Algorithms for identification of Guillain–Barré Syndrome among adolescents in claims databases

A review of the risk and precipitating factors for spontaneous coronary artery dissection

Introduction

Spontaneous coronary artery dissection (SCAD) accounts for 1%-4% of cases of acute coronary syndrome (ACS). SCAD is caused by separation occurring within or between any of the three tunics of the coronary artery wall. This leads to intramural hematoma and/or formation of false lumen in the artery, which leads to ischemic changes or infarction of the myocardium. The incidence of SCAD is higher in women than in men, with a ratio of approximately 9:1. It is estimated that SCAD is responsible for 35% of ACS cases in women under the age of 60. The high frequency is particularly observed during pregnancy and in the peripartum period (first week). Traditional risk factors are rare in patients with SCAD, except for hypertension. Patients diagnosed with SCAD have different combinations of risk factors compared with patients who have atherosclerotic changes in their coronary arteries. We presented the most common so-called "non-traditional" risk factors associated with SCAD patients.

Risk factors and precipitating disorders which are associated with SCAD

In the literature, there are few diseases frequently associated with SCAD, and they are identified as predisposing factors. The predominant cause is fibromuscular dysplasia, followed by inherited connective tissue disorders, systemic inflammatory diseases, pregnancy, use of sex hormones or steroids, use of cocaine or amphetamines, thyroid disorders, migraine, and tinnitus. In recent years, the genetic predisposition for SCAD is also recognized as a predisposing factor. The precipitating factors are also different in women (emotional stress) compared with those in men (physical stress). Women experiencing SCAD frequently describe symptoms of anxiety and depression. These conditions could increase shear stress on the arterial wall and dissection of the coronary artery wall. Despite the advancement of SCAD, we can find significant differences in the clinical presentation between women and men.

Conclusion

When evaluating patients with chest pain or other ACS symptoms who have a low cardiovascular risk, particularly female patients, it is important to consider the possibility of ACS due to SCAD, particularly in conditions often associated with SCAD. This will increase the recognition of SCAD and the timely treatment of affected patients.

Prevalence and incidence of neuromuscular conditions in the UK between 2000 and 2019: A retrospective study using primary care data

BACKGROUND

In the UK, large-scale electronic primary care datasets can provide up-to-date, accurate epidemiological information on rarer diseases, where specialist diagnoses from hospital discharges and clinic letters are generally well recorded and electronically searchable. Current estimates of the number of people living with neuromuscular disease (NMD) have largely been based on secondary care data sources and lacked direct denominators.

OBJECTIVE

To estimate trends in the recording of neuromuscular disease in UK primary care between 2000-2019.

METHODS

The Clinical Practice Research Datalink (CPRD) database was searched electronically to estimate incidence and prevalence rates (per 100,000) for a range of NMDs in each year. To compare trends over time, rates were age standardised to the most recent CPRD population (2019).

RESULTS

Approximately 13 million patients were actively registered in each year. By 2019, 28,230 active patients had ever received a NMD diagnosis (223.6), which was higher among males (239.0) than females (208.3). The most common classifications were Guillain-Barre syndrome (40.1), myasthenia gravis (33.7), muscular dystrophy (29.5), Charcot-Marie-Tooth (29.5) and inflammatory myopathies (25.0). Since 2000, overall prevalence grew by 63%, with the largest increases seen at older ages (≥65-years). However, overall incidence remained constant, though myasthenia gravis incidence has risen steadily since 2008, while new cases of muscular dystrophy fell over the same period.

CONCLUSIONS

Lifetime recording of many NMDs on primary care records exceed current estimates of people living with these conditions; these are important data for health service and care planning. Temporal trends suggest this number is steadily increasing, and while this may partially be due to better recording, it cannot be simply explained by new cases, as incidence remained constant. The increase in prevalence among older ages suggests increases in life expectancy among those living with NMDs may have occurred.

Development and Validation of a Model to Identify Alzheimer's Disease and Related Syndromes in Administrative Data

BACKGROUND

Administrative data are used in the field of Alzheimer's Disease and Related Syndromes (ADRS), however their performance to identify ADRS is unknown.

OBJECTIVE

i) To develop and validate a model to identify ADRS prevalent cases in French administrative data (SNDS), ii) to identify factors associated with false negatives.

