Validation of ICD-9-CM/ICD-10 coding algorithms for the identification of patients with acetaminophen overdose and hepatotoxicity using administrative data

Comparison of EHR Data-Completeness in Patients with Different Types of Medical Insurance Coverage in the United States

Prior studies have demonstrated that misclassification of study variables due to electronic health record (EHR)-discontinuity can be mitigated by restricting EHR-based analyses to subjects with high predicted EHR-continuity based on a simple algorithm. In this study, we compared EHR continuity in populations covered by Medicare, Medicaid, or commercial insurance. Using claims-linked EHRs from a multicenter network in Massachusetts, including Medicare (MA EHR-Medicare cohort) and Medicaid (MA EHR-Medicaid cohort) claims data; and TriNetX (TriNetX cohort) claims-linked EHR data from 11 US-based healthcare organizations, we assessed (1) EHR-continuity quantified by proportion of encounters captured by EHR (capture proportion (CP)); (2) area under receiver operating curve (AUROC) of previously validated model to identify patients with high EHR-continuity (CP ≥ 0.6); (3) misclassification of 40 patient characteristics, quantified by average standardized absolute mean difference (ASAMD). Study participants were ≥ 65 years (Medicare) or ≥ 18 years (Medicaid, TriNetX) with ≥ 365 days of continuous insurance enrollment overlapping with an EHR encounter. We found that the mean CP was 0.30, 0.18, and 0.19 and AUROC of the prediction model to identify patients with high EHR-continuity was 0.92, 0.89, and 0.77 in the MA EHR-Medicare, MA EHR-Medicaid, and TriNetX cohorts, respectively. Restricting to patients with predicted EHR-continuity percentile of top 20%, 50%, and 50% in MA EHR-Medicare, MA EHR-Medicaid, and TriNetX cohorts resulted in acceptable levels of misclassification (ASAMD < 0.1). Using a prediction model to identify cohorts with high EHR-continuity can improve validity, but cutoffs to achieve this goal vary by population.

Acute Respiratory Distress Syndrome in Patients with Subarachnoid Hemorrhage: Incidence, Predictive Factors, and Impact on Mortality

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is a known predictor of poor outcomes in critically ill patients. We sought to examine the role ARDS plays in outcomes in subarachnoid hemorrhage (SAH) patients. Prior studies investigating the incidence of ARDS in SAH patients did not control for SAH severity. Hence, we sought to determine the incidence ARDS in patients diagnosed with aneurysmal SAH and investigate the predisposing risk factors and impact upon outcomes.

METHODS

A retrospective cohort study was conducted using the National Inpatient Sample (NIS) database for the years 2008 to 2014. Multivariate stepwise regression analysis was performed to identify the risk factors and outcome associated with developing ARDS in the setting of SAH.

RESULTS

We identified 170,869 patients with non-traumatic subarachnoid hemorrhage, of whom 6962 were diagnosed with ARDS and of those 4829 required mechanical ventilation. ARDS more frequently developed in high grade SAH patients (1.97 ± 0.05 vs. 1.15 ± 0.01; p < 0.0001). Neurologic predictors of ARDS included cerebral edema (OR 1.892, CI 1.180-3.034, p = 0.0035) and medical predictors included cardiac arrest (OR 4.642, CI 2.273-9.482, p < 0.0001) and cardiogenic shock (OR 2.984, CI 1.157-7.696, p = 0.0239). ARDS was associated with significantly worse outcomes (15.5% vs. 52.9% discharged home, 63.0% vs. 40.8% discharged to rehabilitation facility and 21.5% vs. 6.3% in-hospital mortality).

CONCLUSION

Patients with SAH who developed ARDS were less likely to be discharged home, more likely to need rehabilitation and had a significantly higher risk of mortality. The identification of risk factors contributing to ARDS is helpful for improving outcomes and resource utilization.

Association of FDA Mandate Limiting Acetaminophen (Paracetamol) in Prescription Combination Opioid Products and Subsequent Hospitalizations and Acute Liver Failure

Importance

In January 2011, the US Food and Drug Administration (FDA) announced a mandate to limit acetaminophen (paracetamol) to 325 mg/tablet in combination acetaminophen and opioid medications, with manufacturer compliance required by March 2014.

Objective

To assess the odds of hospitalization and the proportion of acute liver failure (ALF) cases with acetaminophen and opioid toxicity prior to and after the mandate.

Design, Setting, and Participants

This interrupted time-series analysis used hospitalization data from 2007-2019 involving ICD-9/ICD-10 codes consistent with both acetaminophen and opioid toxicity from the National Inpatient Sample (NIS), a large US hospitalization database, and ALF cases from 1998-2019 involving acetaminophen and opioid products from the Acute Liver Failure Study Group (ALFSG), a cohort of 32 US medical centers. For comparison, hospitalizations and ALF cases consistent with acetaminophen toxicity alone were extracted from the NIS and ALFSG.

Exposures

Time prior to and after the FDA mandate limiting acetaminophen to 325 mg in combination acetaminophen and opioid products.

Main Outcomes and Measures

Odds of hospitalization involving acetaminophen and opioid toxicity and percentage of ALF cases from acetaminophen and opioid products prior to and after the mandate.

Results

In the NIS, among 474 047 585 hospitalizations from Q1 2007 through Q4 2019, there were 39 606 hospitalizations involving acetaminophen and opioid toxicity; 66.8% of cases were among women; median age, 42.2 (IQR, 28.4-54.1). In the ALFSG, from Q1 1998 through Q3 2019, there were a total of 2631 ALF cases, of which 465 involved acetaminophen and opioid toxicity; 85.4% women; median age, 39.0 (IQR, 32.0-47.0). The predicted incidence of hospitalizations 1 day prior to the FDA announcement was 12.2 cases/100 000 hospitalizations (95% CI, 11.0-13.4); by Q4 2019, it was 4.4/100 000 hospitalizations (95% CI, 4.1-4.7) (absolute difference, 7.8/100 000 [95% CI, 6.6-9.0]; P < .001). The odds of hospitalizations with acetaminophen and opioid toxicity increased 11%/y prior to the announcement (odds ratio [OR], 1.11 [95% CI, 1.06-1.15]) and decreased 11%/y after the announcement (OR, 0.89 [95% CI, 0.88-0.90]). The predicted percentage of ALF cases involving acetaminophen and opioid toxicity 1 day prior to the FDA announcement was 27.4% (95% CI, 23.3%-31.9%); by Q3 2019, it was 5.3% (95% CI, 3.1%-8.8%) (absolute difference, 21.8% [95% CI, 15.5%-32.4%]; P < .001). The percentage of ALF cases involving acetaminophen and opioid toxicity increased 7% per year prior to the announcement (OR, 1.07 [95% CI, 1.03-1.1]; P < .001) and decreased 16% per year after the announcement (OR, 0.84 [95% CI, 0.77-0.92]; P < .001). Sensitivity analyses confirmed these findings.

Conclusions and Relevance

The FDA mandate limiting acetaminophen dosage to 325 mg/tablet in prescription acetaminophen and opioid products was associated with a statistically significant decrease in the yearly rate of hospitalizations and proportion per year of ALF cases involving acetaminophen and opioid toxicity.

The impact of poisoning in British Columbia: a cost analysis

BACKGROUND

Poisoning, from substances such as illicit drugs, prescribed and over-the-counter medications, alcohol, pesticides, gases and household cleaners, is the leading cause of injury-related death and the second leading cause for injury-related hospital admission in British Columbia. We examined the health and economic costs of poisoning in BC for 2016, using a societal perspective, to support public health policies aimed at minimizing losses to society.

METHODS

Costs by intent, sex and age group were calculated in Canadian dollars using a classification and costing framework based on existing provincial injury data combined with data from the published literature. Direct cost components included fatal poisonings, hospital admissions, emergency department visits, ambulance attendance without transfer to hospital and calls to the British Columbia Drug and Poison Information Centre (BC DPIC) not resulting in ambulance attendance, emergency care or transfer to hospital. Indirect costs, measured as loss of earnings and informal caregiving costs, were also calculated.

RESULTS

We estimate that poisonings in BC totalled $812.5 million in 2016 with $108.9 million in direct health care costs and $703.6 million in indirect costs. Unintentional poisoning injuries accounted for 84% of total costs, 46% of direct costs and 89% of indirect costs. Males accounted for higher proportions of direct costs for all patient dispositions except hospital admissions. Patients aged 25-64 years accounted for higher proportions of direct costs except for calls to BC DPIC, where proportions were highest for children younger than 15 years.

INTERPRETATION

Hospital care expenditures represented the largest direct cost of poisoning, and lost productivity following death represented the largest indirect cost. Quantifying and understanding the financial burden of poisoning has implications not only for government and health care, but also for society, employers, patients and families.

