Relationship between regional spending on vascular care and amputation rate.

IMPORTANCE: Although lower extremity revascularization is effective in preventing amputation, the relationship between spending on vascular care and regional amputation rates remains unclear. OBJECTIVE: To test the hypothesis that higher regional spending on vascular care is associated with lower amputation rates for patients with severe peripheral arterial disease. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of 18,463 US Medicare patients who underwent a major peripheral arterial disease-related amputation during the period between 2003 and 2010. EXPOSURE: Price-adjusted Medicare spending on revascularization procedures and related vascular care in the year before lower extremity amputation, across hospital referral regions. MAIN OUTCOMES AND MEASURES: Correlation coefficient between regional spending on vascular care and regional rates of peripheral arterial disease-related amputation. RESULTS: Among patients who ultimately underwent an amputation, 64% were admitted to the hospital in the year prior to the amputation for revascularization, wound-related care, or both; 36% were admitted only for their amputation. The mean cost of inpatient care in the year before amputation, including costs related to the amputation procedure itself, was $22,405, but it varied from $11,077 (Bismarck, North Dakota) to $42,613 (Salinas, California) (P < .001). Patients in high-spending regions were more likely to undergo vascular procedures as determined by crude analyses (12.0 procedures per 10,000 patients in the lowest quintile of spending and 20.4 procedures per 10,000 patients in the highest quintile of spending; P < .001) and by risk-adjusted analyses (adjusted odds ratio for receiving a vascular procedure in highest quintile of spending, 3.5 [95% CI, 3.2-3.8]; P < .001). Although revascularization was associated with higher spending (R = 0.38, P < .001), higher spending was not associated with lower regional amputation rates (R = 0.10, P = .06). The regions that were most aggressive in the use of endovascular interventions were the regions that were most likely to have high spending (R = 0.42, P = .002) and high amputation rates (R = 0.40, P = .004). CONCLUSIONS AND RELEVANCE: Regions that spend the most on vascular care perform the most procedures, especially endovascular interventions, in the year before amputation. However, there is little evidence that higher regional spending is associated with lower amputation rates. This suggests an opportunity to limit costs in vascular care without compromising quality.

Regional intensity of vascular care and lower extremity amputation rates.

OBJECTIVE: Because patient-level differences do not fully explain the variation in lower extremity amputation rates across the United States, we hypothesized that variation in intensity of vascular care may also affect regional rates of amputation and examined the relationship between the intensity of vascular care and the population-based rate of major lower extremity amputation (above-knee or below-knee) from vascular disease. METHODS: Intensity of vascular care was defined as the proportion of Medicare patients who underwent any vascular procedure in the year before amputation, calculated at the regional level (2003 to 2006), using the 306 hospital referral regions in the Dartmouth Atlas of Healthcare. The relationship between intensity of vascular care and major amputation rate, at the regional level, was examined between 2007 and 2009. RESULTS: Amputation rates varied widely by region, from one to 27 per 10,000 Medicare patients. Compared with regions in the lowest quintile of amputation rate, patients in the highest quintile were commonly African American (50% vs 13%) and diabetic (38% vs 31%). Intensity of vascular care also varied across regions: <35% of patients underwent revascularization in the lowest quintile of intensity, whereas nearly 60% underwent revascularization in the highest quintile. Overall, an inverse correlation was found between intensity of vascular care and the amputation rate, ranging from R = -0.36 for outpatient diagnostic and therapeutic procedures to R = -0.87 for inpatient surgical revascularizations. Analyses adjusting for patient characteristics and socioeconomic status found patients in high-intensity vascular care regions were significantly less likely to undergo amputation without an antecedent attempt at revascularization (odds ratio, 0.37; 95% confidence interval, 0.34-0.37; P < .001). CONCLUSIONS: The intensity of vascular care provided to patients at risk for amputation varies, and regions with the most intensive vascular care have the lowest amputation rate, although the observational nature of these associations do not impart causality. High-risk patients, especially African American diabetic patients residing in low-intensity vascular care regions, represent an important target for systematic efforts to reduce amputation risk.

Racial disparities in survival among injured drivers.