METHODS

Retrospective cohort of subjects ≥ 65 years, living in South-Western France, who attended a memory clinic between April and December 2013. Gold standard for ADRS diagnosis was the memory clinic specialized diagnosis. Memory clinics' data were matched to administrative data (drug reimbursements, diagnoses during hospitalizations, registration with costly chronic conditions). Prediction models were developed for 1-year and 3-year periods of administrative data using multivariable logistic regression models. Overall model performance, discrimination, and calibration were estimated and corrected for optimism by resampling. Youden index was used to define ADRS positivity and to estimate sensitivity, specificity, positive predictive and negative probabilities. Factors associated with false negatives were identified using multivariable logistic regressions.

RESULTS

3360 subjects were studied, 52% diagnosed with ADRS by memory clinics. Prediction model based on age, all-cause hospitalization, registration with ADRS as a chronic condition, number of anti-dementia drugs, mention of ADRS during hospitalizations had good discriminative performance (c-statistic: 0.814, sensitivity: 76.0%, specificity: 74.2% for 2013 data). 419 false negatives (24.0%) were younger, had more often ADRS types other than Alzheimer's disease, moderate forms of ADRS, recent diagnosis, and suffered from other comorbidities than true positives.

CONCLUSION

Administrative data presented acceptable performance for detecting ADRS. External validation studies should be encouraged.

Lack of Association of Spontaneous Coronary Artery Dissection With Autoimmune Disease

BACKGROUND

Case reports and referral-based studies suggest spontaneous coronary artery dissection (SCAD) is associated with autoimmune diseases and causes 2% to 4% of acute coronary syndromes.

OBJECTIVES

This study determined the association of SCAD with autoimmune diseases, together with incidence and recurrence, in a population-based study.

METHODS

This case-control study took place from 1995 to 2018 within the Rochester Epidemiology Project. The study identified cases with SCAD from diagnosis codes and verified them using coronary angiography images, matching each case to 3 control subjects on age, sex, county, and years of medical history. Autoimmune disease history came from a validated, code-based definition. A multivariable logistic regression model calculated the odds ratio (OR) for SCAD among patients with a history of autoimmune disease, adjusting for race and body mass index.

RESULTS

The study identified 114 cases with SCAD (mean age 51 years and 90% women) and 342 matched control subjects. Autoimmune disease occurred in 13 (11%) cases with SCAD and 40 (12%) control subjects (p = 0.93). Even after adjustment, autoimmune diseases were not associated with SCAD (OR: 0.81; 95% confidence interval [CI]: 0.40 to 1.66). SCAD incidence between 2010 and 2018 (2.7 per 100,000; 95% CI: 1.7 to 3.7) was 10-fold higher than the incidence between 1995 and 2009 (0.3 per 100,000; 95% CI: 0.0 to 0.6). SCAD recurrence was 10% (95% CI: 3% to 16%) at 5 years.

CONCLUSIONS

These findings suggested SCAD pathogenesis is noninflammatory and screening for autoimmune diseases based on SCAD alone is not warranted. The code-based incidence of SCAD has increased over time, highlighting the importance of considering SCAD among patients with acute coronary syndromes.

Epidemiological Features and Economic Burden of Guillain-Barré Syndrome in South Korea: A Nationwide Population-Based Study

BACKGROUND AND PURPOSE

Guillain-Barré syndrome (GBS) is rare, but its symptoms are severe and they occasionally lead to long-term disability. Country-specific epidemiological evidence is useful for detecting potential problems at the population level. This study investigated the epidemiological and economic characteristics of GBS in South Korea.

METHODS

The Korean National Health Insurance Service claims data from 2010 to 2016 were used to identify incident cases as newly hospitalized patients with a primary diagnosis of GBS (the 10th revision of the International Classification Disease code of G61.0). New cases were defined as patients not having claim records for GBS within one year prior to the hospital admission for GBS.

RESULTS

The incidence rate increased by 45.6% between 2010 and 2016, from 1.28 to 1.82 per 100,000 population. All age groups other than <20 years showed increasing trends. The incidence rate was highest in those aged 65 years to 74 years. Approximately 72% of the incident GBS cases had antecedent infection within 42 days before GBS was diagnosed. Children younger than 10 years constituted the highest proportion of antecedent infections (93.7%). The average length of stay per GBS hospitalization was 33.5 days. Patients had an average of 7.48 outpatient visits for GBS treatment per year. The economic burden from a societal perspective of treating GBS during the first year was USD 16,428.

CONCLUSIONS

The increasing incidence trend and substantial economic burden of GBS strongly advocate the development of effective strategies for preventing and managing GBS.

