Diagnostic Ionizing Radiation Exposure in a Population-Based Cohort of Children with Inflammatory Bowel Disease

Transcription

1 Diagnostic Ionizing Radiation Exposure in a Population-Based Cohort of Children with Inflammatory Bowel Disease Lena B. Palmer MD, Carol Q. Porter, Michael D. Kappelman MD MPH No relevant financial disclosures

2 Disclosures: I do not have any relevant financial relationships with ihany commercial ilinterests

3 Background Ionizing radiation may increase the risk of malignancy Risk to children is higher than to adults Excess risk of cancer death attributed to CT prior to age 15 estimated at 1:2000 Diagnostic radiation has become an important component of evaluation and management of inflammatory bowel disease (IBD) Little is known about utilization of diagnostic radiation in children with IBD Brenner, Pediatric Radiology 2002; 32: ; Newnham et al. Aliment Pharmacol Ther. 2007;26(7): Desmond et al. Gut Peloquin et al. Am J Gastroenterol. 2008;103(8):

4 Aims 1) To describe the utilization of diagnostic ionizing radiation in a population-based cohort of pediatric patients (age 18) with ulcerative colitis (UC) or Crohn s disease (CD) 2) To determine patient characteristics associated with moderate/high-dosedose radiation exposure

5 Methods Study Design Cross-sectional analysis of health insurance claims, Subjects 3 claims with primary diagnosis of UC or CD or 1 claim & 1 Rx for an IBD-specific medication* Continuously enrolled over 24 month observation period Source of Data PharMetrics Patient t Centric Database (IMS Health, Watertown, MA) 87 health plans, 33 states *Kappelman et al. Clin Gastro Hep. 2007;5(12):

6 Outcome Description All occurrences of 23 diagnostic studies identified via CPT codes X-rays of chest, abdomen, pelvis, bone mineral density, IVP Upper GI series, small bowel series, barium enema, fistulogram, ERCP, cholangiogram, enteroclysis, CT enterography, CT & CTA of head, neck, extremities, chest, coronaries, abdomen, pelvis Studies classified by level of dose Low dose (X-ray); average 0.06 msv Medium dose (Fluoroscopy); average 4.5 msv High dose (CT); average 5.9 msv

7 Imaging Utilization Comparison Age Gender Geographical region (East, South, Midwest, West) IBD medication use (oral/rectal salicylates, infliximab, adalimumab, methotrexate, 6-MP/ azathioprine, and oral steroids) Requirement for hospitalization or inpatient GI surgery Statistical Analysis: Pearson s Chi-Square and Wilcoxon Rank-Sum

8 Regression Analysis Characteristics associated with moderate/ high dose imaging 1 high dose study or 3 medium dose studies Multivariable logistic regression Separate models for UC and CD Some medications not commonly used in UC at the time of the study were excluded from regression modeling due to sparse observations (infliximab & adalimumab)

9 Sample Characteristics

10 Moderate/High Dose Imaging by Disease Type % Receipt Mod/High Dose Imaging Ulcerative Colitis Crohn's Disease

11 Distribution of Study Type, Crohn s Disease 100% 80% 60% 40% 20% 0% Number of Studies Effective Dose CT Fluoroscopy X-ray

12 Factors associated with Moderate/High Dose Imaging

13 Factors associated with Moderate/High Dose Imaging

14 Immunomodulators & Moderate/High Dose Imaging *Crohn s subjects only

15 Summary 33% of Crohn s Disease & 23% of UC exposed to moderate/ high dose imaging Surgery, hospitalization, & oral steroid use are positively associated Immunomodulator use is inversely associated in Immunomodulator use is inversely associated in Crohn s disease subjects unexposed to steroids

16 Potential Limitations Cross-sectional design Administrative data lacks clinical detail Misclassification bias Unable to sub-classify by disease phenotype, extent, severity & time from diagnosisi

17 Strengths Large, population-based pediatric cohort Able to examine UC and CD independently Complete capture of all imaging g studies

18 Conclusions Over 2 years, a substantial proportion of children were exposed to ionizing radiation A lifetime of diagnostic testing will magnify the risk Dose-reduction strategies or alternative Dose reduction strategies or alternative procedures are needed to avoid unnecessary risk of malignancy

19 Acknowledgements Special thanks to Hans Herfarth, MD & Lynn Fordham, MD for their guidance in completion of this work This work was supported by T32 NIH training grant number 5-T32 DK and CGIBD grant number P30 DK

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21 Risk from one Abdominal CT 5-15 yr old 1 in excess risk Brenner, Pediatric Radiology 2002; 32:

22 Effective Dose GI Radiology

23 Total Number of Studies by Study Type #Studies Ulcerative Colitis Crohn's Disease CT Fluoroscopy X-ray

24 Total Effective Dose by Study Type Eff. Dose 4000 (msv) Ulcerative Colitis Crohn's Disease CT Fluoroscopy X-Ray

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26 Lifetime Attributable Risk Brenner, Pediatric Radiology 2002; 32:

27 Quantifying exposure to diagnostic medical radiation in patients with IBD: are we contributing to malignancy? Newnham et al, Alim Pharm Ther 2007: 26 ( ) Single, tertiary IBD referral center (Australia) 100 consecutive pt, 62 CD/48 UC Mean Age 39 (16-84) UK radiation tables used to assign ED*; 50 msv considered high risk Results: Med ED 10 msv (0 277); Med Annual Rate = 5.4 msv 11 % received 50 msv 31 % received no abdominal exposure CD & pt undergoing surgery had increased odds of exposure *ED = Effective Dose OR for UC 0.33 (95%CI ), OR 3.01 (95%CI )

28 Crohn's disease: factors associated with exposure to high levels of diagnostic radiation Desmond et al, Gut 2008: (online) April 29 Single, tertiary referral center (Ireland) 325 pt, Mean age 32 (8 78) July 1992-June 2007; mean f/u 6.7 yrs UK radiation tables used to assign ED; 75 msv considered high risk Results: CT: 16% of exposure, 77% of total ED Mean ED 36.1 msv; Mean annual rate: 8.1 msv 15.5% received >75 msv 24.9% received no exposure

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30 Mean no. studies per pt Mean CED per pt

31 Diagnostic Ionizing Radiation Exposure in a Population-Based Cohort of Patients with IBD Peloquin et al, Am J Gastro 2008;103:1 8 Population based (Olmsted Co) 215 pt, 103 CD/ 112 UC; Mean age at dz 38/ 39 Jan Dec 2001; mean f/u 9 yr ED calculated using institution parameters, individual patient data & published estimates Results: CT: 12% of exposure, 51% / 40% of ED for CD/ UC Med ED= 26.6 msv (0 279) & 10.5 msv (0 251) Med Annual Rate = 3.1 msv / 1.2 msv CD received 2.46 times ED than UC (P = 0.001)

32 Summary Diagnostic medical radiation may increase risk of malignancy Children are more vulnerable to radiation than adults Adults with IBD undergo multiple imaging studies Some exposed to high levels of radiation Little is known about diagnostic medical radiation exposure in children with IBD