920-52 Are Provider Profiles Affected by Risk-adjustment Methodology? Results from the Cooperative Cardiovascular Project

Health care payors and consumers have a growing interest in risk-adjusted provider profiles. Using chart-abstracted clinical data from the Cooperative Cardiovascular Project, we ranked 28 hospitals performing bypass surgery in Alabama and Iowa by their risk-adjusted surgical mortality rates using three published risk-adjustment methodologies: Parsonnet (PI, O’Connor (a) and Hannan (H). In total. 3653 bypass surgery cases performed from 6/92 to 3/93 were reviewed (mean 130 cases/hospital). The discriminatory abilities of each method for predicting surgical mortality were quite similar (area under ROC curves 0.72–0.75). Below, we display the risk-adjusted hospital rankings (comparing observed with expected mortality) by these three riskadjustment techniques:In terms of hospital rankings, there was generally close correlation between any two of the methods (Spearman's R=0.87,0.88, and 0.93, comparing P-O, P-H, and H-O). Rankings for an individual hospital varied, however, an average of ±3.3 ranks (range 0–12 ranks) depending on which riskadjustment methodology was used.ConclusionIn general. published methods of risk-adjustment for bypass surgery accurately identify institutions with low, moderate and high adjusted mortality outcomes. The precise ranking of an individual hospital. however, may vary depending on the risk adjustment method applied

Estimating Fixed Effects: Perfect Prediction and Bias in Binary Response Panel Models, with an Application to the Hospital Readmissions Reduction Program

The maximum likelihood estimator for the regression coefficients, β, in a panel binary response model with fixed effects can be severely biased if N is large and T is small, a consequence of the incidental parameters problem. This has led to the development of conditional maximum likelihood estimators and, more recently, to estimators that remove the O(T–1) bias in β^. We add to this literature in two important ways. First, we focus on estimation of the fixed effects proper, as these have become increasingly important in applied work. Second, we build on a bias-reduction approach originally developed by Kosmidis and Firth (2009) for cross-section data, and show that in contrast to other proposals, the new estimator ensures finiteness of the fixed effects even in the absence of within-unit variation in the outcome. Results from a simulation study document favourable small sample properties. In an application to hospital data on patient readmission rates under the 2010 Affo

Thermodynamic Additivity of Sequence Variations: An Algorithm for Creating High Affinity Peptides Without Large Libraries or Structural Information

BACKGROUND: There is a significant need for affinity reagents with high target affinity/specificity that can be developed rapidly and inexpensively. Existing affinity reagent development approaches, including protein mutagenesis, directed evolution, and fragment-based design utilize large libraries and/or require structural information thereby adding time and expense. Until now, no systematic approach to affinity reagent development existed that could produce nanomolar affinity from small chemically synthesized peptide libraries without the aid of structural information. METHODOLOGY/PRINCIPAL FINDINGS: Based on the principle of additivity, we have developed an algorithm for generating high affinity peptide ligands. In this algorithm, point-variations in a lead sequence are screened and combined in a systematic manner to achieve additive binding energies. To demonstrate this approach, low-affinity lead peptides for multiple protein targets were identified from sparse random sequence space and optimized to high affinity in just two chemical steps. In one example, a TNF-α binding peptide with K(d) = 90 nM and high target specificity was generated. The changes in binding energy associated with each variation were generally additive upon combining variations, validating the basis of the algorithm. Interestingly, cooperativity between point-variations was not observed, and in a few specific cases, combinations were less than energetically additive. CONCLUSIONS/SIGNIFICANCE: By using this additivity algorithm, peptide ligands with high affinity for protein targets were generated. With this algorithm, one of the highest affinity TNF-α binding peptides reported to date was produced. Most importantly, high affinity was achieved from small, chemically-synthesized libraries without the need for structural information at any time during the process. This is significantly different than protein mutagenesis, directed evolution, or fragment-based design approaches, which rely on large libraries and/or structural guidance. With this algorithm, high affinity/specificity peptide ligands can be developed rapidly, inexpensively, and in an entirely chemical manner

