Derivation and Validation of ICD-10 Codes for Identifying Incident Stroke

Importance

Claims data with International Statistical Classification of Diseases, Tenth Revision (ICD-10) codes are routinely used in clinical research. However, the use of ICD-10 codes to define incident stroke has not been validated against expert-adjudicated outcomes in the US population.

Objective

To develop and validate the accuracy of an ICD-10 code list to detect incident stroke events using Medicare inpatient fee-for-service claims data.

Design, Setting, and Participants

This cohort study used data from 2 prospective population-based cohort studies, the Atherosclerosis Risk in Communities (ARIC) study and the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, and included participants aged 65 years or older without prior stroke who had linked Medicare claims data. Stroke events in the ARIC and REGARDS studies were identified via active surveillance and adjudicated by expert review. Medicare-linked ARIC data (2016-2018) were used to develop a list of ICD-10 codes for incident stroke detection. The list was validated using Medicare-linked REGARDS data (2016-2019). Data were analyzed from September 1, 2022, through September 30, 2023.

Exposures

Stroke events detected in Medicare claims vs expert-adjudicated stroke events in the ARIC and REGARDS studies.

Main Outcomes and Measures

The main outcomes were sensitivity and specificity of incident stroke detection using ICD-10 codes.

Results

In the ARIC study, there were 110 adjudicated incident stroke events among 5194 participants (mean [SD] age, 80.1 [5.3] years) over a median follow-up of 3.0 (range, 0.003-3.0) years. Most ARIC participants were women (3160 [60.8%]); 993 (19.1%) were Black and 4180 (80.5%) were White. Using the primary diagnosis code on a Medicare billing claim, the ICD-10 code list had a sensitivity of 81.8% (95% CI, 73.3%-88.5%) and a specificity of 99.1% (95% CI, 98.8%-99.3%) to detect incident stroke. Using any diagnosis code on a Medicare billing claim, the sensitivity was 94.5% (95% CI, 88.5%-98.0%) and the specificity was 98.4% (95% CI, 98.0%-98.8%). In the REGARDS study, there were 140 adjudicated incident strokes among 6359 participants (mean [SD] age, 75.8 [7.0] years) over a median follow-up of 4.0 (range, 0-4.0) years. More than half of the REGARDS participants were women (3351 [52.7%]); 1774 (27.9%) were Black and 4585 (72.1%) were White. For the primary diagnosis code, the ICD-10 code list had a sensitivity of 70.7% (95% CI, 63.2%-78.3%) and a specificity of 99.1% (95% CI, 98.9%-99.4%). For any diagnosis code, the ICD-10 code list had a sensitivity of 77.9% (95% CI, 71.0%-84.7%) and a specificity of 98.9% (95% CI, 98.6%-99.2%).

Conclusions and Relevance

These findings suggest that ICD-10 codes could be used to identify incident stroke events in Medicare claims with moderate sensitivity and high specificity.

Validation of the International Classification of Diseases, Tenth Revision-Clinical Modification Diagnostic Code for Essential Tremor

Background

The positive predictive value (PPV) of the International Classification of Diseases, Ninth Revision-Clinical Modification (ICD-9-CM) code for "essential and other specified forms of tremor" in identifying essential tremor (ET) cases was found to be less than 50%. The ability of the ICD-10-CM G25.0 code for "essential tremor" to identify ET has not been determined. The study objective was to determine the PPV of the G25.0 code.

Methods

Patients in a tertiary health system with a primary care encounter associated with ICD-10-CM code G25.0 in 2022 underwent medical record review to determine if the consensus criteria from the International Parkinson and Movement Disorder Society for an ET diagnosis were met.

Results

442 patients were included. The PPV of G25.0 in identifying probable ET cases was 74.7% (95% confidence interval (CI) 70.4-78.5%). Among patients prescribed propranolol, the PPV improved to 87.8% (95% CI 78.0-93.6%).

Discussion

Compared to the ICD-9-CM code 333.1, G25.0 is superior for identifying ET cases. A potential limitation of this study is that the consensus criteria applied relies on nonspecific physical exam findings which may lead to an overestimation of the PPV of G25.0.

Highlights

The ICD-10-CM diagnosis code for essential tremor has not been previously validated. The objective of this study was to determine the PPV of the G25.0 code. The PPV in identifying essential tremor cases was 74.7%. The PPV improved among patients prescribed propranolol.

Improving Accuracy of Administrative Data for Perforated Appendicitis Classification

INTRODUCTION

Reliance on International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes may misclassify perforated appendicitis with resultant research, fiscal, and public health implications. We aimed to improve the accuracy of administrative data for perforated appendicitis classification relying on ICD-10-CM codes from 2015 to 2018.

METHODS

We conducted a retrospective study of randomly sampled patients aged ≤18 years diagnosed with acute appendicitis from eight children's hospitals. Patients were identified using the Pediatric Health Information System, and true perforation status was determined by medical record review. We developed two algorithms by leveraging Pediatric Health Information System data elements and data mining (DM) approaches. The two developed algorithm performance was compared against algorithms that exclusively relied on ICD-10-CM codes using area under the curve and other measures.

