The impact of statistical adjustment on economic profiles of interventional cardiologists

OBJECTIVES

The objective of this study was to identify preprocedure patient factors associated with percutaneous intervention costs and to examine the impact of these patient factors on economic profiles of interventional cardiologists.

BACKGROUND

There is increasing demand for information about comparative resource use patterns of interventional cardiologists. Economic provider profiles, however, often fail to account for patient characteristics.

METHODS

Data were obtained from Duke Medical Center cost and clinical information systems for 1,949 procedures performed by 13 providers between July 1, 1997, and December 31, 1998. Patient factors that influenced cost were identified using multiple regression analysis. After assessing interprovider variation in unadjusted cost, mixed linear models were used to examine how much cost variability was associated with the provider when patient characteristics were taken into account.

RESULTS

Total hospital costs averaged $15,643 (median, $13,809), $6,515 of which represented catheterization laboratory costs. Disease severity, acuity, comorbid illness and lesion type influenced total costs (R(2) = 38%), whereas catheterization costs were affected by lesion type and acuity (R(2) = 32%). Patient characteristics varied significantly among providers. Unadjusted total costs were weakly associated with provider, and this association disappeared after accounting for patient factors. The provider influence on catheterization costs persisted after adjusting for patient characteristics. Furthermore, the pattern of variation changed: the adjusted analysis identified three new outliers, and two providers lost their outlier status. Only one provider was consistently identified as an outlier in the unadjusted and adjusted analyses.

CONCLUSIONS

Economic profiles of interventional cardiologists may be misleading if they do not adequately adjust for patient characteristics before procedure.

Using observational data to estimate prognosis: an example using a coronary artery disease registry

With the proliferation of clinical data registries and the rising expense of clinical trials, observational data sources are increasingly providing evidence for clinical decision making. These data are viewed as complementary to randomized clinical trials (RCT). While not as rigorous a methodological design, observational studies yield important information about effectiveness of treatment, as compared with the efficacy results of RCTs. In addition, these studies often have the advantage of providing longer-term follow-up, beyond that of clinical trials. Hence, they are useful for assessing and comparing patients' long-term prognosis under different treatment strategies. For patients with coronary artery disease, many observational comparisons have focused on medical therapy versus interventional procedures. In addition to the well-studied problem of treatment selection bias (which is not the focus of the present study), three significant methodological problems must be addressed in the analysis of these data: (i) designation of the therapeutic arms in the presence of early deaths, withdrawals, and treatment cross-overs; (ii) identification of an equitable starting point for attributing survival time; (iii) site to site variability in short-term mortality. This paper discusses these issues and suggests strategies to deal with them. A proposed methodology is developed, applied and evaluated on a large observational database that has long-term follow-up on nearly 10 000 patients.

Sex differences in neurological outcomes and mortality after cardiac surgery: a society of thoracic surgery national database report

BACKGROUND

The purpose of this study was to evaluate whether women undergoing cardiac surgery are more likely to suffer neurological complications than men and whether these complications could explain, at least in part, their higher perioperative mortality.

METHODS AND RESULTS

The Society of Thoracic Surgery National Cardiac Surgery Database was examined for the years 1996 and 1997 to determine the frequency of new neurological events (stroke, transient ischemic attack, or coma) occurring after cardiac surgery. We reviewed clinical information on 416 347 patients (32% women) for whom complete neurological outcome data were available. New neurological events after surgery were higher for women than for men (3.8% versus 2.4%, P=0.001). For the whole group, the 30-day mortality was higher for women than for men (5.7% versus 3.5%, P=0.001), and among those patients who suffered a perioperative neurological event, mortality was also significantly higher for women than men (32% versus 28%, P=0.001). After adjustment for other risk factors (eg, age, history of hypertension and/or diabetes, duration of cardiopulmonary bypass, and other comorbid conditions) by multivariable logistic regression, female sex was independently associated with significantly higher risk of suffering new neurological events after cardiac surgery (OR 1.21, 95% CI 1.14 to 1.28, P=0.001).

CONCLUSIONS

Women undergoing cardiac surgery are more likely than men to suffer new perioperative neurological events, and they have higher 30-day mortality when these complications occur. The higher incidence of perioperative neurological complications in women cannot be explained by currently known risk factors.

