A systematic review of validated methods for identifying anaphylaxis, including anaphylactic shock and angioneurotic edema, using administrative and claims data

Improving Methods of Identifying Anaphylaxis for Medical Product Safety Surveillance Using Natural Language Processing and Machine Learning

We sought to determine whether machine learning and natural language processing (NLP) applied to electronic medical records could improve performance of automated health-care claims-based algorithms to identify anaphylaxis events using data on 516 patients with outpatient, emergency department, or inpatient anaphylaxis diagnosis codes during 2015-2019 in 2 integrated health-care institutions in the Northwest United States. We used one site's manually reviewed gold-standard outcomes data for model development and the other's for external validation based on cross-validated area under the receiver operating characteristic curve (AUC), positive predictive value (PPV), and sensitivity. In the development site 154 (64%) of 239 potential events met adjudication criteria for anaphylaxis compared with 180 (65%) of 277 in the validation site. Logistic regression models using only structured claims data achieved a cross-validated AUC of 0.58 (95% CI: 0.54, 0.63). Machine learning improved cross-validated AUC to 0.62 (0.58, 0.66); incorporating NLP-derived covariates further increased cross-validated AUCs to 0.70 (0.66, 0.75) in development and 0.67 (0.63, 0.71) in external validation data. A classification threshold with cross-validated PPV of 79% and cross-validated sensitivity of 66% in development data had cross-validated PPV of 78% and cross-validated sensitivity of 56% in external data. Machine learning and NLP-derived data improved identification of validated anaphylaxis events.

Direct Versus Indirect Query Performance of ICD-9/-10 Coding to Identify Anaphylaxis

BACKGROUND

Anaphylaxis is an often under =diagnosed, severe allergic event for which epidemiological data are sporadic. Researchers have leveraged administrative and claims data algorithms to study large databases of anaphylactic events; however, little longitudinal data analysis is available after transition to the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM).

OBJECTIVE

Study longitudinal trends in anaphylaxis incidence using direct and indirect query methods.

METHODS

Emergency department (ED) and inpatient data were analyzed from a large state health care administration database from 2011 to 2020. Incidence was calculated using direct queries of anaphylaxis ICD-9-CM and ICD-10-CM codes and indirect queries using a symptom-based ICD-9-CM algorithm and forward mapped ICD-10-CM version to identify undiagnosed anaphylaxis episodes and to assess algorithm performance at the population level.

RESULTS

An average of 2.4 million inpatient and 7.5 million ED observations/y were analyzed. Using the direct query method, annual ED anaphylaxis cases increased steadily from 1,454 (2011) to 4,029 (2019) then declined to 3,341 in 2020 during the coronavirus disease 2019 (COVID-19) pandemic. In contrast, inpatient cases remained relatively steady, with a slight decline after 2015 during the ICD version transition, until a significant drop occurred in 2020. Using the indirect queries, anaphylaxis cases increased markedly after the ICD transition year, especially involving drug-related anaphylaxis.

CONCLUSIONS

Nontypical drug associations with anaphylaxis episodes using the ICD-10-CM version of the algorithm suggest poor performance with drug-related codes. Further, the increased granularity of ICD-10-CM identified potential limitations of a previously validated symptom-based ICD-9-CM algorithm used to detect undiagnosed cases.

Anaphylaxis among elderly emergency department patients in a large health system in New York

BACKGROUND

Anaphylaxis in the elderly is poorly understood.

OBJECTIVE

To elucidate demographic, clinical, and management characteristics of older adults presenting to emergency departments (EDs) with National Institute of Allergy and Infectious Diseases (NIAID) criteria-confirmed anaphylaxis vs milder, non-anaphylactic acute allergic reactions (AARs).

METHODS

A retrospective analysis of ED patients more than or equal to 65 years was conducted, using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or ICD-9-based algorithms incorporating the NIAID diagnostic criteria. Descriptive statistics were generated, and the abovementioned characteristics were compared between cohorts.