RESULTS

Of 1051 clinically validated encounters that were included, 383 (36.4%) patients were identified to have perforated appendicitis. The two algorithms developed using DM approaches primarily leveraged ICD-10-CM codes and length of stay. DM-developed algorithms had a significantly higher accuracy than algorithms relying exclusively on ICD-10-CM (P value < 0.01): sensitivity and specificity for DM-developed algorithms were 0.86-0.88 and 0.95-0.97, respectively, which were overall higher than algorithms that relied on only ICD-10-CM.

CONCLUSIONS

This study provides an algorithm that can improve the accuracy of perforated appendicitis classification using commonly available elements in administrative data. We recommend that this algorithm is used in future appendicitis classification to ensure valid reporting, hospital-level benchmarking, and fiscal or public health assessments.

Validation of the Diagnostic Accuracy Levels of International Classification of Diseases, 10th Revision Codes for Diabetic Ketoacidosis: A Multicentre, Cross-sectional Study of Adults

OBJECTIVES

International Classification of Diseases (ICD) codes are commonly used to identify cases of diabetic ketoacidosis (DKA) in health services research, but they have not been validated. Our aim in this study was to assess the accuracy of ICD, 10th revision (ICD-10) diagnosis codes for DKA.

METHODS

We conducted a multicentre, cross-sectional study using data from 5 hospitals in Ontario, Canada. Each hospitalization event has a single most responsible diagnosis code. We identified all hospitalizations assigned diagnosis codes for DKA. A true case of DKA was defined using laboratory values (serum bicarbonate ≤18 mmol/L, arterial pH ≤7.3, anion gap ≥14 mEq/L, and presence of ketones in urine or blood). Chart review was conducted to validate DKA if laboratory values were missing or the diagnosis of DKA was unclear. Outcome measures included positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of ICD-10 codes in patients with laboratory-defined DKA.

RESULTS

We identified 316,517 hospitalizations. Among these, 312,948 did not have an ICD-10 diagnosis code for DKA and 3,569 had an ICD-10 diagnosis code for DKA. Using a combination of laboratory and chart review, we identified that the overall PPV was 67.0%, the NPV was 99.7%, specificity was 99.6%, and sensitivity was 74.9%. When we restricted our analysis to hospitalizations in which DKA was the most responsible discharge diagnosis (n=3,374 [94.5%]), the test characteristics were PPV 69.8%, NPV 99.7%, specificity 99.7%, and sensitivity 71.9%.

CONCLUSION

ICD-10 codes can identify patients with DKA among those admitted to general internal medicine.

Accuracy of routinely collected hospital administrative discharge data and death certificate ICD-10 diagnostic coding in progressive supranuclear palsy and corticobasal syndrome: a systematic review and validation study

BACKGROUND

We conducted a systematic review to identify existing ICD-10 coding validation studies in progressive supranuclear palsy and corticobasal syndrome [PSP/CBS]) and, in a new study, evaluated the accuracy of ICD-10 diagnostic codes for PSP/CBS in Scottish hospital inpatient and death certificate data.

METHODS

Original studies that assessed the accuracy of specific ICD-10 diagnostic codes in PSP/CBS were sought. Separately, we estimated the positive predictive value (PPV) of specific codes for PSP/CBS in inpatient hospital data (SMR01, SMR04) compared to clinical diagnosis in four regions. Sensitivity was assessed in one region due to a concurrent prevalence study. For PSP, the consistency of the G23.1 code in inpatient and death certificate coding was evaluated across Scotland.

RESULTS

No previous ICD-10 validation studies were identified. 14,767 records (SMR01) and 1497 records (SMR04) were assigned the candidate ICD-10 diagnostic codes between February 2011 and July 2019. The best PPV was achieved with G23.1 (1.00, 95% CI 0.93-1.00) in PSP and G23.9 in CBS (0.20, 95% CI 0.04-0.62). The sensitivity of G23.1 for PSP was 0.52 (95% CI 0.33-0.70) and G31.8 for CBS was 0.17 (95% CI 0.05-0.45). Only 38.1% of deceased G23.1 hospital-coded cases also had this coding on their death certificate: the majority (49.0%) erroneously assigned the G12.2 code.

DISCUSSION

The high G23.1 PPV in inpatient data shows it is a useful tool for PSP case ascertainment, but death certificate coding is inaccurate. The PPV and sensitivity of existing ICD-10 codes for CBS are poor due to a lack of a specific code.

Transition database for rare diseases and its use for clinical documentation

Patients with rare diseases commonly suffer from severe symptoms as well as chronic and sometimes life-threatening effects. Not only the rarity of the diseases but also the poor documentation of rare diseases often leads to an immense delay in diagnosis. One of the main problems here is the inadequate coding with common classifications such as the International Statistical Classification of Diseases and Related Health Problems. Instead, the ORPHAcode enables precise naming of the diseases. So far, just few approaches report in detail how the technical implementation of the ORPHAcode is done in clinical practice and for research. We present a concept and implementation of storing and mapping of ORPHAcodes. The Transition Database for Rare Diseases contains all the information of the Orphanet catalog and serves as the basis for documentation in the clinical information system as well as for monitoring Key Performance Indicators for rare diseases at the hospital. The five-step process (especially using open source tools and the DataVault 2.0 logic) for set-up the Transition Database allows the approach to be adapted to local conditions as well as to be extended for additional terminologies and ontologies.

