Congestive heart failure and outpatient risk of venous thromboembolism: a retrospective, case-control study.

Although CHF has been considered a risk factor for venous thromboembolism, this has not been directly studied. We hypothesized that congestive heart failure would increase the risk of venous thromboembolism in an outpatient population, and that this risk would increase as patients' ventricular function worsened. We conducted a case-control study to examine whether CHF due to left ventricular dysfunction was an independent risk factor for acute venous thromboembolism in outpatients, once established risk factors such as recent surgery and prior venous thromboembolism are taken into account. We reviewed 106 cases of DVT and 603 controls, admitted for diabetes mellitus or infection, matched for month of admission at a VA hospital. Assignment of a diagnosis of venous thromboembolism required a definitive test, as did classification as CHF. In a logistic regression model CHF was an independent predictor of venous thromboembolism. A second logistic regression model showed that the risk of venous thromboembolism increased as the ejection fraction (EF) decreased, with an EF < 20 associated with a venous thromboembolism OR of 38.3 (95% CI 9.6, 152.5). CHF is an independent risk factor for venous thromboembolism, and the risk increases markedly as the EF decreases. These results support the use of anticoagulation in selected patients with CHF.

A trial for comparing methods for eliciting treatment preferences from men with advanced prostate cancer: results from the initial visit.

OBJECTIVE: The objective of this study was to evaluate the convergent validity of 3 types of utility measures: standard gamble, time tradeoff, and rating scale. RESEARCH DESIGN: A prospective cohort of 120 men with advanced prostate cancer were first asked to rank order 8 health states, and then utility values were obtained from each participant for each of the 8 health states through 2 of the 3 techniques evaluated (standard gamble, time tradeoff and rating scale). Participants were randomly assigned to 1 of 3 possible pairs of techniques. The validity of the 3 methods, as measured by the convergence and raw score differences of the techniques, was assessed with ANOVA. The ability of the techniques to differentiate health states was determined. The inconsistencies between rankings and utility values were also measured. Proportions of illogical utility responses were assessed as the percent of times when states with more symptoms were given higher or equal utility values than states with fewer symptoms. RESULTS: There were significant differences in raw scores between techniques, but the values were correlated across health states. Utility values were often inconsistent with the rank order of health states. In addition, utility assessment did not differentiate the health states as well as the rank order. Furthermore, utility values were often illogical in that states with more symptoms received equal or higher utility values than states with fewer symptoms. CONCLUSIONS: Use of the utility techniques in cost-effectiveness analysis and decision making has been widely recommended. The results of this study raise serious questions as to the validity and usefulness of the measures.

The hospital multistay rate as an indicator of quality of care.

OBJECTIVES: To evaluate the hospital multistay rate to determine if it has the attributes necessary for a performance indicator that can be applied to administrative databases. DATA SOURCES/STUDY SETTING: The fiscal year 1994 Veterans Affairs Patient Treatment File (PTF), which contains discharge data on all VA inpatients. STUDY DESIGN: Using a retrospective study design, we assessed cross-hospital variation in (a) the multistay rate and (b) the standardized multistay ratio. A hospital's multistay rate is the observed average number of hospitalizations for patients with one or more hospital stays. A hospital's standardized multistay ratio is the ratio of the geometric mean of the observed number of hospitalizations per patient to the geometric mean of the expected number of hospitalizations per patient, conditional on the types of patients admitted to that hospital. DATA COLLECTION/EXTRACTION METHODS: Discharge data were extracted for the 135,434 VA patients who had one or more admissions in one of seven disease groups. PRINCIPAL FINDINGS: We found that 17.3 percent (28,300) of the admissions in the seven disease categories were readmissions. The average number of stays per person (multistay rate) for an average of seven months of follow-up ranged from 1.15 to 1.45 across the disease categories. The maximum standardized multistay ratio ranged from 1.12 to 1.39. CONCLUSIONS: This study has shown that the hospital multistay rate offers sufficient ease of measurement, frequency, and variation to potentially serve as a performance indicator.

