Association between tissue loss type and amputation risk among Medicare patients with concomitant diabetes and peripheral arterial disease.

OBJECTIVE: Prior studies have described risk factors associated with amputation in patients with concomitant diabetes and peripheral arterial disease(DM/PAD). However, the association between the severity and extent of tissue loss type and amputation risk remains less well-described. We aimed to quantify the role of different tissue loss types in amputation risk among patients with DM/PAD, in the context of demographic, preventive, and socioeconomic factors. METHODS: Applying ICD-9 and ICD-10 codes to Medicare claims data(2007-2019), we identified all patients with continuous fee-for-service Medicare coverage diagnosed with DM/PAD. Eight tissue loss categories were established using ICD-9 and ICD-10 diagnosis codes, ranging from lymphadenitis(least severe) to gangrene(most severe). We created a Cox proportional hazards model to quantify associations between tissue loss type and one- and five-year amputation risk, adjusting for age, race/ethnicity, sex, rurality, income, comorbidities, and preventive factors. Regional variation in DM/PAD rates and risk-adjusted amputation rates was examined at the hospital referral region(HRR) level. RESULTS: We identified 12,257,174 patients with DM/PAD(48% male, 76% White, 10% prior myocardial infarction, 30% chronic kidney disease). While 2.2 million patients(18%) had some form of tissue loss, 10.0 million patients(82%) did not. The one-year crude amputation rate(major and minor) was 6.4% in patients with tissue loss, and 0.4% in patients without tissue loss. Among patients with tissue loss, one-year any amputation rate varied from 0.89% for patients with lymphadenitis to 26% for patients with gangrene. One-year amputation risk varied from two-fold for patients with lymphadenitis(aHR 1.96, 95%CI 1.43-2.69) to 29-fold for patients with gangrene(aHR 28.7, 95%CI 28.1-29.3), compared to patients without tissue loss. No other demographic variable including age, sex, race, or region incurred a hazard ratio for one- or five-year amputation risk higher than the least severe tissue loss category. Results were similar across minor and major amputation, and one- and five-year amputation outcomes. At a regional level, higher DM/PAD rates were inversely correlated with risk-adjusted five-year amputation rates(R2=0.43). CONCLUSION: Among 12 million patients with DM/PAD, the most significant predictor of amputation was presence and extent of tissue loss, with an association greater in effect size than any other factor studied. Tissue loss could be used in awareness campaigns as a simple marker of high-risk patients. Patients with any type of tissue loss require expedited wound care, revascularization as appropriate, and infection management to avoid amputation. Establishing systems of care to provide these interventions in regions with high amputation rates may prove beneficial for these populations.

A Retrospective Analysis of Surgical Acuity & Procedure Volume Before & During the COVID-19 Pandemic.

INTRODUCTION: In March 2020, the American College of Surgeons recommended postponing elective procedures amid the COVID-19 pandemic. We used Medicare claims to analyze changes in surgical and interventional procedure volumes from 2016 to 2021. METHODS: We studied 37 common surgical and interventional procedures using 5% Medicare claims files from January 1, 2016, through December 31, 2021. Procedures were classified according to American College of Surgeons guidelines as low, intermediate, or high acuity, and counts were analyzed per calendar year quarter (Q1-Q4), with stratification by sex and race/ethnicity. RESULTS: We observed 1,840,577 procedures and identified two periods of marked decline. In Q2 2020, overall procedure counts decreased by 32.2%, with larger declines in low (41.1%) and intermediate (30.8%) acuity procedures. High acuity procedures declined the least (18.2%). Overall volumes increased afterward but never returned to baseline. Another marked decline occurred in Q4 2021, with all acuity levels having declined to a similar extent (40.1%, 44.2%, and 46.9% for low, intermediate, and high acuity, respectively). High and intermediate acuity procedures declined more in Q4 2021 than Q2 2020 (P = 0.002). Similar patterns were observed across sex and race/ethnicity strata. CONCLUSIONS: Two major procedural volume declines occurred between 2020 and 2022 during the COVID-19 pandemic in the United States. High acuity (life or limb threatening) procedures were least affected in the first decline (Q2 2020) but not spared in second decline (Q4 2021). Future efforts should prioritize preserving high-acuity access during times of stress.