Prediction of operative mortality after valve replacement surgery

OBJECTIVES

We sought to develop national benchmarks for valve replacement surgery by developing statistical risk models of operative mortality.

BACKGROUND

National risk models for coronary artery bypass graft surgery (CABG) have gained widespread acceptance, but there are no similar models for valve replacement surgery.

METHODS

The Society of Thoracic Surgeons National Cardiac Surgery Database was used to identify risk factors associated with valve surgery from 1994 through 1997. The population was drawn from 49,073 patients undergoing isolated aortic valve replacement (AVR) or mitral valve replacement (MVR) and from 43,463 patients undergoing CABG combined with AVR or MVR. Two multivariable risk models were developed: one for isolated AVR or MVR and one for CABG plus AVR or CABG plus MVR.

RESULTS

Operative mortality rates for AVR, MVR, combined CABG/AVR and combined CABG/ MVR were 4.00%, 6.04%, 6.80% and 13.29%, respectively. The strongest independent risk factors were emergency/salvage procedures, recent infarction, reoperations and renal failure. The c-indexes were 0.77 and 0.74 for the isolated valve replacement and combined CABG/valve replacement models, respectively. These models retained their predictive accuracy when applied to a prospective patient population undergoing operation from 1998 to 1999. The Hosmer-Lemeshow goodness-of-fit statistic was 10.6 (p = 0.225) for the isolated valve replacement model and 12.2 (p = 0.141) for the CABG/valve replacement model.

CONCLUSIONS

Statistical models have been developed to accurately predict operative mortality after valve replacement surgery. These models can be used to enhance quality by providing a national benchmark for valve replacement surgery.

Challenges in comparing risk-adjusted bypass surgery mortality results: results from the Cooperative Cardiovascular Project

OBJECTIVES

We sought to evaluate the predictive accuracy of four bypass surgery mortality clinical risk models and to examine the extent to which hospitals' risk-adjusted surgical outcomes vary depending on which risk-adjustment method is applied.

BACKGROUND

Cardiovascular "report cards" often compare risk-adjusted surgical outcomes; however, it is unclear to what extent the risk-adjustment process itself may affect these metrics.

METHODS

As part of the Cooperative Cardiovascular Project's Pilot Revascularization Study, we compared the predictive accuracy of four bypass clinical risk models among 3,654 Medicare patients undergoing surgery at 28 hospitals in Alabama and Iowa. We also compared the agreement in hospital-level risk-adjusted bypass outcome performance ratings depending on which of the four risk models was applied.

RESULTS

Although the four risk models had similar discriminatory abilities (C-index, 0.71 to 0.74), certain models tended to overpredict mortality in higher-risk patients. There was high correlation between a hospital's risk-adjusted mortality rates regardless of which of the four models was used (correlation between risk-adjusted rating, 0.93 to 0.97). In contrast, there was limited agreement in which hospitals were identified as "performance outliers" depending on which risk-adjustment model was used and how outlier status was defined.

CONCLUSIONS

A hospital's risk-adjusted bypass surgery mortality rating, relative to its peers, was consistent regardless of the risk-adjustment model applied, supporting their use as a means of provider performance feedback. Designation of performance outliers, however, can vary significantly depending on the benchmark and methods used for this determination.

Acute and long-term cost implications of coronary stenting

OBJECTIVES

We compared the acute and one year medical costs and outcomes of coronary stenting with those for balloon angioplasty (percutaneous transluminal coronary angioplasty) in contemporary clinical practice.

BACKGROUND

While coronary stent implantation reduces the need for repeat revascularization, it has been associated with significantly higher acute costs compared with coronary angioplasty.

METHODS

We studied patients treated at Duke University between September 1995 and June 1996 who received either coronary stent (n = 384) or coronary angioplasty (n = 159) and met eligibility criteria. Detailed cost data were collected initially and up to one year following the procedure. Our primary analyses compared six and 12 month cumulative costs for coronary angioplasty- and stent-treated cohorts. We also compared treatment costs after excluding nontarget vessel interventions; after limiting analysis to those without prior revascularization; and after risk-adjusting cumulative cost estimates.