Post-approval Safety Surveillance Study of Golimumab in the Treatment of Rheumatic Disease Using a United States Healthcare Claims Database

Background and Objective

Golimumab is a fully human anti-tumor necrosis factor monoclonal antibody approved for the treatment of rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS). This study estimated rates of prespecified outcomes in patients with RA, PsA or AS initiating golimumab versus matched patients initiating non-biologic systemic (NBS) medications.

Methods

Patients enrolled in a US health plan with rheumatic disease who initiated a study medication were accrued between April 2009 and November 2014. Golimumab initiators were matched by propensity score to NBS initiators in a 1:4 ratio. Outcomes were identified through September 2015. As-treated, as-matched, and nested case–control (NCC) analyses were conducted in the matched cohorts. Sensitivity analyses evaluated the impact of residual confounding and nondifferential misclassification of exposure and outcomes.

Results

Risks of outcomes were similar between golimumab and NBS initiators. In the as-treated analysis, the rate ratio (RR) for depression was elevated during current golimumab use versus golimumab non-use in the NBS cohort [RR 1.45, 95% confidence interval (CI) 1.31–1.61]. This finding was not replicated in as-matched (RR 1.08, 95% CI 0.97–1.19) or NCC (odds ratio 1.01, 95% CI 0.78–1.31) analyses, which focused on incident cases. Sensitivity analyses suggest that depression was sensitive to misclassification, and the RR changed from greater than to less than one across a plausible range of specificity.

Conclusions

This study suggests that there is no association between exposure to golimumab and an increased risk of prespecified outcomes. Increased depression risk in the as-treated analysis was not replicated in other analyses and may be associated with residual imbalance in baseline history or severity of depression.

Electronic supplementary material

The online version of this article (10.1007/s40261-020-00959-7) contains supplementary material, which is available to authorized users.

Incidence of Guillain-Barré Syndrome is not Associated with Influenza Vaccination in the Elderly

We aimed to analyze the incidence of Guillain-Barré syndrome (GBS) and its association with influenza vaccination (IV) in the elderly population. This study included 2470 patients hospitalized with GBS (G61.0) between 2014 and 2016 based on the Korean National Health Insurance Service (NHIS) claims data. We reviewed every medical claim in the 42 days preceding GBS diagnosis looking for precedent causes of GBS. To assess the relationship between IV and the development of GBS, data from the NHIS and the National Vaccination Registry were combined and analyzed. Using a self-controlled case series (SCCS) approach, we calculated the incidence rate ratio by setting the risk period as 42 days following vaccination. The annual background incidence of GBS was estimated at 4.15 per 100,000 persons. More than half of the patients with newly developed GBS had a previous infection or surgery. The incidence of GBS within 42 days of IV was estimated at 0.32 per 100,000 vaccinated persons. SCCS analysis showed that the risk of GBS was not significantly higher. While GBS can potentially develop from various infections, no association was found between GBS and IV. These results will contribute to developing an evidence-based vaccine policy that includes a clear causality assessment of adverse events.

Incidence of Campylobacter-Associated Guillain-Barré Syndrome Estimated from Health Insurance Data

Guillain-Barré syndrome (GBS) is sometimes preceded by Campylobacter infection. We estimated the cumulative incidence of Campylobacter-associated GBS in the United States using a retrospective cohort design. We identified a cohort of patients with an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis code of "intestinal infection due to Campylobacter" (008.43) using MarketScan Research Databases for 2004-2013. Campylobacter patients with an encounter for "acute infective polyneuritis" (AIP; ICD-9-CM 357.0) were identified. Patients with an inpatient encounter having AIP as the principal diagnosis were considered probable GBS cases. Patients with probable GBS ≤8 weeks after the Campylobacter encounter were considered probable Campylobacter-associated GBS cases. For comparison, we repeated this analysis for patients with "other Salmonella infections" (ICD-9-CM: 003). Among 9315 Campylobacter patients, 16 met the case definition for probable GBS. Two were hospitalized with probable GBS ≤8 weeks after the encounter listing a Campylobacter diagnosis (9 and 54 days) and were considered probable cases of Campylobacter-associated GBS; this results in an estimated cumulative incidence of 21.5 per 100,000 Campylobacter patients (95% confidence interval [CI]: 3.7-86.6), or 5% of all estimated GBS cases. The remaining 14 patients were diagnosed with probable GBS on the same encounter (n = 12) or 1-3 days (n = 2), before the encounter listing the Campylobacter diagnosis. Including these cases increased the cumulative incidence to 172 per 100,000 Campylobacter cases (95% CI: 101.7-285.5), 41% of estimated GBS cases. This study, using a method not previously applied to United States data, supports other data that Campylobacter is an important contributor to GBS, accounting for at least 5% and possibly as many as 41% of all GBS cases. These data can be used to inform estimates of the burden of Campylobacter infections, including economic cost.