Early mechanical ventilation for grade IV hepatic encephalopathy is associated with increased mortality among patients with cirrhosis: an exploratory study

BACKGROUND

Unresponsive patients with toxic-metabolic encephalopathies often undergo endotracheal intubation for the primary purpose of preventing aspiration events. However, among patients with pre-existing systemic comorbidities, mechanical ventilation itself may be associated with numerous risks such as hypotension, aspiration, delirium, and infection. Our primary aim was to determine whether early mechanical ventilation for airway protection was associated with increased mortality in patients with cirrhosis and grade IV hepatic encephalopathy.

METHODS

The National Inpatient Sample was queried for hospital stays due to grade IV hepatic encephalopathy among patients with cirrhosis between 2016 and 2019. After applying our exclusion criteria, including cardiopulmonary failure, data from 1,975 inpatient stays were analyzed. Patients who received mechanical ventilation within 2 days of admission were compared to those who did not. Univariable and multivariable logistic regression analyses were performed to identify clinical factors associated with in-hospital mortality.

RESULTS

Of 162 patients who received endotracheal intubation during the first 2 hospital days, 64 (40%) died during their hospitalization, in comparison to 336 (19%) of 1,813 patients in the comparator group. In multivariable logistic regression analysis, mechanical ventilation was the strongest predictor of in-hospital mortality in our primary analysis (adjusted odds ratio, 3.00; 95% confidence interval, 2.14-4.20; P<0.001) and in all sensitivity analyses.

CONCLUSIONS

Mechanical ventilation for the sole purpose of airway protection among patients with cirrhosis and grade IV hepatic encephalopathy may be associated with increased in-hospital mortality. Future studies are necessary to confirm and further characterize our findings.

US Hospital Stays in Children and Adolescents With Acetaminophen Poisoning

OBJECTIVES

Acetaminophen poisoning occurs in all age groups; however, hospital-based outcomes of children with these poisonings were not well characterized. Our objectives were to describe the incidence, characteristics, and outcomes of hospital stays in children with acetaminophen poisoning and evaluate the contribution of intentionality.

METHODS

We used the 2016 Kids' Inpatient Database and validated International Classification of Diseases, 10th Revision diagnostic codes to identify hospitalizations of children aged 0 to 19 years for acetaminophen poisoning. We used standard survey methods to generate weighted population estimates and describe characteristics and outcomes, both overall and stratified by intentionality.

RESULTS

There were 9935 (95% confidence interval [CI], 9252-10 619) discharges from acute care hospitals for acetaminophen poisoning in U.S. children aged 0 to 19 years during 2016, corresponding to a population rate of 12.1 (95% CI, 11.3-12.9) hospitalizations per 100 000 children. Most hospitalizations for both intentional and unintentional acetaminophen poisoning occurred in females, with a strongly age-related sex distribution. Median length of stay was 2 days (interquartile range, 1-4 days); however, nearly half of discharges were subsequently transferred to another type of facility (eg, psychiatric hospital). Median hospital charges for acute care were $14 379 (interquartile range, $9162-$23 114), totaling $204.7 million (95% CI, $187.4-$221.9) in aggregate. Of 31 632 hospital discharges associated with self-harm medication poisoning in children aged 0 to 19 years, acetaminophen was the single most commonly implicated agent.

CONCLUSIONS

Acetaminophen poisoning was the most common cause of U.S. hospital stays associated with medication self-harm poisoning. More effective acetaminophen poisoning prevention strategies are needed, which may reduce the burden of this common adolescent malady.

Oral Fluoroquinolone Use and the Risk of Acute Liver Injury: A Nationwide Cohort Study

BACKGROUND

Antibiotics are considered to be among the most frequent causes of drug-related acute liver injury (ALI). Although many ALIs have mild and reversible clinical outcomes, there is substantial risk of severe reactions leading to acute liver failure, need for liver transplant, and death. Recent studies have raised concerns of hepatotoxic potential related to the use of fluoroquinolones.

METHODS

This study examined the risk of ALI associated with oral fluoroquinolone treatment compared with amoxicillin (419 930 courses, propensity score matched 1:1). The information on drug use was collected from a national, registry-based cohort derived from all Swedish adults aged 40-85 years.

RESULTS

During a follow-up period of 60 days, users of oral fluoroquinolones had a >2-fold risk of ALI compared to users of amoxicillin (hazard ratio, 2.32 [95% confidence interval {CI}, 1.01-5.35). The adjusted absolute risk difference for use of fluoroquinolones as compared to amoxicillin was 4.94 (95% CI, .04-16.3) per 1 million episodes.

CONCLUSIONS

In this propensity score-matched study, fluoroquinolone treatment was associated with an increased risk of ALI in the first 2 months after starting treatment.

A Computable Phenotype for Autosomal Dominant Polycystic Kidney Disease

Background

A computable phenotype is an algorithm used to identify a group of patients within an electronic medical record system. Developing a computable phenotype that can accurately identify patients with autosomal dominant polycystic kidney disease (ADPKD) will assist researchers in defining patients eligible to participate in clinical trials and other studies. Our objective was to assess the accuracy of a computable phenotype using International Classification of Diseases 9th and 10th revision (ICD-9/10) codes to identify patients with ADPKD.

Methods

We reviewed four random samples of approximately 250 patients on the basis of ICD-9/10 codes from the EHR from the Kansas University Medical Center database: patients followed in nephrology clinics who had ICD-9/10 codes for ADPKD (Neph+), patients seen in nephrology clinics without ICD codes for ADPKD (Neph-), patients who were not followed in nephrology clinics with ICD codes for ADPKD (No Neph+), and patients not seen in nephrology clinics without ICD codes for ADPKD (No Neph-). We reviewed the charts and determined ADPKD status on the basis of internationally accepted diagnostic criteria for ADPKD.

Results

The computable phenotype to identify patients with ADPKD who attended nephrology clinics has a sensitivity of 99% (95% confidence interval [95% CI], 96.4 to 99.7) and a specificity of 84% (95% CI, 79.5 to 88.1). For those who did not attend nephrology clinics, the sensitivity was 97% (95% CI, 93.3 to 99.0), and a specificity was 82% (95% CI, 77.4 to 86.1).

Conclusion

A computable phenotype using the ICD-9/10 codes can correctly identify most patients with ADPKD, and can be utilized by researchers to screen health care records for cohorts of patients with ADPKD with acceptable accuracy.

Sleep disorders are associated with acetaminophen-induced adverse reactions and liver injury

Risk factors related to the development of acetaminophen (APAP)-induced adverse reactions and liver injury remain uncertain. Sleep disorders have been linked to some health outcomes. This study examined the associations of sleep disorders with APAP-induced adverse reactions or liver injury and the possible mechanisms. From NIS database, adverse reactions, liver injury and sleep disorders were identified. Factors associated with the risk of the total adverse effects or liver injury were examined with logistic regression. From Gene Expression Omnibus database, datasets GSE111828, containing transcriptome data based on RNA-seq analysis from liver samples extracted from mice post APAP administration, and GSE92913, containing transcriptome data based on microarray analysis from liver samples extracted from mice with sleep deprivation, were analyzed. A total of 4372754 patients without and 91314 patients with sleep disorders were eligible for analyses. Both before and after propensity score matching, APAP-induced adverse reactions were higher in patients with sleep disorders than in patients without. In multivariate regression, sleep disorders were associated with higher odds of APAP-induced adverse reactions (adjusted OR [aOR] 2.005, 95 % CI 1.343-2.995) and liver injury (aOR 2.788, 95 % CI 1.310-5.932). Genes that were enriched in bile secretion and retinol metabolism and PPAR signaling pathways were basically down-regulated in livers of mice after APAP administration and livers of mice with sleep deprivation. This study shows that sleep disorders may be novel independent risk factors for APAP-associated adverse reactions and liver injury and provides bioinformation linking sleep disorders to increased risk of APAP-induced liver injury.

Specificity of International Classification of Diseases codes for bronchopulmonary dysplasia: an investigation using electronic health record data and a large insurance database

OBJECTIVE

International Classification of Diseases (ICD) codes in electronic health records (EHRs) are increasingly used for health services research, in spite of unknown diagnostic accuracy. The accuracy of ICD codes to identify bronchopulmonary dysplasia (BPD) is unknown.

STUDY DESIGN

Retrospective cohort study in a single-center NICU (n = 166) to evaluate sensitivity and specificity of ICD-10 codes for the diagnosis of BPD. Analysis of large insurance claims database (n = 7887) to determine date of assignment of the code.