Trends of Concomitant Diabetes and Peripheral Artery Disease and Lower Extremity Amputation in US Medicare Patients, 2007 to 2019.

BACKGROUND: Previous studies demonstrate geographic and racial/ethnic variation in diagnosis and complications of diabetes and peripheral artery disease (PAD). However, recent trends for patients diagnosed with both PAD and diabetes are lacking. We assessed the period prevalence of concurrent diabetes and PAD across the United States from 2007 to 2019 and regional and racial/ethnic variation in amputations among Medicare patients. METHODS: Using Medicare claims from 2007 to 2019, we identified patients with both diabetes and PAD. We calculated period prevalence of concomitant diabetes and PAD and incident cases of diabetes and PAD for every year. Patients were followed to identify amputations, and results were stratified by race/ethnicity and hospital referral region. RESULTS: 9 410 785 patients with diabetes and PAD were identified (mean age, 72.8 [SD, 10.94] years; 58.6% women, 74.7% White, 13.2% Black, 7.3% Hispanic, 2.8% Asian/API, and 0.6% Native American). Period prevalence of diabetes and PAD was 23 per 1000 beneficiaries. We observed a 33% relative decrease in annual new diagnoses throughout the study. All racial/ethnic groups experienced a similar decline in new diagnoses. Black and Hispanic patients had on average a 50% greater rate of disease compared with White patients. One- and 5-year amputation rates remained stable at ≈1.5% and 3%, respectively. Native American, Black, and Hispanic patients were at greater risk of amputation compared with White patients at 1- and 5-year time points (5-year rate ratio range, 1.22-3.17). Across US regions, we observed differential amputation rates, with an inverse relationship between the prevalence of concomitant diabetes and PAD and overall amputation rates. CONCLUSIONS: Significant regional and racial/ethnic variation exists in the incidence of concomitant diabetes and PAD among Medicare patients. Black patients in areas with the lowest rates of PAD and diabetes are at disproportionally higher risk for amputation. Furthermore, areas with higher prevalence of PAD and diabetes have the lowest rates of amputation.

Deriving International Classification of Diseases, 9th and 10th revision, codes for identifying and following up patients with diabetic lower extremity ulcers.

Objective: Administrative claims data offer a rich data source for clinical research. However, its application to the study of diabetic lower extremity ulceration is lacking. Our objective was to create a widely applicable framework by which investigators might derive and refine the International Classification of Diseases, 9th and 10th revision (ICD-9 and ICD-10, respectively) codes for use in identifying diabetic, lower extremity ulceration. Methods: We created a seven-step process to derive and refine the ICD-9 and ICD-10 coding lists to identify diabetic lower extremity ulcers. This process begins by defining the research question and the initial identification of a list of ICD-9 and ICD-10 codes to define the exposures or outcomes of interest. These codes are then applied to claims data, and the rates of clinical events are examined for consistency with prior research and changes across the ICD-9 to ICD-10 transition. The ICD-9 and ICD-10 codes are then cross referenced with each other to further refine the lists. Results: Using this method, we started with 8 ICD-9 and 43 ICD-10 codes used to identify lower extremity ulcers in patients with known diabetes and peripheral arterial disease and examined the association of ulceration with lower extremity amputation. After refinement, we had 45 ICD-9 codes and 304 ICD-10 codes. We then grouped the codes into eight clinical exposure groups and examined the rates of amputation as a rudimentary test of validity. We found that the rate of lower extremity amputation correlated with the severity of lower extremity ulceration. Conclusions: We identified 45 ICD-9 and 304 ICD-10 ulcer codes, which identified patients at risk of amputation from diabetes and peripheral artery disease. Although further validation at the medical record level is required, these codes can be used for claims-based risk stratification for long-term outcomes assessment in the treatment of patients at risk of limb loss.

Using a cohort study of diabetes and peripheral artery disease to compare logistic regression and machine learning via random forest modeling.

