Comparative Accuracy of ICD-9 vs ICD-10 Codes for Acute Appendicitis

Power Has Pitfalls: (In)accuracy of Administrative Data for Nonoperative Management of Appendicitis

INTRODUCTION

Nonoperative management (NOM) of uncomplicated appendicitis is increasingly common. Effectiveness of NOM has been studied by identifying patients via International Classification of Diseases (ICD) 9/ICD-10 codes for uncomplicated appendicitis and no code for appendectomy. We sought to assess the accuracy of such administrative definitions.

METHODS

We retrospectively identified patients with ICD-9/ICD-10 codes for appendicitis at five sites across the United States. Initial management plan and clinical severity were recorded by trained abstractors. We identified a gold standard cohort of patients with surgeon-diagnosed uncomplicated appendicitis and planned NOM. We defined two administrative cohorts with ICD-9/ICD-10 codes for uncomplicated appendicitis and either no surgery during initial admission (definition #1) or no surgery on day 0-1 of admission (definition #2). We compared each definition to the gold standard.

RESULTS

Among 1224 patients with uncomplicated appendicitis, 72 (5.9%) underwent planned NOM. NOM patients were older (median [Q1-Q3] of 37 [27-56] versus 32 [25-44] y) and less frequently male (51.4% versus 54.9%), White (54.1% versus 67.6%), and privately insured (38.9% versus 50.2%) than patients managed operatively. Definition #1 had sensitivity of 0.81 and positive predictive value of 0.87 for NOM of uncomplicated appendicitis. Definition #2 had sensitivity of 0.83 and positive predictive value of 0.72. The gold standard cohort had a true failure/recurrence rate of 23.6%, compared with apparent rates of 25.4% and 39.8%, respectively.

CONCLUSIONS

Administrative definitions are prone to misclassification in identifying planned NOM of uncomplicated appendicitis. This likely impacts outcomes in studies using administrative databases. Investigators should disclose how misclassification may affect results and select an administrative definition that optimally balances sensitivity and specificity for their research question.

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.

Automated vs. manual coding of neuroimaging reports via natural language processing, using the international classification of diseases, tenth revision

Objective

Natural language processing (NLP) can generate diagnoses codes from imaging reports. Meanwhile, the International Classification of Diseases (ICD-10) codes are the United States' standard for billing/coding, which enable tracking disease burden and outcomes. This cross-sectional study aimed to test feasibility of an NLP algorithm's performance and comparison to radiologists' and physicians' manual coding.

Methods

Three neuroradiologists and one non-radiologist physician reviewers manually coded a randomly-selected pool of 200 craniospinal CT and MRI reports from a pool of >10,000. The NLP algorithm (Radnosis, VEEV, Inc., Minneapolis, MN) subdivided each report's Impression into "phrases", with multiple ICD-10 matches for each phrase. Only viewing the Impression, the physician reviewers selected the single best ICD-10 code for each phrase. Codes selected by the physicians and algorithm were compared for agreement.

Results

The algorithm extracted the reports' Impressions into 645 phrases, each having ranked ICD-10 matches. Regarding the reviewers' selected codes, pairwise agreement was unreliable (Krippendorff α = 0.39-0.63). Using unanimous reviewer agreement as "ground truth", the algorithm's sensitivity/specificity/F2 for top 5 codes was 0.88/0.80/0.83, and for the single best code was 0.67/0.82/0.67. The engine tabulated "pertinent negatives" as negative codes for stated findings (e.g. "no intracranial hemorrhage"). The engine's matching was more specific for shorter than full-length ICD-10 codes (p = 0.00582x10-3).

Conclusions

Manual coding by physician reviewers has significant variability and is time-consuming, while the NLP algorithm's top 5 diagnosis codes are relatively accurate. This preliminary work demonstrates the feasibility and potential for generating codes with reliability and consistency. Future works may include correlating diagnosis codes with clinical encounter codes to evaluate imaging's impact on, and relevance to care.

Racial, Ethnic, and Socioeconomic Disparities in Glaucoma Onset and Severity in a Diverse Nationwide Cohort in the United States

PRCIS

Racial/ethnic minorities are diagnosed with glaucoma at younger ages, and Blacks are more likely to be diagnosed with moderate-to-severe glaucoma. In addition, we highlight a gap in the use of diagnosis codes.

