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CORE Metadata, citation and similar papers at core.ac.uk Provided by Cronfa at Swansea University Cronfa - Swansea University Open Access Repository _____________________________________________________________ This is an author produced version of a paper published in: World Journal of Gastroenterology Cronfa URL for this paper: http://cronfa.swan.ac.uk/Record/cronfa19005 _____________________________________________________________ Paper: Button, L., Roberts, S., Goldacre, M., Akbari, A., Rodgers, S. & Williams, J. (2010). Hospitalized prevalence and 5- year mortality for IBD: Record linkage study. World Journal of Gastroenterology, 16(4), 431-437. http://dx.doi.org/10.3748/wjg.v16.i4.431 _____________________________________________________________ This item is brought to you by Swansea University. Any person downloading material is agreeing to abide by the terms of the repository licence. Copies of full text items may be used or reproduced in any format or medium, without prior permission for personal research or study, educational or non-commercial purposes only. The copyright for any work remains with the original author unless otherwise specified. The full-text must not be sold in any format or medium without the formal permission of the copyright holder. Permission for multiple reproductions should be obtained from the original author. Authors are personally responsible for adhering to copyright and publisher restrictions when uploading content to the repository. http://www.swansea.ac.uk/library/researchsupport/ris-support/ Online Submissions: http://www.wjgnet.com/1007-9327office World J Gastroenterol 2010 January 28; 16(4): 431-438 [email protected] ISSN 1007-9327 (print) doi:10.3748/wjg.v16.i4.431 © 2010 Baishideng. All rights reserved. ORIGINAL ARTICLE Hospitalized prevalence and 5-year mortality for IBD: Record linkage study Lori A Button, Stephen E Roberts, Michael J Goldacre, Ashley Akbari, Sarah E Rodgers, John G Williams Lori A Button, Stephen E Roberts, Ashley Akbari, Sarah ized prevalence of CD was slightly higher in the most E Rodgers, John G Williams, School of Medicine, Swansea deprived areas, but there was no association between University, Swansea SA2 8PP, United Kingdom social deprivation and hospitalized prevalence of UC. Michael J Goldacre, Unit of Health-Care Epidemiology, Mortality was 6.8% and 14.6% after 1 and 5 years University of Oxford, Oxford OX2 7LF, United Kingdom follow-up for CD, and 9.2% and 20.8% after 1 and 5 Author contributions: Roberts SE initiated the study; Roberts years for UC. For both CD and UC, there was little dis- SE, Williams JG and Goldacre MJ designed the study; Roberts cernible association between mortality and social dep- SE and Button LA reviewed the literature; Button LA and Akbari A undertook the analyses; Rodgers SE undertook the GIS rivation, distance from hospital, urban/rural residence analyses; Roberts SE, Button LA, Goldacre MJ and Williams JG and geography. interpreted the study findings and wrote the manuscript. Supported by The Health Foundation CONCLUSION: CD and UC have distinct demographic Correspondence to: Dr. Stephen E Roberts, School of profiles. The higher prevalence of hospitalized CD in Medicine, Swansea University, Singleton Park, Swansea, SA2 more deprived areas may reflect higher prevalence and 8PP, United Kingdom. [email protected] higher hospital dependency. Telephone: +44-1792-513426 Fax: +44-1792-513423 Received: August 24, 2009 Revised: October 17, 2009 © 2010 Baishideng. All rights reserved. Accepted: October 24, 2009 Published online: January 28, 2010 Key words: Crohn’s disease; Ulcerative colitis; Preva- lence; Mortality; Record linkage Peer reviewer: Tauseef Ali, Assistant Professor, Department of Abstract Gastroenterology, University of Oklahoma, WP 1360 Digestive AIM: To establish the hospitalized prevalence of se- Disease, 920 SL Young Blvd, Oklahoma City, OK 73104, vere Crohn’s disease (CD) and ulcerative colitis (UC) in United States Wales from 1999 to 2007; and to investigate long-term mortality after hospitalization and associations with so- Button LA, Roberts SE, Goldacre MJ, Akbari A, Rodgers SE, cial deprivation and other socio-demographic factors. Williams JG. Hospitalized prevalence and 5-year mortality for IBD: Record linkage study. World J Gastroenterol 2010; METHODS: Record linkage of administrative inpatient 16(4): 431-438 Available from: URL: http://www.wjgnet. and mortality data for 1467 and 1482 people hospital- com/1007-9327/full/v16/i4/431.htm DOI: http://dx.doi. ised as emergencies for ≥ 3 d for CD and UC, respec- org/10.3748/wjg.v16.i4.431 tively. The main outcome measures were hospitalized prevalence, mortality rates and standardized mortality ratios for up to 5 years follow-up after hospitalization. INTRODUCTION RESULTS: Hospitalized prevalence was 50.1 per 100 000 population for CD and 50.6 for UC. The hospi- Inflammatory bowel disease (IBD), comprising mainly talized prevalence of CD was significantly higher P( < Crohn’s disease (CD) and ulcerative colitis (UC), can be 