RESULTS

The sensitivity of any BPD-related ICD codes ranged from 0.82 to 0.95, while the specificity ranged from 0.25 to 0.36. In a large national insurance database, the most common date of ICD-9 or ICD-10 code assignment was the day of birth, which is inconsistent with the clinical definition.

CONCLUSIONS

ICD codes registered for BPD are unlikely to accurately reflect the current clinical definition and should be interpreted with caution.

Hospitalisations for non-fatal overdose among people with a history of opioid dependence in New South Wales, Australia, 2001-2018: Findings from the OATS retrospective cohort study

BACKGROUND

To examine, among a cohort of opioid dependent people with a history of opioid agonist treatment (OAT), the frequency and incidence rates of non-fatal overdose (NFOD) hospital separations over time, by age and sex.

METHODS

Retrospective cohort study of people with a history of OAT using state-wide linked New South Wales (NSW) data. The incidence of NFOD hospital separations involving an opioid, sedative, stimulant or alcohol was defined according to the singular or combination of poisoning/toxic effect using ICD-10-AM codes. Crude incidence rates were calculated by gender, age group and calendar year.

RESULTS

There were 31.8 (31.3-32.3) NFOD per 1,000 person-years (PY). Opioid NFOD incidence was higher in women than men: incidence rate ratio (IRR) 1.11 per 1,000PY; 95 %CI: [1.06-1.17]; women had higher sedative NFOD rates than men, IRR 1.27 per 1,000PY [1.21-1.34]. Participants ≤25 years, 26-30yrs, and 31-35yrs had higher incidence of opioid NFOD compared to 46+yrs, with IRRs of: 1.45 per 1,000PY; [1.32-1.59]; 1.20 per 1,000PY; [1.11-1.30] and 1.22 per 1,000PY; [1.13-1.32], respectively. Between 2006-7 and 2016-17, the cohort accounted for 19 % of NSW opioid NFOD episodes, 12 % of sedative, 14 % of stimulant and 5 % of acute alcohol-related NFOD.

CONCLUSIONS

Hospital stays due to NFOD are a relatively frequent occurrence among opioid-dependent people. There are clear differences in rates and substances involved by sex, age and over time. Evidence-based interventions that prevent overdose among people who are opioid dependent need to be delivered to scale, including widespread community provision of naloxone.

Treatment with isoniazid or rifampin for latent tuberculosis infection: population-based study of hepatotoxicity, completion and costs

Clinical trials suggest less hepatotoxicity and better adherence with 4 months rifampin (4R) versus 9 months isoniazid (9H) for treating latent tuberculosis infection (LTBI). Our objectives were to compare frequencies of severe hepatic adverse events and treatment completion, and direct health system costs of LTBI regimens 4R and 9H, in the general population of the province of Quebec, Canada, using provincial health administrative data.Our retrospective cohort included all patients starting rifampin or isoniazid regimens between 2003 and 2007. We estimated hepatotoxicity from hospitalisation records, treatment completion from community pharmacy records and direct costs from billing records and fee schedules. We compared rifampin to isoniazid using logistic (hepatotoxicity), log-binomial (completion), and gamma (costs) regression, with adjustment for age, co-morbidities and other confounders.10 559 individuals started LTBI treatment (9684 isoniazid; 875 rifampin). Rifampin patients were older with more baseline co-morbidities. Severe hepatotoxicity risk was higher with isoniazid (n=15) than rifampin (n=1), adjusted OR=2.3 (95% CI: 0.3-16.1); there were two liver transplants and one death with isoniazid and none with rifampin. Overall, patients without co-morbidities had lower hepatotoxicity risk (0.1% versus 1.0%). 4R completion (53.5%) was higher than 9H (36.9%), adjusted RR=1.5 (95% CI: 1.3-1.7). Mean costs per patient were lower for rifampin than isoniazid: adjusted cost ratio=0.7 (95% CI: 0.5-0.9).Risk of severe hepatotoxicity and direct costs were lower, and completion was higher, for 4R than 9H, after adjustment for age and co-morbidities. Severe hepatotoxicity resulted in death or liver transplant in three patients receiving 9H, compared with no patients receiving 4R.

External Validation of an Algorithm to Identify Patients with High Data-Completeness in Electronic Health Records for Comparative Effectiveness Research

Objective

Electronic health records (EHR) data-discontinuity, i.e. receiving care outside of a particular EHR system, may cause misclassification of study variables. We aimed to validate an algorithm to identify patients with high EHR data-continuity to reduce such bias.

Materials and Methods

We analyzed data from two EHR systems linked with Medicare claims data from 2007 through 2014, one in Massachusetts (MA, n=80,588) and the other in North Carolina (NC, n=33,207). We quantified EHR data-continuity by Mean Proportion of Encounters Captured (MPEC) by the EHR system when compared to complete recording in claims data. The prediction model for MPEC was developed in MA and validated in NC. Stratified by predicted EHR data-continuity, we quantified misclassification of 40 key variables by Mean Standardized Differences (MSD) between the proportions of these variables based on EHR alone vs the linked claims-EHR data.

Results

The mean MPEC was 27% in the MA and 26% in the NC system. The predicted and observed EHR data-continuity was highly correlated (Spearman correlation=0.78 and 0.73, respectively). The misclassification (MSD) of 40 variables in patients of the predicted EHR data-continuity cohort was significantly smaller (44%, 95% CI: 40–48%) than that in the remaining population.

Discussion

The comorbidity profiles were similar in patients with high vs low EHR data-continuity. Therefore, restricting an analysis to patients with high EHR data-continuity may reduce information bias while preserving the representativeness of the study cohort.

Conclusion

We have successfully validated an algorithm that can identify a high EHR data-continuity cohort representative of the source population.

Effects of poor hepatic reserve in cirrhotic patients with bacterial infections: A population-based study

OBJECTIVE

Ascites, hepatic encephalopathy, hepatorenal syndrome, spontaneous bacterial peritonitis, and esophageal variceal bleeding are major complications associated with cirrhosis. The presence of these complications indicates poor hepatic reserve. This study aimed to identify the effects of poor hepatic reserve on mortality in cirrhotic patients with bacterial infections.

PATIENTS AND METHODS

The Taiwan National Health Insurance Database was used to identify 43,042 cirrhotic patients with bacterial infections hospitalized between January 1, 2010, and December 31, 2013, after propensity score matching analysis. Of these, 21,521 cirrhotic patients had major cirrhotic-related complications and were considered to have poor hepatic reserve.

RESULTS

Mortality rates at 30 and 90 days were 24.2% and 39.5% in the poor hepatic reserve group and 12.8% and 21.7% in the good hepatic reserve group, respectively (P < 0.001 for each group). The cirrhotic patients with poor hepatic reserve (hazard ratio [HR], 2.10; 95% confidence interval [CI] = 2.03-2.18; P < 0.001) had significantly increased mortality at 90 days. The mortality HRs in patients with one, two, and three or more complications compared to patients without complications were 1.92 (95% CI = 1.85-1.99, P < 0.001), 2.61 (95% CI = 2.47-2.77, P < 0.001), and 3.81 (95% CI = 3.18-4.57, P < 0.001), respectively.

CONCLUSION

In cirrhotic patients with bacterial infections, poor hepatic reserve is associated with a poor prognosis. The presence of three or more cirrhotic-related complications increases mortality almost four folds.

Disparities in Access to Mental Health Services Among Patients Hospitalized for Deliberate Drug Overdose

OBJECTIVE

The authors examined patient and hospitalization characteristics associated with receiving a mental health assessment and disposition to an inpatient psychiatric facility among patients hospitalized for deliberate drug overdose.

METHODS

This retrospective analysis of 2012-2013 South Carolina all-payer data included adults ages 18-64 with at least one inpatient admission for a primary diagnosis of deliberate illicit or pharmaceutical drug overdose (N=2,686). Outcomes were receipt of a mental health assessment and disposition to an inpatient psychiatric facility. Multivariable logistic regression models were used to estimate the effects of patient and hospitalization characteristics on study outcomes.

RESULTS

Non-Hispanic blacks and people of other races-ethnicities were less likely than non-Hispanic whites to receive a mental health assessment (non-Hispanic blacks, adjusted odds ratio [AOR]=0.52, 95% CI=0.34-0.81; other races-ethnicities, AOR=0.24, 95% CI=0.12-0.49). Non-Hispanic blacks were also less likely than non-Hispanic whites to be discharged to an inpatient psychiatric facility than to home (AOR=0.60, 95% CI=0.47-0.77). Compared with persons without insurance, those with insurance, except those with Medicaid, were more likely to be discharged to an inpatient psychiatric facility than to home (Medicare, AOR=3.06, 95% CI=2.36-3.96; private, AOR=2.78, 95% CI=2.23-3.47; other, AOR=7.58, 95% CI=4.21-13.6).