BACKGROUND: This study illustrates the use of logistic regression and machine learning methods, specifically random forest models, in health services research by analyzing outcomes for a cohort of patients with concomitant peripheral artery disease and diabetes mellitus. METHODS: Cohort study using fee-for-service Medicare beneficiaries in 2015 who were newly diagnosed with peripheral artery disease and diabetes mellitus. Exposure variables include whether patients received preventive measures in the 6 months following their index date: HbA1c test, foot exam, or vascular imaging study. Outcomes include any reintervention, lower extremity amputation, and death. We fit both logistic regression models as well as random forest models. RESULTS: There were 88,898 fee-for-service Medicare beneficiaries diagnosed with peripheral artery disease and diabetes mellitus in our cohort. The rate of preventative treatments in the first six months following diagnosis were 52% (n = 45,971) with foot exams, 43% (n = 38,393) had vascular imaging, and 50% (n = 44,181) had an HbA1c test. The directionality of the influence for all covariates considered matched those results found with the random forest and logistic regression models. The most predictive covariate in each approach differs as determined by the t-statistics from logistic regression and variable importance (VI) in the random forest model. For amputation we see age 85 + (t = 53.17) urban-residing (VI = 83.42), and for death (t = 65.84, VI = 88.76) and reintervention (t = 34.40, VI = 81.22) both models indicate age is most predictive. CONCLUSIONS: The use of random forest models to analyze data and provide predictions for patients holds great potential in identifying modifiable patient-level and health-system factors and cohorts for increased surveillance and intervention to improve outcomes for patients. Random forests are incredibly high performing models with difficult interpretation most ideally suited for times when accurate prediction is most desirable and can be used in tandem with more common approaches to provide a more thorough analysis of observational data.

Effect of a Decision Aid on Agreement Between Patient Preferences and Repair Type for Abdominal Aortic Aneurysm: A Randomized Clinical Trial.

Importance: Patients with abdominal aortic aneurysm (AAA) can choose open repair or endovascular repair (EVAR). While EVAR is less invasive, it requires lifelong surveillance and more frequent aneurysm-related reinterventions than open repair. A decision aid may help patients receive their preferred type of AAA repair. Objective: To determine the effect of a decision aid on agreement between patient preference for AAA repair type and the repair type they receive. Design, Setting, and Participants: In this cluster randomized trial, 235 patients were randomized at 22 VA vascular surgery clinics. All patients had AAAs greater than 5.0 cm in diameter and were candidates for both open repair and EVAR. Data were collected from August 2017 to December 2020, and data were analyzed from December 2020 to June 2021. Interventions: Presurgical consultation using a decision aid vs usual care. Main Outcomes and Measures: The primary outcome was the proportion of patients who had agreement between their preference and their repair type, measured using χ2 analyses, κ statistics, and adjusted odds ratios. Results: Of 235 included patients, 234 (99.6%) were male, and the mean (SD) age was 73 (5.9) years. A total of 126 patients were enrolled in the decision aid group, and 109 were enrolled in the control group. Within 2 years after enrollment, 192 (81.7%) underwent repair. Patients were similar between the decision aid and control groups by age, sex, aneurysm size, iliac artery involvement, and Charlson Comorbidity Index score. Patients preferred EVAR over open repair in both groups (96 of 122 [79%] in the decision aid group; 81 of 106 [76%] in the control group; P = .60). Patients in the decision aid group were more likely to receive their preferred repair type than patients in the control group (95% agreement [93 of 98] vs 86% agreement [81 of 94]; P = .03), and κ statistics were higher in the decision aid group (κ = 0.78; 95% CI, 0.60-0.95) compared with the control group (κ = 0.53; 95% CI, 0.32-0.74). Adjusted models confirmed this association (odds ratio of agreement in the decision aid group relative to control group, 2.93; 95% CI, 1.10-7.70). Conclusions and Relevance: Patients exposed to a decision aid were more likely to receive their preferred AAA repair type, suggesting that decision aids can help better align patient preferences and treatments in major cardiovascular procedures. Trial Registration: ClinicalTrials.gov Identifier: NCT03115346.

The Impact of Work Status and Age in Choosing Type of Abdominal Aortic Aneurysm Repair.