0.05) in females (57.4) than in males (42.2), and was one of the most severe gastrointestinal disorders with [1] highest in people aged 16-29 years, but the prevalence a significant health and economic burden . Presenting of UC was similar in males (51.0) and females (50.1), commonly in adolescence, IBD often results in debilitating and increased continuously with age. The hospital- morbidity and frequent relapses that impact heavily on WJG|www.wjgnet.com 431 January 28, 2010|Volume 16|Issue 4| Button LA et al . IBD hospitalized prevalence and mortality educational, social, professional and family life[1-3]. It covers 17 district general or teaching hospitals in eight CD has increased in many countries in the past few NHS hospital trusts across 22 health boards, and serves decades, with highest prevalence often reported in west- the Welsh population of 3 million. We used record linkage ern regions such as Northern and Western Europe and of inpatient and mortality data because this enabled all North America[3-7]. In the United Kingdom, the incidence repeat hospital admissions to be identified for the same of UC has shown greater stability over time[6,8], while CD patients, and enabled deaths following discharge from has continued to rise in many but not in all regions[7,9-13]. hospital to be identified, as well as in-hospital deaths. Most studies have reported that CD is more common in The International Classification of Diseases, 10th females than in males[8,10,11,13-16], whereas for UC, higher Edition (ICD-10) codes used were: K50 for CD and K51 [3,17,18] [2,19] risks have been reported in females or in males , as for UC. Patients with an emergency hospital admission of well as similar risks for females and males[20,21]. three or more consecutive days were classified as severe In the United Kingdom, the prevalence of IBD is cases and included in the study. We selected only those not known accurately, although based on regional stud- admissions for which CD or UC was recorded as the ies, it is thought to affect approximately 150 000 peo- principal diagnosis on the discharge record, and selected ple[1]. Of these, the majority have active IBD, with many only the first admissions for each patient that met the having severe IBD that may lead to substantial inpatient study inclusion criteria during the 8-year study period stays. Our study focused on severe IBD, which we define from 1999 to 2007. We excluded all elective admissions, as an emergency admission to hospital with a length of all day cases and inpatient admissions lasting < 3 d, all stay of ≥ 3 d, because we wanted to study people who admissions subsequent to the first admission, and all were acutely ill with severe IBD. Inclusion of all patients admissions for which CD and UC were recorded on the admitted to hospital, regardless of length of stay, would discharge record as secondary diagnoses to other diseases have covered a wide spectrum of disease severity, from such as colorectal malignancy. elective day case investigation of IBD and admissions Hospitalized prevalence rates for CD and UC were for elective surgery, to emergency care of patients who calculated per 100 000 resident population, using the were severely ill with IBD. numbers of severe hospitalized cases as the numerators Little is known about the prevalence of severe IBD and the Welsh residential population as the denominators. in the United Kingdom, how it varies geographically, and The direct method and the standard European population its relationship with social deprivation. Mortality follow- were used to standardize the prevalence rates. Mortality ing hospitalization for IBD is significant[22], but few stud- rates following hospital admission were calculated using ies have been based on long-term follow-up. Additional- the numbers of deaths (from all causes) as the numerators, ly, little is known about the effect on mortality of social and the total number of hospitalized cases, in the same deprivation and other socio-demographic factors such as time periods, as the denominators. Mortality rates were area of residence and distance from hospital. These are expressed as percentages and calculated at 1 and 5 years important aspects of the epidemiology of IBD in the follow-up from the date of hospital admission. United Kingdom, which are important to understand in To establish how mortality among the CD and UC planning service provision and treatment. patients compared with that in the general population, we The main objective of this study was to establish the used standardized mortality ratios (SMRs). These were prevalence of UC and CD that was severe enough to re- calculated by applying the age- and sex-specific mortality quire admission to hospital for ≥ 3 d, and to report on rates in the general Welsh population to the numbers of subsequent mortality after up to 5 years follow-up. Wales study patients in the corresponding age- and sex-specific has a population of 3 million, and a mixed urban and ru- strata, to calculate the expected number of deaths in the ral geography, with areas of significant social deprivation.