Validity and reliability International Classification of Diseases-10 codes for all forms of injury: A systematic review

BACKGROUND

Intentional and unintentional injuries are a leading cause of death and disability globally. International Classification of Diseases (ICD), Tenth Revision (ICD-10) codes are used to classify injuries in administrative health data and are widely used for health care planning and delivery, research, and policy. However, a systematic review of their overall validity and reliability has not yet been done.

OBJECTIVE

To conduct a systematic review of the validity and reliability of external cause injury ICD-10 codes.

METHODS

MEDLINE, EMBASE, COCHRANE, and SCOPUS were searched (inception to April 2023) for validity and/or reliability studies of ICD-10 external cause injury codes in all countries for all ages. We examined all available data for external cause injuries and injuries related to specific body regions. Validity was defined by sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Reliability was defined by inter-rater reliability (IRR), measured by Krippendorff's alpha, Cohen's Kappa, and/or Fleiss' kappa.

RESULTS

Twenty-seven published studies from 2006 to 2023 were included. Across all injuries, the mean outcome values and ranges were sensitivity: 61.6% (35.5%-96.0%), specificity: 91.6% (85.8%-100%), PPV: 74.9% (58.6%-96.5%), NPV: 80.2% (44.6%-94.4%), Cohen's kappa: 0.672 (0.480-0.928), Krippendorff's alpha: 0.453, and Fleiss' kappa: 0.630. Poisoning and hand and wrist injuries had higher mean sensitivity (84.4% and 96.0%, respectively), while self-harm and spinal cord injuries were lower (35.5% and 36.4%, respectively). Transport and pedestrian injuries and hand and wrist injuries had high PPVs (96.5% and 92.0%, respectively). Specificity and NPV were generally high, except for abuse (NPV 44.6%).

CONCLUSIONS AND SIGNIFICANCE

The validity and reliability of ICD-10 external cause injury codes vary based on the injury types coded and the outcomes examined, and overall, they only perform moderately well. Future work, potentially utilizing artificial intelligence, may improve the validity and reliability of ICD codes used to document injuries.

Assessment of International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) Code Assignment Validity for Case Finding of Medication-related Hypoglycemia Acute Care Visits Among Medicare Beneficiaries

OBJECTIVE

Administrative claims are commonly relied upon to identify hypoglycemia. We assessed validity of 14 International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis code assignments to identify medication-related hypoglycemia leading to acute care encounters.

RESEARCH DESIGN AND METHODS

A multisite, retrospective medical record review study was conducted in a sample of Medicare beneficiaries prescribed outpatient diabetes medications and who received hospital care between January 1, 2016 and September 30, 2017. Diagnosis codes were validated with structured medical record review using prespecified criteria (clinical presentation, blood glucose values, and treatments for hypoglycemia). Sensitivity, specificity, and positive and negative predictive value (PPV, NPV) were calculated and adjusted using sampling weights to correct for partial verification bias.

RESULTS

Among 990 encounters (496 cases, 494 controls), hypoglycemia codes demonstrated moderate PPV (69.2%; 95% confidence interval: 65.0-73.0) and moderate sensitivity (83.9%; 95% confidence interval: 70.0-95.5). Codes performed better at identifying hypoglycemic events among emergency department/observation encounters compared with hospitalizations (PPV 92.9%, sensitivity 100.0% vs. PPV 53.7%, sensitivity 71.0%). Accuracy varied by diagnosis position, especially for hospitalizations, with PPV of 95.6% versus 46.5% with hypoglycemia in primary versus secondary positions. Use of adverse event/poisoning codes did not improve accuracy; reliance on these codes alone would have missed 97% of true hypoglycemic events.

CONCLUSIONS

Accuracy of International Classification of Diseases, Tenth Revision codes in administrative claims to identify medication-related hypoglycemia varied substantially by encounter type and diagnosis position. Consideration should be given to the trade-off between PPV and sensitivity when selecting codes, encounter types, and diagnosis positions to identify hypoglycemia.

Diagnostic accuracy of ICD code versus discharge summary-based query for endocarditis cohort identification

