasalazine or 5-aminosalicylic acid (5-ASA).0%). the rate of colectomy was 10. 282 (33.1%). Frequency of extraintestinal manifestations in patients with ulcerative colitis.3%) used oral or systemic glucocorticosteroids. which is according to a recent follow-up studies that reported only 7.13 and European countries (15%). Previous studies have shown different frequencies regarding the extent of the disease. an interesting finding was the low frequency (6. the age of onset for UC (almost equally present in both sexes) and a high percentage of nonsmokers are similar to the reports in other countries.5%) similar to that reported in the Iranian and US populations13. Interestingly. and consequently studies are commonly hospital-based. in terms of dietary habits and smoking.14–16 In the present study. sacroiliitis (3.4% to 15%) in countries from Northern Europe and the United States. the epidemiology and clinical characteristics are still unknown. Most helminths stimulate the production of TH2 cytokines [interleukin (IL)-4. IL-9. some clinical features of UC are different compared with other populations such as a high frequency of pancolitis and extraintestinal manifestations (PSC) and also the low rate of familial aggregation.1%. An important finding from this study is the increasing frequency of new UC cases diagnosed in the last decade in Mexico.20 In this study.5%).5%). These results confirmed that the incidence of UC is increasing in Mexico and it is according to other studies from Canada.9%). 223 . The possible explanations of this increased TABLE 1.1%) and Korean (24.3% 28% 2% 1. Epidemiology of inflammatory bowel disease in Asia. 2004. et al.96:687–691.24:1271–1275. 224 Volume 43. 9.31:1–20. 1994. 4. Jarnerot G. 2004. Epidemiology of inflammatory bowel disease over a 10-year period in Florence (1978-1987). Gut. Am J Gastroenterol. Bernstein CN. Lygren I. Garrido A. 2001. et al.218 ulcerative colitis cases in China. Satsangi J. Bahari A. Gastroenterology. et al. 6. 20. Haug K. 21. 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