CONCLUSIONS

Non-Hispanic white race-ethnicity and having insurance were predictive of receipt of a mental health assessment and disposition to an inpatient psychiatric facility among patients hospitalized for deliberate drug overdose. Study findings can inform clinical strategies and interventions aimed at reducing mental health care disparities among populations who are vulnerable to overdose or suicide.

Validity of hospital ICD-10-GM codes to identify acute liver injury in Germany

PURPOSE

Acute liver injury (ALI) is an important adverse drug reaction. We estimated the positive predictive values (PPVs) of ICD-10-GM codes of ALI used in an international postauthorisation safety study (PASS).

METHODS

Analyses used routine data (2007 to 2016, adults) from a German academic hospital in a cross-sectional design. Two algorithms from the PASS were applied to extract potential cases from the hospital information system: specific end point (A) (discharge diagnosis of liver disease-specific codes) and less specific end point (B) (discharge and outpatient-specific and nonspecific codes suggestive of liver injury). ALI cases were confirmed on the basis of plasma liver enzyme activity elevation. Secondary analysis was performed following exclusion of cases with known cancer, chronic liver, biliary and pancreatic disease, heart failure, and alcohol-related disorders, as applied in the PASS.

RESULTS

On the basis of ICD codes: outcome A, 154 cases (143 with case notes and lab data for case verification); outcome B, 485 cases (357 with case notes and lab data). ALI was confirmed in 71 outcome A cases, PPV of 49.7% (95% confidence interval [CI], 41.2%-58.1%), and 100 outcome B cases, PPV of 28.0% (95% CI, 23.4%-33.0%). Applying exclusion criteria increased PPV (95% CI) to 62.7% (50.0%-74.2%) for outcome A and 45.7% (37.2%-54.3%) for outcome B.

CONCLUSIONS

In safety studies on hepatotoxicity based on routine data using ICD-10-GM discharge codes and when validation of potential cases is not feasible, only the more specific codes should be used to describe ALI, and competing diagnoses for liver injury should be excluded to avoid substantial misclassification.

Out-of-system Care and Recording of Patient Characteristics Critical for Comparative Effectiveness Research

BACKGROUND

It is unclear how out-of-system care or electronic health record (EHR) discontinuity (i.e., receiving care outside of an EHR system) may affect validity of comparative effectiveness research using these data. We aimed to compare the misclassification of key variables in patients with high versus low EHR continuity.

METHODS

The study cohort comprised patients ages ≥65 identified in electronic health records from two US provider networks linked with Medicare insurance claims data from 2007 to 2014. By comparing electronic health records and claims data, we quantified EHR continuity by the proportion of encounters captured by the EHRs (i.e., "capture proportion"). Within levels of EHR continuity, for 40 key variables, we quantified misclassification by mean standardized differences between coding based on EHRs alone versus linked claims and EHR data.

RESULTS

Based on 183,739 patients, we found that mean capture proportion in a single electronic health record system was 16%-27% across two provider networks. Patients with highest level of EHR continuity (capture proportion ≥ 80%) had 11.4- to 17.4-fold less variable misclassification, when compared with those with lowest level of EHR continuity (capture proportion< 10%). Capturing at least 60% of the encounters in an EHR system was required to have reasonable variable classification (mean standardized difference <0.1). We found modest differences in comorbidity profiles between patients with high and low EHR continuity.

CONCLUSIONS

EHR discontinuity may lead to substantial misclassification in key variables. Restricting comparative effectiveness research to patients with high EHR continuity may confer a favorable benefit (reducing information bias) to risk (losing generalizability) ratio.

Risk and Prognosis of Acute Liver Injury Among Hospitalized Patients with Hemodynamic Instability: A Nationwide Analysis

Risk and Prognosis of Acute Liver Injury Among Hospitalized Patients with Hemodynamic Instability: A Nationwide Analysis Introduction and aim. Critically ill patients in states of circulatory failure are at risk of acute liver injury, from mild elevations in aminotransferases to substantial rises consistent with hypoxic hepatitis or "shock liver". The present study aims to quantify the national prevalence of acute liver injury in patients with hemodynamic instability, identify risk factors for its development, and determine predictors of mortality.

MATERIAL AND METHODS

The 2009-2010 Nationwide Inpatient Sample was interrogated using ICD-9-CM codes for hospital admissions involving states of hemodynamic lability. Multivariable logistic regression was used to evaluate the risks of acute liver injury and death in patients with baseline liver disease, congestive heart failure, malnutrition, and HIV.

RESULTS

Of the 2,865,446 patients identified in shock, 4.60% were found to have acute liver injury. A significantly greater proportion of patients with underlying liver disease experienced acute liver injury (22.03%) and death (28.47%) as compared to those without liver disease (3.18% and 18.82%, respectively). The odds of developing acute liver injury were increased in all baseline liver diseases studied, including all-cause cirrhosis, hepatitis B, hepatitis C, alcoholic liver disease, and non-alcoholic fatty liver disease, as well as in congestive heart failure and malnutrition. All-cause cirrhosis and alcoholic liver disease, however, conferred the greatest risk. Similar trends were seen with mortality. HIV was not a predictor for acute liver injury.

CONCLUSION

Liver injury is a major concern among patients with protracted circulatory instability, especially those suffering from underlying liver disease, heart failure, or malnutrition.

Identifying Patients With High Data Completeness to Improve Validity of Comparative Effectiveness Research in Electronic Health Records Data

Electronic health record (EHR)-discontinuity, i.e., having medical information recorded outside of the study EHR system, is associated with substantial information bias in EHR-based comparative effectiveness research (CER). We aimed to develop and validate a prediction model identifying patients with high EHR-continuity to reduce this bias. Based on 183,739 patients aged ≥65 in EHRs from two US provider networks linked with Medicare claims data from 2007-2014, we quantified EHR-continuity by mean proportion of encounters captured (MPEC) by the EHR system. We built a prediction model for MPEC using one EHR system as training and the other as the validation set. Patients with top 20% predicted EHR-continuity had 3.5-5.8-fold smaller misclassification of 40 CER-relevant variables, compared to the remaining study population. The comorbidity profiles did not differ substantially by predicted EHR-continuity. These findings suggest that restriction of CER to patients with high predicted EHR-continuity may confer a favorable validity to generalizability trade-off.

Development and validation of case-finding algorithms for the identification of patients with anti-neutrophil cytoplasmic antibody-associated vasculitis in large healthcare administrative databases

PURPOSE

The aim of this study was to develop and validate case-finding algorithms for granulomatosis with polyangiitis (Wegener's, GPA), microscopic polyangiitis (MPA), and eosinophilic GPA (Churg-Strauss, EGPA).

METHODS

Two hundred fifty patients per disease were randomly selected from two large healthcare systems using the International Classification of Diseases version 9 (ICD9) codes for GPA/EGPA (446.4) and MPA (446.0). Sixteen case-finding algorithms were constructed using a combination of ICD9 code, encounter type (inpatient or outpatient), physician specialty, use of immunosuppressive medications, and the anti-neutrophil cytoplasmic antibody type. Algorithms with the highest average positive predictive value (PPV) were validated in a third healthcare system.

RESULTS

An algorithm excluding patients with eosinophilia or asthma and including the encounter type and physician specialty had the highest PPV for GPA (92.4%). An algorithm including patients with eosinophilia and asthma and the physician specialty had the highest PPV for EGPA (100%). An algorithm including patients with one of the diagnoses (alveolar hemorrhage, interstitial lung disease, glomerulonephritis, and acute or chronic kidney disease), encounter type, physician specialty, and immunosuppressive medications had the highest PPV for MPA (76.2%). When validated in a third healthcare system, these algorithms had high PPV (85.9% for GPA, 85.7% for EGPA, and 61.5% for MPA). Adding the anti-neutrophil cytoplasmic antibody type increased the PPV to 94.4%, 100%, and 81.2% for GPA, EGPA, and MPA, respectively.

CONCLUSION

Case-finding algorithms accurately identify patients with GPA, EGPA, and MPA in administrative databases. These algorithms can be used to assemble population-based cohorts and facilitate future research in epidemiology, drug safety, and comparative effectiveness. Copyright © 2016 John Wiley & Sons, Ltd.

The incidence, presentation, outcomes, risk of mortality and economic data of drug-induced liver injury from a national database in Thailand: a population-base study

Background

Toxic liver diseases are mainly caused by drug-induced liver injury (DILI). We assessed incidences and outcomes of DILI including associated factors for mortality.

