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.

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.

Short-Term Concerns Primarily Determine Patient Preference for Abdominal Aortic Aneurysm Repair.

INTRODUCTION: Abdominal aortic aneurysm (AAA) repair may be performed through open or endovascular approaches, but the factors influencing a patient's repair-type preference are not well characterized. Here we performed a qualitative analysis to better understand factors influencing patient preference within the Preference for Open Versus Endovascular Repair of AAA Trial. METHODS: Open-ended responses regarding primary (n = 21) and secondary (n = 47) factors influencing patient preference underwent qualitative analysis using the constant comparative method with iterative reviews. Codes were used to generate themes and themes grouped into categories, with each step conducted via consensus agreement between three researchers. Relative prevalence of themes were compared to ascertain trends in patient preference. RESULTS: Patient responses regarding both primary and secondary factors fell into four categories: Short-term concerns, long-term concerns, advice & experience, and other. Patients most frequently described short-term concerns (23) as their primary influence, with themes including post-op complications, hospitalization & recovery, and intraoperative concerns. Long-term concerns were more prevalent (20) as secondary factors, which included themes such as survival, and chronic management. The average age of patients voicing only long-term concerns as a primary factor was 11 years younger than those listing only short-term concerns. CONCLUSION: Short-term concerns relating to the procedure and recovery are more often the primary factor influencing patient preference, while long term concerns play a more secondary role. Long-term concerns are more often a primary factor in younger patients. Vascular surgeons should consider this information in shared decision making to reach an optimal outcome.

Epidemiology of peripheral artery disease.

Peripheral artery disease (PAD) is the clinical manifestation of atherosclerosis that primarily affects peripheral arteries within the lower extremities. In this brief review, we describe the epidemiology and burden of disease of PAD within the United States, particularly among high-risk populations. Although the prevalence of PAD continues to increase and is typically higher among the elderly as well as men, women in lower socioeconomic strata are affected at rates two times that of men. Among racial/ethnic groups, Black and African-American patients both experience higher rates of disease as well as lower rates of access to preventative care. Moreover, despite an overall decrease in amputation rates among all patients with PAD, high-risk populations remain disproportionally affected. Specifically, patients in rural areas, African-American and Native-American patients, and those of low socioeconomic status carry the highest risk of amputation. Efforts to improve care among PAD patients should target these high-risk populations and offer comprehensive, evidence-based preventative care. Wide adoption and integration of these practices into comprehensive care models may help to mitigate amputation in the highest-risk populations. As our treatment pathways continue to evolve, we must place further emphasis on patient input and quality of life as we work toward continual improvement in the care of patients with PAD.

Vascular applications of contrast-enhanced ultrasound imaging.

OBJECTIVE: Contrast-enhanced ultrasound (CEUS) imaging is a powerful noninvasive modality offering numerous potential diagnostic and therapeutic applications in vascular medicine. CEUS imaging uses microbubble contrast agents composed of an encapsulating shell surrounding a gaseous core. These microbubbles act as nearly perfect intravascular reflectors of ultrasound energy and may be used to enhance the overall contrast and quality of ultrasound images. The purpose of this narrative review is to survey the current literature regarding CEUS imaging and discuss its diagnostic and therapeutic roles in current vascular and selected nonvascular applications. METHODS: The PubMed, MEDLINE, and Embase databases were searched until July 2016 using the PubMed and Ovid Web-based search engines. The search terms used included contrast-enhanced, microbubble, ultrasound, carotid, aneurysm, and arterial. RESULTS: The diagnostic and therapeutic utility of CEUS imaging has grown exponentially, particularly in the realms of extracranial carotid arterial disease, aortic disease, and peripheral arterial disease. Studies have demonstrated that CEUS imaging is diagnostically superior to conventional ultrasound imaging in identifying vessel irregularities and measuring neovascularization to assess plaque vulnerability and end-muscle perfusion. Groups have begun to use microbubbles as agents in therapeutic applications for targeted drug and gene therapy delivery as well as for the enhancement of sonothrombolysis. CONCLUSIONS: The emerging technology of microbubbles and CEUS imaging holds considerable promise for cardiovascular medicine and cancer therapy given its diagnostic and therapeutic utility. Overall, with proper training and credentialing of technicians, the clinical implications are innumerable as microbubble technology is rapidly bursting onto the scene of cardiovascular medicine.