Timothy R. Card

Venous thromboembolism during active disease and remission in inflammatory bowel disease: a cohort study.

BACKGROUND Patients with inflammatory bowel disease who develop deep vein thrombosis or pulmonary embolism often have active disease at the time of thromboembolism. We therefore aimed to quantify the risk of venous thromboembolism prospectively during different activity phases of inflammatory bowel disease. METHODS From the General Practice Research Database, we matched patients with prospectively recorded inflammatory bowel disease from November, 1987, until July, 2001 with up to five controls by age, sex, and general practice. A flare was defined as the period 120 days after a new corticosteroid prescription. We used Cox regression analysis with time-varying covariates to accommodate changes in the state of inflammatory bowel disease, and whether patients were at high risk of venous thromboembolism after hospitalisation. FINDINGS 13 756 patients with inflammatory bowel disease and 71 672 matched controls were included in the analysis, and of these 139 patients and 165 controls developed venous thromboembolism. Overall, patients with inflammatory bowel disease had a higher risk of venous thromboembolism than did controls (hazard ratio 3.4, 95% CI 2.7-4.3; p<0.0001; absolute risk 2.6 per 1000 per person-years). At the time of a flare, however, this increase in risk was much more prominent (8.4, 5.5-12.8; p<0.0001; 9.0 per 1000 person-years). This relative risk at the time of a flare was higher during non-hospitalised periods (15.8, 9.8-25.5; p<0.0001; 6.4 per 1000 person-years) than during hospitalised periods (3.2, 1.7-6.3; p=0.0006; 37.5 per 1000 person-years). INTERPRETATION Trials of primary prophylaxis of venous thromboembolism are warranted to find out whether this important complication can be prevented. FUNDING National Association for Colitis and Crohns Disease.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

Malignancy and mortality in people with coeliac disease: population based cohort study

Abstract Objective To quantify the risks of malignancy and mortality in people with coeliac disease compared with the general population. Design Population based cohort study. Setting General practice research database. Participants 4732 people with coeliac disease and 23 620 matched controls. Main outcome measures Hazard ratios for malignancy and mortality. Results Of the 4732 people with coeliac disease, 134 (2.8%) had at least one malignancy and 237 (5.0%) died. The overall hazard ratios were: for any malignancy 1.29 (95% confidence interval 1.06 to 1.55), for mortality 1.31 (1.13 to 1.51), for gastrointestinal cancer 1.85 (1.22 to 2.81), for breast cancer 0.35 (0.17 to 0.72), for lung cancer 0.34 (0.13 to 0.95), and for lymphoproliferative disease 4.80 (2.71 to 8.50). The increased risk was primarily in the first year after diagnosis, with the risk for only lymphoproliferative disease remaining significantly raised thereafter. After excluding events in the year after diagnosis, the hazard ratio for malignancy was 1.10 (0.87 to 1.39) and for mortality was 1.17 (0.98 to 1.38), giving absolute excess rates of 6 and 17 per 10 000 person years, respectively. Conclusions People with coeliac disease have modest increases in overall risks of malignancy and mortality. Most of this excess risk occurs in the year of follow up after diagnosis. People with coeliac disease also have a noticeably reduced risk of breast cancer. The mechanism of this merits further attention as it may provide insights into the cause of this common malignancy.

Risk of oesophageal cancer in Barrett’s oesophagus and gastro-oesophageal reflux

Background and aims: While patients with Barrett’s oesophagus develop oesophageal adenocarcinoma more frequently than the general population, it has controversially been suggested that gastro-oesophageal reflux (GORD) itself is a more important determinant of risk. In order to assess the validity of this suggestion, we examined the risk of oesophageal cancer in patients with Barrett’s and with GORD compared with the general population in a community based cohort study. Methods: Cohorts of patients with Barrett’s (n = 1677), oesophagitis (n = 6392), and simple reflux (n = 6328), and a reference cohort (n = 13416) were selected from the General Practice Research Database. The last three cohorts were matched to the Barrett’s cohort by general practitioner practice, age, and sex. Cox’s regression analysis was used to calculate relative risks for oesophageal cancer. Standardised incidence ratio methodology was used to estimate the relative risks for oesophageal adenocarcinoma. Results: A total of 137 oesophageal cancers were identified, of which 94 prevalent cases were excluded. The hazard ratios for oesophageal cancer were 10.6 (5.1–22.0), 2.2 (0.9–5.2), and 1.7 (0.7–4.5) in the Barrett’s, oesophagitis, and reflux cohorts compared with the reference cohort, respectively. The corresponding relative risks for oesophageal adenocarcinoma were 29.8 (9.6–106), 4.5 (1.04–19.6), and 3.1 (0.6–14.2). Conclusion: Barrett’s oesophagus increases the risk of oesophageal cancer approximately 10 times and oesophageal adenocarcinoma approximately 30 times compared with the general population. There is only a modestly increased risk of oesophageal cancer in patients with reflux who have no record of Barrett’s oesophagus. Our findings therefore do not support the suggestion that gastro-oesophageal reflux disease itself predisposes to cancer.