Methods

We performed a population-based study of hospitalized patients with DILI. Information was retrieved from the Nationwide Hospital Admission Data using ICD-10 code of toxic liver diseases (K71) and additional codes (T36–T65). The associated factors were analyzed with log-rank test, univariate and multiple cox regression analysis.

Results

During 2009–2013, a total of 159,061 (average 21,165 per year) admissions were related to liver diseases. 6,516 admissions (1,303 per year) were due to toxic liver diseases. The most common type of toxic liver disease was acute hepatitis (33.5 %). In-hospital and 90-day mortality rates were 3.4 % and 17.2 %. DILI with cirrhosis yielded the highest in-hospital and 90-day mortality rates (15.8 % and 47.4 %). Acetaminophen, cirrhosis and age ≥ 60 years were seen in 0.5 %, 8.3 % and 50.1 % of patients who died versus 5 %, 2.3 % and 32.4 % of survivors. Factors associated with mortality were cirrhosis (HR 2.72, 95 % CI: 2.33–3.19), age ≥60 years (HR 2.16, 95 % CI: 1.96–2.38), human immunodeficiency viral infection (HR 2.11, 95 % CI: 1.88–2.36), chronic kidney disease (HR 1.59, 95 % CI: 1.33–1.90), chronic obstructive pulmonary disease and bronchiectasis (HR 1.55, 95 % CI: 1.17–2.04), malnutrition (HR 1.43, 95 % CI: 1.10–1.86) and male (HR 1.31, 95 % CI: 1.21–1.43). Acetaminophen DILI yielded lower risks of mortality (HR 0.24, 95 % CI: 0.13–0.42). The most common causes of DILI were acetaminophen (35.0 %) and anti-tuberculous drugs (34.7 %).

Conclusions

DILI is an uncommon indication for hospitalization carrying lower risks of death except in patients with non-acetaminophen, cirrhosis, elderly or concomitant diseases.

A fourfold increase of oesophageal variceal bleeding in cirrhotic patients with a history of oesophageal variceal bleeding

INTRODUCTION

Large, recent population-based data for evaluating the predictors of oesophageal variceal bleeding (OVB) among cirrhotic patients is still lacking. This study aimed to determine the cumulative incidence of OVB among cirrhotic patients and identify the predictors of OVB occurrence.

METHODS

Patient information on 38,172 cirrhotic patients without a history of OVB, who were discharged between 1 January 2007 and 31 December 2007, was obtained from the Taiwan National Health Insurance Database for this study. All patients were followed up for three years. Death was the competing risk when calculating the cumulative incidences and hazard ratios (HRs) of OVB.

RESULTS

OVB was present in 2,609 patients (OVB group) and absent in 35,563 patients (non-OVB group) at hospitalisation. During the three-year follow-up period, the cumulative incidence of OVB was 44.5% and 11.3% in the OVB and non-OVB group, respectively (p < 0.001). Modified Cox regression analysis showed that the HR of OVB history was 4.42 for OVB occurrence (95% confidence interval [CI] 4.13-4.74). Other predictors for OVB occurrence included hepatocellular carcinoma (HR 1.16, 95% CI 1.09-1.24), young age (HR 0.98, 95% CI 0.98-0.98), ascites (HR 1.46, 95% CI 1.37-1.56), alcohol-related disorders (HR 1.20, 95% CI 1.12-1.28), peptic ulcer bleeding (HR 1.26, 95% CI 1.13-1.41) and diabetes mellitus (HR 1.14, 95% CI 1.06-1.23).

CONCLUSION

Cirrhotic patients have a fourfold increased risk of future OVB following the first incidence of OVB.

Trends in rates of acetaminophen-related adverse events in the United States

PURPOSE

The goal of this study is to summarize trends in rates of adverse events attributable to acetaminophen use, including hepatotoxicity and mortality.

METHODS

A comprehensive analysis of data from three national surveillance systems estimated rates of acetaminophen-related events identified in different settings, including calls to poison centers (2008-2012), emergency department visits (2004-2012), and inpatient hospitalizations (1998-2011). Rates of acetaminophen-related events were calculated per setting, census population, and distributed drug units.

RESULTS

Rates of poison center calls with acetaminophen-related exposures decreased from 49.5/1000 calls in 2009 to 43.5/1000 calls in 2012. Rates of emergency department visits for unintentional acetaminophen-related adverse events decreased from 58.0/1000 emergency department visits for adverse drug events in 2009 to 50.2/1000 emergency department visits in 2012. Rates of hospital inpatient discharges with acetaminophen-related poisoning decreased from 119.8/100 000 hospitalizations in 2009 to 108.6/100 000 hospitalizations in 2011. After 2009, population rates of acetaminophen-related events per 1 million census population decreased for poison center calls and hospitalizations, while emergency department visit rates remained stable. However, when accounting for drug sales, the rate of acetaminophen-related events (per 1 million distributed drug units) increased after 2009. Prior to 2009, the rates of acetaminophen-related hospitalizations had been slowly increasing (p-trend = 0.001).

CONCLUSIONS

Acetaminophen-related adverse events continue to be a public health burden. Future studies with additional time points are necessary to confirm trends and determine whether recent risk mitigation efforts had a beneficial impact on acetaminophen-related adverse events. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Validation of coding algorithms for the identification of patients hospitalized for alcoholic hepatitis using administrative data

Background

Epidemiologic studies of alcoholic hepatitis (AH) have been hindered by the lack of a validated International Classification of Disease (ICD) coding algorithm for use with administrative data. Our objective was to validate coding algorithms for AH using a hospitalization database.

Methods

The Hospital Discharge Abstract Database (DAD) was used to identify consecutive adults (≥18 years) hospitalized in the Calgary region with a diagnosis code for AH (ICD-10, K70.1) between 01/2008 and 08/2012. Medical records were reviewed to confirm the diagnosis of AH, defined as a history of heavy alcohol consumption, elevated AST and/or ALT (<300 U/L), serum bilirubin >34 μmol/L, and elevated INR. Subgroup analyses were performed according to the diagnosis field in which the code was recorded (primary vs. secondary) and AH severity. Algorithms that incorporated ICD-10 codes for cirrhosis and its complications were also examined.

Results

Of 228 potential AH cases, 122 patients had confirmed AH, corresponding to a positive predictive value (PPV) of 54 % (95 % CI 47–60 %). PPV improved when AH was the primary versus a secondary diagnosis (67 % vs. 21 %; P < 0.001). Algorithms that included diagnosis codes for ascites (PPV 75 %; 95 % CI 63–86 %), cirrhosis (PPV 60 %; 47–73 %), and gastrointestinal hemorrhage (PPV 62 %; 51–73 %) had improved performance, however, the prevalence of these diagnoses in confirmed AH cases was low (29–39 %).

Conclusions

In conclusion the low PPV of the diagnosis code for AH suggests that caution is necessary if this hospitalization database is used in large-scale epidemiologic studies of this condition.

Clinical and economic characteristics of emergency department visits due to acetaminophen toxicity in the USA

OBJECTIVES

To estimate the number of acetaminophen (APAP) toxicity-related emergency department (ED) visits, and to assess their associated clinical and economic burden in the USA from 2006 to 2010.

DESIGN

Cross-sectional, retrospective, large-scale database study.

SETTING

Non-federal, non-rehabilitation, community EDs in the USA.

PARTICIPANTS

Inclusion criteria included any listed diagnosis identifying poisoning by aromatic analgesics paracetamol/APAP or associated supplementary code. Generalised linear models were used to investigate the association between outcomes of inpatient admission, mortality, requirement of invasive mechanical ventilation, charges and inpatient lengths of stay based on patient, hospital and clinical characteristics.

RESULTS

Across the 625.2 million ED visits in the USA from 2006 to 2010, 411,811 APAP-related toxicity ED visits were observed, with 45.5% resulting in inpatient admission, 4.7% requiring invasive mechanical ventilation and 0.6% involving death. Overall, the incidence proportion was 27.10 per 100,000 US population, exceeding 70 per 100,000 at age 2 years and ages 16-18 years. The total national bill was $1.06 billion per year (US$ 2014), and predominantly involved females (65.5%) and intentional self-harm (58.4%), which were notably higher within the 12-20 years age category (female(12-20 years)=74.8%, intentional self-harm(12-20 years)=71.4%). Behavioural and mental health comorbidities were relatively common and associated with an increased relative risk of admission and likelihood of charges almost entirely across all age categories of ≥12 years within the multivariable analyses. The number of ED visits did not appreciably change over time, decreasing by <2% from 2006 to 2010 (n=1351). Multivariable results also suggested no consistent change in outcomes across the study's time horizon.