Prior studies on racial and ethnic disparities in survival after motor vehicle crashes have examined only population-based death rates or have been restricted to hospitalized patients. In the current study, we examined 3 components of crash survival by race/ethnicity: survival overall, survival to reach a hospital, and survival among those hospitalized. Nine years of data (from 2000 through 2008) from the National Automotive Sampling System Crashworthiness Data System were used to examine white non-Hispanic, black non-Hispanic, and Hispanic drivers aged ≥ 15 years with serious injuries (injury severity scores of ≥ 9). By using multivariable logistic regression, we found that a driver's race/ethnicity was not significantly associated with overall survival after being injured in a crash (for blacks, odds ratio (OR) = 0.69, 95% confidence interval (CI): 0.36, 1.32; for Hispanics, OR = 1.00, 95% CI: 0.59, 1.72), and blacks and Hispanics were equally likely to survive to be treated at a hospital compared with whites (for blacks, OR = 1.00, 95% CI: 0.52, 1.93; for Hispanics, OR = 1.13, 95% CI: 0.71, 1.79). However, among patients who were treated at a hospital, blacks were 50% less likely to survive 30 days compared with whites (OR = 0.50, 95% CI: 0.33, 0.76). The disparity in survival after serious traffic injuries among blacks appears to occur after hospitalization, not in prehospital survival.

Early discharge does not increase readmission or mortality after high-risk vascular surgery.

PURPOSE: Clinical pathways aimed at reducing hospital length of stay following vascular surgery have been broadly implemented to reduce costs. However, early hospital discharge may adversely affect the risk of readmission or mortality. To address this question, we examined the relationship between early discharge and 30-day outcomes among patients undergoing a high-risk vascular surgery procedure, thoracic aortic aneurysm (TAA) repair. METHODS: Using Medicare claims from 2000 to 2007, we identified all patients who were discharged home following elective thoracic endovascular aneurysm repair (TEVAR) and open repair for nonruptured TAAs. For each procedure, we examined the correlation between early discharge (<3 days for TEVAR, <7 days for open TAA repair) and 30-day readmission, 30-day mortality, and hospital costs. Predictors of readmission were evaluated using logistic regression models controlling for patient comorbidities, perioperative complications, and discharge location. RESULTS: Our sample included 9764 patients, of which 7850 (80%) underwent open TAA repair, and 1914 (20%) underwent TEVAR. Patients discharged to home early were more likely to be female (66% early vs 56% late), Caucasian (94% early vs 91% late), younger (73 years early vs 74 years late), and have fewer comorbidities (mean Charlson score: 0.7 early vs 1.0 late) than patients discharged home late (all P < .01). As compared with patients who were discharged late, patients discharged home early following uncomplicated open TAA repair and TEVAR had significantly lower 30-day readmission rates ([open: 17% vs 24%; P < .001] [TEVAR: 12% vs 23%; P < .001]) and hospital costs ([open: $73,061 vs $136,480; P < .001] [TEVAR: $58,667 vs $128,478; P < .001]), without an observed increase in 30-day postdischarge mortality. In multivariable analysis, early hospital discharge was associated with a significantly lower likelihood of readmission following both open TAA repair (odds ratio, 0.70; 95% confidence interval, 0.57-0.85; P < .001) and TEVAR (odds ratio, 0.57; 95% confidence interval, 0.38-0.85; P < .01) procedures. CONCLUSIONS: Discharging patients home early following uncomplicated TEVAR or open TAA repair is associated with reduced hospital costs without adversely impacting 30-day readmission or mortality rates. These data support the safety and cost-effectiveness of programs aimed at early hospital discharge in selected vascular surgery patients.

Mortality in rural locations after severe injuries from motor vehicle crashes.