RESULTS

Baseline clinical characteristics were generally similar between the two treatment groups. The mean in-hospital cost for stent patients was $3,268 higher than for those receiving coronary angioplasty ($14,802 vs. $11,534, p < 0.001). However, stent patients were less likely to be rehospitalized (22% vs. 34%, p = 0.002) or to undergo repeat revascularization (9% vs. 26%, p = 0.001) than coronary angioplasty patients within six months of the procedure. As such, mean cumulative costs at 6 months ($19,598 vs. $19,820, p = 0.18) and one year ($22,140 vs. $22,571, p = 0.26) were similar for the two treatments. Adjusting for baseline predictors of cost and selectively examining target vessel revascularization, or those without prior coronary intervention yielded similar conclusions.

CONCLUSIONS

In contemporary practice, coronary stenting provides equivalent or better one-year patient outcomes without increasing cumulative health care costs.

A comparison of 0.5% bupivacaine, 0.5% ropivacaine, and 0.75% ropivacaine for interscalene brachial plexus block

The onset time and duration of action of ropivacaine during an interscalene block are not known. The potentially improved safety profile of ropivacaine may allow the use of higher concentrations to try and speed onset time. We compared bupivacaine and ropivacaine to determine the optimal long-acting local anesthetic and concentration for interscalene brachial plexus block. Seventy-five adult patients scheduled for outpatient shoulder surgery under interscalene block were entered into this double-blind, randomized study. Patients were assigned (n = 25 per group) to receive an interscalene block using 30 mL of 0.5% bupivacaine, 0.5% ropivacaine, or 0.75% ropivacaine. All solutions contained fresh epinephrine in a 1:400,000 concentration. At 1-min intervals after local anesthetic injection, patients were assessed to determine loss of shoulder abduction and loss of pinprick in the C5-6 dermatomes. Before discharge, patients were asked to document the time of first oral narcotic use, when incisional discomfort began, and when full sensation returned to the shoulder. The mean onset time of both motor and sensory blockade was <6 min in all groups. Duration of sensory blockade was similar in all groups as defined by the three recovery measures. We conclude that there is no clinically important difference in times to onset and recovery of interscalene block for bupivacaine 0.5%, ropivacaine 0.5%, and ropivacaine 0.75% when injected in equal volumes.

IMPLICATIONS

In this study, we demonstrated a similar efficacy between equal concentrations of ropivacaine and bupivacaine. In addition, increasing the concentration of ropivacaine from 0.5% to 0.75% fails to improve the onset or duration of interscalene brachial plexus block.

Use of a prognostic treadmill score in identifying diagnostic coronary disease subgroups

BACKGROUND

Exercise testing is useful in the assessment of symptomatic patients for diagnosis of significant or extensive coronary disease and to predict their future risk of cardiac events. The Duke treadmill score (DTS) is a composite index that was designed to provide survival estimates based on results from the exercise test, including ST-segment depression, chest pain, and exercise duration. However, its usefulness for providing diagnostic estimates has yet to be determined.

METHODS AND RESULTS

A logistic regression model was used to predict significant (>/=75% stenosis) and severe (3-vessel or left main) coronary artery disease, and a Cox regression analysis was used to predict cardiac survival. After adjustment for baseline clinical risk, the DTS was effectively diagnostic for significant (P<0.0001) and severe (P<0.0001) coronary artery disease. For low-risk patients (score >/=+5), 60% had no coronary stenosis >/=75% and 16% had single-vessel >/=75% stenosis. By comparison, 74% of high-risk patients (score <-11) had 3-vessel or left main coronary disease. Five-year mortality was 3%, 10%, and 35% for low-, moderate-, and high-risk DTS groups (P<0.0001).

CONCLUSIONS

The composite DTS provides accurate diagnostic and prognostic information for the evaluation of symptomatic patients evaluated for clinically suspected ischemic heart disease.

The effects of New York's bypass surgery provider profiling on access to care and patient outcomes in the elderly

OBJECTIVE

The aim of this study was to examine the effects of provider profiling on bypass surgery access and outcomes in elderly patients in New York.