Guillain-Barré syndrome in Denmark: validation of diagnostic codes and a population-based nationwide study of the incidence in a 30-year period

Purpose: To validate the diagnostic codes for Guillain-Barré syndrome (GBS) in the Danish National Patient Registry (DNPR). Secondly, to examine 30-year trends in the incidence of GBS in Denmark. Patients and methods: We used the DNPR to identify all patients aged 16 and above diagnosed with a primary GBS diagnosis at any Danish department of neurology between 1987 and 2016. Medical files were reviewed according to the clinical criteria of the National Institute of Neurological Disorders and Stroke Committee and classified according to the Brighton criteria. The incidence rate (IR) was calculated based on data from 1987 to 2016 and stratified by season, gender, and age. Results: Over 30 years, we identified 2,319 patients aged 16 and above in the DNPR. From a validation cohort of 573 patients, we were able to retrieve 425 (74.2%) medical files; 356 GBS diagnoses were confirmed. The overall positive predictive value was 83.8% (95% confidence interval (CI): 80.0-87.0). In 99% of the confirmed patients, the Brighton criteria level 1-3 for GBS were met. The IR was fairly stable over 30 years at 1.77 per 100,000 person years (95% CI: 1.70-1.84). The incidence was higher in the winter season (IR ratio compared with summer: 1.18 (95% CI: 1.09-1.29)), and was strongly associated with male gender (IR ratio vs females: 1.44 (95% CI: 1.33-1.57)). IRs rose with age at diagnosis, particularly after the age of 50 in both men and women and a minor peak was observed for total IR in young adults. Conclusion: Primary diagnostic codes for GBS at Danish departments of neurology have high validity. The DNPR is a well-suited data source for epidemiological research on GBS. The Danish nationwide 30-year GBS IR is stable over time and similar to GBS IRs reported in other European and North American populations.

Surgery and risk of Guillain-Barré syndrome: A French nationwide epidemiologic study

OBJECTIVE

To assess the association between Guillain-Barré syndrome (GBS) and recent surgery based on French nationwide data.

METHODS

Data were extracted from the French health administrative databases (SNIIRAM/PMSI). All patients hospitalized for GBS between 2009 and 2014 were identified by ICD-10 code G61.0 as main diagnosis. Patients previously hospitalized for GBS in 2006, 2007, and 2008 were excluded. Surgical procedures were identified from the hospital database. Hospitalizations for surgery with no infection diagnosis code entered during the hospital stay were also identified. The association between GBS and a recent surgical procedure was estimated using a case-crossover design. Case and referent windows were defined as 1-60 days and 366-425 days before GBS hospitalization, respectively. Analyses were adjusted for previous episodes of gastroenteritis and respiratory tract infection, identified by drug dispensing data.

RESULTS

Of the 8,364 GBS cases included, 175 and 257 patients had undergone a surgical procedure in the referent and case windows, respectively (adjusted odds ratio [OR] = 1.53, 95% confidence interval [CI]: 1.25-1.88). A slightly weaker association was observed for surgical procedures with no identified infection during the hospitalization (OR = 1.40, 95% CI: 1.12-1.73). Regarding the type of surgery, only surgical procedures on bones and digestive organs were significantly associated with GBS (OR and 95% CI = 2.78 [1.68-4.60] and 2.36 [1.32-4.21], respectively).

CONCLUSION

In this large nationwide epidemiologic study, GBS was moderately associated with any type of recent surgery and was more strongly associated with bone and digestive organ surgery.

An imputation method for calculating and comparing autoimmune disease incidence using partial case review

PURPOSE

Estimate incidence of autoimmune conditions in a population who received HPV4 vaccine and a comparison unvaccinated population. Electronic health record (EHR) data may contain inaccurate or incomplete coding, while manual chart review of all cases may not be feasible. We propose a method to estimate incidence using EHR data and case review for a sample.