BACKGROUND: Mortality from traffic crashes is often higher in rural regions, and this may be attributable to decreased survival probability after severe injury. METHODS: Data were obtained from the National Automotive Sampling System - General Estimates System (NASS-GES) for 2002-2008. Using weighted survey logistic regression, three injury outcomes were analyzed: (a) Death overall, (b) Severe injury (incapacitating or fatal), and (c) Death, after severe injury. Models controlled for (pre-crash) person, event, and county level factors. RESULTS: The sample included 883,473 motorists. Applying weights, this represented a population of 98,411,993. Only 2% of the weighted sample sustained a severe injury, and 9% of these severely injured motorists died. The probability of death overall and the probability of severe injury increased with older age, safety belt nonuse, vehicle damage, high speed, and early morning crashes . Males were less likely to be severely injured, but more likely to die if severely injured. Motorists in southern states were more likely to have severe injuries, but not more likely to die if severely injured. Motorists who crashed in very rural counties were significantly more likely to die overall, and were more likely to die if severely injured. CONCLUSIONS: Motorists with severe injury are more likely to die in rural areas, after controlling for person- and event-specific factors.

Peanut allergy diagnoses among children residing in Olmsted County, Minnesota.

BACKGROUND: Peanut allergy is a major health concern, particularly in developed countries. Research indicates that as many as 2% of children are allergic to peanuts, which represents a 3-fold increase in diagnoses over the past 2 decades. OBJECTIVE: This population-based descriptive study used the Rochester Epidemiology Project to estimate the prevalence in 2007 and annual incidence rates of peanut allergy diagnoses from 1999 to 2007 among children residing in Olmsted County, Minnesota. METHODS: Residents of Olmsted County from January 1, 1999, through December 31, 2007, who received medical care at a Rochester Epidemiology Project facility and provided research authorization were eligible for the study. A medical chart review of 547 potential diagnoses resulted in 244 prevalent and 170 incident cases. Annual rates, crude and adjusted for age and sex, were standardized with the use of the indirect method to the Olmsted County population data in 1999. Incidence rate ratios were estimated with Poisson regression. RESULTS: The prevalence in 2007 was 0.65%. Female children were less likely to be diagnosed than male children (incidence rate ratio = 0.18; 95% CI, 0.07-0.48). Children aged birth to 2 years were significantly more likely to be diagnosed than older children aged 3-17 years (incidence rate ratio = 0.001; 95% CI, 0.0004-0.004). A significant 3-fold increasing trend was observed in diagnoses over time from 2.05 cases per 10,000 children in 1999 to 6.88 cases per 10,000 in 2007. CONCLUSIONS: Peanut allergies are an increasing concern in Olmsted County, Minnesota, as indicated by a 3-fold increase in diagnoses from 2.05 per 10,000 children in 1999 to 6.88 per 10,000 children in 2007.

Variation in the use of lower extremity vascular procedures for critical limb ischemia.

BACKGROUND: Many believe that variation in vascular practice may affect limb salvage rates in patients with severe peripheral arterial disease. However, the extent of variation in procedural vascular care obtained by patients with critical limb ischemia (CLI) remains unknown. METHODS AND RESULTS: By using Medicare 2003 to 2006 data, we identified all patients with CLI who underwent major lower extremity amputation in the 306 hospital referral regions described in the Dartmouth Atlas of Healthcare. For each patient, we studied the use of lower extremity vascular procedures (open surgery or endovascular intervention) in the year before amputation. Our main outcome measure was the intensity of vascular care, defined as the proportion of patients in the hospital referral region undergoing a vascular procedure in the year before amputation. Overall, 20,464 patients with CLI underwent major lower extremity amputations during the study period, and collectively underwent 25,800 vascular procedures in the year before undergoing amputation. However, these procedures were not distributed evenly: 54% of patients had no vascular procedures performed in the year before amputation, 14% underwent 1 vascular procedure, and 32% underwent >1 vascular procedure. In the regions in the lowest quintile of vascular intensity, vascular procedures were performed in 32% of patients. Conversely, in the regions in the highest quintile of vascular intensity, revascularization was performed in 58% of patients in the year before amputation (P<0.0001). In analyses accounting for differences in age, sex, race, and comorbidities, patients in high-intensity regions were 2.4 times as likely to undergo revascularization in the year before amputation than patients in low-intensity regions (adjusted odds ratio, 2.4; 95% CI, 2.1-2.6; P<0.001). CONCLUSIONS: Significant variation exists in the intensity of vascular care provided to patients in the year before major amputation. In some regions, patients receive intensive care, whereas in other regions, far less vascular care is provided. Future work is needed to determine the association between intensity of vascular care and limb salvage.

National trends and regional variation of open and endovascular repair of thoracic and thoracoabdominal aneurysms in contemporary practice.