BACKGROUND

Since 1989, New York (NY) has compiled provider-specific bypass surgery mortality reports. While some have proposed that "provider profiling" has led to lower surgical mortality rates, critics have suggested that such programs lower in-state procedural access (increasing out-of-state transfers) without improving patient outcomes.

METHODS

Using national Medicare data, we examined trends in the percentages of NY residents aged 65 years or older receiving out-of-state bypass surgery between 1987 and 1992 (before and after program initiation). We also examined in-state procedure use among elderly myocardial infarction patients during this period. Finally, we compared trends in surgical outcomes in NY Medicare patients with those for the rest of the nation.

RESULTS

Between 1987 and 1992, the percentage of NY residents receiving bypass out-of-state actually declined (from 12.5% to 11.3%, p < 0.01 for trend). An elderly patient's likelihood for bypass following myocardial infarction in NY increased significantly since the program's initiation. Between 1987 and 1992, unadjusted 30-day mortality rates following bypass declined by 33% in NY Medicare patients compared with a 19% decline nationwide (p < 0.001). As a result of this improvement, NY had the lowest risk-adjusted bypass mortality rate of any state in 1992.

CONCLUSIONS

We found no evidence that NY's provider profiling limited procedure access in NY's elderly or increased out-of-state transfers. Despite an increasing preoperative risk profile, procedural outcomes in NY improved significantly faster than the national average.

Economic assessment of low-molecular-weight heparin (enoxaparin) versus unfractionated heparin in acute coronary syndrome patients: results from the ESSENCE randomized trial. Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q wave Coronary Events [unstable angina or non-Q-wave myocardial infarction]

BACKGROUND

In the ESSENCE trial, subcutaneous low-molecular-weight heparin (enoxaparin) reduced the 30-day incidence of death, myocardial infarction, and recurrent angina relative to intravenous unfractionated heparin in 3171 patients with acute coronary syndrome (unstable angina or non-Q-wave myocardial infarction). No increase in major bleeding was seen.

METHODS AND RESULTS

Of the 936 ESSENCE patients randomized in the United States, 655 had hospital billing data collected. For the remainder, hospital costs were imputed with a multivariable linear regression model (R2=.86). Physician fees were estimated from the Medicare Fee Schedule. During the initial hospitalization, major resource use was reduced for enoxaparin patients, with the largest effect seen with coronary angioplasty (15% versus 20% for heparin, P=.04). At 30 days, these effects persisted, with the largest reductions seen in diagnostic catheterization (57% versus 63% for heparin, P=.04) and coronary angioplasty (18% versus 22%, P=.08). All resource use trends seen in the US cohort were also evident in the overall ESSENCE study population. In the United States, the mean cost of a course of enoxaparin therapy was $155, whereas that for heparin was $80. The total medical costs (hospital, physician, drug) for the initial hospitalization were $11 857 for enoxaparin and $12620 for heparin, a cost advantage for the enoxaparin arm of $763 (P=.18). At the end of 30 days, the cumulative cost savings associated with enoxaparin was $1172 (P=.04). In 200 bootstrap samples of the 30-day data, 94% of the samples showed a cost advantage for enoxaparin.

CONCLUSIONS

In patients with acute coronary syndrome, low-molecular-weight heparin (enoxaparin) both improves important clinical outcomes and saves money relative to therapy with standard unfractionated heparin.

Comparing risk-adjustment methods for provider profiling

Risk-adjustment and provider profiling have become common terms as the medical profession attempts to measure quality and assess value in health care. One of the areas of care most thoroughly developed in this regard is quality assessment for coronary artery bypass grafting (CABG). Because in-hospital mortality following CABG has been studied extensively, risk-adjustment mechanisms are already being used in this area for provider profiling. This study compares eight different risk-adjustment methods as applied to a CABG surgery population of 28 providers. Five of the methods use an external risk-adjustment algorithm developed in an independent population, while the other three rely on an internally developed logistic model. The purposes of this study are to: (i) create a common metric by which to display the results of these various risk-adjustment methodologies with regard to dichotomous outcomes such as in-hospital mortality, and (ii) to compare how these risk-adjustment methods quantify the 'outlier' standing of providers. Section 2 describes the data, the external and internal risk-adjustment algorithms, and eight approaches to provider profiling. Section 3 then demonstrates the results of applying these methods on a data set specifically collected for quality improvement.