CONCLUSIONS

A substantial public health impact of APAP toxicity-related cases was observed in the US from 2006 to 2010, with incidence proportions peaking at age 2 years and ages 16-18 years. After controlling for numerous factors, no consistent change was observed over the 5-year time horizon concerning outcomes of admission, mortality, invasive mechanical ventilation, charges or length of stay.

Population-representative incidence of drug-induced acute liver failure based on an analysis of an integrated health care system

BACKGROUND & AIMS

Medications are a major cause of acute liver failure (ALF) in the United States, but no population-based studies have evaluated the incidence of ALF from drug-induced liver injury. We aimed to determine the incidence and outcomes of drug-induced ALF in an integrated health care system that approximates a population-based cohort.

METHODS

We performed a retrospective cohort study using data from the Kaiser Permanente Northern California (KPNC) health care system between January 1, 2004, and December 31, 2010. We included all KPNC members age 18 years and older with 6 months or more of membership and hospitalization for potential ALF. The primary outcome was drug-induced ALF (defined as coagulopathy and hepatic encephalopathy without underlying chronic liver disease), determined by hepatologists who reviewed medical records of all KPNC members with inpatient diagnostic and laboratory criteria suggesting potential ALF.

RESULTS

Among 5,484,224 KPNC members between 2004 and 2010, 669 had inpatient diagnostic and laboratory criteria indicating potential ALF. After medical record review, 62 (9.3%) were categorized as having definite or possible ALF, and 32 (51.6%) had a drug-induced etiology (27 definite, 5 possible). Acetaminophen was implicated in 18 events (56.3%), dietary/herbal supplements in 6 events (18.8%), antimicrobials in 2 events (6.3%), and miscellaneous medications in 6 events (18.8%). One patient with acetaminophen-induced ALF died (5.6%; 0.06 events/1,000,000 person-years) compared with 3 patients with non-acetaminophen-induced ALF (21.4%; 0.18/1,000,000 person-years). Overall, 6 patients (18.8%) underwent liver transplantation, and 22 patients (68.8%) were discharged without transplantation. The incidence rates of any definite drug-induced ALF and acetaminophen-induced ALF were 1.61 events/1,000,000 person-years (95% confidence interval, 1.06-2.35) and 1.02 events/1,000,000 person-years (95% confidence interval, 0.59-1.63), respectively.

CONCLUSIONS

Drug-induced ALF is uncommon, but over-the-counter products and dietary/herbal supplements are its most common causes.

Validity of diagnostic codes and laboratory tests of liver dysfunction to identify acute liver failure events

PURPOSE

Identification of acute liver failure (ALF) is important for post-marketing surveillance of medications, but the validity of using ICD-9 diagnoses and laboratory data to identify these events within electronic health records is unknown. We examined positive predictive values (PPVs) of hospital ICD-9 diagnoses and laboratory tests of liver dysfunction for identifying ALF within a large, community-based integrated care organization.

METHODS

We identified Kaiser Permanente Northern California health plan members (2004-2010) with a hospital diagnosis suggesting ALF (ICD-9 570, 572.2, 572.4, 572.8, 573.3, 573.8, or V42.7) plus an inpatient international normalized ratio ≥1.5 (off warfarin) and total bilirubin ≥5.0 mg/dL. Hospital records were reviewed by hepatologists to adjudicate ALF events. PPVs for confirmed outcomes were determined for individual ICD-9 diagnoses, diagnoses plus prescriptions for hepatic encephalopathy treatment, and combinations of diagnoses in the setting of coagulopathy and hyperbilirubinemia.

RESULTS

Among 669 members with no pre-existing liver disease, chart review confirmed ALF in 62 (9%). Despite the presence of co-existing coagulopathy and hyperbilirubinemia, individual ICD-9 diagnoses had low PPVs (range, 5-15%); requiring prescriptions for encephalopathy treatment did not increase PPVs of these diagnoses (range, 2-23%). Hospital diagnoses of other liver disorders (ICD-9 573.8) plus hepatic coma (ICD-9 572.2) had high PPV (67%; 95%CI, 9-99%) but only identified two (3%) ALF events.

CONCLUSIONS

Algorithms comprising relevant hospital diagnoses, laboratory evidence of liver dysfunction, and prescriptions for hepatic encephalopathy treatment had low PPVs for confirmed ALF events. Studies of ALF will need to rely on medical records to confirm this outcome.

Risk factors for mortality in patients with alcoholic hepatitis and assessment of prognostic models: A population-based study

BACKGROUND

Severe alcoholic hepatitis (AH) is associated with a substantial risk for short-term mortality.

OBJECTIVES

To identify prognostic factors and validate well-known prognostic models in a Canadian population of patients hospitalized for AH.

METHODS

In the present retrospective study, patients hospitalized for AH in Calgary, Alberta, between January 2008 and August 2012 were included. Stepwise logistic regression models identified independent risk factors for 90-day mortality, and the discrimination of prognostic models (Model for End-stage Liver Disease [MELD] and Maddrey discriminant function [DF]) were examined using areas under the ROC curves.

RESULTS

A total of 122 patients with AH were hospitalized during the study period; the median age was 49 years (interquartile range [IQR] 42 to 55 years) and 60% were men. Median MELD score and Maddrey DF on admission were 21 (IQR 18 to 24) and 45 (IQR 26 to 62), respectively. Seventy-three percent of patients received corticosteroids and⁄or pentoxifylline, and the 90-day mortality was 17%. Independent predictors of mortality included older age, female sex, international normalized ratio, MELD score and Maddrey DF (all P<0.05). For discrimination of 90-day mortality, the areas under the ROC curves of the prognostic models (MELD 0.64; Maddrey DF 0.68) were similar (P>0.05). At optimal cut-offs of ≥22 for MELD score and ≥37 for Maddrey DF, both models excluded death with high certainty (negative predictive values 90% and 96%, respectively).

CONCLUSIONS

In patients hospitalized for AH, well-known prognostic models can be used to predict 90-day mortality, particularly to identify patients with a low risk for death.

ICD-10 codes used to identify adverse drug events in administrative data: a systematic review

BACKGROUND

Adverse drug events, the unintended and harmful effects of medications, are important outcome measures in health services research. Yet no universally accepted set of International Classification of Diseases (ICD) revision 10 codes or coding algorithms exists to ensure their consistent identification in administrative data. Our objective was to synthesize a comprehensive set of ICD-10 codes used to identify adverse drug events.

METHODS

We developed a systematic search strategy and applied it to five electronic reference databases. We searched relevant medical journals, conference proceedings, electronic grey literature and bibliographies of relevant studies, and contacted content experts for unpublished studies. One author reviewed the titles and abstracts for inclusion and exclusion criteria. Two authors reviewed eligible full-text articles and abstracted data in duplicate. Data were synthesized in a qualitative manner.

RESULTS

Of 4241 titles identified, 41 were included. We found a total of 827 ICD-10 codes that have been used in the medical literature to identify adverse drug events. The median number of codes used to search for adverse drug events was 190 (IQR 156-289) with a large degree of variability between studies in the numbers and types of codes used. Authors commonly used external injury (Y40.0-59.9) and disease manifestation codes. Only two papers reported on the sensitivity of their code set.

CONCLUSIONS

Substantial variability exists in the methods used to identify adverse drug events in administrative data. Our work may serve as a point of reference for future research and consensus building in this area.

Liver stiffness by transient elastography predicts liver-related complications and mortality in patients with chronic liver disease

Background

Liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is a validated method for noninvasively staging liver fibrosis. Most hepatic complications occur in patients with advanced fibrosis. Our objective was to determine the ability of LSM by TE to predict hepatic complications and mortality in a large cohort of patients with chronic liver disease.

Methods

In consecutive adults who underwent LSM by TE between July 2008 and June 2011, we used Cox regression to determine the independent association between liver stiffness and death or hepatic complications (decompensation, hepatocellular carcinoma, and liver transplantation). The performance of LSM to predict complications was determined using the c-statistic.

Results

Among 2,052 patients (median age 51 years, 65% with hepatitis B or C), 87 patients (4.2%) died or developed a hepatic complication during a median follow-up period of 15.6 months (interquartile range, 11.0–23.5 months). Patients with complications had higher median liver stiffness than those without complications (13.5 vs. 6.0 kPa; P<0.00005). The 2-year incidence rates of death or hepatic complications were 2.6%, 9%, 19%, and 34% in patients with liver stiffness <10, 10–19.9, 20–39.9, and ≥40 kPa, respectively (P<0.00005). After adjustment for potential confounders, liver stiffness by TE was an independent predictor of complications (hazard ratio [HR] 1.05 per kPa; 95% confidence interval [CI] 1.03–1.06). The c-statistic of liver-stiffness for predicting complications was 0.80 (95% CI 0.75–0.85). A liver stiffness below 20 kPa effectively excluded complications (specificity 93%, negative predictive value 97%); however, the positive predictive value of higher results was sub-optimal (20%).