PURPOSE

The purpose of this study was to analyze patterns of diagnosis coding usage and validate epidemiologic patterns of glaucoma onset and severity among primary glaucoma patients within the National Institutes of Health All of Us database.

PATIENTS AND METHODS

We used International Classification of Disease diagnosis codes to build 4 cohorts of patients with mild, moderate, severe, and unspecified stage glaucoma (N=2982). Descriptive analyses were stratified by disease stage, and mean age at diagnosis was compared across racial and ethnic groups. Multivariable ordinal regression was used to examine risk factors for increasing glaucoma severity.

RESULTS

Of 2982 participants, 1714 (57%) had unspecified severity staging. Black/African Americans and other races were diagnosed with glaucoma at significantly younger ages compared with Whites (means 60 and 60 vs. 66 y; P <0.001). Hispanic/Latino participants also had an earlier mean age of diagnosis (61 vs. 65 y; P =0.001). Black/African Americans had higher odds of more severe glaucoma (odds ratio: 2.20, 95% CI, 1.62-3.30; P <0.001) than Whites when adjusting for socioeconomic characteristics.

CONCLUSIONS

Black, Hispanic/Latino, and other minority participants are diagnosed with glaucoma at younger ages, and Blacks are more likely to be diagnosed with moderate-to-severe glaucoma. These findings validate prior population-based studies. Furthermore, we observed a gap in the use of diagnosis codes, as only 43% of participants had a specified severity stage in this national cohort. This may have implications for large-scale observational research concerning glaucoma severity, as electronic health records and claims databases typically lack other measures of disease progression, such as imaging and visual field data.

Nationwide Outcomes After Thoracoscopic Versus Open Resection of Congenital Pulmonary Airway Malformations in Newborns

Purpose: Elective resection of congenital pulmonary airway malformations (CPAM) has been debated for decades and varies significantly between individual surgeons. However, few studies have compared outcomes and costs associated with thoracoscopic and open thoracotomy approaches on a national level. This study sought to compare nationwide outcomes and resource utilization in infants undergoing elective lung resection for CPAM. Materials and Methods: The Nationwide Readmission Database was queried from 2010 to 2014 for newborns who underwent elective surgical resection of CPAM. Patients were stratified by operative approach (thoracoscopic versus open). Demographics, hospital characteristics, and outcomes were analyzed using standard statistical tests. Results: A total of 1716 newborns with CPAM were identified. Elective readmission for pulmonary resection was performed in 12% (n = 198), with 63% of resections completed at a different hospital than the newborn stay. Most resections were thoracoscopic (75%), compared to only 25% via thoracotomy. Infants treated with thoracoscopic resection were more often male (78% versus 62% open, P = .040) and were older at the time of resection. Patients who had an open thoracotomy experienced a higher rate of serious complications (40% versus 10% thoracoscopic, P < .001), including postoperative hemorrhage, tension pneumothorax, and pulmonary collapse. Readmission costs were higher for infants treated via thoracotomy (P < .001). Conclusion: Thoracoscopic lung resection for CPAM is associated with lower cost and fewer postoperative complications than thoracotomy. Most resections are performed at different hospitals than the place of birth, which may affect long-term outcomes from single institutional studies. These findings may be used to address costs and improve future evaluations of elective CPAM resections.

Age-related disparities and trends in national healthcare spending for management of appendicitis in the United States: A retrospective cost-analysis

BACKGROUND

Changes in clinical care for appendicitis have impacted healthcare use associated with treatment. We evaluated national trends and assessed factors associated with healthcare costs for appendicitis in the United States.

DESIGN

The Disease Expenditure Project, the Global Burden of Disease study, and the National Inpatient Sample were used to estimate total national expenditures, per-capita costs for incident cases, and factors associated with inpatient costs for appendicitis management, respectively. The national estimates of appendicitis costs were obtained from 1996 to 2016. Appendicitis incidence was estimated to calculate per-capita costs. After application of survey weights for the stratified sample design, 191,180 weighted discharges for appendicitis from the 2016 National Inpatient Sample study were evaluated. The Disease Expenditure Project and the Global Burden of Disease study were used to estimate total and per-capita spending. Temporal trends were evaluated using joinpoint regression, expressed as annual percent change. Multivariable linear regression was used to evaluate patient factors associated with total hospital charges.