Assessing the performance of utility techniques in the absence of a gold standard.

BACKGROUND: Utility techniques are the most commonly used means to assess patient preferences for health outcomes. However, whether utility techniques produce valid measures of preference has been difficult to determine in the absence of a gold standard. OBJECTIVE: To introduce and demonstrate two methods that can be used to evaluate how well utility techniques measure patients' preferences. SUBJECTS AND DESIGN: Patients treated for advanced prostate cancer (n = 57) first ranked eight health states in order of preference. Four utility techniques were then used to elicit patients' utilities for each health state. MEASURES: The rating scale, standard gamble, time trade-off, and a modified version of willingness-to-pay techniques were used to elicit patients' utilities. Technique performance was assessed by computing a differentiation and inconsistency score for each technique. RESULTS: Differentiation scores indicated the rating scale permitted respondents to assign unique utility values to about 70% of the health states that should have received unique values. When the other techniques were used, about 40% or less of the health states that should have received unique utility scores actually did receive unique utility scores. Inconsistency scores, which indicate how often participants assign utility scores that contradict how they value health states, indicated that the willingness-to-pay technique produced the lowest rate of inconsistency (10%). However, this technique did not differ significantly from the rating scale or standard gamble on this dimension. CONCLUSIONS: Differentiation and inconsistency offer a means to evaluate the performance of utility techniques, thereby allowing investigators to determine the extent to which utilities they have elicited for a given decision problem are valid. In the current investigation, the differentiation and inconsistency methods indicated that all four techniques performed at sub-optimal levels, though the rating scale out-performed the standard gamble, time trade-off, and willingness-to-pay techniques.

The association of quality of care and occurrence of in-hospital, treatment-related complications.

BACKGROUND: Little data exist supporting the association of quality of care and nonfatal adverse outcomes in hospitalized patients, yet those outcomes are routinely scrutinized in quality assessment efforts. OBJECTIVE: To determine whether measurable differences in quality of care are associated with the occurrence of non-fatal, in-hospital, and treatment-related complications. DESIGN: Retrospective cohort study. SUBJECTS: A total of 2,268 patients who were discharged alive from 9 Southwestern Veterans Affairs Medical Centers with congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD) or diabetes mellitus. MEASURES: Retrospective chart review was performed to collect information on patient severity of illness, in-hospital complication occurrence, and process quality of care. Process quality was assessed as the adherence scores for admission work-up and for treatment during the hospital stay. Process quality represents the proportion of applicable admission or treatment criteria that were met by that patient's care providers. Once severity of illness was taken into account Cox proportional hazards regression was used to assess the independent contribution of process quality of care to complication occurrence. RESULTS: Higher admission work-up adherence scores for COPD patients and higher treatment adherence scores for COPD and diabetes patients were associated with a lower risk of complication occurrence. The adjusted risk ratios of complications for higher versus lower adherence scores (with 95% CI) were 0.64 (0.43, 0.97) and 0.52 (0.33, 0.80) for admission and treatment, respectively, in COPD patients, and 0.51 (0.31, 0.83) for treatment in diabetics. No significant association was found in CHF patients. CONCLUSION: Better admission work-up and treatment quality in COPD patients, as well as treatment quality in diabetic patients, are associated with lower risk of nonfatal treatment-related complications in the study population.

International Classification of Diseases, 9th Revision, Clinical Modification codes in discharge abstracts are poor measures of complication occurrence in medical inpatients.

OBJECTIVES: The authors tested the ability of International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes in discharge abstracts to identify medical inpatients who experienced an in-hospital complication, using complications identified through chart review as the gold standard. METHODS: Two sets of ICD-9-CM codes were used: an inclusive set including many medical diagnoses that may also be coexistent complicating conditions on admission rather than complications and an exclusive set consisting primarily of ICD-9-CM-specified complication and adverse drug event codes. RESULTS: Neither set performed well as a diagnostic test for complication occurrence according to receiver operating characteristic analysis (ROC areas were 0.61 for the inclusive set and 0.55 for the exclusive set). Sensitivities of the ICD-9-CM codes for complications were 0.34 for the inclusive set and 0.14 for the exclusive set. Corresponding positive predictive values were 0.32 and 0.37, respectively. Sensitivities of code definitions for individual complications were generally poor, less than 0.5 in most cases. CONCLUSIONS: The authors conclude that ICD-9-CM codes in discharge abstracts are poor measures of complication occurrence.