INTRODUCTION: The PReferences for Open Versus Endovascular Repair of Abdominal Aortic Aneurysm (PROVE-AAA) trial aimed to determine the efficacy of a validated decision aid to enable better alignment between patient preference and their ultimate repair. We sought to determine the key factors influencing the decision-making of veterans for endovascular repair of abdominal aortic aneurysm (EVAR) or open surgical repair (OSR). METHODS: A total of 235 veterans in the PROVE-AAA trial were asked their information sources regarding repairs, employment status, and preferred intervention. Answers were coded and analyzed using conventional content analysis to generate nonoverlapping themes, then stratified by employment status. RESULTS: Forty-two patients (17.8% of enrollees) provided their source of information for OSR prior to using a decision aid. 81% of retired veterans were greater than 70 y old, while 58% of nonretired veterans were greater than 70 (P = 0.003). The most common information source was from a vascular surgeon/professional or unspecified MD/other health professionals (51.4%), while sources from outside this group made up the remaining 48.5%. The most preferred procedure was EVAR. However, nonretired individuals were more likely to prefer OSR. These data on information source and preferred procedure were similar in patients who provided their source for EVAR. CONCLUSIONS: Veterans in the PROVE-AAA study were more likely to be retired and more likely to rely on information from an unspecified MD/other health professionals for EVAR. Although both retired and nonretired veterans preferred EVAR the most, nonretired veterans were more likely to prefer OSR despite being younger.

Validation of an indirect linkage algorithm to combine registry data with Medicare claims.

BACKGROUND: The linkage of registries to Medicare claims data can help extend follow-up for patients receiving medical devices. In the present study, we tested and validated an algorithm that does not require patient identifiers to link data from a national vascular registry and Medicare claims data. METHODS: We used data from the Vascular Quality Initiative (VQI), a registry capturing data from >600 centers for several different vascular procedures, and Medicare claims from 2003 to 2018. We restricted the study to patients aged ≥65 years who had fee-for-service entitlement at their procedure. We performed an indirect linkage to combine the VQI and Medicare data at the patient level using a sequential algorithm based on the patient's date of birth, sex, zip code, procedure date, and procedure facility. We compared the indirectly linked cohort against a reference standard of a cohort directly linked using Social Security numbers. We calculated the matching rate and accuracy overall and before and after October 2015 when the International Classification of Diseases, 10th revision (ICD-10) system was adopted in the United States. RESULTS: A total of 144,045 VQI-Medicare-linked patients were in the reference standard cohort. Using the indirect linking algorithm, we matched 133,966 of the 144,045 VQI patients to their Medicare claims with a matching rate of 93.0%. Of the 133,966 patients, 133,104 were correctly matched (matching accuracy, 99.4%). The matching rate was higher when the indirect linkage was implemented using the ICD-10 coded data than using the ICD-9 coded data (94.0% vs 92.2%). The accuracy of the indirect linkage remained high for all procedure modules after the ICD-10 coding change (overall, 99.4%; range, 99.0%-99.7%). CONCLUSIONS: In the present study, we successfully used indirect identifiers to link the VQI data to Medicare claims with >90% success and >99% accuracy. When direct linkage of the registry claims data using Social Security numbers is not possible because of availability or confidentiality, or both, our algorithm for indirect linkage provides a suitable alternative. The matching rate and accuracy will help ensure the accuracy of long-term follow-up and the completeness and representativeness of linked databases for relevant research and quality improvement initiatives.

A Mixed-Methods Evaluation of Patient Education Materials for Colorectal Cancer.