Studies of infective endocarditis (IE) have relied on International Classification of Disease (ICD) codes to identify cases, a method vulnerable to misclassification. Clinical narrative data could offer greater accuracy and richness to cohort identification. We evaluated two algorithms: 1. a standard query of ICD-9/10 billing codes, with or without procedure codes for echocardiogram and 2. a text query of discharge summaries (DS) that selected on the term “endocarditis” in fields headed by “Discharge Diagnosis” or “Admission Diagnosis” or similar. Further coding extracted valve involved and organism responsible if present. All cases were chart reviewed using pre-specified criteria. Positive predictive value (PPV), sensitivity and specificity were calculated. The ICD-based query identified 612 individuals from July 2015 to July 2019 who had a hospital billing code for infective endocarditis; of these, 534 had an echocardiogram. The DS query identified 387 cases. PPV for the DS query was 84.5% (95% CI 80.6%, 87.8%) compared with 72.4% (95% CI 68.7%, 75.8%) for ICD only (P < .001) and 75.8% (95% CI 72.0%, 79.3%) for ICD + echo queries (P = .002). Sensitivity was 75.9% for DS query and 86.8% to 93.4% for ICD queries (P < .02 for these comparisons). Specificity was high for all queries >94%. The DS query also yielded valve data (prosthetic, tricuspid, aortic, etc) in 60% and microbiologic agent in 73% of identified cases with an accuracy of 94% and 90%, respectively when assessed by chart review. Compared with ICD-based queries, text-based queries of discharge summaries have the potential to improve precision of IE case ascertainment and extract key clinical variables.

Comparative assessment of manual chart review and ICD claims data in evaluating immunotherapy-related adverse events

BACKGROUND

The aim of this retrospective study was to demonstrate that irAEs, specifically gastrointestinal and pulmonary, examined through International Classification of Disease (ICD) data leads to underrepresentation of true irAEs and overrepresentation of false irAEs, thereby concluding that ICD claims data are a poor approach to electronic health record (EHR) data mining for irAEs in immunotherapy clinical research.

METHODS

This retrospective analysis was conducted in 1,063 cancer patients who received ICIs between 2011 and 2017. We identified irAEs by manual review of medical records to determine the incidence of each of our endpoints, namely colitis, hepatitis, pneumonitis, other irAE, or no irAE. We then performed a secondary analysis utilizing ICD claims data alone using a broad range of symptom and disease-specific ICD codes representative of irAEs.

RESULTS

16% (n = 174/1,063) of the total study population was initially found to have either pneumonitis 3% (n = 37), colitis 7% (n = 81) or hepatitis 5% (n = 56) on manual review. Of these patients, 46% (n = 80/174) did not have ICD code evidence in the EHR reflecting their irAE. Of the total patients not found to have any irAEs during manual review, 61% (n = 459/748) of patients had ICD codes suggestive of possible irAE, yet were not identified as having an irAE during manual review.

DISCUSSION

Examining gastrointestinal and pulmonary irAEs through the International Classification of Disease (ICD) data leads to underrepresentation of true irAEs and overrepresentation of false irAEs.

IC-Behavior: An interdisciplinary taxonomy of behaviors

Academic disciplines are often organized according to the behaviors they examine. While most research on a behavior tends to exist within one discipline, some behaviors are examined by multiple disciplines. Better understanding of behaviors and their relationships should enable knowledge transfer across disciplines and theories, thereby dramatically improving the behavioral knowledge base. We propose a taxonomy built on the World Health Organization's International Classification of Functioning, Disability, and Health (ICF), but design the taxonomy as a stand-alone extension rather than an improvement to ICF. Behaviors considered important enough to serve as the dependent variable in articles accepted for publication in top journals were extracted from nine different behavioral and social disciplines. A six-step development and validation process was employed, leading to the final taxonomy. A hierarchy of behaviors under the top banner of Engaging in activities/participating, reflective of ICF's D. hierarchy was constructed with eight immediate domains addressing behaviors ranging from learning, exercising, self-care, and substance use. The resulting International Classification of Behaviors (IC-Behavior), provides a behavior taxonomy targeted towards the interdisciplinary integration of nomological networks relevant to behavioral theories. While IC-Behavior has been labeled v.1.0 to communicate that it is by no means an endpoint, it has empirically shown to provide flexibility for the addition of new behaviors and is tested in the health domain.

Identifying Medicare beneficiaries with dementia

BACKGROUND/OBJECTIVES

No data exist regarding the validity of International Classification of Disease (ICD)-10 dementia diagnoses against a clinician-adjudicated reference standard within Medicare claims data. We examined the accuracy of claims-based diagnoses with respect to expert clinician adjudication using a novel database with individual-level linkages between electronic health record (EHR) and claims.

DESIGN

In this retrospective observational study, two neurologists and two psychiatrists performed a standardized review of patients' medical records from January 2016 to December 2018 and adjudicated dementia status. We measured the accuracy of three claims-based definitions of dementia against the reference standard.

SETTING

Mass-General-Brigham Healthcare (MGB), Massachusetts, USA.

PARTICIPANTS

From an eligible population of 40,690 fee-for-service (FFS) Medicare beneficiaries, aged 65 years and older, within the MGB Accountable Care Organization (ACO), we generated a random sample of 1002 patients, stratified by the pretest likelihood of dementia using administrative surrogates.

INTERVENTION

None.

MEASUREMENTS

We evaluated the accuracy (area under receiver operating curve [AUROC]) and calibration (calibration-in-the-large [CITL] and calibration slope) of three ICD-10 claims-based definitions of dementia against clinician-adjudicated standards. We applied inverse probability weighting to reconstruct the eligible population and reported the mean and 95% confidence interval (95% CI) for all performance characteristics, using 10-fold cross-validation (CV).