Relationship between diabetes mellitus and long-term survival after coronary bypass and angioplasty

BACKGROUND

Recent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease.

METHODS AND RESULTS

By analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91).

CONCLUSIONS

Although diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.

Impact of early discharge after coronary artery bypass graft surgery on rates of hospital readmission and death. The Ischemic Heart Disease (IHD) Patient Outcomes Research Team (PORT) Investigators

OBJECTIVES

This study examined the impact of early hospital discharge on short-term clinical outcomes of elderly patients treated with coronary artery bypass graft surgery (CABG) in the United States in 1992.

BACKGROUND

Protocols that encourage earlier discharge of patients who have had CABG have been implemented across the country. Although delivery of efficient care benefits both patients and providers, premature discharge can adversely affect clinical outcomes, resulting in increased hospital readmissions and higher long-term costs.

METHODS

We examined the prevalence of early discharge (postoperative length of stay < or = 5 days) among 83,347 non-health maintenance organization (HMO) Medicare patients who underwent CABG in the United States in 1992. Using logistic regression models, we identified patient characteristics associated with early discharge and obtained risk-adjusted rates of death and readmission or death for postoperative lengths of stay between 4 and 14 days.

RESULTS

In 1992, 6% of Medicare patients undergoing CABG were discharged within 5 days of the operation. The prevalence of early discharge varied considerably among states, ranging from 1% to 21%. Patients discharged early tended to be younger and male and have fewer comorbid illnesses. Risk-adjusted rates of death and death or cardiovascular readmission were lowest among patients discharged early.

CONCLUSIONS

As of 1992, early discharge of elderly patients treated with CABG in non-HMO settings was not associated with higher 60-day rates of death or readmission. This suggests that physicians were able to identify low risk candidates for early discharge. Variation across the nation in early discharge rates, along with the percentage of patients without major risk factors for adverse outcomes, suggests that higher rates of early discharge might be safely achieved.

Relationship between physician and hospital coronary angioplasty volume and outcome in elderly patients

BACKGROUND

With the expectation that physicians who perform larger numbers of coronary angioplasty procedures will have better outcomes, the American College of Cardiology/ American Heart Association guidelines recommend minimum physician volumes of 75 procedures per year. However, there is little empirical data to support this recommendation.

METHODS AND RESULTS

We examined in-hospital bypass surgery and death after angioplasty according to 1992 physician and hospital Medicare procedure volume. In 1992, 6115 physicians performed angioplasty on 97,478 Medicare patients at 984 hospitals. The median numbers of procedures performed per physician and per hospital were 13 (interquartile range, 5 to 25) and 98 (interquartile range, 40 to 181), respectively. With the assumption that Medicare patients composed one half to one third of all patients undergoing angioplasty, these median values are consistent with an overall physician volume of 26 to 39 cases per year and an overall hospital volume of 196 to 294 cases per year. After adjusting for age, sex, race, acute myocardial infarction, and comorbidity, low-volume physicians were associated with higher rates of bypass surgery (P < .001) and low-volume hospitals were associated with higher rates of bypass surgery and death (P < .001). Improving outcomes were seen up to threshold values of 75 Medicare cases per physician and 200 Medicare cases per hospital.

CONCLUSIONS

More than 50% of physicians and 25% of hospitals performing coronary angioplasty in 1992 were unlikely to have met the minimum volume guidelines first published in 1988, and these patients had worse outcomes. While more recent data are required to determine whether the same relationships persist after the introduction of newer technologies, this study suggests that adherence to minimum volume standards by physicians and hospitals will lead to better outcomes for elderly patients undergoing coronary angioplasty.

Geographic variation in resource use for coronary artery bypass surgery. IHD Port Investigators

OBJECTIVES

The purpose of this study was to examine the national variability in patient-level cost and length of stay for coronary artery bypass grafting (CABG) in Medicare patients.