METHODS

Suspected incident cases were identified using ICD-9 codes, laboratory results and medications related to the condition. A random sample of charts was reviewed to confirm the diagnosis and determine disease onset date. Multiple imputation, using a Monte Carlo model including age and disease indicators was used to impute case status of non-reviewed cases. Incidence rate was calculated in each imputed dataset, with median and percentiles giving a distribution for the estimated incidence rate. Sensitivity analyses compared modeled results to results without imputation and results where imputation was applied to the subset of cases identified using specific ICD-9 codes.

RESULTS

The model accounted for differential case confirmation rates by age and method of case identification, identifying a potential safety signal that was missed relying on EHR data alone.

CONCLUSIONS

This method may be useful for computing incidence when full case review is not feasible.

Prenatal Tdap immunization and risk of maternal and newborn adverse events

Many countries recommend combined tetanus toxoid, reduced diphtheria toxoid and acellular pertussis immunization (Tdap) during pregnancy to stimulate transplacental transmission of pertussis antibodies to newborns. The immune system can be altered during pregnancy, potentially resulting in differing immunization risks in pregnant women. The safety of widespread Tdap immunization during pregnancy needs to be established. Our objective was to assess whether prenatal Tdap immunization was associated with adverse birth outcomes, and to evaluate the effect of timing of Tdap administration on these outcomes. We identified pregnancies at delivery in a large insurance claims database (2010-2014). Tdap immunization was categorized as optimal prenatal (27+weeks), early prenatal (<27weeks), postpartum (≤7days post-delivery), or none. Medical claims were searched to identify maternal adverse immunization reactions (e.g. anaphylaxis, fever, Guillian-Barre syndrome [GBS]), adverse birth outcomes (e.g. preeclampsia/eclampsia, premature rupture or membranes, chorioamnionitis) and newborn outcomes (e.g. respiratory distress, pulmonary hypertension, neonatal jaundice). Women with optimal or early prenatal Tdap were compared to those not immunized in pregnancy, using propensity score-weighted log-binomial regression and Cox proportional hazards models to estimate risk ratios (RR) and hazard ratios (HR). We identified 1,079,034 deliveries and 677,075 linked newborns; 11.5% were immunized optimally and 2.3% immunized early. There were 1 case of post-immunization anaphylaxis, and 12 cases of maternal encephalopathy (all post- delivery); there were no cases of GBS. Optimally-timed immunization was associated with small increased relative risks of: chorioamnionitis [RR=1.11, (95% CI: 1.07-1.15), overall risk=2.8%], and postpartum hemorrhage [RR=1.23 (95% DI: 1.18-1.28), overall risk=2.4%]; however, these relative increases corresponded to low absolute risk increases. Tdap was not associated with increased risk of any adverse newborn outcome. Overall, prenatal Tdap immunization was not associated with newborn adverse events, but potential associations with chorioamnionitis consistent with one previous study and postpartum hemorrhage require further investigation.

Quantitative Bias Analysis in Regulatory Settings

Nonrandomized studies are essential in the postmarket activities of the US Food and Drug Administration, which, however, must often act on the basis of imperfect data. Systematic errors can lead to inaccurate inferences, so it is critical to develop analytic methods that quantify uncertainty and bias and ensure that these methods are implemented when needed. "Quantitative bias analysis" is an overarching term for methods that estimate quantitatively the direction, magnitude, and uncertainty associated with systematic errors influencing measures of associations. The Food and Drug Administration sponsored a collaborative project to develop tools to better quantify the uncertainties associated with postmarket surveillance studies used in regulatory decision making. We have described the rationale, progress, and future directions of this project.

Guillain-Barré syndrome following the 2009 pandemic monovalent and seasonal trivalent influenza vaccination campaigns in Spain from 2009 to 2011: outcomes from active surveillance by a neurologist network, and records from a country-wide hospital discharge database

Background

Studies have shown a slight excess risk in Guillain-Barré syndrome (GBS) incidence associated with A(H1N1)pdm09 vaccination campaign and seasonal trivalent influenza vaccine immunisations in 2009–2010. We aimed to assess the incidence of GBS as a potential adverse effect of A(H1N1)pdm09 vaccination.

Methods

A neurologist-led network, active at the neurology departments of ten general hospitals serving an adult population of 4.68 million, conducted GBS surveillance in Spain in 2009–2011. The network, established in 1996, carried out a retrospective and a prospective study to estimate monthly alarm thresholds in GBS incidence and tested them in 1998–1999 in a pilot study. Such incidence thresholds additionally to observation of GBS cases with immunisation antecedent in the 42 days prior to clinical onset were taken as alarm signals for 2009–2011, since November 2009 onwards. For purpose of surveillance, in 2009 we updated both the available centres and the populations served by the network. We also did a retrospective countrywide review of hospital-discharged patients having ICD-9-CM code 357.0 (acute infective polyneuritis) as their principal diagnosis from January 2009 to December 2011.