RESULTS

In 2016, total spending on appendicitis was $9.3 billion (95% confidence interval: $8.0-$10.8], a 2-fold increase from $4.7 billion ($4.0-$5.3) in 1996. Per-capita spending decreased significantly after 2011 (annual percent change -3.7% [-4.4% to -2.9%]). Patients ≥65 years accounted for 64.1% (61.1%-67.3%) of total spending for appendicitis. The hospital charges for older patients were significantly higher among those undergoing appendectomy.

CONCLUSION

Overall healthcare spending for appendicitis has doubled from 1996 to 2016, but per capita spending has decreased since 2011, driven by improved efficiency of inpatient care. Nearly two-thirds of spending is on patients ≥65 years, with significantly higher costs associated with surgical management in this population.

Higher Complication Rates for Total versus Partial Thyroidectomy in the Pediatric Population

INTRODUCTION

This study aims to analyze the relative risks for total thyroidectomies by comparing complication rates for total versus partial thyroidectomy in the pediatric population.

METHODS

We queried the Kids' Inpatient Database (KID) 1997-2012 for all cases of total (n = 3253) or partial (n = 2380) thyroidectomy. We then designed a propensity score matching model and compared total versus partial thyroidectomy based on surgical complications and outcomes.

RESULTS

In our cohort, the median age was 16 years and 79% were females. Those treated at a specialty pediatric hospital or pediatric unit in a general hospital comprised 73% of all patients. The most common indications for surgery were malignancy (46%) and goiter (42%). The most common complications were hypocalcemia and nerve injury with an unweighted incidence of 9% (n = 174) and 3% (n = 57) respectively. When compared to partial thyroidectomy, total thyroidectomy was associated with increased rates of postoperative complications. Additionally, the median length of stay was significantly higher for total thyroidectomy patients.

CONCLUSIONS

This is the largest analysis to date comparing outcomes for total versus partial thyroidectomy in the pediatric population. Surgeons should consider the increased rates of hypocalcemia and nerve injury complications when selecting total compared to partial thyroidectomy in children.

Validity of the coding for appendicitis, appendectomy, and diagnostic laparoscopy in the Danish National Patient Registry

BACKGROUND AND OBJECTIVE

We aimed to validate the diagnostic accuracy of appendicitis, its severity, its description, and the surgical approach, including open or laparoscopic appendectomy and diagnostic laparoscopy, in the Danish National Patient Registry (DNPR) against information from the electronic medical records.

METHODS

A random sample of 1046 patients of all ages and sexes recorded in the DNPR from the Capital Region of Denmark during 2010-2015 was investigated. Patients' admission had to include a discharge code for appendicitis (K35-K379) according to the International Classification of Disease version 10 (ICD-10) alone or in combination with a surgical code for appendectomy or the surgical code for a diagnostic laparoscopy. We calculated the positive predictive values (PPVs) with 95% confidence intervals.

RESULTS

Data from a total of 1018 patients were available for data analysis. The ICD-10 codes for appendicitis resulted in a good PPV of >95% when combined with a surgical code. ICD-10 codes combined with the surgical codes could discriminate between uncomplicated and complicated appendicitis with some caution as the PPVs ranged from 68% to 93%. Only the surgical code for laparoscopic appendectomy yielded a good PPV (99%) for the actual surgical approach. The surgical code for a diagnostic laparoscopy alone did not cover a normal diagnostic laparoscopy.

CONCLUSIONS

The diagnostic accuracy of appendicitis and appendectomy in routinely collected administrative health data is good for ICD-10 codes for appendicitis in combination with a surgical code and especially for laparoscopic appendectomy. Uncomplicated and complicated appendicitis can be distinguished with some caution.

Postdischarge Racial and Ethnic Disparities in Pediatric Appendicitis: A Mediation Analysis

INTRODUCTION

Significant racial and ethnic disparities exist for children presenting with acute appendicitis; however, it is unknown if disparities persist after initial management and hospital discharge.

MATERIALS AND METHODS

We performed a retrospective cohort study of children (aged < 18 y) who underwent treatment for acute appendicitis in 47 U.S. Children's Hospitals between 2017 and 2019. Primary outcomes were 30-d emergency department (ED) visits and 30-d inpatient readmission. Hierarchical multivariable logistic regression models were developed to determine the association of race and ethnicity on the primary outcomes. Inverse odds-weighted mediation analyses were used to estimate the degree to which complicated disease, insurance status, urbanicity, and residential socioeconomic status- mediated disparate outcomes.