RESULTS

Beneficiaries had an average age of 75.3 years and were predominately female (59%) and non-Hispanic whites (93%). The adjudicated prevalence of dementia in the eligible population was 7%. The best-performing definition demonstrated excellent accuracy (CV-AUC 0.94; 95% CI 0.92-0.96) and was well-calibrated to the reference standard of clinician-adjudicated dementia (CV-CITL <0.001, CV-slope 0.97).

CONCLUSION

This study is the first to validate ICD-10 diagnostic codes against a robust and replicable approach to dementia ascertainment, using a real-world clinical reference standard. The best performing definition includes diagnostic codes with strong face validity and outperforms an updated version of a previously validated ICD-9 definition of dementia.

Accuracy of the Geriatric Depression Scale (GDS)-4 and GDS-5 for the screening of depression among older adults: A systematic review and meta-analysis

BACKGROUND

The Geriatric Depression Scale (GDS) is a widely used instrument to assess depression in older adults. The short GDS versions that have four (GDS-4) and five items (GDS-5) represent alternatives for depression screening in limited-resource settings. However, their accuracy remains uncertain.

OBJECTIVE

To assess the accuracy of the GDS-4 and GDS-5 versions for depression screening in older adults.

METHODS

Until May 2020, we systematically searched PubMed, PsycINFO, Scopus, and Google Scholar; for studies that have assessed the sensitivity and specificity of GDS-4 and GDS-5 for depression screening in older adults. We conducted meta-analyses of the sensitivity and specificity of those studies that used the Diagnostic and Statistical Manual of Mental Disorders (DSM) or the International Classification of Diseases-10 (ICD-10) as reference standard. Study quality was assessed with the QUADAS-2 tool. We performed bivariate random-effects meta-analyses to calculate the pooled sensitivity and specificity with their 95% confidence intervals (95% CI) at each reported common cut-off. For the overall meta-analyses, we evaluated each GDS-4 version or GDS-5 version separately by each cut-off, and for investigations of heterogeneity, we assessed altogether across similar GDS versions by each cut-off. Also, we assessed the certainty of evidence using the GRADE methodology.

RESULTS

Twenty-three studies were included and meta-analyzed, assessing eleven different GDS versions. The number of participants included was 5048. When including all versions together, at a cut-off 2, GDS-4 had a pooled sensitivity of 0.77 (95% CI: 0.70-0.82) and a pooled specificity of 0.75 (0.68-0.81); while GDS-5 had a pooled sensitivity of 0.85 (0.80-0.90) and a pooled specificity of 0.75 (0.69-0.81). We found results for more than one GDS-4 version at cut-off points 1, 2, and 3; and for more than one GDS-5 version at cut-off points 1, 2, 3, and 4. Mostly, significant subgroup differences at different test thresholds across versions were found. The accuracy of the different GDS-4 and GDS-5 versions showed a high heterogeneity. There was high risk of bias in the index test domain. Also, the certainty of the evidence was low or very low for most of the GDS versions.

CONCLUSIONS

We found several GDS-4 and GDS-5 versions that showed great heterogeneity in estimates of sensitivity and specificity, mostly with a low or very low certainty of the evidence. Altogether, our results indicate the need for more well-designed studies that compare different GDS versions.

Evaluating the association between American Association for the Surgery of Trauma emergency general surgery anatomic severity grades and clinical outcomes using national claims data

BACKGROUND

Emergency general surgery (EGS) encompasses a heterogeneous population of acutely ill patients, and standardized methods for determining disease severity are essential for comparative effectiveness research and quality improvement initiatives. The American Association for the Surgery of Trauma (AAST) has developed a grading system for the anatomic severity of 16 EGS conditions; however, little is known regarding how well these AAST EGS grades can be approximated by diagnosis codes in administrative databases.

METHODS

We identified adults admitted for 16 common EGS conditions in the 2012 to 2017q3 National Inpatient Sample. Disease severity strata were assigned using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes based on AAST EGS anatomic severity grades. We evaluated whether assigned EGS severity (multiple strata or dichotomized into less versus more complex) were associated with in-hospital mortality, complications, length of stay, discharge disposition, and costs. Analyses were adjusted for age, sex, comorbidities, hospital traits, geography, and year.

RESULTS

We identified 10,886,822 EGS admissions. The number of anatomic severity strata derived from ICD-9/10-CM codes varied by EGS condition and by year. Four conditions mapped to four strata across all years. Two conditions mapped to four strata with ICD-9-CM codes but only two or three strata with ICD-10-CM codes. Others mapped to three or fewer strata. When dichotomized into less versus more complex disease, patients with more complex disease had worse outcomes across all 16 conditions. The addition of multiple strata beyond a binary measure of complex disease, however, showed inconsistent results.

CONCLUSION

Classification of common EGS conditions according to anatomic severity is feasible with International Classification of Diseases codes. No condition mapped to five distinct severity grades, and the relationship between increasing grade and outcomes was not consistent across conditions. However, a standardized measure of severity, even if just dichotomized into less versus more complex, can inform ongoing efforts aimed at optimizing outcomes for EGS patients across the nation.

LEVEL OF EVIDENCE

Prognostic, level III.

