Seasonal variation in U.S. hospitalizations for chronic limb-threatening ischemia.

BACKGROUND: Seasonal variation in coronary artery disease is well described, with a peak in the winter and a trough in the summer. However, little is known about seasonal trends in hospital admission for critical limb-threatening ischemia (CLTI) and associated outcomes. METHODS: Patients admitted with CLTI from January 1, 2012 through August 31, 2015 were identified in the Healthcare Cost and Utilization Project's National Inpatient Sample based upon administrative claims diagnosis codes. The primary outcome was seasonal hospitalization incidence, and secondary outcomes included mortality rates and rates of in-hospital major and minor amputations among nondiabetics and diabetics. RESULTS: Of 1,276,745 hospitalizations for CLTI during the study period, 28.3% occurred in the spring, the peak admission season, and 19.1% occurred in the fall, the nadir. In-hospital mortality was highest during the winter (adjusted odds ratio [OR]: 1.08; 95% confidence interval [CI]: 1.03-1.14), and followed the highest seasonal rates of influenza in the fall; however, other important comorbidities did not differ significantly by season. For the overall cohort, there was no significant seasonal variation in rates of major or minor amputation, although seasonal rates were different according to diabetic status. Patients without diabetes had the highest odds of amputation in the spring (OR 1.07; 95% CI: 1.02-1.12), although this trend was not identified among patients with diabetes. CONCLUSIONS: There is significant seasonal variability in CLTI admissions and mortality but minimal variability in amputation rates. Understanding the seasonal variation in CLTI may help to identify individuals at greatest risk for hospitalization and death through patient and provider education efforts.

Predictors of Underutilization of Medical Therapy in Patients Undergoing Endovascular Revascularization for Peripheral Artery Disease.

OBJECTIVES: The aim of this study was to explore discharge prescription rates of guideline-directed medical therapy (GDMT), defined as aggregate antiplatelet agent, statin, and ACE inhibitor or angiotensin receptor blocker use after endovascular lower extremity (LE) peripheral vascular intervention. BACKGROUND: Little is known about contemporary GDMT prescription following LE PVI. METHODS: Sex, age, and comorbid conditions were related to discharge GDMT prescription among patients undergoing LE PVI for symptomatic peripheral artery disease in the 2014-2018 Vascular Study Group of New England Vascular Quality Initiative. Multivariate logistic regression was used to identify independent predictors of discharge GDMT prescription. RESULTS: Among 12,316 patients, only 47.4% (n = 5,844) were discharged on GDMT after LE PVI. Most patients were discharged on antiplatelet agents (95.2%), with statins (83.5%) and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (55.8%) prescribed less often. A higher proportion of patients were on Class 1 guideline-recommended therapy with antiplatelet agents and statins (80.5%). In multivariate analysis, female sex, older age, end-stage renal disease, chronic limb-threatening ischemia, and congestive heart failure were negative predictors of discharge GDMT prescription, while hypertension, diabetes, coronary artery disease, and prior LE PVI or bypass were positive predictors. CONCLUSIONS: Fewer than one-half of patients undergoing LE PVI are discharged on appropriate GDMT. As expected, traditional atherosclerotic risk factors and measures of greater atherosclerotic disease burden were associated with a greater likelihood of GDMT prescription. However, women and patients with the highest risk for atherothrombosis and limb loss were least likely to be prescribed these agents. Provider- and patient-directed educational efforts are needed to close these treatment gaps.