Identification of Inpatient Allergic Drug Reactions Using ICD-9-CM Codes.

BACKGROUND: The study of allergic drug reactions has been limited because of challenges in identifying and confirming cases. OBJECTIVE: To determine the utility of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for identifying inpatient allergic drug reactions and to compare findings with previous data in the emergency department. METHODS: By reviewing medical records of inpatients with ICD-9-CM codes and E codes suggestive of allergic drug reactions at a large urban academic medical center, we determined codes that yielded the most drug allergy cases and identified culprit drugs. RESULTS: In 2005 and 2010, 3337 and 5282 possible allergic drug reactions during hospitalization were identified and 1367 were reviewed. Allergic drug reactions were found in 409 (30.1%) of the reviewed charts, with 172 (29.7%) in 2005 and 237 (30.5%) in 2010. The codes that identified the highest percentage of true allergic drug reactions were dermatitis due to drug (693.0), allergic urticaria (708), angioneurotic edema (995.1), and anaphylaxis (995.0). Antibiotics were the most common cause (44.4%); however, multiple drug classes were often identified as likely culprit drugs. CONCLUSION: Specific ICD-9-CM codes can identify patients with allergic drug reactions, with antibiotics accounting for almost half of true reactions. Most patients with codes 693.0, 995.1, 708, and 995.0 had allergic drug reactions, with 693.0 as the highest yield code. An aggregate of multiple specific codes consistently identifies a cohort of patients with confirmed allergic drug reactions.

Muscular Dystrophy Surveillance, Tracking, and Research Network pilot: Population-based surveillance of major muscular dystrophies at four U.S. sites, 2007-2011.

BACKGROUND: For 10 years, the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) conducted surveillance for Duchenne and Becker muscular dystrophy (DBMD). We piloted expanding surveillance to other MDs that vary in severity, onset, and sources of care. METHODS: Our retrospective surveillance included individuals diagnosed with one of nine eligible MDs before or during the study period (January 2007-December 2011), one or more health encounters, and residence in one of four U.S. sites (Arizona, Colorado, Iowa, or western New York) at any time within the study period. We developed case definitions, surveillance protocols, and software applications for medical record abstraction, clinical review, and data pooling. Potential cases were identified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes 359.0, 359.1, and 359.21 and International Classification of Diseases, Tenth Revision (ICD-10) codes G71.0 and G71.1. Descriptive statistics were compared by MD type. Percentage of MD cases identified by each ICD-9-CM code was calculated. RESULTS: Of 2,862 cases, 32.9% were myotonic, dystrophy 25.8% DBMD, 9.7% facioscapulohumeral MD, and 9.1% limb-girdle MD. Most cases were male (63.6%), non-Hispanic (59.8%), and White (80.2%). About, half of cases were genetically diagnosed in self (39.1%) or family (6.2%). About, half had a family history of MD (48.9%). The hereditary progressive MD code (359.1) was the most common code for identifying eligible cases. The myotonic code (359.21) identified 83.4% of eligible myotonic dystrophy cases (786/943). CONCLUSIONS: MD STARnet is the only multisite, population-based active surveillance system available for MD in the United States. Continuing our expanded surveillance will contribute important epidemiologic and health outcome information about several MDs.

Utility of ICD-9-CM Codes for Identification of Allergic Drug Reactions.

BACKGROUND: The epidemiology of allergic drug reactions is poorly understood due, in large part, to difficulty in identifying true cases in population data sets. Use of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes is a potentially valuable approach that requires formal evaluation. OBJECTIVE: To better understand the utility of ICD-9-CM codes for identification of allergic drug reactions, including the validation of specific codes by chart review. METHODS: We reviewed randomly sampled medical records of patients treated in the emergency department (ED) between January 1, 2001, and December 31, 2006, with ICD-9-CM codes for drug allergy and E codes (E930-949) for adverse drug reactions. RESULTS: During the 6-year period, 11,130 charts were identified by ICD-9-CM and E codes and 1,634 were reviewed. Allergic drug reactions were found in 444 (27%) of the reviewed ED visits. The codes that identified the highest percentage of true allergic drug reactions were dermatitis due to drug (693.0; 87%), adverse reaction to drug (995.2; 52%), and anaphylaxis (995.0; 38%). Patients with both an ICD-9-CM code and an E code had a high likelihood of having an allergic drug reaction (76%). Most allergic drug reactions were attributed to antibiotics (42%), intravenous contrast (7%), and nonsteroidal anti-inflammatory drugs (6%). The estimated frequency of allergic drug reactions increased from 0.49% of ED visits in 2001 to 0.94% in 2012. CONCLUSIONS: Specific ICD-9-CM and E codes can be used in combination to identify allergic drug reactions. Further study of these codes in the inpatient and outpatient settings is necessary to better understand the utility of diagnosis codes for improving epidemiologic research on drug allergy.

Trends in nontuberculous mycobacterial disease in hospitalized subjects in Spain (1997-2010) according to HIV infection.

OBJECTIVES: The aim of the study was to estimate the incidence of nontuberculous mycobacterial (NTM) disease and the rate of NTM disease-related mortality and to analyse trends in these variables according to HIV infection. METHODS: We performed a retrospective study for the period 1997-2010 using data from the Minimum Basic Data Set (MBDS) provided by the Spanish Ministry of Health. The exposure variables were: (i) HIV infection (HIV positive versus HIV negative); (ii) calendar period in relation to widespread use of combination antiretroviral therapy (cART) [1997-1999 (early cART period), 2000-2003 (middle cART period) and 2004-2010 (late cART period)]. The outcome variables were (i) new NTM disease diagnosis and (ii) mortality. RESULTS: A total of 3729 cases of incident NTM disease were collected in MBDS, 1795 in the HIV-negative group and 1934 in the HIV-positive group, among whom 602 deaths occurred, 223 in the HIV-negative group and 379 in the HIV-positive group. The incidence of NTM disease and the rate of NTM disease-related mortality were 1000-fold higher in the HIV-positive group than in the HIV-negative group. Regarding the incidence of NTM disease, in the HIV-negative group the incidence increased from 2.91 to 3.97 events per 1,000,000 patient-years from 1997-1999 to 2004-2010 (P < 0.001), while in the HIV-positive group the incidence decreased from 2.29 to 0.71 events per 1000 patient-years from 1997-1999 to 2004-2010 (P < 0.001). Regarding mortality, in the HIV-negative group mortality increased from 2.63 to 4.26 events per 10,000,000 patient-years from 1997-1999 to 2000-2003 (P = 0.059), and then the rate stabilized at around 3.87 events per 10,000,000 patient-years in 2004-2010 (P = 0.128), while in the HIV-positive group mortality decreased from 4.28 to 1.39 events per 10,000 patient-years from 1997-1999 to 2004-2010 (P < 0.001). CONCLUSIONS: HIV infection was associated with a higher NTM disease incidence and higher NTM disease-related mortality than in the general population, but these rates decreased in the HIV-positive group from 1997-1999 to 2004-2010, whereas the NTM disease incidence increased in the HIV-negative group.