The Challenges of Using ICD codes to Perform a Comparative Analysis between Patients with Penetrating Cardiac Injuries who Underwent Non-Resuscitative Thoracotomy versus Sternotomy

BACKGROUND

Comparative morbidity after either sternotomy or non-resuscitative thoracotomy in penetrating cardiac injuries (PCI) is unknown.

METHODS

Retrospective review of adults with PCI who underwent either sternotomy or non-resuscitative thoracotomy using the National Trauma Data Bank 2007-2015. Since there is no unique International Classification of Diseases Procedure Coding System (ICD-PCS) codes assigned for resuscitative vs. non-resuscitative thoracotomy, and both procedures were coded as "thoracotomy", propensity score (PS) methods were applied to avoid inclusion of resuscitative thoracotomy.

RESULTS

Despite well PS matching on injury severity score the non-thoracotomy group compared to the sternotomy group had a significantly increased risk of mortality (30 percent vs 8 percent, p<0.0001). The morbidity differed as well-25 percent vs. 12 percent, p=0.0007.

CONCLUSIONS

The differences in mortality in PCI patients who underwent non-resuscitative thoracotomy vs. sternotomy may be biased by unintentional inclusion of resuscitative thoracotomy. To accurately capture thoracotomy type, separate unique resuscitative and non-resuscitative thoracotomy procedure codes should be created in future revisions of the ICD PCS.

Development and Testing of Compatible Diagnosis Code Lists for the Functional Comorbidity Index: International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, 10th Revision, Clinical Modification

BACKGROUND

The Functional Comorbidity Index (FCI) was developed for community-based adult populations, with function as the outcome. The original FCI was a survey tool, but several International Classification of Diseases (ICD) code lists-for calculating the FCI using administrative data-have been published. However, compatible International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and ICD-10-CM versions have not been available.

OBJECTIVE

We developed ICD-9-CM and ICD-10-CM diagnosis code lists to optimize FCI concordance across ICD lexicons.

RESEARCH DESIGN

We assessed concordance and frequency distributions across ICD lexicons for the FCI and individual comorbidities. We used length of stay and discharge disposition to assess continuity of FCI criterion validity across lexicons.

SUBJECTS

State Inpatient Databases from Arizona, Colorado, Michigan, New Jersey, New York, Utah, and Washington State (calendar year 2015) were obtained from the Healthcare Cost and Utilization Project. State Inpatient Databases contained ICD-9-CM diagnoses for the first 3 calendar quarters of 2015 and ICD-10-CM diagnoses for the fourth quarter of 2015. Inpatients under 18 years old were excluded.

MEASURES

Length of stay and discharge disposition outcomes were assessed in separate regression models. Covariates included age, sex, state, ICD lexicon, and FCI/lexicon interaction.

RESULTS

The FCI demonstrated stability across lexicons, despite small discrepancies in prevalence for individual comorbidities. Under ICD-9-CM, each additional comorbidity was associated with an 8.9% increase in mean length of stay and an 18.5% decrease in the odds of a routine discharge, compared with an 8.4% increase and 17.4% decrease, respectively, under ICD-10-CM.

CONCLUSION

This study provides compatible ICD-9-CM and ICD-10-CM diagnosis code lists for the FCI.

Differential-diagnostic confusion and non-specificity of affective symptoms and anxiety: An empirical study of first-admission patients

In everyday clinical work, psychiatrists encounter patients who present with symptoms spanning several diagnostic categories, e.g., showing signs of a psychosis, depression, and anxiety. This raises the critical question of which symptoms hold precedence over other and, by extension, which diagnosis is the right diagnosis. ICD-10 and DSM-5 do not provide unambiguous answers to this question and therefore psychiatry remains exposed to diagnostic disagreement with consequences for treatment and research. We explored symptom distribution in a sample of 98 first-admission psychiatric patients. We extracted and categorized singular symptoms into symptom domains: anxiety, mania, delusions, hallucinations, first-rank symptoms, and negative symptoms. Most symptoms were seen in most disorders. We found symptoms of depression and anxiety in almost all patients. Thus, just counting symptoms do not seem to be a valid way to make diagnoses. We elaborately discuss these issues in the context of the differential-diagnosis between schizophrenia and depression. Finally, we suggest that a combination of a criteria- and Gestalt-based approach to diagnosing mental disorders may contribute to counteract some of the current differential-diagnostic confusion.

Linking the effect of psoriatic arthritis-related foot involvement to the Leeds Foot Impact Scale using the International Classification for Functioning, Disability and Health: a study to assess content validity

BACKGROUND

Previous research to describe the impact of foot involvement in psoriatic arthritis has used the Leeds Foot Impact Scale in Rheumatoid Arthritis (LFIS-RA) in the current absence of any psoriatic arthritis foot-specific tools. However, the LFIS-RA is a rheumatoid arthritis disease-specific outcome measure and its content validity for evaluating the experiences of people with psoriatic arthritis-related foot involvement is unknown. The study objective was to determine the content validity of the LFIS-RA for assessing people with psoriatic arthritis, using the International Classification of Functioning, Disability and Health (ICF) as the frame of reference.