Conclusions

Liver stiffness by TE accurately predicts the risk of death or hepatic complications in patients with chronic liver disease. TE may facilitate the estimation of prognosis and guide management of these patients.

The feasibility and reliability of transient elastography using Fibroscan®: a practice audit of 2335 examinations

BACKGROUND

Liver stiffness measurement (LSM) using transient elastography is widely used in the management of patients with chronic liver disease.

OBJECTIVES

To examine the feasibility and reliability of LSM, and to identify patient and operator characteristics predictive of poorly reliable results.

METHODS

The present retrospective study investigated the frequency and determinants of poorly reliable LSM (interquartile range [IQR]⁄median LSM [IQR⁄M] >30% with median liver stiffness ≥7.1 kPa) using the FibroScan (Echosens, France) over a three-year period. Two experienced operators performed all LSMs. Multiple logistic regression analyses examined potential predictors of poorly reliable LSMs including age, sex, liver disease, the operator, operator experience (<500 versus ≥500 scans), FibroScan probe (M versus XL), comorbidities and liver stiffness. In a subset of patients, medical records were reviewed to identify obesity (body mass index ≥30 kg⁄m2).

RESULTS

Between July 2008 and June 2011, 2335 patients with liver disease underwent LSM (86% using the M probe). LSM failure (no valid measurements) occurred in 1.6% (n=37) and was more common using the XL than the M probe (3.4% versus 1.3%; P=0.01). Excluding LSM failures, poorly reliable LSMs were observed in 4.9% (n=113) of patients. Independent predictors of poorly reliable LSM included older age (OR 1.03 [95% CI 1.01 to 1.05]), chronic pulmonary disease (OR 1.58 [95% CI 1.05 to 2.37), coagulopathy (OR 2.22 [95% CI 1.31 to 3.76) and higher liver stiffness (OR per kPa 1.03 [95% CI 1.02 to 1.05]), including presumed cirrhosis (stiffness ≥12.5 kPa; OR 5.24 [95% CI 3.49 to 7.89]). Sex, diabetes, the underlying liver disease and FibroScan probe were not significant. Although reliability varied according to operator (P<0.0005), operator experience was not significant. In a subanalysis including 434 patients with body mass index data, obesity influenced the rate of poorly reliable results (OR 2.93 [95% CI 0.95 to 9.05]; P=0.06).

CONCLUSIONS

FibroScan failure and poorly reliable LSM are uncommon. The most important determinants of poorly reliable results are older age, obesity, higher liver stiffness and the operator, the latter emphasizing the need for adequate training.

Risk of Cardiovascular Events, Stroke, Congestive Heart Failure, Interstitial Lung Disease, and Acute Liver Injury: Dronedarone versus Amiodarone and Other Antiarrhythmics

No published studies have evaluated the risks of cardiovascular (CV) events, stroke, congestive heart failure (CHF), interstitial lung disease (ILD), and severe acute liver injury (ALI) related to antiarrhythmics treatment in real-world clinical practice setting. We examined the relationship between the above events and the selected antiarrhythmics in the real-world setting in the US. Using a retrospective cohort design, the hazard ratios of the outcome events were analyzed from 10,455 adult patients with a diagnosis of atrial fibrillation/atrial flutter and a new treatment with dronedarone (comparison drug), amiodarone, sotalol, flecainide, or propafenone between 07/20/2009 and 12/31/2010 from the Clinformatics Data MartTM database. The patients were followed until: 1) switch to another antiarrhythmic drug, 2) occurrence of the outcome event, 3) end of enrollment, or 4) end of the study period, whichever occurred first. No significant differences were observed in the hazard ratios of the outcome events between dronedarone, amiodarone, and the other antiarrhythmics, except that amiodarone was associated with a higher risk of CV events (adjusted HR = 1.7, 95%CI: 1.1-2.4) and stroke (adjusted HR = 2.0, 95%CI: 1.33.2), compared to dronedarone, especially amongst patients without a CHF history (adjusted HR = 2.4, 95%CI: 1.4-3.8 and 2.2, 95%CI: 1.23.9). A higher risk of CHF was also associated with amiodarone in patients without history of CHF at baseline (adjusted HR = 2.7, 95%CI: 2.03.6). In this real-world investigation, no difference in risk was observed between dronedarone, sotalol, and propafenone initiators for CV events, stroke, CHF, ILD, and ALI. Amiodarone was associated with higher risks of CV events, stroke, and CHF than dronedarone in patients without a CHF history, indicating dronedarone could be an alternative therapy option with lower risk of CV events than amiodarone for the above patients.

Adverse events in patients with liver cancer

This study aimed to further the understanding of the incidence of adverse events (AEs) in a population-based representative liver cancer population where there is currently a lack of knowledge. We carried out a retrospective cohort study using data from an administrative claims database between 1 January 2004 and 31 December 2010. Patients were included in the study if they had at least one primary liver cancer diagnosis [International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM): 155.0] and a metastatic diagnosis [ICD-9-CM: 196.x, 197.x (except 197.7), 198.x or 199.0]. We estimated the incidence rate (IR) and 95% confidence interval (CI) for each AE under study. Of the patients identified, 1292 fulfilled the inclusion and exclusion criteria. The most common AEs were nausea and vomiting (IR=878.5/1000 person-years; 95% CI=799.5-963.1). Other common AEs were hypertension (IR=648.7/1000 person-years; 95% CI=569.2-736.1) and hemorrhage (IR=580.0/1000 person-years; 95% CI=518.6-646.6). The least common AEs were rare dermatologic diseases such as Stevens-Johnson syndrome and toxic epidermal necrolysis where no cases were observed. The rates detailed in this analysis are helpful in understanding the benefit risk of treating patients with liver cancer in the real world. Although no formal comparisons were performed, the increased risk of certain events observed in sorafenib-treated patients from this analysis mirrors the risks reported on the label for sorafenib. Therefore, this analysis provided a reasonable assessment of the AEs that patients with liver cancer experience in the real world.

Validity of diagnostic codes to identify cases of severe acute liver injury in the US Food and Drug Administration's Mini-Sentinel Distributed Database

PURPOSE

The validity of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes to identify diagnoses of severe acute liver injury (SALI) is not well known. We examined the positive predictive values (PPVs) of hospital ICD-9-CM diagnoses in identifying SALI among health plan members in the Mini-Sentinel Distributed Database (MSDD) for patients without liver/biliary disease and for those with chronic liver disease (CLD).

METHODS

We selected random samples of members (149 without liver/biliary disease; 75 with CLD) with a principal hospital diagnosis suggestive of SALI (ICD-9-CM 570, 572.2, 572.4, 572.8, 573.3, 573.8, or V42.7) in the MSDD (2009-2010). Medical records were reviewed by hepatologists to confirm SALI events. PPVs of codes and code combinations for confirmed SALI were determined by CLD status.

RESULTS

Among 105 members with available records and no liver/biliary disease, SALI was confirmed in 26 (PPV, 24.7%; 95%CI, 16.9-34.1%). Combined hospital diagnoses of acute hepatic necrosis (570) and liver disease sequelae (572.8) had high PPV (100%; 95%CI, 59.0-100%) and identified 7/26 (26.9%) events. Among 46 CLD members with available records, SALI was confirmed in 19 (PPV, 41.3%; 95%CI, 27.0-56.8%). Acute hepatic necrosis (570) or hepatorenal syndrome (572.4) plus any other SALI code had a PPV of 83.3% (95%CI, 51.6-97.9%) and identified 10/19 (52.6%) events.

CONCLUSIONS

Most individual hospital ICD-9-CM diagnoses had low PPV for confirmed SALI events. Select code combinations had high PPV but did not capture all events.

Fluoroquinolone therapy and idiosyncratic acute liver injury: a population-based study

BACKGROUND

Although fluoroquinolones are sometimes associated with mild, transient elevations in aminotransferase levels, serious acute liver injury is uncommon. Regulatory warnings have identified moxifloxacin as presenting a particular risk of hepatotoxicity. Thus, we examined the risk of idiosyncratic acute liver injury associated with the use of moxifloxacin relative to other selected antibiotic agents.

METHODS

We conducted a population-based, nested, case-control study using health care data from Ontario for the period April 2002 to March 2011. We identified cases as outpatients aged 66 years or older with no history of liver disease, and who were admitted to hospital for acute liver injury within 30 days of receiving a prescription for 1 of 5 broad-spectrum antibiotic agents: moxifloxacin, levofloxacin, ciprofloxacin, cefuroxime axetil or clarithromycin. For each case, we selected up to 10 age- and sex-matched controls from among patients who had received a study antibiotic, but who were not admitted to hospital for acute liver injury. We calculated odds ratios (ORs) to determine the association between admission to hospital and previous exposure to an antibiotic agent, using clarithromycin as the reference.