RESULTS

Of 164 eligible visits, 71 (43.3%), 90 (54.9%), and 3 (1.8%) cases were identified by ICD-9 codes, the algorithms, or both, respectively. Only half fulfilled NIAID diagnostic criteria. Compared with the non-anaphylactic AAR group, criteria-confirmed anaphylaxis group had lower drug allergy rates (43.9% vs 61.0%, P = .03) but higher food allergy rates (26.8% vs 12.2%, P = .02). For the criteria-confirmed anaphylaxis group, presenting signs and symptoms in descending frequency were mucocutaneous, respiratory, cardiovascular, and gastrointestinal. Criteria-confirmed anaphylaxis group had higher rates of prior anaphylaxis (13.4% vs 2.4%, P = .009), pre-ED (12.2% vs 0.0%, P = .001) or ED (72.0% vs 4.9%, P < .001) epinephrine administration, and allergy referral (17.1% vs 2.4%, P = .002). Tryptase levels were rarely ordered, occurring once in the criteria-confirmed anaphylaxis group and never in the non-anaphylactic AAR group. Despite low mortality (n = 1), 64.6% of the criteria-confirmed anaphylaxis cohort required hospitalization, with 23.2% admitted to intensive care unit.

CONCLUSION

Diagnosis of elderly ED patients with anaphylaxis remains suboptimal. Identifying NIAID criteria-confirmed cases remain challenging, using the existing methods. Management of these patients poorly adheres to current guidelines.

Physician adjudication of angioedema diagnosis codes in a population of patients with heart failure prescribed angiotensin-converting enzyme inhibitor therapy

PURPOSE

Our objective was to calculate the positive predictive value (PPV) of the ICD-9 diagnosis code for angioedema when physicians adjudicate the events by electronic health record review. Our secondary objective was to evaluate the inter-rater reliability of physician adjudication.

METHODS

Patients from the Cardiovascular Research Network previously diagnosed with heart failure who were started on angiotensin-converting enzyme inhibitors (ACEI) during the study period (July 1, 2006 through September 30, 2015) were included. A team of two physicians per participating site adjudicated possible events using electronic health records for all patients coded for angioedema for a total of five sites. The PPV was calculated as the number of physician-adjudicated cases divided by all cases with the diagnosis code of angioedema (ICD-9-CM code 995.1) meeting the inclusion criteria. The inter-rater reliability of physician teams, or kappa statistic, was also calculated.

RESULTS

There were 38 061 adults with heart failure initiating ACEI in the study (21 489 patient-years). Of 114 coded events that were adjudicated by physicians, 98 angioedema events were confirmed for a PPV of 86% (95% CI: 80%, 92%). The kappa statistic based on physician inter-rater reliability was 0.65 (95% CI: 0.47, 0.82).

CONCLUSIONS

ICD-9 diagnosis code of 995.1 (angioneurotic edema, not elsewhere classified) is highly predictive of angioedema in adults with heart failure exposed to ACEI.

Validity of hospital ICD-10-GM codes to identify anaphylaxis

PURPOSE

Anaphylaxis (ANA) is an important adverse drug reaction. We examined positive predictive values (PPV) and other test characteristics of ICD-10-GM code algorithms for detecting ANA as used in a multinational safety study (PASS).

METHODS

We performed a cross-sectional study on routine data from a German academic hospital (2004-2019, age ≥ 18). Chart review was used for case verification. Potential cases were identified from the hospital administration system. The main outcome required at least one of the following: any type of specific in-hospital code (T78.2, T88.6, and T80.5) OR specific outpatient code in combination with a symptom code OR in-hospital non-specific code (T78.4, T88.7, and Y57.9) in combination with two symptom codes. PPV were calculated with 95% confidence interval. Sensitivity analyses modified type of codes, unit of analysis, verification criteria and time period. The most specific algorithm used only primary codes for ANA (numbers added in brackets).

RESULTS

Four hundred and sixteen eligible cases were evaluated, and 78 (37) potential ANA cases were identified. PPV were 62.8% (95% CI 51.1-73.5) (main) and 77.4% (58.9-90.4) (most specific). PPV from all modifications ranged from 12.9% to 80.6%. The sensitivity of the main algorithm was 66.2%, specificity 91.5%, and negative predictive value 92.6%. Corresponding figures for the most specific algorithm were 32.4%, 98.0%, and 87.0%.

CONCLUSIONS

The PPV of the main algorithm seems of acceptable validity for use in comparative safety research but will underestimate absolute risks by about a third. Restriction to primary discharge codes markedly improves PPV to the expense of reducing sensitivity.