OBJECTIVES: Successful surgical management of thoracic aortic aneurysms (TAA) and thoracoabdominal aortic aneurysms (TAAA) has historically relied upon open surgical repair (OSR). More recently, the advent and application of thoracic endovascular stent graft aneurysm repair (TEVAR) permutations have become increasingly performed in contemporary practice. To better determine the effect of TEVAR techniques on OSR, we examined national and regional trends in treatment use. METHODS: All Medicare patients from 1998 through 2007 undergoing isolated TAA and TAAA repair were analyzed using a clinically validated algorithm using diagnostic International Classification of Disease 9th revision (ICD-9; 441.1, 441.2, 441.6, 441.7, 441.9) codes and procedural (ICD-9 OSR: 38.35, 38.45 and TEVAR: 39.73, 39.79) codes. Differential rates of OSR and TEVAR were compared across census tract regions during the study interval. RESULTS: Total complex aortic repairs increased by 60%, from 10.8 to 17.8/100,000, between 1998 and 2007 (P < .001). A dramatic increase occurred in TEVAR (not performed in 1998, 5.8/100,000 in 2007) during the study period, but OSR rates remained stable during the same interval (10.7 to 12.0/100,000 in 2007, P = NS). There was substantial regional variation for both OSR and TEVAR. This regional variation was greater in OSR (range, 8.8-16.7/100,000) than in TEVAR (range, 4.5-6.9/100,000). CONCLUSIONS: Degenerative TAA and TAAA aneurysms are being repaired in the United States at an increasing rate. This reflects the rapid acceptance of TEVAR, which apparently supplements rather than supplants OSR. There appears to be greater regional variation in OSR compared with TEVAR. These data may have significant implications for those interested in the effect of new technologies on health care and cost containment.

Explaining regional disparities in traffic mortality by decomposing conditional probabilities.

BACKGROUND: In the USA, the mortality rate from traffic injury is higher in rural and in southern regions, for reasons that are not well understood. METHODS: For 1754 (56%) of the 3142 US counties, we obtained data allowing for separation of the deaths/population rate into deaths/injury, injuries/crash, crashes/exposure and exposure/population, with exposure measured as vehicle miles travelled. A 'decomposition method' proposed by Li and Baker was extended to study how the contributions of these components were affected by three measures of rural location, as well as southern location. RESULTS: The method of Li and Baker extended without difficulty to include non-binary effects and multiple exposures. Deaths/injury was by far the most important determinant in the county-to-county variation in deaths/population, and accounted for the greatest portion of the rural/urban disparity. After controlling for the rural effect, injuries/crash accounted for most of the southern/northern disparity. CONCLUSIONS: The increased mortality rate from traffic injury in rural areas can be attributed to the increased probability of death given that a person has been injured, possibly due to challenges faced by emergency medical response systems. In southern areas, there is an increased probability of injury given that a person has crashed, possibly due to differences in vehicle, road, or driving conditions.

Risk profiles of progression in primary focal segmental glomerulosclerosis.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is a component of childhood nephrotic syndrome occurring in 10%-20% of all cases. Over time, 25%-50% of children with FSGS develop kidney failure disease. We followed a cohort of children with FSGS in order to delineate the risk profile of progression to kidney failure (KF). METHODS: We evaluated patient data collected from 1977 to 2002 at a regional mid-Atlantic nephrology center in the United States. KF was defined primarily for those patients whose serum creatinine (SCr) value doubled compared with the SCr value from a previous visit. Patients who received dialysis or a kidney transplant were also defined as having KF. We analyzed patient data for those who had at least two visits with SCr values recorded. Various baseline characteristics of patients who had developed KF and those with no kidney failure (NKF) were compared. Hazard ratios and correlation were used to further investigate potential risk factors of the kidney failure. We also compared the inverse SCr trend for KF and NKF patients using weighted linear regression. RESULTS: Thirty-four of 43 FSGS patients had adequate follow-up data. About 60% of the patients developed KF over the study period. The average age of the KF patients at diagnosis of FSGS was 9 years, and that of NKF patients 12 years (P=0.05). FSGS patients with KF had a significantly higher mean diastolic blood pressure (DBP) at baseline, compared to those with NKF (P<0.0001). Other baseline characteristics including race, body mass index (BMI), systolic blood pressure, total cholesterol, urinary protein/creatinine ratio and calculated glomerular filtration rate (cGFR) were not significantly different. Baseline DBP was a significant risk factor in progression to KF (HR: 1.03; 95%CI: 1.01-1.06). Inverse SCr values were significantly decreased over time in KF patients (P=0.01). CONCLUSIONS: The data of this study indicate that children diagnosed with FSGS who are younger than 10 years and have elevated baseline DBP are more likely to develop kidney failure. The non-significant hazard ratios for other baseline characteristics including gender, race, and BMI are not instrumental risk factors. These results may help understand what may affect progression towards kidney failure in children with FSGS.

