Impact of Policies on the Rise in Sepsis Incidence, 2000–2010

Clinical Infectious Diseases MAJOR ARTICLE Impact of Policies on the Rise in Sepsis Incidence, Shruti K. Gohil, 1 Chenghua Cao, 1 Michael Phelan, 2 Thomas Tjoa, 1 Chanu Rhee, 3 Richard Platt, 3 and Susan S. Huang 1 ; for the Centers for Disease Control and Prevention Epicenters Program Division of Infectious Diseases & Health Policy Research Institute, University of California, Irvine School of Medicine, and 2 Department of Statistics, University of California, Irvine; and 3 Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts (See the Editorial Commentary by Cluzet and Lautenbach on pages 704–6.) Background. Sepsis hospitalizations have increased dramatically in the last decade. It is unclear whether this represents an actual rise in sepsis illness or improved capture by coding. We evaluated the impact of Centers of Medicare and Medicaid Services (CMS) guidance after newly introduced sepsis codes and medical severity diagnosis-related group (MS-DRG) systems on sepsis trends. Methods. In this retrospective cohort study of California hospitalizations from January 2000 to December 2010, sepsis was iden- tiﬁed by International Classiﬁcation of Diseases, Ninth Revision (ICD-9) coding (Dombrovskiy method). Sepsis-associated mortality rates were calculated. Logistic regression models evaluated variables associated with sepsis and mortality. Segmented regression time series analysis assessed changes in sepsis frequency for (1) baseline (January 2000 to September 2003); (2) post-CMS guidelines on sepsis coding (October 2003 to September 2007); and (3) after the introduction of MS-DRG (October 2007 to December 2010). Results. Annual hospitalizations with sepsis diagnoses tripled within a decade, from 21.1 to 59.9 cases per 1000 admissions, with a 2.8- and 2.0-fold increase in severe and nonsevere sepsis, respectively, whereas annual admissions remained unchanged and sepsis- associated mortality decreased. Greatest increases were seen for severe sepsis present on admission (3.8-fold increase). Increases in sepsis were temporally correlated with CMS coding guidance and MS-DRG introduction after adjustment for comorbidity and other factors. Conclusions. Sepsis rate increases were associated with introduction of CMS-issued guidance for new sepsis ICD-9 coding and MS- DRGs. Coding artifact (“up-capture” of less severely ill septic patients) may be contributing to the apparent rise in sepsis incidence and decline in mortality. Epidemiologic trends based on administrative data should account for policy-related effects. Keywords. sepsis; healthcare policy; sepsis epidemiology; sepsis mortality. Sepsis, a dangerous inﬂammatory response to infection, is a major cause of morbidity and mortality worldwide [1, 2]. Hos- pitalizations for sepsis have increased steadily during the last 2 decades in the United States. Sepsis accounted for 1.7 million hospitalizations in 2009 and now ranks as the most expensive condition associated with hospitalization, at $15.4 billion in costs annually [2–4]. The alarming rise in sepsis rates has sparked national and global efforts to improve awareness, early recognition, diagno- sis, and management [1, 2]. Meanwhile, signiﬁcant changes in sepsis coding criteria, deﬁnitions, and reimbursements have oc- curred. After the introduction of new International Classiﬁca- tion of Diseases, Ninth Revision (ICD-9) codes in the 995.9x series (October 2002) allowing speciﬁc sepsis diagnosis within a single code, the Centers for Medicare and Medicaid Services Received 14 July 2015; accepted 29 October 2015; published online 19 January 2016. Correspondence: S. K. Gohil, University of California, Irvine Medical Center, Department of Medicine, Division of Infectious Diseases, 333 City Blvd W, City Tower Ste 400, Orange, CA 92868 (skgohil@uci.edu). Clinical Infectious Diseases ® 2016;62(6):695–703 © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com. DOI: 10.1093/cid/civ1019 (CMS) issued guidance on appropriate sepsis coding in October 2003 [5–7]. In October 2007, CMS overhauled the previous di- agnosis-related group (DRG) reimbursement system into the current medical severity DRG (MS-DRG) system in an effort to tie reimbursements to medical severity [8]. Together, these changes have the potential to affect coding practices via increased ease of coding for sepsis and ﬁnancial incentives to capture sepsis cases. It is unclear if sepsis rate increases as measured by large-scale administrative data sets can be fully accounted for by an actual rise in septic illness or whether these trends may, in part, rep- resent an “up-capture” of sepsis due to surveillance bias, where- by individuals not previously categorized as having sepsis might be more likely to be categorized as such [2, 3, 9, 10]. Policy effects on coding practices can have important impact on the epidemiology of other parameters, such as sepsis-associated mortality. Understanding limitations of administrative data to track trends in sepsis burden over time has important public health and policy implications, particularly in the context of government mandates for protocolled sepsis care and public re- porting of sepsis-related outcomes [11]. We sought to evaluate the potential impact of these national policy changes on sepsis frequency and sepsis-associated Policy Impacts on Sepsis Epidemiology CID 2016:62 (15 March)