Acute myocardial infarction: clinical characteristics, management and outcome in a metropolitan Veterans Affairs Medical Center teaching hospital.

OBJECTIVES: The influence of race and age on thrombolytic therapy, invasive cardiac procedures and outcomes was assessed in a Veterans Affairs teaching hospital. The influence of Q wave evolution on the use of invasive cardiac procedures and outcome was also assessed. BACKGROUND: It is not well known how early revascularization procedures for acute myocardial infarction are delivered or influence survival in a Veterans Affairs patient population. METHODS: From October 1993 to October 1995, all patients with myocardial infarction were identified by elevated creatine kinase, MB fraction (CK-MB) and one of the following: chest pain or shortness of breath during the preceding 24 h or electrocardiographic (ECG) abnormalities. RESULTS: Racial groups were similar in terms of age, time to ECG, peak CK and length of hospital stay. Mortality increased with age (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.33 to 2.81). A trend toward increased mortality occurred for race other than Caucasian. Patients meeting ECG criteria were given thrombolytic agents in 49% of cases, but age, comorbidity count and Hispanic race decreased the probability of thrombolytic use. Cardiac catheterization was performed more often after thrombolytic agents (OR 1.85, 95% CI 0.97 to 3.54), but less often in African-Americans (OR 0.59, 95% CI 0.35 to 1.02), older patients (OR 0.39, 95% CI 0.24 to 0.64) or patients with heart failure (OR 0.30, 95% CI 0.17 to 0.52). Patients evolving non-Q wave infarctions were older and had increased comorbidity counts and trends toward increased mortality. Angioplasty was chosen less for patients > or = 65 years old (p = 0.02); angioplasty and coronary artery bypass graft surgery were performed less in patients > or = 70 years old (p = 0.02). Patients treated invasively had lower mortality rates than those treated medically (p < 0.02). CONCLUSIONS: The use of thrombolytic agents and invasive treatment plans declined with age, and mortality increased with age. Trends toward increased mortality occurred with non-Q wave infarctions and race other than Caucasian.

Identifying complications and low provider adherence to normative practices using administrative data.

OBJECTIVE: This study investigated whether unexpected length of stay (LOS) could be used as an indicator to identify hospital patients who experienced complications or whose care exhibited low adherence to normative practices. DATA SOURCES AND STUDY SETTING: We analyzed 1,477 cases admitted for one of three medical conditions. All cases were discharged from one of nine participating Department of Veterans Affairs (VA) hospitals from October 1987 through September 1989. Analyses used administrative data and information abstracted through chart reviews that included severity of illness indicators, complications, and explicit process of care criteria reflecting adherence to normative practices. STUDY DESIGN: We developed separate multiple linear regression models for each disease using LOS as the dependent measure and variables that could be assumed present at the time of admission as explanatory variables. Unexpectedly long LOS (i.e., discharges with high residuals) was used to target complications and unexpectedly short LOS was used to target cases whose care might have exhibited low adherence to normative practices. Information gleaned from chart reviews served as the gold standard for determining actual complications and low adherence. PRINCIPAL FINDINGS: Analyses of administrative data showed that unexpectedly long LOS identified complications with sensitivities ranging from 40 through 62 percent across the three conditions. Positive predictive values all were at greater than chance levels (p < .05). This represented substantial improvement over identification of complications using ICD-9-CM codes contained in the administrative database where sensitivities were from 26 through 39 percent. Unexpectedly short LOS identified low provider adherence with sensitivities ranging from 33 through 45 percent with positive predictive values all above chance levels (p < .05). The addition to the LOS models of chart-based severity of illness information helped explain LOS, but failed to facilitate identification of complications or low adherence beyond what was accomplished using administrative data. CONCLUSIONS: Administrative data can be used to target cases when seeking to identify complications or low provider adherence to normative practices. Targeting can be accomplished through the creation of indirect measures based on unexpected LOS. Future efforts should be devoted to validating unexpected LOS as a hospital-level quality indicator. RELEVANCE/IMPACT: Scrutiny of unexpected LOS holds promise for enhancing the usefulness of administrative data as a resource for quality initiatives.