Determinants of appropriate use of angiotensin-converting enzyme inhibitors after acute myocardial infarction in persons \u3e or = 65 years of age

We sought to determine how often angiotensin-converting enzyme (ACE) inhibitors are prescribed as a discharge medication among eligible patients \u3e or = 65 years old with an acute myocardial infarction; to identify patient characteristics associated with the decision to prescribe ACE inhibitors; and to determine the factors associated with the decision to obtain an evaluation of left ventricular function among patients who have no contraindications to ACE inhibitors. We addressed these aims with an observational study of consecutive elderly Medicare beneficiary survivors of an acute myocardial infarction hospitalized in Alabama, Connecticut, Iowa, and Wisconsin between June 1992 and February 1993. Among the 5,453 patients without a contraindication to ACE inhibitors at discharge, 3,528 (65%) had an evaluation of left ventricular function. Of the 1,228 patients without a contraindication to ACE inhibitors who had a left ventricular ejection fraction \u3c or = 40%, 548 (45%) were prescribed the medication at discharge. In a multivariable analysis, an increased prescribed use of ACE inhibitors at discharge was correlated with several factors, including diabetes mellitus, congestive heart failure, ventricular tachycardia, and loop diuretics as a discharge medication. Patients admitted after the publication of the Survival and Ventricular Enlargement (SAVE) trial were significantly more likely to receive ACE inhibitors, although the absolute improvement in utilization was small in the 6 months after the trial results were published. In conclusion, improving the identification of appropriate patients for ACE inhibitors and increasing the prescription of ACE inhibitors for ideal patients may provide an excellent opportunity to improve care

Improving the quality of care for Medicare patients with acute myocardial infarction: results from the Cooperative Cardiovascular Project

CONTEXT: Medicare has a legislative mandate for quality assurance, but the effectiveness of its population-based quality improvement programs has been difficult to establish. OBJECTIVE: To improve the quality of care for Medicare patients with acute myocardial infarction. DESIGN: Quality improvement project with baseline measurement, feedback, remeasurement, and comparison samples. SETTING: All acute care hospitals in the United States. PATIENTS: Preintervention and postintervention samples included all Medicare patients in Alabama, Connecticut, Iowa, and Wisconsin discharged with principal diagnoses of acute myocardial infarctions during 2 periods, June 1992 through December 1992 and August 1995 through November 1995. Indicator comparisons were made with a random sample of Medicare patients in the rest of the nation discharged with acute myocardial infarctions from August 1995 through November 1995. Mortality comparisons involved all Medicare patients nationwide with inpatient claims for acute myocardial infarctions during 2 periods, June 1992 through May 1993 and August 1995 through July 1996. INTERVENTION: Data feedback by peer review organizations. MAIN OUTCOME MEASURES: Quality indicators derived from clinical practice guidelines, length of stay, and mortality. RESULTS: Performance on all quality indicators improved significantly in the 4 pilot states. Administration of aspirin during hospitalization in patients without contraindications improved from 84% to 90% (P\u3c .001), and prescription of beta-blockers at discharge improved from 47% to 68% (P \u3c .001). Mortality at 30 days decreased from 18.9% to 17.1% (P = .005) and at 1 year from 32.3% to 29.6% (P \u3c .001). These improvements in quality occurred during a period when median length of stay decreased from 8 days to 6 days. Performance on all quality indicators except reperfusion was better in the pilot states than in the rest of the nation in 1995, and the differences were statistically significant for aspirin use at discharge (P \u3c .001), beta-blocker use (P \u3c .001), and smoking cessation counseling (P = .02). Postinfarction mortality was not significantly different between the pilot states and the rest of the nation during the baseline period, although it was slightly but significantly better in the pilot states during the follow-up period (absolute mortality difference at 1 year, 0.9%; P = .004). CONCLUSIONS: The quality of care for Medicare patients with acute myocardial infarction has improved in the Cooperative Cardiovascular Project pilot states. Performance on the defined quality indicators appeared to be better in the pilot states than in the rest of the nation in 1995 and was associated with reduced mortality