Results

Among 141 confirmed of 148 notified cases of GBS or Miller-Fisher syndrome, Brighton 1–2 criteria in 96 %, not a single patient was identified with clinical onset during the 42-day time interval following A(H1N1)pdm09 vaccination. In contrast, seven cases were seen during a similar period after seasonal campaigns. Monthly incidence figures did not, however, exceed the upper 95 % CI limit of expected incidence. A retrospective countrywide review of the registry of hospital-discharged patients having ICD-9-CM code 357.0 (acute infective polyneuritis) as their principal diagnosis did not suggest higher admission rates in critical months across the period December 2009-February 2010.

Conclusions

Despite limited power and underlying reporting bias in 2010–2011, an increase in GBS incidence over background GBS, associated with A(H1N1)pdm09 monovalent or trivalent influenza immunisations, appears unlikely.

Assessment of text documentation accompanying uncoded diagnoses in computerized health insurance claims in Japan

Background

Uncoded diagnoses in health insurance claims (HICs) may introduce bias into Japanese health statistics dependent on computerized HICs. This study’s aim was to identify the causes and characteristics of uncoded diagnoses.

Methods

Uncoded diagnoses from computerized HICs (outpatient, inpatient, and the diagnosis procedure-combination per-diem payment system [DPC/PDPS]) submitted to the National Health Insurance Organization of Kumamoto Prefecture in May 2010 were analyzed. The text documentation accompanying the uncoded diagnoses was used to classify diagnoses in accordance with the International Classification of Diseases-10 (ICD-10). The text documentation was also classified into four categories using the standard descriptions of diagnoses defined in the master files of the computerized HIC system: 1) standard descriptions of diagnoses, 2) standard descriptions with a modifier, 3) non-standard descriptions of diagnoses, and 4) unclassifiable text documentation. Using these classifications, the proportions of uncoded diagnoses by ICD-10 disease category were calculated.

Results

Of the uncoded diagnoses analyzed (n = 363 753), non-standard descriptions of diagnoses for outpatient, inpatient, and DPC/PDPS HICs comprised 12.1%, 14.6%, and 1.0% of uncoded diagnoses, respectively. The proportion of uncoded diagnoses with standard descriptions with a modifier for Diseases of the eye and adnexa was significantly higher than the overall proportion of uncoded diagnoses among every HIC type.

Conclusions

The pattern of uncoded diagnoses differed by HIC type and disease category. Evaluating the proportion of uncoded diagnoses in all medical facilities and developing effective coding methods for diagnoses with modifiers, prefixes, and suffixes should reduce number of uncoded diagnoses in computerized HICs and improve the quality of HIC databases.

Expert panel assessment of acute liver injury identification in observational data

BACKGROUND

Observational data are useful for studying drug safety; however, to be effective, accurate outcome measurement is paramount.

OBJECTIVES

This study compared alternative outcome definitions for acute liver injury (ALI) and explored opportunities for improving ALI identification in observational data.

METHODS

The Truven MarketScan® Lab Database (MSLR) was used to identify patients meeting at least 1 of 4 ALI definitions, including definitions based on diagnosis codes, laboratory measures, or combinations of diagnoses, procedures, and/or laboratory measures. Expert panelists reviewed patient data using a Web dashboard. Panelists determined whether they believed the patient had ALI and identified factors influencing their decision. Logistic regression models explored which factors were influential in case determination.

RESULTS

Overall, only 37 of 208 reviewed patients (17.8%) were classified as cases. The diagnosis-based definition yielded no positive cases and the laboratory-based definition yielded the most positive cases (31 of 60). The most influential factors in case classification were occurrence of procedures after the index date (OR = 13.2, 95% CI = 5.3-32.9), no occurrence of drug treatments before the index date (OR = 4.6; 95% CI = 1.6-13.2), occurrence of drug treatments before the index date (OR = 0.3; 95% CI = 0.1-0.6), and no drug treatments after the index date (OR = 0.2; 95% CI = 0.0-0.5).

CONCLUSIONS

Comparing ALI definitions illustrated tradeoffs between the number of plausible cases identified and the likelihood of cases being classified as positive. Future research should refine ALI case definitions, considering the import of laboratory results, procedures, and drugs in defining a case.