BACKGROUND: Patient education materials are created by professional organizations to inform patients about their disease and its treatment. However, it remains unclear if these materials are appropriate for patients. OBJECTIVE: This study aims to broadly evaluate the education materials for patients with colorectal cancer. DESIGN: Patient education materials from the National Comprehensive Cancer Network, the National Cancer Institute, and the American Society of Colon and Rectal Surgeons were assessed quantitatively by using 1) the Flesch-Kincaid readability formula and 2) the Patient Education Material Assessment Tool. The Patient Education Material Assessment Tool scores materials in 2 domains: understandability and actionability. These materials were further evaluated qualitatively via an exploratory focus group with patients and their caregivers (n = 5) and semi-structured interviews with board-certified/eligible colorectal surgeons (n = 10). SETTING: This study was conducted at academic centers and a regional professional society meeting. PARTICIPANTS: The mean patient age was 63. Most surgeons (8/10) practiced in an academic setting, and 4/10 were female. MAIN OUTCOME MEASURES: The primary outcomes measured were reading grade level and domain scores for the Patient Education Material Assessment Tool. Qualitative data were recorded, transcribed, and coded. Themes were generated through data interpretation and data reduction. RESULTS: Materials ranged from 7th to 11th grade reading level. National Comprehensive Cancer Network materials scored highest for understandability (92.2% ± 6.1%, mean ± SD), followed by National Cancer Institute (84.0% ± 6.6%) and American Society of Colon and Rectal Surgeons (82.2% ± 6.3%) materials. Actionability scores varied; the National Comprehensive Cancer Network materials scored 82.5% ± 1.7%, whereas the National Cancer Institute and American Society of Colon and Rectal Surgeons materials scored 23.3% ± 6.7% and 50.0% ± 8.2%. Critical gaps were identified in the content of these materials. Patients wanted more information about self-care, both emotional and physical. Specifically, patients sought details about postoperative bowel function. Whereas surgeons wanted information about the typical hospital course and recovery, all wanted materials to be customizable. LIMITATIONS: A limited number of materials were reviewed, and patient focus groups were exploratory. CONCLUSIONS: Commonly available printed education materials for colorectal cancer are written at a high reading grade level, vary in their usability, and neglect important details about postoperative recovery. See Video Abstract at http://links.lww.com/DCR/B535. EVALUACIN DE MTODOS MIXTOS DE MATERIALES EDUCATIVOS PARA PACIENTES SOBRE CNCER COLORECTAL: ANTECEDENTES:Los materiales educativos para pacientes son creados por organizaciones profesionales para informar a los pacientes sobre su enfermedad y su tratamiento. Sin embargo, no está claro si estos materiales son apropiados para los pacientes.OBJETIVO:Evaluar ampliamente los materiales para el cáncer colorrectal.DISEÑO:Los materiales educativos para pacientes de la Red Nacional Integral del Cáncer (NCCN), el Instituto Nacional del Cáncer (NCI) y la Sociedad Americana de Cirujanos de Colon y Recto (ASCRS) se evaluaron cuantitativamente utilizando (1) la fórmula de legibilidad de Flesch-Kincaid y (2) la herramienta de evaluación de material educativo para pacientes. La Herramienta de evaluación de materiales educativos para pacientes califica los materiales en dos dominios: comprensibilidad y viabilidad. Estos materiales fueron evaluados cualitativamente a través de un grupo de enfoque exploratorio con pacientes y sus cuidadores (n = 5) y entrevistas semiestructuradas con cirujanos colorrectales certificados o elegibles para certificación por el consejo (n = 10).ESCENARIO:Centros académicos y un encuentro regional de una sociedad profesional.PACIENTES:La edad media de los pacientes fue de 63 años. La mayoría de los cirujanos (8/10) practicaban en un entorno académico, y 4/10 eran mujeres.PRINCIPALES MEDIDAS DE RESULTADO:Nivel de grado de lectura y puntajes de dominios para la Herramienta de evaluación de materiales educativos para pacientes. Los datos cualitativos se registraron, transcribieron y codificaron. Los temas se generaron mediante la interpretación y la reducción de datos.RESULTADOS:Los materiales variaron desde el nivel de lectura del 7° al 11° grado. Los materiales de la NCCN obtuvieron la puntuación más alta en comprensibilidad (92.2 ± 6.1%, media ± DE), seguidos por los materiales de NCI (84.0 ± 6.6%) y ASCRS (82.2 ± 6.3%). Los puntajes de viabilidad variaron; Los materiales de NCCN obtuvieron una puntuación de 82.5 ± 1.7%, mientras que los materiales de NCI y ASCRS obtuvieron una puntuación de 23.3 ± 6.7% y 50.0 ± 8.2%, respectivamente. Se identificaron lagunas críticas en el contenido de estos materiales. Los pacientes querían más información sobre el autocuidado, tanto emocional como físico. Específicamente, los pacientes buscaron detalles sobre la función intestinal posoperatoria. Mientras que los cirujanos querían información sobre el curso hospitalario típico y la recuperación, y todos querían que los materiales fueran personalizables.LIMITACIONES:Se revisó una cantidad limitada de materiales y los grupos de enfoque de pacientes fueron exploratorios.CONCLUSIONES:Los materiales educativos impresos comúnmente disponibles para el cáncer colorrectal están escritos a un alto nivel de grado de lectura, varían en su usabilidad y omiten detalles importantes sobre la recuperación postoperatoria. Consulte Video Resumen en http://links.lww.com/DCR/B535.