5-Aminosalicylate use and colorectal cancer risk in inflammatory bowel disease: a large epidemiological study.

Background and aims: The objective of this study was to evaluate the risk of colorectal cancer (CRC) in patients taking aminosalicylates (5-ASA) for inflammatory bowel disease (IBD). Methods: The General Practice Research Database (GPRD) which contains the primary care records of five million people in the UK was used to identify users of mesalazine, balsalazide, olsalazine, or sulfasalazine with a history of IBD. In a nested case control analysis, each incident CRC case with any use of a 5-ASA in the six months before the CRC diagnosis was matched by age, sex, and calendar time to six control patients who were also currently using a 5-ASA. Patients were then classified according to regularity of use. The analysis was controlled for body mass index, IBD duration, history of colorectal polyps, use of non-steroidal anti-inflammatory drugs, paracetamol, aspirin, immunosuppressants, oral and rectal glucocorticoids, prior gastrointestinal hospitalisation, recorded colonoscopy, and number of visits to the general practitioner for IBD symptoms in the 6–24 months before diagnosis. Results: The study population included 18 969 patients, of whom 100 had developed CRC during 5-ASA exposure. Most of these cases had a history of ulcerative colitis (76 patients). In the case control analysis, regular users, defined as having six or more 5-ASA prescriptions in the previous 12 months, were found to have a decreased risk of CRC compared with irregular users (crude odds ratio (OR) 0.7 (0.44–1.03); adjusted OR 0.60 (0.38–0.96)). Regular users of sulfasalazine with 6–12 prescriptions before had an adjusted OR of 0.95 (0.22–4.11); with 13–30 prior prescriptions this was 0.41 (0.14–1.20) and with >30 prior prescriptions this was 0.77 (0.37–1.60). For mesalazine users, these values were 1.13 (0.49–2.59), 0.30 (0.11–0.83), and 0.31 (0.11–0.84), respectively. Conclusion: These results show that regular 5-ASA use is associated with some reduction in the risk of CRC developing in ulcerative colitis.

The epidemiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed.

General population based study of the impact of tricyclic and selective serotonin reuptake inhibitor antidepressants on the risk of acute myocardial infarction

Objective: To investigate the impact of tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) on the risk of first acute myocardial infarction (MI). Design: Case–control analysis and a self controlled case series. Setting: 644 general practices throughout England, Scotland, Wales, and Northern Ireland. Patients: Over 60 000 cases of MI and 360 000 age, sex, and practice matched controls randomly selected from the UK General Practice Research Database. Main outcome measures: Matched odds ratios and incidence rate ratios estimating whether there is an acute or prolonged increased risk of MI after exposure to TCA and SSRI drugs and individual drugs within these families. Results: Case–control analysis found an initial increased risk of MI after TCA exposure (for example, at 1–7 days after the first dothiepin prescription: odds ratio (OR) 1.90, 95% confidence interval (CI) 1.15 to 3.14) or SSRI exposure (for example, at 1–7 days after first fluoxetine prescription: OR 2.59, 95% CI 1.44 to 4.66). In the self controlled analysis the equivalent risk estimates were an incidence rate ratio of 1.43, 95% CI 0.92 to 2.22 for dothiepin and an incidence rate ratio of 1.66, 95% CI 1.01 to 2.71 for fluoxetine. Conclusions: Antidepressant prescriptions are associated with an increased risk of MI. The size of these effects is similar for TCA and SSRI exposures; however, the lack of specificity between types of antidepressants and the lower risks found in the self controlled analysis suggest that these associations are more likely due to factors relating to underlying depression and health services utilisation than to specific adverse drug effects.