METHOD

Concepts within each item of the LFIS-RA were linked to the best-matched ICF categories using established linking rules, which enable a systematic and standardised linking process. All concepts were independently linked to the ICF by 2 investigators with different professional backgrounds, which included occupational therapy and podiatry. The list of ICF categories derived from previous research that pertained to the foot in psoriatic arthritis was then compared with the ICF categories linked to the LFIS-RA. The comparison was undertaken in order to determine the extent to which concepts important and relevant to people with psoriatic arthritis-related foot involvement were addressed.

RESULTS

Thirty-five distinct ICF categories were linked to the LFIS-RA, which related to body functions (44%), activities and participation (35%), environmental factors (16%) and body structure (5%). In comparison with the ICF categories derived from concepts of the foot in psoriatic arthritis previously defined, the LFIS-RA provided coverage of key constructs including pain, functioning, daily activities, footwear restrictions and psychological impact. Other concepts of importance in psoriatic arthritis such as skin and toenail involvement, self-management and paid employment were not addressed in the LFIS-RA.

CONCLUSION

Content validity of the LFIS-RA to determine the impact of foot functional impairments and disability in people with psoriatic arthritis was not supported by the results of this study. Future work should consider the development of a psoriatic arthritis foot-specific patient reported outcome measure, using the LFIS-RA as an important foundation.

Accuracy of ICD-9 codes in identifying patients with peptic ulcer and gastrointestinal hemorrhage in the regional healthcare administrative database of Umbria

Background

Peptic ulcer is a widespread disease, frequently complicated by perforation and bleeding. Administrative databases are useful tool to perform epidemiological and drug utilization studies, but they need a validation process based on a comparison with the original data contained in the medical charts. Our aim was to evaluate the accuracy of the ICD-9 codes in identifying patients with peptic ulcer and gastrointestinal hemorrhage in the regional administrative database of Umbria.

Methods

The index test of our study was the hospital discharge abstract database of the Umbria region (Italy), while the reference standard was the clinical information collected in the medical charts. The study population were adult patients with a hospital discharge for peptic ulcer or gastrointestinal hemorrhage in the period 2012–2014. A random sample of cases and non-cases was selected and the corresponding medical charts were reviewed. Cases of peptic ulcer were confirmed based on endoscopy, radiology, and surgery, while adjudication of gastrointestinal hemorrhage was based on presence of hematemesis, melena, and rectal bleeding.

Results

Overall, we reviewed 445 clinical charts of cases and 80 clinical charts of non-cases. The diagnostic accuracy results were: code 531 (gastric ulcer), sensitivity and NPV 98%, specificity 88%, and PPV 91%; code 532 (duodenal ulcer), sensitivity and NPV 100%, specificity and PPV 98%; code 534 (gastrojejunal ulcer), sensitivity and NPV 100%, specificity 70%, and PPV 45%; code 578 (gastrointestinal hemorrhage), sensitivity 96%, specificity 90%, PPV and NPV 94%.

Conclusions

Our results showed a high level of diagnostic accuracy for most of the codes considered. The ICD-9 code 534 of gastrojejunal ulcer had a lower level of specificity and PPV due to false positives, being mainly misclassifications for coding errors. These validated codes can be used for future epidemiological studies and for health services research.

Assessment of the Accuracy of Using ICD-9 Diagnosis Codes to Identify Pneumonia Etiology in Patients Hospitalized With Pneumonia

IMPORTANCE

Administrative databases may offer efficient clinical data collection for studying epidemiology, outcomes, and temporal trends in health care delivery. However, such data have seldom been validated against microbiological laboratory results.

OBJECTIVE

To assess the validity of International Classification of Diseases, Ninth Revision (ICD-9) organism-specific administrative codes for pneumonia using microbiological data (test results for blood or respiratory culture, urinary antigen, or polymerase chain reaction) as the criterion standard.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional diagnostic accuracy study conducted between February 2017 and June 2019 using data from 178 US hospitals in the Premier Healthcare Database. Patients were aged 18 years or older admitted with pneumonia and discharged between July 1, 2010, and June 30, 2015. Data were analyzed from February 14, 2017, to June 27, 2019.

EXPOSURES

Organism-specific pneumonia identified from ICD-9 codes.

MAIN OUTCOMES AND MEASURES

Sensitivity, specificity, positive predictive value, and negative predictive value of ICD-9 codes using microbiological data as the criterion standard.

RESULTS

Of 161 529 patients meeting inclusion criteria (mean [SD] age, 69.5 [16.2] years; 51.2% women), 35 759 (22.1%) had an identified pathogen. ICD-9-coded organisms and laboratory findings differed notably: for example, ICD-9 codes identified only 14.2% and 17.3% of patients with laboratory-detected methicillin-sensitive Staphylococcus aureus and Escherichia coli, respectively. Although specificities and negative predictive values exceeded 95% for all codes, sensitivities ranged downward from 95.9% (95% CI, 95.3%-96.5%) for influenza virus to 14.0% (95% CI, 8.8%-20.8%) for parainfluenza virus, and positive predictive values ranged downward from 91.1% (95% CI, 89.5%-92.6%) for Staphylococcus aureus to 57.1% (95% CI, 39.4%-73.7%) for parainfluenza virus.