Translating coding lists in administrative claims-based research for cardiovascular procedures.

BACKGROUND: To effectively use administrative claims for healthcare research, clinical events must be inferred from coding data according to validated algorithms. In October 2015, the United States transitioned from the International Classification of Diseases Ninth Revision (ICD-9) to the Tenth Revision (ICD-10). We describe our method to derive new ICD-10 codes for outcomes after vascular procedures from our prior, validated ICD-9 codes. METHODS: We began with validated ICD-9 coding lists known to represent outcomes after lower extremity revascularization, thoracic aortic endograft placement, abdominal aortic aneurysm reintervention, and carotid revascularization. We used the publicly available general equivalence mapping tools to derive corresponding ICD-10 codes for each of the ICD-9 codes in our current lists. The resulting lists were then manually reviewed by multiple authors to ensure clinical relevance for appropriate event detection. Clinically nonrelevant and duplicated codes were removed. RESULTS: A total of 475 ICD-9 codes were translated to ICD-10 with a 98-fold increase (n = 46,630) in the total number of codes. Overall, we found that 77% of codes (n = 35,833) were either duplicated or not clinically relevant upon manual review. For example, for thoracic aortic endograft placement, 97 ICD-9 codes mapped to 14,661 ICD-10 codes in total. A total of 890 codes were removed as duplicates and 9035 codes were removed during manual clinical review. The resultant, reviewed list contained 4736 ICD-10 codes representing a 49-fold increase from the initial ICD-9 list. Findings were similar across the other procedures studied. CONCLUSIONS: ICD-10 has expanded the number of codes necessary to describe outcomes after vascular procedures. More than 75% of the codes obtained using the general equivalence mapping database were either duplicated or not clinically relevant. Manual review of codes by researchers with clinical knowledge of the procedures is imperative.

Characterizing Reimbursements for Medicare Patients Receiving Endovascular Abdominal Aortic Aneurysm Repair at Vascular Quality Initiative Centers.

BACKGROUND: Endovascular aortic aneurysm repair (EVR) has a major financial impact on health care systems. We characterized reimbursement for index EVR hospitalizations among Medicare beneficiaries having surgery at Vascular Quality Initiative (VQI) centers. METHODS: We linked Medicare claims to VQI clinical registry data for patients undergoing EVR from 2003 to 2015. Analysis was limited to patients fully covered by fee-for-service Medicare parts A and B in the year of their operation and assigned a corresponding diagnosis-related group for EVR. The primary outcome was Medicare's reimbursement for inpatient hospital and professional services, adjusted to 2015 dollars. We performed descriptive analysis of reimbursement over time and univariate analysis to evaluate patient demographics, clinical characteristics, procedural variables, and postoperative events associated with reimbursement. This informed a multilevel regression model used to identify factors independently associated with EVR reimbursement and quantify VQI center-level variation in reimbursement. RESULTS: We studied 9,403 Medicare patients who underwent EVR at VQI centers during the study period. Reimbursements declined from $37,450 ± $9,350 (mean ± standard deviation) in 2003 to $27,723 ± $10,613 in 2015 (test for trend, P < 0.001). For patients experiencing a complication (n = 773; 8.2%), mean reimbursement for EVR was $44,858 ± $23,825 versus $28,857 ± $9,258 for those without complications (P < 0.001). Intestinal ischemia, new dialysis requirement, and respiratory compromise each doubled Medicare's average reimbursement for EVR. After adjusting for diagnosis-related group, several patient-level factors were independently associated with higher Medicare reimbursement; these included ruptured abdominal aortic aneurysm (+$2,372), additional day in length of stay (+$1,275), and being unfit for open repair (+$501). Controlling for patient-level factors, 4-fold variation in average reimbursement was seen across VQI centers. CONCLUSIONS: Reimbursement for EVR declined between 2003 and 2015. We identified preoperative clinical factors independently associated with reimbursement and quantified the impact of different postoperative complications on reimbursement. More work is needed to better understand the substantial variation observed in reimbursement at the center level.