Development and validation of a predictive model algorithm to identify anaphylaxis in adults with type 2 diabetes in U.S. administrative claims data

PURPOSE

To use medical record adjudication and predictive modeling methods to develop and validate an algorithm to identify anaphylaxis among adults with type 2 diabetes (T2D) in administrative claims.

METHODS

A conventional screening algorithm that prioritized sensitivity to identify potential anaphylaxis cases was developed and consisted of diagnosis codes for anaphylaxis or relevant signs and symptoms. This algorithm was applied to adults with T2D in the HealthCore Integrated Research Database (HIRD) from 2016 to 2018. Clinical experts adjudicated anaphylaxis case status from redacted medical records. We used confirmed case status as an outcome for predictive models developed using lasso regression with 10-fold cross-validation to identify predictors and estimate the probability of confirmed anaphylaxis.

RESULTS

Clinical adjudicators reviewed medical records with sufficient information from 272 adults identified by the anaphylaxis screening algorithm, which had an estimated Positive Predictive Value (PPV) of 65% (95% confidence interval [CI]: 60%-71%). The predictive model algorithm had a c-statistic of 0.95. The model's probability threshold of 0.60 excluded 89% (84/94) of false positives identified by the screening algorithm, with a PPV of 94% (95% CI: 91%-98%). The model excluded very few true positives (15 of 178), and identified 92% (95% CI: 87%-96%) of the cases selected by the screening algorithm.

CONCLUSIONS

Predictive modeling techniques yielded an accurate algorithm with high PPV and sensitivity for identifying anaphylaxis in administrative claims. This algorithm could be considered in future safety studies using similar claims data to reduce potential outcome misclassification.

New York State cases of anaphylaxis in elderly patients from 2000 to 2010

BACKGROUND

Limited information is available on the effect of anaphylaxis, a severe, potentially life-threatening allergic reaction, in the elderly population.

OBJECTIVE

To elucidate the frequency of anaphylaxis and the demographic characteristics of elderly patients admitted to New York hospitals from 2000 to 2010.

METHODS

A retrospective analysis of hospitalized patients aged 65 years and older in New York from 2000 to 2010 was conducted using the Statewide Planning and Research Cooperative System, a statewide administrative database. Cases were identified using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or an ICD-9-based diagnostic algorithm incorporating the National Institutes of Allergy and Infectious Disease diagnostic criteria. The χ² test was used to measure the association between demographic characteristics and group membership. Regression was used to model group and age as a function of hospital rates.

RESULTS

A total of 3673 hospitalizations were analyzed. Anaphylaxis ICD-9 codes identified 1790 cases (48.7%), the algorithms identified 1701 cases (46.3.%), and 182 cases (5.0%) were identified by both. Hospitalization rates increased significantly during this period (P < .001). Women comprised 61.5% and people of white race comprised 69.8% of the sample. Distribution by age differed by ascertainment method (ICD-9 vs algorithm) among the early-old group (65-74 years of age; 53.8% vs 41.8%) and among the late-old group (≥85 years of age; 11.2% vs 19.3%).

CONCLUSION

Hospitalization rates and anaphylaxis cases increased during the study period among the hospitalized elderly population of New York. Relying on anaphylaxis ICD-9 codes alone missed approximately half of possible cases. The identification and possibly the effect of anaphylaxis among the elderly population may differ, depending on age, race, payer, New York County, and disposition.

Non-Vitamin K Antagonist Oral Anticoagulants and Angioedema: A Cohort and Case-Crossover Study

INTRODUCTION

Patients taking non-vitamin K antagonist oral anticoagulants (NOACs) such as dabigatran, rivaroxaban, and apixaban have reported experiencing angioedema in randomized trials and routine care.

OBJECTIVE

The aim of this study was to quantify the association between NOACs and angioedema relative to warfarin among routinely treated patients with atrial fibrillation in a cohort study. We also compared warfarin users with non-users in a case-crossover study.