RESULTS

A total of 67,303 patients were included. Compared with Non-Hispanic White children, Non-Hispanic Black (NHB) (odds ratio [OR] 1.40, 95% confidence interval [CI] 1.23-1.59) and Hispanic/Latinx (HL) children (OR 1.55, 95% CI 1.44-1.67) had higher odds of ED visits. Only NHB children had higher odds of readmission (OR 1.43, 95% CI 1.30-1.57). On a multivariable analysis, NHB (adjusted OR 1.19, 95% CI 1.04-1.36) and HL (adjusted OR 1.19, 95% CI 1.09-1.31) children had higher odds of ED visits. Insurance, disease severity, socioeconomic status, and urbanicity mediated 61.6% (95% CI 29.7-100%) and 66.3% (95% CI 46.9-89.3%) of disparities for NHB and HL children, respectively.

CONCLUSIONS

Children of racial and ethnic minorities are more likely to visit the ED after treatment for acute appendicitis, but HL patients did not have a corresponding increase in readmission. These differences were mediated mainly by insurance status and urban residence. A lack of appropriate postdischarge education and follow-up may drive disparities in healthcare utilization after pediatric appendicitis.

Diabetes as a Risk Factor for Perforated Appendicitis: A National Analysis

BACKGROUND

A few important risk factors play into rates of perforation following acute appendicitis. Diabetes may be an additional risk factor due to various systemic complications that may contribute to perforation and additional adverse outcomes following acute appendicitis, all of which currently remains unknown in the United States.

METHODS

Adult patients with acute appendicitis under 65 years of age were identified from the National Inpatient Sample between 2012 and 2014 and the distribution of baseline variables was examined across diabetic status using Rao-Scott chi square and student's t-test. A propensity score match was implemented for a conditional logistic regression that assessed differences in rates of perforation, outcomes, as well as postoperative complications.

RESULTS

Among all patients with acute appendicitis, approximately 7% had diabetes. Diabetics were more likely to experience perforated appendicitis (odds ratio 95% confidence interval 1.093 (1.029, 1.160); P = .0036), experience a longer length of stay (1.540 (1.434, 1.654); P < .0001), receive an open appendectomy (1.139 (1.05, 1.236); P = .0018), and experience postoperative cardiovascular complications (2.103 (1.325, 3.340)); P = .0016).

DISCUSSION

Diabetic adult patients under 65 years of age with acute appendicitis experience higher rates in perforation, a longer length of stay, more open surgical approach, and cardiovascular postoperative complications. Diabetes should be one of many risk factors considered in the evaluation and management of perforation following acute appendicitis.

Caveat emptor: The accuracy of claims data in appendicitis research

BACKGROUND

International Classification of Disease, ninth/tenth revision codes are used to identify patients with appendicitis and classify severity of disease for research and hospital reimbursement. We sought to determine accuracy of International Classification of Disease, ninth/tenth revision codes in classifying appendicitis as uncomplicated versus complicated (defined as perforated, necrotic, or abscess) compared with the clinical gold standard: surgeon characterization of the appendix in the operative report.

METHODS

Retrospective review of operative reports and discharge International Classification of Disease, ninth/tenth revision codes for patients ≥18 years old who underwent noninterval, nonincidental appendectomy between January 2012 and December 2019 at a tertiary referral center. Sensitivity, specificity, and positive predictive value were calculated for International Classification of Disease, ninth/tenth revision codes to classify appendicitis accurately as complicated compared with surgeon description. ICD-9/10 codes and surgeon description were categorized into complicated/uncomplicated based on the American Association for the Surgery of Trauma grading system.

RESULTS

In the study, 1,495 patients with acute appendicitis underwent appendectomy. Per surgeon description, 200 (13%) were complicated and 1,295 (87%) uncomplicated. Compared with surgeon description, discharge International Classification of Disease, ninth/tenth revision codes did not accurately identify complicated appendicitis: sensitivity = 0.68, positive predictive value = 0.77. As a sensitivity analysis, the cohort was stratified by public versus private payers, and the results did not change.

CONCLUSION

International Classification of Disease, ninth/tenth revision codes do not accurately identify surgeon-described complicated appendicitis. Nearly one-third of the cases of complicated appendicitis were coded as uncomplicated. Such misclassification negatively impacts reimbursement for complicated appendicitis care and could lead to misleading results in research and quality improvement activities that rely on these codes.