11/8/2011. Administrative Definitions of Rheumatoid Arthritis: Rising Prevalence Regardless of Definition Used. No Disclosures. Background.

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1 Administrative Definitions of Rheumatoid Arthritis: Rising Prevalence Regardless of Definition Used Christine A. Peschken, Carol A. Hitchon, Hui Chen, Allan Garland, Hani S. El-Gabalawy, Charles N. Bernstein and Ruth Ann Marrie. University of Manitoba, Winnipeg, MB, Canada No Disclosures American College of Rheumatology Annual Scientific Meeting November 9 th 2011 Background Administrative healthcare databases provide large comprehensive longitudinal datasets to determine trends in chronic disease prevalence, management and outcomes. Their accuracy for identifying RA must be established, given their use for billing purposes and the diagnostic uncertainty inherent in the disease. Recent studies suggest temporal changes in the incidence and prevalence of RA but are inconclusive. 1 Previous studies using administrative datasets have also suggested under-treatment of RA patients, with large gaps in care Myasoedova E, Crowson CS, Kremers HM, Therneau TM, Gabriel SE. Is the incidence of rheumatoid arthritis rising?: results from Olmsted County, Minnesota, Arthritis Rheum Jun;62(6): Lacaille D, Anis AH, Guh DP, Esdaile JM. Gaps in care for rheumatoid arthritis: a population study. Arthritis Rheum Apr 15;53(2):241-8 Background The province of Manitoba has a population of 1,230,270 (June 2010) The province has a universal publicly funded healthcare system covering the entire population. The Population Health Research Data Repository is a comprehensive collection of health-related databases comprising residents of Manitoba. The Administrative Health Database holds records for virtually all physician contacts and hospital admissions, and includes records of all prescriptions filled, regardless of payer. Methods Hospital and physician claims for RA were extracted from the Administrative Health Database to compare the effect of different case definitions on the 5-year period prevalence of RA from 1985 to For each 5 year interval, the mid-year population was used as the denominator. For physician claims, we identified RA using the International classification of diseases' (ICD)-9 code 714. For hospital claims we identified RA using the ICD-9 code 714 from 1985 to 2004, and the ICD-10 codes M05 & M06 from 2004 onward. Methods Four case definitions were used: 1. 2 RA claims 2 months apart from any physician or hospitalization, during the 5 year periods RA claims 2 months apart from any physician or hospitalization during the 5 year periods, but excluded if there was a subsequent claim for another inflammatory arthritis or if not confirmed when seen by a rheumatologist. 2,3 2. MacLean CH, Louie R, Leake B, McCaffrey DF, Paulus HE, Brook RH, et al. Quality of care for patients with rheumatoid arthritis. JAMA 2000; 284: Lacaille D, Anis AH, Guh DP, Esdaile JM. Gaps in care for rheumatoid arthritis: a population study. Arthritis Rheum Apr 15;53(2):

2 Methods Four case definitions were used: 3. 5 claims ever for RA while registered in the database by any physician or hospitalization if registered in the database at least 3 years; or 3 claims if registered in the database for < 3 years. 4, RA claims 2 months apart from a rheumatologist during the 5 year periods. 4.Marrie RA, Yu N, Blanchard J, Leung S, Elliott L. The rising prevalence and changing age distribution of multiple sclerosis in Manitoba. Neurology Feb 9;74(6): : Bernstein CN, Blanchard JF, Rawsthorne P, Wajda A. Epidemiology of Crohn's disease and ulcerative colitis in a central Canadian province: a population-based study. Am J Epidemiol May 15;149(10): Methods: RA Medication Use The Prescription database became available in 1994 Within each case definition, the proportion of patients who had received at least one of the following prescriptions was determined for the three 5 year periods from : Systemic glucocorticoids DMARDs other than methotrexate (sulfasalazine, minocycline, cyclophosphamide, cyclosporine, leflunomide, azathioprine, sodium aurothiomalate, auranofin, aurothioglucose, penicillamine, hydroxychloroquine ) Methotrexate (oral or injectable) Biologic medications (available in 2000) (etanercept, infliximab, anakinra, adalimumab, rituximab, abatacept ) Results: Results: Definition 1: at least two claims, greater than 2 months apart, by any physician. Definition 2: at least two claims, greater than 2 months apart, by any physician. Excluded if there was a subsequent claim for another inflammatory arthritis or if not confirmed when seen by a rheumatologist Results: Results: Definition 3: at least 5 claims ever for RA while registered in the database if registered in the database at least 3 years; or 3 claims if registered in the database for < 3 years. Definition 4: at least two claims, greater than 2 months apart, by a rheumatologist. 2