METHODS

We utilized a cohort design that drew eligible patients from the Truven Health MarketScan Commercial database, the Optum^© Clinformatics^® Data Mart, and Medicare. Within each database, we compared the 6-month relative rate of angioedema among new users of NOACs (dabigatran, rivaroxaban, apixaban) and new users of warfarin. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for confounders using propensity score stratification, and meta-analyzed the database-specific HRs using a random-effects model. We also estimated an odds ratio (OR) for the association between warfarin and angioedema using a case-crossover design, a self-controlled design that controls for time-invariant confounders.

RESULTS

In the cohort study, we observed 249 incident angioedema events among 267,681 NOAC initiators and 281,143 warfarin initiators across all databases. The meta-analyzed HR for angioedema comparing any NOAC versus warfarin was 0.98 (95% CI 0.76-1.27). In the case-crossover design, the OR for the association between warfarin and angioedema was 0.91 (95% CI 0.68-1.21) based on 431 cases.

CONCLUSIONS

Our estimates were inconsistent with substantial short-term relative increases in the rate of angioedema associated with oral anticoagulant therapy.

Challenges and Opportunities for Using Big Health Care Data to Advance Medical Science and Public Health

Methodological advancements in epidemiology, biostatistics, and data science have strengthened the research world's ability to use data captured from electronic health records (EHRs) to address pressing medical questions, but gaps remain. We describe methods investments that are needed to curate EHR data toward research quality and to integrate complementary data sources when EHR data alone are insufficient for research goals. We highlight new methods and directions for improving the integrity of medical evidence generated from pragmatic trials, observational studies, and predictive modeling. We also discuss needed methods contributions to further ease data sharing across multisite EHR data networks. Throughout, we identify opportunities for training and for bolstering collaboration among subject matter experts, methodologists, practicing clinicians, and health system leaders to help ensure that methods problems are identified and resulting advances are translated into mainstream research practice more quickly.

Angioedema Among Hypertensive Patients Treated with Aliskiren or Other Antihypertensive Medications in the United States

BACKGROUND

A non-interventional study suggested that use of angiotensin-converting enzyme inhibitors (ACEIs) or aliskiren was associated with an angioedema risk three times that of beta-blockers (BBs).

OBJECTIVE

The aim was to assess angioedema incidence rates (IRs) and the relative angioedema risk of aliskiren compared to other antihypertensive drugs (AHDs).

METHODS

A cohort study in hypertensive patients with an AHD prescription between 2007 and 2012 was conducted using data from the US PharMetrics Plus™ claims database. Angioedema was identified using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM) code 995.1. Additionally, a nested case-control analysis was conducted to assess the relative angioedema risk of aliskiren or other AHDs versus BBs.

RESULTS

A total of 3,090,114 patients were included (aliskiren n = 30,720). There were 15,744 angioedema events (IR 2.28/1000 person-years; 95% confidence interval (CI) 2.24-2.32). Aliskiren IRs were: any aliskiren 2.58 (2.08-3.17), aliskiren monotherapy 1.71 (0.74-3.37), aliskiren fixed-dose combination (FDC) 1.27 (0.41-2.96), and aliskiren free-standing combination (FSC) 2.93 (2.31-3.66). The case-control analysis included 15,100 angioedema cases and 60,400 controls; the angioedema risk for both aliskiren monotherapy and FDC was not significantly different from BBs [adjusted odds ratio (adjOR) 0.99 (95% CI 0.45-2.20) and 1.06 (0.40-2.76)]; aliskiren FSC was associated with an increased angioedema risk [adjOR 3.29 (2.42-4.48)], mainly driven by concomitant ACEI use [adjOR 7.03 (4.10-12.05)].

CONCLUSIONS

The IR and risk of angioedema in patients with aliskiren monotherapy or FDC are comparable to BBs. The higher IR and risk of angioedema identified in the aliskiren FSC group may largely be driven by the concomitant use of ACEIs.

Positive predictive values of International Classification of Diseases, 10th revision codes for dermatologic events and hypersensitivity leading to hospitalization or emergency room visit among women with postmenopausal osteoporosis in the Danish and Swedish national patient registries

BACKGROUND

Clinical epidemiology research studies, including pharmacoepidemiology and pharmacovigilance studies, use routinely collected health data, such as diagnoses recorded in national health and administrative registries, to assess clinical effectiveness and safety of treatments. We estimated positive predictive values (PPVs) of International Classification of Diseases, 10th revision (ICD-10) codes for primary diagnoses of dermatologic events and hypersensitivity recorded at hospitalization or emergency room visit in the national patient registries of Denmark and Sweden among women with postmenopausal osteoporosis (PMO).