Validating Publicly Available Crosswalks for Translating ICD-9 to ICD-10 Diagnosis Codes for Cardiovascular Outcomes Research.

Background On October 1, 2015, the Center for Medicare and Medicaid Services transitioned from the International Classification of Diseases, Ninth Revision ( ICD-9) to the ICD, Tenth Revision ( ICD-10) compendium of codes for diagnosis and billing in health care, but translation between the two is often inexact. Here we describe a validated crosswalk to translate ICD-9 codes into ICD-10 codes, with a focus on complications after carotid revascularization and endovascular aortic aneurysm repair. Methods and Results We devised an 8-step process to derive and validate ICD-10 codes from existing ICD-9 codes. We used publicly available sources, including the General Equivalence Mapping database, to translate ICD-9 codes used in prior work to ICD-10 codes. We defined ICD-10 codes as validated if they were concordant with the initial ICD-9 codes after manual comparison by two physicians. Our primary validation measure was the percent of valid ICD-10 codes out of the total ICD-10 codes obtained during translation. We began with 126 ICD-9 diagnosis codes used for complication identification after carotid revascularization procedures, and 97 ICD-9 codes for complications after endovascular aortic aneurysm procedures. Translation generated 143 ICD-10 codes for carotid revascularization, a 14% increase from the initial 126 codes. Manual comparison demonstrated 98% concordance, with 99% agreement between the reviewers. Similarly, we identified 108 ICD-10 codes for endovascular aortic aneurysm repair, an 11% increase from the initial 97 ICD-9 codes. We again noted excellent concordance and agreement (98% and 100%, respectively). Manual review identified 4 ICD-10 codes incorrectly translated from ICD-9 codes for carotid revascularization, and 3 codes incorrectly translated for endovascular aortic aneurysm repair. Conclusions Algorithms to crosswalk lists of ICD-9 codes to ICD-10 codes can leverage electronic resources to minimize the burden of code translation. However, manual review for code validation may be necessary, with collaboration across institutions for researchers to share their efforts.

A pilot study for long-term outcome assessment after aortic aneurysm repair using Vascular Quality Initiative data matched to Medicare claims.

OBJECTIVE: Accurate and complete long-term postoperative outcome data are critical to improving value in health care delivery. The Society for Vascular Surgery Vascular Quality Initiative (VQI) is an important tool to achieve this goal in vascular surgery. To improve on the capture of long-term outcomes after vascular surgery procedures for patients in the VQI, we sought to match VQI data to Medicare claims for comprehensive capture of major clinical outcomes in the first several years after vascular procedures. METHODS: Patient and procedure characteristics for abdominal aortic aneurysm procedures captured in the Society for Vascular Surgery VQI between January 1, 2002, and December 31, 2013, were matched to Medicare claims data using an indirect identifier methodology. Late outcomes captured in the VQI and in Medicare claims were compared. RESULTS: Matching procedures yielded 9895 endovascular aneurysm repair (EVAR) patients (82.4% of eligible VQI patients) and 3405 open aneurysm repair (OAR) patients (74.4% of eligible). Comparison of patients who did and did not match to a Medicare claim demonstrated similar patient and procedure characteristics. Evaluation of late outcomes revealed good patient-level agreement on mortality for both EVAR (κ, 0.64) and OAR (κ, 0.82). Postoperative reintervention rates demonstrated lower agreement for both EVAR (κ, 0.26) and OAR (κ, 0.16). CONCLUSIONS: This work demonstrates the feasibility of an algorithm using indirect identifiers to match VQI patients and procedures to Medicare claims data. The refinement of this strategy will focus on establishing and improving algorithms related to identifying and categorizing late events after EVAR and may serve as a mechanism to ensure that the best quality follow-up information is achieved within the VQI.