Expected source of payment and use of hospital services for coronary atherosclerosis.

To study associations between payer and provision of services for patients hospitalized for coronary atherosclerosis, the authors analyzed abstracts of 24,424 discharges from California acute care hospitals during 1989. Services examined included receipt of coronary artery bypass surgery, percutaneous transluminal coronary angioplasty (PTCA), long length of stay (LOS) without revascularization, and overall LOS. Regression techniques controlled demographic factors and comorbidities. The privately insured were 96% more likely to undergo revascularization (either bypass or PTCA) than Medicaid discharges and 117% more likely than the uninsured. Odds of revascularization for Medicare and health maintenance organization discharges resembled those for the privately insured. Analyzed separately, PTCA was far more likely among the privately insured than Medicaid beneficiaries and the uninsured. In addition, the adjusted odds for PTCA were 52% greater for the privately insured than for health maintenance organization discharges. The greatest likelihood of long LOS without revascularization and the greatest overall LOS was observed for Medicaid discharges. Strong associations, consistent with financial incentives to provide care, exist between payer and provision of services. Future studies need to address whether variations in process result from differences in thresholds for procedure performance, differences in admission practices, or both.

In-hospital complications among survivors of admission for congestive heart failure, chronic obstructive pulmonary disease, or diabetes mellitus.

OBJECTIVE: To determine the frequency of hospital complications among survivors of inpatient treatment for congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), or diabetes mellitus (DM). DESIGN: Retrospective cohort study. SETTING: Nine Veterans Affairs hospitals in the southern United States. PATIENTS: 1,837 men veterans discharged alive following hospitalization for CHF, COPD, or DM between January 1987 and December 1989. This patient population represents a subset of cases gathered to study the process of care in the hospital and subsequent early readmission; thus, veterans who died in the hospital were not included. MEASUREMENTS: Medical record review to record the occurrence of any of 30 in-hospital complications such as cardiac arrest, nosocomial infections, or delirium (overall agreement between two reviewers = 84%, kappa = 0.37). RESULTS: Complications occurred in 15.7% of the CHF cases, 13.1% of the COPD cases, and 14.8% of the DM cases. Hypoglycemic reactions were the most frequent individual adverse events in the CHF and DM cases (3.6% and 11.4% of the cases, respectively), and theophylline toxicity was most frequent among the COPD cases (4.9%). Patient age, the presence of comorbid diseases, and the Acute Physiology Score (APS) of APACHE II were associated with complication occurrence. For each disease, the patients who had a complication had significantly longer mean hospital stays than did the patients who did not have complications (14.6 to 14.9 days vs 7.2 to 8.2 days, p < 0.01). CONCLUSIONS: Complications are frequent among patients discharged alive with CHF, COPD, or DM. The patients who experienced complications were more ill on admission and had longer hospital stays.

Postoperative adverse events of cholecystectomy in the Medicare population.

We explored the use of postoperative adverse events of cholecystectomy as possible screens for poor quality of care. Retrospective analysis of clinical data abstracted from hospital charts between 1985-1986 was conducted on a random sample of 3,182 cholecystectomy cases. Severity of illness models were developed predicting adverse events following cholecystectomy in patients with and without bile duct exploration. Outcome measures included 17 nonfatal adverse events and death within 30 days of admission. Adverse event rates were 23.2% for cases with bile duct exploration and 14.4% for cases without bile duct exploration. Cross-validated R-squareds and C-statistics showed that models had real, although modest, predictive power. We conclude that clinically meaningful adverse events of cholecystectomy can be successfully identified through chart abstraction.