METHODS

This validation study included women with PMO identified from the Danish and Swedish national patient registries (2005-2014). Medical charts of the potential cases served as the gold standard for the diagnosis confirmation and were reviewed and adjudicated by physicians.

RESULTS

We obtained and reviewed 189 of 221 sampled medical records (86%). The overall PPV was 92.4% (95% confidence interval [CI], 85.1%-96.3%) for dermatologic events, while the PPVs for bullous events and erythematous dermatologic events were 52.5% (95% CI, 37.5%-67.1%) and 12.5% (95% CI, 2.2%-47.1%), respectively. The PPV was 59.0% (95% CI, 48.3%-69.0%) for hypersensitivity; however, the PPV of hypersensitivity increased to 100.0% (95% CI, 67.6%-100.0%) when restricting to diagnostic codes for anaphylaxis. The overall results did not vary by country.

CONCLUSION

Among women with PMO, the PPV for any dermatologic event recorded as the primary diagnosis at hospitalization or at an emergency room visit was high and acceptable for epidemiologic research in the Danish and Swedish national patient registries. The PPV was substantially lower for hypersensitivity leading to hospitalization or emergency room visit.

A Simple Allergist-Led Intervention Improves Resident Training in Anaphylaxis

Physicians underrecognize and undertreat anaphylaxis. Effective interventions are needed to improve physician knowledge and competency regarding evidence-based anaphylaxis diagnosis and management (ADAM). We designed and evaluated an educational program to improve ADAM in pediatrics, internal medicine, and emergency medicine residents from two academic medical centers. Anonymous questionnaires queried participants' demographics, prior ADAM clinical experience, competency, and comfort. A pretest assessing baseline knowledge preceded a 45-minute allergist-led evidence-based presentation, including practice with epinephrine autoinjectors, immediately followed by a posttest. A follow-up test assessed long-term knowledge retention twelve weeks later. 159 residents participated in the pretest, 152 participated in the posttest, and 86 participated in the follow-up test. There were no significant differences by specialty or site. With a possible score of 10, the mean pretest score (7.31 ± 1.50) was lower than the posttest score (8.79 ± 1.29) and follow-up score (8.17 ± 1.72) (P < 0.001 for both). Although participants' perceived confidence in diagnosing or managing anaphylaxis improved from baseline to follow-up (P < 0.001 for both), participants' self-reported clinical experience with ADAM or autoinjector use was unchanged. Allergist-led face-to-face educational intervention improves residents' short-term knowledge and perceived confidence in ADAM. Limited clinical experience or reinforcement contributes to the observed decreased knowledge.

Epidemiology of anaphylaxis

Knowledge about the epidemiology of anaphylaxis is based on data from various sources: clinical practice, large secondary clinical and administrative databases of primary care or hospitalized patients, and recent surveys with representative samples of the general population. As several similar results are often reported in several publications and populations, such findings are highly like to be robust. One such finding is that the incidence and prevalence of anaphylaxis are higher than previously thought. Publications from the last 5 years reveal an incidence of between 50 and 112 episodes per 100 000 person-years; estimated prevalence is 0.3-5.1% depending on the rigour of the definitions used. Figures are higher in children, especially those aged 0-4 years. Publications from various geographical areas based on clinical and administrative data on hospitalized patients suggest that the frequency of admissions due to anaphylaxis has increased (5-7-fold in the last 10-15 years). Other publications point to a geographic gradient in the incidence of anaphylaxis, with higher frequencies recorded in areas with few hours of sunlight. However, these trends could be the result of factors other than a real change in the incidence of anaphylaxis, such as changes in disease coding and in the care provided. Based on data from the records of voluntary declarations of death by physicians and from large national databases, death from anaphylaxis remains very infrequent and stands at 0.35-1.06 deaths per million people per year, with no increases observed in the last 10-15 years. Although anaphylaxis can be fatal, recurrence of anaphylaxis--especially that associated with atopic diseases and hymenoptera stings--affects 26.5-54% of patients.

