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Incidence of Churg-Strauss Syndrome in Asthma Drug Users: A Population-Based Perspective
LESLIE R. HARROLD, SUSAN E. ANDRADE, ALAN S. GO, A. SONIA BUIST, MARK EISNER, WILLIAM M. VOLLMER, K. ARNOLD CHAN, E. ANN FRAZIER, PETER F. WELLER, MICHAEL E. WECHSLER, ROBERT A. YOOD, KOURTNEY J. DAVIS, and RICHARD PLATT
ABSTRACT.
Objective. To estimate the incidence of Churg-Strauss syndrome (CSS) among a large population of asthma drug users. Methods. A retrospective study was conducted among patients who had been dispensed asthma drugs at 3 managed care organizations. Adults who received ≥ 3 dispensings of an asthma drug during any consecutive 12-month period between January 1, 1995 and June 30, 2000 were identified. Information on patient age, gender, enrollment status, asthma drugs dispensed, and inpatient and outpatient diagnoses and procedures was obtained from automated databases. Chart reviews were performed on persons identified by combinations of diagnostic and billing codes indicative of CSS. A rheumatologist reviewed abstracted information on all subjects; those who met ≥ 2 American College of Rheumatology criteria for CSS were reviewed by 2 clinical experts. Each clinical expert independently rated the cases; disagreements were resolved by consensus. Cases classified as having "probable/definite" CSS were included in these analyses. The incidence of CSS was estimated overall and according to patient gender, age, and calendar year. Results. From a population of 184,667 asthma drug users contributing 606,184 person-years of exposure, 21 incident cases of CSS were identified (overall incidence of 34.6 per million person-years; 95% confidence interval 21.4 to 53.0). Incidence rates did not differ by gender and age group. The incidence rates for 1995, 1996, 1997, 1998, 1999, and the first 6 months of 2000 were 0, 22, 52, 75, 14, and 14 per million person-years respectively. Conclusions. Results from this population-based study suggest a somewhat lower incidence of CSS in asthma drug users than previously reported and provides important information as to the risk of developing CSS from a population-based perspective. (J Rheumatol 2005;32:1076-80) Key Indexing Terms:
CHURG-STRAUSS SYNDROME
From the Meyers Primary Care Institute, University of Massachusetts Medical School and Fallon Foundation, Worcester, MA; Kaiser Permanente of Northern California, Oakland, CA and University of California, San Francisco; Center for Health Research and Oregon Health & Science University, Portland, OR; Channing Laboratory, Harvard School of Public Health and Harvard Medical School, and Harvard Pilgrim Health Care, Boston, MA; GlaxoSmithKline, Research Triangle Park, NC; and the HMO Research Network Center for Education and Research in Therapeutics. Supported by grants from GlaxoSmithKline and from the Agency for Healthcare Research and Quality (HS10391). L.R. Harrold, MD, MPH; S.E. Andrade, ScD, Meyers Primary Care Institute, University of Massachusetts Medical School and Fallon Foundation, and HMO Research Network Center for Education and Research in Therapeutics; A.S. Go, MD, Kaiser Permanente of Northern California, University of California, and HMO Research Network Center for Education and Research in Therapeutics; A.S. Buist, MD, Center for Health Research, Oregon Health & Science University, and HMO Research Network Center for Education and Research in Therapeutics; M. Eisner, MD, Kaiser Permanente of Northern California, University of California, and HMO Research Network Center for Education and Research in Therapeutics; W.M. Vollmer, PhD, Center for Health Research and HMO Research Network Center for Education and Research in Therapeutics; K.A Chan, MD, ScD, Channing Laboratory and Harvard School of Public Health and HMO Research Network Center for Education and Research in Therapeutics; E.A. Frazier, PhD, Center for Health Research and HMO Research Network Center for Education and Research in Therapeutics; P.F. Weller, MD; M.E. Wechsler, MD, Harvard Medical School; R.A. Yood, MD, Meyers Primary Care Institute, University of Massachusetts Medical School and Fallon Foundation, and HMO Research Network Center for Education and Research in Therapeutics; K.J. Davis, PhD, GlaxoSmithKline, Research Triangle Park; R. Platt, MD, MS, Harvard Medical School and HMO Research Network Center for Education and Research in Therapeutics. Address reprint requests to Dr. L.R. Harrold, Department of Medicine, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester MA, 01655. E-mail: HarroldL@ummhc.org Accepted for publication January 10, 2005. |