CONCLUSIONS AND RELEVANCE

In this study, ICD-9 codes did not reliably capture pneumonia etiology identified by laboratory testing; because of the high specificities of ICD-9 codes, however, administrative data may be useful in identifying risk factors for resistant organisms. The low sensitivities of the diagnosis codes may limit the validity of organism-specific pneumonia prevalence estimates derived from administrative data.

Drowning: epidemiology, prevention, pathophysiology, resuscitation, and hospital treatment

This narrative review discusses the evidence relevant to key aspects of drowning, which is defined by the World Health Organization as the process of respiratory difficulty caused by submersion/immersion in liquid. The length of time the victim is submerged is a key factor in survival and neurologic damage. Although respiratory distress and hypoxia are the main events, other complications affecting various systems and organs may develop. Drowning is one of the main causes of accidental death worldwide, yet deaths from drowning are underestimated and morbidity is unknown. Prevention is essential for reducing both mortality and morbidity, but if prevention fails, the speed of access to and the quality of prehospital and hospital care will determine the prognosis. It is therefore essential to understand the factors and mechanisms involved in these emergencies.

Treatment of retinopathy of prematurity (ROP) outside International Classification of ROP (ICROP) guidelines

AIM

To evaluate the incidence and clinical indications for which eyes were treated for retinopathy of prematurity (ROP) outside the guidelines set by International Classification of ROP (ICROP).

METHODS

Medical records of the patients treated at a single tertiary care ophthalmology hospital for ROP from January 2016 to December 2019 were retrospectively analysed to evaluate the indications for which they were treated.

RESULTS

Out of 241 eyes, 33 eyes (13.7%) were treated outside the guidelines. The reasons for the treatment outside the guidelines were structural changes (n = 24, 72.7%), persistent stage 3 ROP that did not show any sign of regression for 6 weeks (n = 7, 21.2%) and active ROP with fellow eye being treated (n = 2, 6.1%). The recorded specific structural changes were tangential traction with temporal vessel straightening concerning for macular distortion and ectopia (n = 5, 15.2%), and stage 3 neovascularisation or ridge with anteroposterior traction with risk of progression to stage 4 disease (n = 19, 57.6%). Pre-plus disease was present in 11 eyes (33.3%).After the treatment, ROP stages regressed and retinal vessels grew either until the ora or at least into zone III in all the treated eyes. None of the eyes showed worsening of structural changes after treatment. The mean follow-up of the patients was 12.4 ± 11.7 months.

CONCLUSION

Experts occasionally recommend treatment in eyes with disease milder than type 1 ROP. This study may help paediatric retinal practitioners in decision-making in borderline cases.

The necessity of developing a two-stage qualification in ICD-11

In the International Classification of Diseases, 10th Revision (ICD-10) two opposing principles are combined and mixed: atheoreticity that is necessary for the natural classification and commitment to nosology. Implementation of these principles requires a two-stage qualification. The first stage should be narrative detailed syndromological qualifications with identification of psychotic level of disorders. As for the second stage, the qualification should be nosological, based on complete clinical analysis, which is far from being possible to realize at once. ICD-10, specifically brought to nosological certainty, may remain the natural foundation for nosological qualification. Implementation of the syndromic qualification at the first stage will allow to consider nosological features of each syndrome at the second stage and to expand the list of criteria in different clusters. Such a suggestion opens the prospect for subsequent revisions of the ICD and allows to direct our efforts and those of practitioners to the unified channel, where the statistical goals would not be implemented at the expense of the research ones.

The association between Bell's palsy and rheumatoid arthritis: A longitudinal study

This study aimed to evaluate the relationship between Bell's palsy and rheumatoid arthritis in a national sample cohort from Korea.Data were collected for individuals ≥20 years old from 2002 to 2013 in the Korean National Health Insurance Service-National Sample Cohort. We extracted data for patients with rheumatoid arthritis (n = 7628) and 1:4-matched controls (n = 30,512) and analyzed the occurrence of Bell's palsy in both groups. Matching was performed based on age, sex, income, and region of residence. Rheumatoid arthritis was diagnosed according to International Classification of Disease-10 (ICD-10) codes (M05-M06) and the prescription of biological agents and/or disease-modifying antirheumatic drugs. Bell's palsy patients were diagnosed according to ICD-10 code H912 and treatment ≥2 times with steroids. Adjusted hazard ratios (HRs) were calculated using stratified Cox proportional hazard models for the Charlson comorbidity index and 95% confidence intervals (CIs). Subgroup analyses based on age and sex were also performed.The rates of Bell's palsy were similar between the rheumatoid arthritis group (0.5% [38/7628]) and the control group, with no significant difference (0.4% [124/30,512], P = .270). The adjusted HR for Bell's palsy was 1.12 (95% CI, 0.78-1.62) in the rheumatoid arthritis group (P = .540). In the subgroup analyses according to age and sex, the relationship between Bell's palsy and rheumatoid arthritis did not reach statistical significance.The risk of Bell's palsy was not increased in patients with rheumatoid arthritis.