Decreased Serum Epinephrine in Children With Positive Skin Prick Test

Objectives

To evaluate the association between catecholamine levels and skin prick test results among children.

Methods

Two hundred eight first grade children from one elementary school were invited to participate in this study. Skin prick test (SPT) for six allergens (2 house dust mites, cat, dog, mugwort, and pollen mixture) was performed, and patient demographic information was recorded. The parents were surveyed using questionnaires about rhinitis-related symptoms. Finally, venous blood sampling was done to measure catecholamine levels (epinephrine, norepinephrine, and dopamine) by high-performance liquid chromatography.

Results

Out of 208 children, 174 (106 boys and 68 girls) enrolled in this study. Ninety-six of the children (55%) had negative SPT (nonsensitization group), while 78 (45%) had a positive SPT to at least one of six allergens (sensitization group). The diagnosis of chronic rhinitis was more prevalent in the sensitization group (35.9%) than nonsensitization group (26.0%), however the finding was not significant (P=0.186). Epinephrine levels were decreased between the sensitization group compared to the nonsensitization group (P=0.004). There was no difference in norepinephrine and dopamine levels (P>0.05).

Conclusion

Epinephrine levels are lower in children with positive SPT compared to controls, however, the level of the catecholamine was not associated with the presence or absence of rhinitis symptoms.

Pharmacovigilance Considerations for Biosimilars in the USA

In 2015, five or more biosimilars may be approved in the USA. Because no two biologic medicines are identical, postapproval safety monitoring will be critical to detect potential differences in safety signals between a biosimilar, its reference product, and other biosimilars. Postapproval safety monitoring in the USA uses two signal detection systems: spontaneous reporting systems (SRSs) and active surveillance (AS) systems. Both depend on accurate identification of the specific product(s) dispensed or administered to patients, which may be compromised when products from multiple manufacturers share common drug nomenclature or coding. Product identification can present challenges across different healthcare settings, including inpatient and ambulatory care. Common oral-dosage drugs are predominantly dispensed directly to patients by pharmacists, whereas most injectable drugs, including biologics, are administered to patients by healthcare professionals in outpatient clinics or hospitals. Thus, the effectiveness of SRS and AS mechanisms in both pharmacy and medical channels must be given greater consideration as biotechnology matures. In this article, we describe these systems and their limitations. We identify challenges and opportunities for product-specific safety surveillance of biologics in both the pharmacy and medical settings and provide recommendations to improve biologic safety surveillance under the current and future systems envisioned in the Drug Quality and Security Act. As biosimilars are integrated into existing pharmacovigilance systems, distinguishable nonproprietary names and codes for all biologics, as well as other opportunities to improve traceability (e.g., increased use of barcodes), must be considered to ensure patient safety and confidence in this new class of drugs.

The Validity of Claims-Based Algorithms to Identify Serious Hypersensitivity Reactions and Osteonecrosis of the Jaw

Validation of claims-based algorithms to identify serious hypersensitivity reactions and osteonecrosis of the jaw has not been performed in large osteoporosis populations. The objective of this project is to estimate the positive predictive value of the claims-based algorithms in older women with osteoporosis enrolled in Medicare. Using the 2006-2008 Medicare 5% sample data, we identified potential hypersensitivity and osteonecrosis of the jaw cases based on ICD-9 diagnosis codes. Potential hypersensitivity cases had a 995.0, 995.2, or 995.3 diagnosis code on emergency department or inpatient claims. Potential osteonecrosis of the jaw cases had ≥1 inpatient or outpatient physician claim with a 522.7, 526.4, 526.5, or 733.45 diagnosis code or ≥2 claims of any type with a 526.9 diagnosis code. All retrieved records were redacted and reviewed by experts to determine case status: confirmed, not confirmed, or insufficient information. We calculated the positive predictive value as the number of confirmed cases divided by the total number of retrieved records with sufficient information. We requested 412 potential hypersensitivity and 304 potential osteonecrosis of the jaw records and received 174 (42%) and 84 (28%) records respectively. Of 84 potential osteonecrosis of the jaw cases, 6 were confirmed, resulting in a positive predictive value (95% CI) of 7.1% (2.7, 14.9). Of 174 retrieved potential hypersensitivity records, 95 were confirmed. After exclusion of 25 records with insufficient information for case determination, the overall positive predictive value (95% CI) for hypersensitivity reactions was 76.0% (67.5, 83.2). In a random sample of Medicare data, a claim-based algorithm to identify serious hypersensitivity reactions performed well. An algorithm for osteonecrosis of the jaw did not, partly due to the inclusion of diagnosis codes that are not specific for osteoporosis of the jaw.