METHODS

Retrospective multivariate regression analysis was done using Medicare administrative files and American Hospital Association files. Patients in the study had an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure code for CABG, with accompanying 1990 procedure data, in the Medicare Provider Analysis and Review File (n = 92,449).

RESULTS

Outcome measures used were inpatient cost (exclusive of professional fees) and inpatient length of stay associated with bypass admission. The national average cost of bypass surgery was $22,847 (median $18,783), with an accompanying average length of stay of 16 days (median 13 days). Multivariate regression analysis revealed that patient-level cost and length of stay were related to clinical, demographic, hospital, and regional characteristics (R2 = 25% and 16%, respectively). After accounting for these characteristics at the patient level, considerable variation among states persisted in both cost and length of stay. In addition, states with similar adjusted lengths of stay varied widely with respect to adjusted cost. No relation was found at the state level between level of resource use and either procedural mortality or 60-day mortality/readmission rates.

CONCLUSIONS

Considerable variability exists among states in patient-level cost and length of stay for CABG surgery, after adjusting to the extent possible for clinical, demographic, hospital, and regional characteristics. The lack of association at the state level between resource use and rates of mortality and hospital readmission suggests that costs could be reduced in many areas of the United States without compromising quality of care.

Racial variation in the use of coronary-revascularization procedures. Are the differences real? Do they matter?

BACKGROUND

Studies have reported that blacks undergo fewer coronary-revascularization procedures than whites, but it is not clear whether the clinical characteristics of the patients account for these differences or whether they indicate underuse of the procedures in blacks or overuse in whites.

METHODS

In a study at Duke University of 12,402 patients (10.3 percent of whom were black) with coronary disease, we calculated unadjusted and adjusted rates of angioplasty and bypass surgery in blacks and whites after cardiac catheterization. We also examined patterns of treatment after stratifying the patients according to the severity of disease, angina status, and estimated survival benefit due to revascularization. Finally, we compared five-year survival rates in blacks and whites.

RESULTS

After adjustment for the severity of disease and other characteristics, blacks were 13 percent less likely than whites to undergo angioplasty and 32 percent less likely to undergo bypass surgery. The adjusted black:white odds ratios for receiving these procedures were 0.87 (95 percent confidence interval, 0.73 to 1.03) and 0.68 (95 percent confidence interval, 0.56 to 0.82), respectively. The racial differences in rates of bypass surgery persisted among those with severe anginal symptoms (31 percent of blacks underwent surgery, vs. 45 percent of whites, P<0.001) and among those predicted to have the greatest survival benefit from revascularization (42 percent vs. 61 percent, P<0.001). Finally, unadjusted and adjusted rates of survival for five years were significantly lower in blacks than in whites.

CONCLUSIONS

Blacks with coronary disease were significantly less likely than whites to undergo coronary revascularization, particularly bypass surgery - a difference that could not be explained by the clinical features of their disease. The differences in treatment were most pronounced among those predicted to benefit the most from revascularization. Since these differences also correlated with a lower survival rate in blacks, we conclude that coronary revascularization appears to be underused in blacks.

Outcome of acute myocardial infarction according to the specialty of the admitting physician

BACKGROUND

In order to limit costs, health care organizations in the United States are shifting medical care from specialists to primary care physicians. Although primary care physicians provide less resource-intensive care, there is little information concerning the effects of this strategy on outcomes.

METHODS

We examined mortality according to the specialty of the admitting physician among 8241 Medicare patients who were hospitalized for acute myocardial infarction in four states during a seven-month period in 1992. Proportional-hazards regression models were used to examine survival up to one year after the myocardial infarction. To determine the generalizability of our findings, we also examined insurance claims and survival data for all 220,535 patients for whom there were Medicare claims for hospital care for acute myocardial infarction in 1992.

RESULTS

After adjustment for characteristics of the patients and hospitals, patients who were admitted to the hospital by a cardiologist were 12 percent less likely to die within one year than those admitted by a primary care physician (P<0.001). Cardiologists also had the highest rate of use of cardiac procedures and medications, including medications (such as thrombolytic agents and beta-blockers) that are associated with improved survival.