3 Results: Medications: Proportion of Patients Receiving 1 Glucocorticoid Prescriptions, According to RA definition Used Regardless of definition used, prevalence rates increased over the 25 year time period. In the most recent time period the prevalence was 0.38%-0.70%, depending on the case definition. Medications: Proportion of Patients Receiving 1 Glucocorticoid Prescriptions, According to RA definition Used Proportion Medications: of Proportion Patients Receiving of Patients 1 Glucocorticoid Receiving 1 Glucocorticoid Prescriptions, According Prescriptions, to RA According definition to Used RA definition Used Medications: Proportion of Patients Receiving 1 DMARD (non-mtx) Prescription, According to RA definition Used Proportion Medications: of Patients Proportion Receiving of Patients 1 DMARD Receiving (non-mtx) 1 DMARD Prescription, (non-mtx) 3

4 Proportion Medications: of Patients Proportion Receiving of Patients 1 DMARD Receiving (non-mtx) 1 DMARD Prescription, (non-mtx) Medications: Proportion of Patients Receiving 1 Methotrexate Prescription, According to RA definition Used Proportion Medications: of Patients Proportion Receiving of Patients 1 Methotrexate Receiving 1 Methotrexate Prescription, Proportion Medications: of Patients Proportion Receiving of Patients 1 Methotrexate Receiving 1 Methotrexate Prescription, Medications: Proportion of Patients Receiving 1 Biologic Prescription, According to RA definition Used Proportion Medications: of Patients Proportion Receiving of Patients 1 Biologic Receiving Prescription, 1 Biologic 4

5 Proportion Medications: of Patients Proportion Receiving of Patients 1 Biologic Receiving Prescription, 1 Biologic Medications: Proportion of Patients Receiving 1 of Any RA specific Prescriptions, According to RA definition Used Proportion of Patients Receiving 1 Prescriptions According to RA Definition: Definition 1. 2 RA claims > 2 months apart, with exclusions Proportion of Patients Receiving 1 Prescription According to RA Definition: Definition 3. 5 RA claims, cumulative 51.1% 49.7% 51.2% Glucocorticoids 45.9% 48.6% 53.6% DMARDS (non-mtx) 25.6% 38.5% 51.5% Methotrexate 0.0% 4.8% 10.4% Biologics 71.7% 75.9% 84.0% Any 59.2% 55.6% 57.0% Glucocorticoids 57.9% 59.4% 59.6% DMARDS (non-mtx) 34.5% 52.1% 62.6% Methotrexate 0.0% 6.3% 13.2% Biologics 84.2% 86.9% 91.8% Any Proportion of Patients Receiving 1 Prescription According to RA Definition: Definition 4. 2 RA claims from Rheumatologist 61.9% 60.6% 55.5% Glucocorticoids 77.4% 75.7% 68.6% DMARDS (non-mtx) 40.9% 64.0% 68.6% Methotrexate 0.0% 10.0% 17.8% Biologics 93.5% 97.1% 96.2% Any Irrespective of the case definition used, we found a steady rise in the prevalence of RA over the 25 year period. This may reflect true increased incidence, or improved ascertainment due to increasing awareness of RA among physicians, particularly with respect to early diagnosis of RA. Reduced mortality may also be a contributor 5

6 Improved ascertainment is supported by the sharp increase in the number of rheumatologists in the region between 2000 and This study also demonstrates that only about half of RA patients are followed by rheumatologists, with most receiving no or episodic rheumatology care. Rheumatology care was associated with higher rates of treatment. A case definition requiring cumulative claims may provide the best sensitivity and specificity. Linkage with a clinical database to validate this case definition is ongoing. This study also suggests the care gap may be improving, with more aggressive treatment in recent years. Further efforts at determining continuity of DMARD use, frequency of combination therapy, and disease outcomes are also underway. Thank You 6