Angioedema deaths in the United States, 1979-2010

BACKGROUND

Hospital admission data indicate that the angioedema incidence has increased during the past several decades. Little is known about mortality trends.

OBJECTIVES

To count the number of deaths associated with angioedema in the United States, investigate correlations with age, sex, race, and other contributory causes, and analyze trends from 1979 to 2010.

METHODS

All US death certificates in which angioedema was listed as an underlying or contributing cause of death during 1979 to 2010 were analyzed. Age-adjusted mortality rates were analyzed by age, sex, and race. Other conditions designated as the underlying cause of death were investigated.

RESULTS

From 1979 to 2010, there were 5,758 deaths in which angioedema was listed as a contributing cause. The age-adjusted death rate for hereditary angioedema decreased from 0.28 (95% confidence interval [CI] 0.25-0.32) to 0.06 (95% CI 0.05-0.08) per million persons per year. Conversely, mortality for angioedema increased from 0.24 (95% CI 0.21-0.27) to 0.34 (95% CI 0.31-0.37) per million. Blacks constituted 55% of angioedema deaths that were associated with use of angiotensin-converting enzyme inhibitors. On death certificates that listed hereditary angioedema as the underlying cause of death, cancer (frequently lymphoma or leukemia) was the second most commonly listed cause.

CONCLUSION

Angioedema-associated deaths were very rare from 1979 to 2010. Hereditary angioedema deaths became even more so, whereas nonhereditary angioedema deaths increased. Risks associated with angiotensin-converting enzyme inhibitors were higher in blacks. Lack of specific coding for acquired angioedema most likely explains the observed association between cancer and hereditary angioedema. In the future, more granular coding systems may help distinguish hereditary from acquired angioedema.

Case fatality and population mortality associated with anaphylaxis in the United States

BACKGROUND

Anaphylaxis is a serious allergic reaction that can cause death; however, the actual risk of death is unclear.

OBJECTIVE

We sought to estimate the case fatality rate among hospitalizations or emergency department (ED) presentations for anaphylaxis and the mortality rate associated with anaphylaxis for the general population.

METHODS

This was a population-based epidemiologic study using 3 national databases: the Nationwide Inpatient Sample (NIS; 1999-2009), the Nationwide Emergency Department Sample (NEDS; 2006-2009), and Multiple Cause of Death Data (MCDD; 1999-2009). Sources for these databases are hospital and ED discharge records and death certificates, respectively.

RESULTS

Case fatality rates were between 0.25% and 0.33% among hospitalizations or ED presentations with anaphylaxis as the principal diagnosis (NIS+NEDS, 2006-2009). These rates represent 63 to 99 deaths per year in the United States, approximately 77% of which occurred in hospitalized patients. The rate of anaphylaxis-related hospitalizations increased from 21.0 to 25.1 per million population between 1999 and 2009 (annual percentage change, 2.23%; 95% CI, 1.52% to 2.94%), contrasting with a decreasing case fatality rate among hospitalizations (annual percentage change, -2.35%; 95% CI, -4.98% to 0.34%). Overall mortality rates ranged from 0.63 to 0.76 per million population (186-225 deaths per year, MCDD) and appeared stable in the last decade (annual percentage change, -0.31%; 95% CI, -1.54% to 0.93%).

CONCLUSION

From 2006 to 2009, the overwhelming majority of hospitalizations or ED presentations for anaphylaxis did not result in death, with an average case fatality rate of 0.3%. Anaphylaxis-related hospitalizations increased steadily in the last decade (1999-2009), but this increase was offset by the decreasing case fatality rate among those hospitalized; both inpatient and overall mortality rates associated with anaphylaxis appeared stable and were well under 1 per million population. Although anaphylactic reactions are potentially life-threatening, the probability of dying is actually very low. With the prevalence of anaphylaxis on the increase, practitioners need to stay vigilant and follow the treatment guidelines to further reduce anaphylaxis-related deaths.