Predicting the occurrence of adverse events after coronary artery bypass surgery.

OBJECTIVE: To determine whether adverse events occurring after coronary artery bypass surgery in Medicare patients can be predicted from clinical variables representing illness severity at admission. DESIGN: Retrospective analysis of clinical data abstracted from hospital charts, with development and validation using half-samples of the database. A logistic model was developed using illness severity at admission to predict the occurrence of an adverse event after bypass surgery. SETTING: Hospitals in seven states. PATIENTS: Random sample of 2213 Medicare patients 65 years of age or more who underwent bypass surgery between January 1985 and June 1986. OUTCOME MEASURE: The occurrence of death within 30 days of admission or any of 13 nonfatal postoperative adverse events (for example, myocardial infarction, congestive heart failure, and wound infection). RESULTS: Thirty-three percent of patients had one or more postoperative adverse events or died within 30 days of admission. Mortality within 30 days of admission was 6.6%; each adverse event was associated with increased mortality (range, 7.5% to 66.7%). Admission predictors of the occurrence of an adverse event included a history of bypass surgery, emergent surgery, a history of chronic obstructive pulmonary disease, the presence of an infiltrate on admission chest radiograph, a pulse of 110 beats/min or more, age, blood urea nitrogen of 10.7 mmol/L (30 mg/dL) or more, acute myocardial infarction at admission, and a history of myocardial infarction; the presence of one- or two-vessel disease was negatively associated with the occurrence of an adverse event. The model c-statistic was 0.64. CONCLUSIONS: Severity of illness at admission has modest predictive power with respect to adverse-event occurrence in Medicare patients who undergo bypass surgery.

Postoperative adverse events of common surgical procedures in the Medicare population.

Mortality rates are the most widely used measure in assessing patient outcome from hospitalization. However, they may be an insensitive measure of quality for surgical patients because death is a relatively rare outcome. A random sample of patient data (n = 8126) selected from the Medicare files of seven states was used to identify, through chart abstraction, clinical postoperative complications of surgery that could serve as measures of quality. Four surgical procedures were studied: 1) coronary artery bypass grafting; 2) coronary angioplasty; 3) cholecystectomy; and 4) prostatectomy. Severity at admission was controlled for using severity-of-illness models developed with chart-abstracted data to predict adverse events after these four procedures. 30-day mortality rates ranged from 1.0% to 6.6%, while the prevalence of postoperative adverse events identified from chart review was greater (6.9% to 33.3%). There were significant differences between patients with and without adverse events. For example, coronary artery bypass graft patients with adverse events had prolonged postsurgical lengths of stay (18.5 +/- 13.2 vs. 13.2 +/- 6.2, P less than 0.001) and higher mortality rates (15.2% vs. 2.6%, P less than 0.001). The R-square values using clinical indicators at admission to predict the occurrence of any adverse event ranged from 0.05 to 0.13. Clinically meaningful adverse events of surgery can be successfully identified through chart abstraction and appear to be valid measures of postoperative complications among surgical patients. Severity adjustment at admission only modestly predicts the occurrence of these adverse events.

Plasma cell leukemia and hyperviscosity syndrome.

A 56-year-old man had dyspnea, weight loss, hemoptysis, and a generalized bleeding diathesis. Physical examination disclosed hepatosplenomegaly, congestive heart failure, and multiple sites of bleeding. Severe anemia, thrombocytopenia, rouleaux formation, and a leukocytosis with circulating immature plasma cells were observed, along with azotemia, hyperuricemia, and marked elevation of total proteins with a monoclonal IgG kappa spike. The finding of increased serum viscosity confirmed the clinical impression of the hyperviscosity syndrome. Emergency plasma exchange produced marked improvement in the clinical manifestations of hyperviscosity syndrome. Systemic chemotherapy resulted in a partial remission of the disease, but the patient ultimately died of complications of treatment. In this review, we discuss the diagnosis and management of the hyperviscosity syndrome.