Hip fractures in patients with inflammatory bowel disease and their relationship to corticosteroid use: a population based cohort study

Background: Inflammatory bowel disease (IBD) is known to be associated with reduced bone density but the extent to which this results in an increased risk of fracture and the contribution of corticosteroid therapy are unclear. We have conducted a large cohort study to address these issues. Methods: We selected subjects within the General Practice Research Database (GPRD) with a diagnosis of IBD and up to five matched controls for each patient. We derived dates of recorded hip fractures and also information on smoking, use of corticosteroids, and a number of other drugs. We calculated the absolute risk of fracture and the relative risk as a hazard ratio corrected for available confounders by Cox regression. Results: Seventy two hip fractures were recorded in 16 550 IBD cases and 223 in 82 917 controls. Cox modelling gave an unadjusted relative risk of hip fracture of 1.62 (95% confidence interval (CI) 1.24–2.11) for all IBD, 1.49 (1.04–2.15) for ulcerative colitis (UC) and 2.08 (1.36–3.18) for Crohn’s disease (CD). Multivariate modelling showed that both current and cumulative use of corticosteroids and use of opioid analgesics confounded this relationship. After adjusting for confounding, the relative risk was 1.41 (0.94–2.11) for UC and 1.68 (1.01–2.78) for CD. Conclusion: The risk of hip fracture is increased approximately 60% in IBD patients. Corticosteroid use is a contributor to this, both in the long term as previously recognised and also in an acute reversible manner. The majority of hip fracture risk in IBD patients however cannot be attributed to steroid use.

Risk of Cancer in Inflammatory Bowel Disease Treated With Azathioprine: A UK Population-Based Case–Control Study

OBJECTIVES:Azathioprine is an accepted treatment of inflammatory bowel disease (IBD), but concerns exist regarding its carcinogenic potential. Studies in renal transplant and rheumatology patients have reported an increased cancer risk. In IBD, studies suggest a small increased risk of lymphoma and protection against colorectal cancer, but the overall risk of malignancy has not been established.METHODS:We conducted a nested case–control study using the General Practice Research Database. Records of IBD patients were examined for azathioprine prescriptions and cancers. Prescriptions per year of follow-up were grouped for analysis. Azathioprine use was compared between IBD cases (with a diagnosed cancer) and IBD controls (without).RESULTS:Overall, 15,471 patients with IBD and over 1 year of appropriate data were identified. Among these, 392 developed cancer, of whom 10.5% received at least one prescription for azathioprine, compared with 1,914 (12.7%) of the controls. Analyzing the occurrence of any cancer against azathioprine prescription showed a nonsignificant protective effect (odds ratio (OR)=0.92, 95% confidence interval (CI)=0.79–1.06). Correction for the effects of age and smoking removed this effect (OR=1.04, 95% CI=0.89–1.21). Diagnosis of lymphoma was associated with ever use of azathioprine with OR of 3.22, CI=1.01–10.18.CONCLUSIONS:We found evidence of an increased risk of lymphoma, which is consistent with previous studies. We found no overall increase in risk of cancer in individuals with IBD who had taken azathioprine. Our study does not show a need for azathioprine cessation in the medium term in IBD because of the risk of malignancy.

Antibiotic use and the development of Crohn’s disease

Background: Few environmental determinants of Crohn’s disease are well established. Some observational data exist to implicate antibiotic use as a risk factor but these are derived from studies using questionnaires to assess reported antibiotic use that were susceptible to recall bias. We have therefore explored this relationship in prospectively gathered data. Methods: We selected incident cases of Crohn’s disease from the General Practice Research Database with at least five years of data prior to diagnosis. Controls with five years of complete data were randomly selected. Data were extracted on smoking, drug prescriptions, age, sex, and a variety of symptoms and diagnoses that might be indicative of occult Crohn’s disease. Logistic regression was used to investigate the relationship between antibiotic use and Crohn’s disease. Results: A total of 587 Crohn’s disease cases and 1460 controls were available for analysis. We found that antibiotic use 2–5 years pre-diagnosis occurred in 71% of cases compared with 58% of controls (p<0.001), and the median number of courses was two in the cases and one in the controls (p<0.001). Adjusting for age, sex, smoking, and use of other drugs, antibiotic use had an odds ratio of 1.32 (1.05–1.65). We were unable to show specificity to any subgroup of antibacterials. Associations similar to that with antibiotics were also found with oral contraceptive, cardiovascular, and neurological drugs. Conclusions: We found a statistically significant association between Crohn’s disease and prior antibiotic use. This cannot be explained by recall bias, but due to lack of specificity it is unclear whether it is causal.