Concomitant chronic pulmonary diseases and their association with hospital outcomes in patients with anaphylaxis and other allergic conditions: a cohort study

OBJECTIVES

To determine if chronic pulmonary diseases adversely impact selected outcomes in hospitalised patients who have various allergic conditions including anaphylaxis.

DESIGN

A population-based cohort study.

PARTICIPANTS

A statewide hospital inpatient discharge database from Texas, USA, covering the years 2004-2007 was analysed. Patients with anaphylaxis and other allergic conditions were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Within each group of patients (the overall group with various selected allergic conditions and the subgroup with anaphylaxis), the exposure variables were 11 chronic pulmonary diseases including asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.

PRIMARY OUTCOME MEASURES

Admission to an intensive care unit, a prolonged (>3 days) hospital stay, receipt of mechanical ventilation and death in hospital. Logistic regression was used to calculate adjusted OR and 95% CI for these four outcomes.

RESULTS

30 390 patients with allergic conditions were identified, of whom 2410 had anaphylaxis. The following results pertain to the subcohort of patients with anaphylaxis. Median age was 50 years (range 0-95 years) and 1470 (61%) were female. The hospital mortality was 2.7%. Although asthma was not associated with hospital mortality (OR=1.27, 95% CI 0.55 to 2.90), asthmatics had more than twice the odds of non-asthmatics of receiving mechanical ventilation (OR=2.45, 95% CI 1.81 to 3.33). Chronic bronchitis, COPD, emphysema and interstitial lung diseases (ILDs) were also associated with an increased risk of requiring mechanical ventilation. Chronic bronchitis and COPD were associated with a prolonged length of stay: OR=2.69 (95% CI 1.45 to 4.98) and OR=1.86 (95% CI 1.30 to 2.66), respectively. ILD was the only chronic pulmonary disease associated with an elevated risk of hospital mortality: OR=8.71 (95% CI 1.48 to 51.20).

CONCLUSIONS

In this unique analysis of a large database, we found that asthma, COPD and other chronic pulmonary diseases increased the risk of adverse outcomes among hospitalised patients with anaphylaxis.

The U.S. Food and Drug Administration's Mini-Sentinel program: status and direction

The Mini-Sentinel is a pilot program that is developing methods, tools, resources, policies, and procedures to facilitate the use of routinely collected electronic healthcare data to perform active surveillance of the safety of marketed medical products, including drugs, biologics, and medical devices. The U.S. Food and Drug Administration (FDA) initiated the program in 2009 as part of its Sentinel Initiative, in response to a Congressional mandate in the FDA Amendments Act of 2007. After two years, Mini-Sentinel includes 31 academic and private organizations. It has developed policies, procedures, and technical specifications for developing and operating a secure distributed data system comprised of separate data sets that conform to a common data model covering enrollment, demographics, encounters, diagnoses, procedures, and ambulatory dispensing of prescription drugs. The distributed data sets currently include administrative and claims data from 2000 to 2011 for over 300 million person-years, 2.4 billion encounters, 38 million inpatient hospitalizations, and 2.9 billion dispensings. Selected laboratory results and vital signs data recorded after 2005 are also available. There is an active data quality assessment and characterization program, and eligibility for medical care and pharmacy benefits is known. Systematic reviews of the literature have assessed the ability of administrative data to identify health outcomes of interest, and procedures have been developed and tested to obtain, abstract, and adjudicate full-text medical records to validate coded diagnoses. Mini-Sentinel has also created a taxonomy of study designs and analytical approaches for many commonly occurring situations, and it is developing new statistical and epidemiologic methods to address certain gaps in analytic capabilities. Assessments are performed by distributing computer programs that are executed locally by each data partner. The system is in active use by FDA, with the majority of assessments performed using customizable, reusable queries (programs). Prospective and retrospective assessments that use customized protocols are conducted as well. To date, several hundred unique programs have been distributed and executed. Current activities include active surveillance of several drugs and vaccines, expansion of the population, enhancement of the common data model to include additional types of data from electronic health records and registries, development of new methodologic capabilities, and assessment of methods to identify and validate additional health outcomes of interest.