Regional variation in carotid artery stenting and endarterectomy in the Medicare population.

BACKGROUND: To describe geographic variation in population-based rates of carotid artery stenting (CAS) and carotid endarterectomy (CEA) performed in Medicare beneficiaries. METHODS AND RESULTS: Medicare claims and enrollment data were used to calculate age, sex, and race-adjusted rates of CAS and CEA for Medicare beneficiaries in each of 306 hospital referral regions between 1998 and 2007. Procedures were identified using a combination of Current Procedural Terminology codes as well as diagnostic and procedural ICD-9 codes. Overall, the rate of carotid revascularization has fallen slightly over the last decade (3.8 procedures per 1000 in 1998, 3.1 procedures per 1000 in 2007; P<0.0001). Although the use of CEA decreased, from 3.6 to 2.5 procedures per 1000 beneficiaries in 2007 (P<0.0001), the use of CAS has increased >4-fold between 1998 and 2007, growing from 0.1 to 0.6 CAS procedures per 1000 beneficiaries (P<0.0001). Further, CAS rapidly disseminated across the country over the last decade. In 1998, 66% of hospital referral regions had a hospital that performed CAS; however, by 2007, nearly all (95%) hospital referral regions performed CAS (P<0.0001). Last, in regions with the highest utilization rates of CAS, it appeared that CAS was performed as a substitute for CEA. There was little evidence that CAS was being performed in addition to CEA, as no correlation existed between regional rates of CAS and CEA (r=0.06). CONCLUSIONS: Even though CEA was used less frequently in 2007 than 1998, the use of CAS has grown significantly. Although regional variation in the use of CEA has remained fairly constant, regional variation has increased in the use of CAS. Given these changes in practice patterns, careful examination of the efficacy and cost-effectiveness of CAS is necessary.

Changes in the use of carotid revascularization among the medicare population.

HYPOTHESIS: It remains unknown if the increasing use of carotid artery stenting (CAS) has caused a change in the population-based use of carotid endarterectomy (CEA). We sought to examine national trends in carotid revascularization. DESIGN: Retrospective cohort study. SETTING: Academic research. PATIENTS: All Medicare beneficiaries (MCBEs) between January 1, 1998, through December 31, 2004. MAIN OUTCOME MEASURES: We examined the frequency of CEA and CAS using Current Procedural Terminology codes for CEA, peripheral stent insertion, and cerebrovascular disease. To exclude patients who underwent stenting of a peripheral artery other than the carotid artery, we excluded all patients with a primary diagnostic code for peripheral vascular disease. RESULTS: We identified 134 194 claims for carotid revascularization (9386 claims for CAS and 124 808 claims for CEA). The overall incidence of carotid revascularization procedures decreased slightly between 1998 and 2004, from 388.1 to 345.8 procedures per 100 000 MCBEs (11% decrease, P < .02). Between 1998 and 2004, the incidence of CEA decreased from 373.4 to 309.3 procedures per 100 000 MCBEs (17% decrease, P < .01), while the incidence of CAS increased from 14.6 to 36.4 procedures per 100 000 MCBEs (149% increase, P < .01). CONCLUSIONS: While rates of carotid revascularization in the Medicare population slightly decreased between 1998 and 2004, the use of CAS dramatically increased. Whether this represents a substitution of CAS for CEA vs a broadening of indications for carotid revascularization using CAS is unknown but is of interest to patients and third-party payers and requires future investigation.