RESULTS

A total of 144 patients were admitted to hospital for acute liver injury within 30 days of receiving a prescription for one of the identified drugs. Of these patients, 88 (61.1%) died while in hospital. After multivariable adjustment, use of either moxifloxacin (adjusted OR 2.20, 95% confidence interval [CI] 1.21-3.98) or levofloxacin (adjusted OR 1.85, 95% CI 1.01-3.39) was associated with an increase in risk of acute liver injury relative to the use of clarithromycin. We saw no such risk associated with the use of either ciprofloxacin or cefuroxime axetil.

INTERPRETATION

Among older outpatients with no evidence of liver disease, moxifloxacin and levofloxacin were associated with an increased risk of acute liver injury relative to clarithromycin.

Active safety monitoring of newly marketed medications in a distributed data network: application of a semi-automated monitoring system

We developed a semi-automated active monitoring system that uses sequential matched-cohort analyses to assess drug safety across a distributed network of longitudinal electronic health-care data. In a retrospective analysis, we show that the system would have identified cerivastatin-induced rhabdomyolysis. In this study, we evaluated whether the system would generate alerts for three drug-outcome pairs: rosuvastatin and rhabdomyolysis (known null association), rosuvastatin and diabetes mellitus, and telithromycin and hepatotoxicity (two examples for which alerting would be questionable). Over >5 years of monitoring, rate differences (RDs) in comparisons of rosuvastatin with atorvastatin were -0.1 cases of rhabdomyolysis per 1,000 person-years (95% confidence interval (CI): -0.4, 0.1) and -2.2 diabetes cases per 1,000 person-years (95% CI: -6.0, 1.6). The RD for hepatotoxicity comparing telithromycin with azithromycin was 0.3 cases per 1,000 person-years (95% CI: -0.5, 1.0). In a setting in which false positivity is a major concern, the system did not generate alerts for the three drug-outcome pairs.

Dental pain as a risk factor for accidental acetaminophen overdose: a case-control study

Patients frequent take acetaminophen to treat dental pain. One previous study found a high rate of overuse of nonprescription analgesics in an emergency dental clinic.

OBJECTIVES

The purpose of this study is to determine if patients with dental pain are more likely to be treated for accidental acetaminophen poisoning than patients with other types of pain.

METHODS

We conducted a case-control study at 2 urban hospitals. Cases were identified by chart review of patients who required treatment for accidental acetaminophen poisoning. Controls were self-reported acetaminophen users taking therapeutic doses identified during a survey of emergency department patients. For our primary analysis, the reason for taking acetaminophen was categorized as dental pain or not dental pain. Our primary outcome was the odds ratio of accidental overdose to therapeutic users after adjustment for age, sex, alcoholism, and use of combination products using logistic regression.

RESULTS

We identified 73 cases of accidental acetaminophen poisoning and 201 therapeutic users. Fourteen accidental overdose patients and 4 therapeutic users reported using acetaminophen for dental pain. The adjusted odds ratio for accidental overdose due to dental pain compared with other reasons for use was 12.8 (95% confidence interval, 4.2-47.6).

CONCLUSIONS

We found that patients with dental pain are at increased risk to accidentally overdose on acetaminophen compared with patients taking acetaminophen for other reasons. Emergency physicians should carefully question patients with dental pain about overuse of analgesics.

Validation of coding algorithms for the identification of patients with primary biliary cirrhosis using administrative data

BACKGROUND

Large-scale epidemiological studies of primary biliary cirrhosis (PBC) have been hindered by difficulties in case ascertainment.

OBJECTIVE

To develop coding algorithms for identifying PBC patients using administrative data--a widely available data source.

METHODS

Population-based administrative databases were used to identify patients with a diagnosis code for PBC from 1994 to 2002. Coding algorithms for confirmed PBC (two or more of antimitochondrial antibody positivity, cholestatic liver biochemistry and/or compatible liver histology) were derived using chart abstraction data as the reference. Patients with a recorded PBC diagnosis but insufficient confirmatory data were classified as 'suspected PBC'.

RESULTS

Of 189 potential PBC cases, 119 (60%) had confirmed PBC and 28 (14%) had suspected PBC. The optimal algorithm including two or more uses of a PBC code had a sensitivity of 94% (95% CI 71% to 100%) and positive predictive values of 73% (95% CI 61% to 75%) for confirmed PBC, and 89% (95% CI 82% to 94%) for confirmed or suspected PBC. Sensitivity analyses revealed greater accuracy among women, and with the use of multiple data sources and one or more years of data. Inclusion of diagnosis codes for conditions frequently misclassified as PBC did not improve algorithm performance.

CONCLUSIONS

Administrative databases can reliably identify patients with PBC and may facilitate epidemiological investigations of this condition.

Epidemiology and natural history of primary biliary cirrhosis in a Canadian health region: a population-based study

The recent epidemiology and outcomes of primary biliary cirrhosis (PBC) in North America are incompletely described, partly due to difficulties in case ascertainment. In light of their availability, broad coverage, and limited expense, administrative databases may facilitate such investigations. We used population-based administrative data (inpatient, ambulatory care, and physician billing databases) and a validated International Classification of Diseases coding algorithm to describe the epidemiology and natural history of PBC in the Calgary Health Region (population approximately 1.1 million). Between 1996 and 2002, the overall age/sex-adjusted annual incidence of PBC was 30.3 cases per million (48.4 per million in women, 10.4 per million in men). Although the incidence remained stable, the prevalence increased from 100 per million in 1996 to 227 per million in 2002 (P < 0.0005). Among 137 incident cases with a total follow-up of 801 person-years from diagnosis (median 5.8 years), 27 patients (20%) died and six (4.4%) underwent liver transplantation. The estimated 10-year probabilities of survival, liver transplantation, and transplant-free survival were 73% (95% confidence interval [CI] 60%-83%), 6% (95% CI 2.5%-12.6%), and 68% (95% CI 55%-78%), respectively. Survival in PBC patients was significantly lower than that of the age/sex-matched Canadian population (standardized mortality ratio 2.87; 95% CI 1.89-4.17); male sex (hazard ratio [HR] 3.80; 95% CI 1.85-7.82) and an older age at diagnosis (HR per additional year, 1.06; 95% CI 1.03-1.10) were independent predictors of mortality.

CONCLUSION

This population-based study demonstrates that the burden of PBC in Canada is high and growing. Survival of PBC patients is significantly lower than that of the general population, emphasizing the importance of developing new therapies for this condition.

Hepatitis C is a predictor of acute liver injury among hospitalizations for acetaminophen overdose in the United States: a nationwide analysis

Acute liver injury (ALI) following acetaminophen overdose (AO) occurs in less than 10% of cases, but that risk is increased among alcoholics and those with chronic alcoholic liver disease. We sought to assess whether coexistent hepatitis C virus (HCV) infection potentiated the hepatotoxic effects of acetaminophen. We queried the Nationwide Inpatient Sample (1998-2005), a 20% sample of U.S. hospitals, to identify admissions for AO using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Outcomes were development of ALI (ICD-9-CM: 570.0, 572.2, 573.3), in-hospital mortality, severe liver failure, and resource utilization. There were 42,781 admissions for AO in the sample, yielding a national estimate of 210,436 AO hospitalizations. HCV prevalence increased from 0.5% to 1.5% between 1998 and 2005 (P < 0.0001). The rate of ALI was 7.2%. After adjusting for confounders and excluding patients with cirrhosis, the risk of ALI increased with HCV (adjusted odds ratio [aOR] 1.80; 95% confidence interval [CI]: 1.30-2.48), nonalcoholic fatty liver disease (aOR 7.43; 95% CI: 3.30-16.7), alcoholic liver disease (aOR 6.46; 95% CI: 4.53-9.21), and malnutrition (aOR 3.84; 95% CI: 2.61-5.65). HCV was associated with greater risk of progression to severe liver failure (aOR 3.55; 95% CI: 1.88-6.70). Crude mortality was higher in patients with HCV compared to those without HCV (2.1% versus 0.9%, P = 0.01); patients with ALI had an overall mortality of 8.6%. Length of stay was longer in patients with HCV (4.0 versus 2.6 days, P < 0.0001). Admissions with coexistent HCV also incurred two-fold higher hospital charges than those that did not ($21,400 versus $11,400, P < 0.0001).

CONCLUSION

Our retrospective analysis suggests that patients with HCV may be at increased risk of ALI following AO. These findings warrant further confirmation in prospective studies.