23 research outputs found
Some basic aspects of quantum phase transitions
Several basic problems of the theory of quantum phase transitions are
reviewed. The effect of the quantum correlations on the phase transition
properties is considered with the help of basic models of statistical physics.
The effect of quenched disorder on the quantum phase transitions is also
discussed. The review is performed within the framework of the thermodynamic
scaling theory and by the most general methods of statistical physics for the
treatment of phase transitions: general length-scale arguments, exact
solutions, mean field approximation, Hubbard-Stratonovich transformation,
Feynman path integral approach, and renormalization group in the field
theoretical variant. Some new ideas and results are presented. Outstanding
theoretical problems are mentioned.Comment: 81 pages, Latex2e, 8 figures, Phys. Rep.(2003) in pres
Use of Medicare Claims to Identify US Hospitals with a High Rate of Surgical Site Infection after Hip Arthroplasty
ObjectiveTo assess the ability of Medicare claims to identify US hospitals with high rates of surgical site infection (SSI) after hip arthroplasty.DesignRetrospective cohort study.SettingAcute care US hospitals.ParticipantsFee-for-service Medicare patients 65 years of age and older who underwent hip arthroplasty in US hospitals from 2005 through 2007.MethodsHospital rankings were derived from claims codes suggestive of SSI, adjusted for age, sex, and comorbidities, while using generalized linear mixed models to account for hospital volume. Medical records were obtained for validation of infection on a random sample of patients from hospitals ranked in the best and worst deciles of performance. We then calculated the risk-adjusted odds of developing a chart-confirmed SSI after hip arthroplasty in hospitals ranked by claims into worst- versus best-performing deciles.ResultsAmong 524,892 eligible Medicare patients who underwent hip arthroplasty at 3,296 US hospitals, a patient who underwent surgery in a hospital ranked in the worst-performing decile based on claims-based evidence of SSI had 2.9-fold higher odds of developing a chart-confirmed SSI relative to a patient with the same age, sex, and comorbidities in a hospital ranked in the best-performing decile (95% confidence interval, 2.2-3.7).ConclusionsMedicare claims successfully distinguished between hospitals with high and low SSI rates following hip arthroplasty. These claims can identify potential outlier hospitals that merit further evaluation. This strategy can also be used to validate the completeness of public reporting of SSI
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Medicare claims can be used to identify US hospitals with higher rates of surgical site infection following vascular surgery.
BackgroundSurgical site infections (SSIs) following vascular surgery have high morbidity and costs, and are increasingly tracked as hospital quality measures.ObjectiveTo assess the ability of Medicare claims to identify US hospitals with high SSI rates after vascular surgery.Research designUsing claims from fee-for-service Medicare enrollees of age 65 years and older who underwent vascular surgery from 2005 to 2008, we derived hospital rankings using previously validated codes suggestive of SSI, with individual-level adjustment for age, sex, and comorbidities. We then obtained medical records for validation of SSI from hospitals ranked in the best and worst deciles of performance, and used logistic regression to calculate the risk-adjusted odds of developing an SSI in worst-decile versus best-decile hospitals.ResultsAmong 203,023 Medicare patients who underwent vascular surgery at 2512 US hospitals, a patient undergoing surgery in a hospital ranked in the worst-performing decile based on claims had 2.5 times higher odds of developing a chart-confirmed SSI relative to a patient with the same age, sex, and comorbidities in a hospital ranked in the best-performing decile (95% confidence interval, 2.0-3.1). SSI confirmation among patients with claims suggesting infection was similar across deciles, and we found similar findings in analyses limited to deep and organ/space SSIs. We report on diagnosis codes with high sensitivity for identifying deep and organ/space SSI, with one-to-one mapping to ICD-10-CM codes.ConclusionsClaims-based surveillance offers a standardized and objective methodology that can be used to improve SSI surveillance and to validate hospitals' publicly reported data
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Medicare claims can be used to identify US hospitals with higher rates of surgical site infection following vascular surgery.
BackgroundSurgical site infections (SSIs) following vascular surgery have high morbidity and costs, and are increasingly tracked as hospital quality measures.ObjectiveTo assess the ability of Medicare claims to identify US hospitals with high SSI rates after vascular surgery.Research designUsing claims from fee-for-service Medicare enrollees of age 65 years and older who underwent vascular surgery from 2005 to 2008, we derived hospital rankings using previously validated codes suggestive of SSI, with individual-level adjustment for age, sex, and comorbidities. We then obtained medical records for validation of SSI from hospitals ranked in the best and worst deciles of performance, and used logistic regression to calculate the risk-adjusted odds of developing an SSI in worst-decile versus best-decile hospitals.ResultsAmong 203,023 Medicare patients who underwent vascular surgery at 2512 US hospitals, a patient undergoing surgery in a hospital ranked in the worst-performing decile based on claims had 2.5 times higher odds of developing a chart-confirmed SSI relative to a patient with the same age, sex, and comorbidities in a hospital ranked in the best-performing decile (95% confidence interval, 2.0-3.1). SSI confirmation among patients with claims suggesting infection was similar across deciles, and we found similar findings in analyses limited to deep and organ/space SSIs. We report on diagnosis codes with high sensitivity for identifying deep and organ/space SSI, with one-to-one mapping to ICD-10-CM codes.ConclusionsClaims-based surveillance offers a standardized and objective methodology that can be used to improve SSI surveillance and to validate hospitals' publicly reported data