CONCLUSIONS

Health care strategies that shift the care of elderly patients with myocardial infarction from cardiologists to primary care physicians lower rates of use of resources (and potentially lower costs), but they may also cause decreased survival. Additional information is needed to elucidate how primary care physicians and specialists should interact in the care of severely ill patients.

Impact of an interactive video on decision making of patients with ischemic heart disease

An experimental pilot study using repeated measures to examine the impact of an interactive video program on the decision making of patients with ischemic heart disease was carried on at a tertiary care center and a Veterans Affairs hospital. The patients (n = 80, mean age 61.1 years, 77% male, 75% white, 26.7% with acute myocardial infarction), who had undergone diagnostic cardiac catheterization and were found to have significant coronary artery disease (> or = 75% stenosis in at least one vessel), watched the Shared Decision-Making Program (SDP) for Ischemic Heart Disease (IHD), a novel interactive video system designed to provide information necessary for patients to participate actively in decision making. This program compares medical therapy, angioplasty, and bypass surgery through a physician narrator, patient testimonials, and empirically-based, patient-specific outcome estimates of short-time complications and long-term survival. Before and after viewing the SDP, patients completed surveys containing multiple choice questions and Likert scales. They rated the program as more helpful than all other decision aids except the physician, and after viewing the SDP they expressed increased confidence in their treatment choice and decreased confidence in alternative options (p = .0001). The greatest effects appeared to be concentrated in those patients with less education (p = .04), and the program appeared to increase anxiety in nonwhite patients compared with white patients (p = 0.07).

Predicting the presence of choledocholithiasis in patients with symptomatic cholelithiasis

OBJECTIVES

Accurate preoperative prediction of choledocholithiasis is essential in order to minimize patient risk and curtail health care expenditures. This study was designed to identify independent risk factors for choledocholithiasis in patients who had undergone cholecystectomy for symptomatic cholelithiasis and to develop a predictive model based on those factors.

METHODS

The charts of 1264 consecutive patients who had undergone cholecystectomy at one of three North Carolina hospitals between January 1, 1989 and December 31, 1991 were reviewed; 465 of these patients had confirmed presence or absence of choledocholithiasis by cholangiography and/or common bile duct exploration and were eligible for analysis. Candidate predictor variables included age and maximum preoperative values for each of the following: temperature, alkaline phosphatase, bilirubin, AST, amylase, white blood cell count, and common bile duct diameter. Model development and validation were conducted using standard data-splitting (60% "training," 40% "test") and logistic regression techniques.

RESULTS

Choledocholithiasis was confirmed in 115 (25%) of the 465 eligible patients. Univariate analysis identified bilirubin, common bile duct diameter, AST, temperature, alkaline phosphatase, and age as predictors. Multivariable analysis subsequently identified bilirubin, common bile duct diameter, AST, alkaline phosphatase, and age as independent predictors of choledocholithiasis. A final model containing these variables (except age, whose contribution to the model was small) accurately predicted choledocholithiasis (c-index = 0.76).

CONCLUSIONS

Accurate estimates of choledocholithiasis risk can be made using maximum preoperative bilirubin, common bile duct diameter, AST, and alkaline phosphatase values. Use of the model may help physicians select those patients with symptomatic cholelithiasis who would most likely benefit from further investigation to exclude choledocholithiasis.

Outcomes of coronary artery bypass graft surgery in 24,461 patients aged 80 years or older

BACKGROUND

Coronary artery bypass graft surgery is increasingly common in patients of age > or = 80 years. Single-institution reviews have cited a wide range of mortality results after bypass surgery in this age group, in part because of limited sample sizes. Using claims data, we examined recent national trends in the use and outcomes of bypass surgery in the very elderly.

METHODS AND RESULTS

From an examination of Medicare data from 1987 through 1990, we identified 24,461 patients of age > or = 80 years who underwent bypass surgery. We compared surgical outcomes in these patients with those in Medicare patients of age 65 to 70 years. We found that the national use of bypass surgery in patients of age > or = 80 years increased 67% between 1987 and 1990. Compared with patients of age 65 to 70 years, the very elderly had significantly longer postoperative hospital stays (mean, 14.3 versus 10.4 days), higher charges (mean, $48,200 versus $38,000), and greater costs (mean, $27,200 versus $21,700). In-hospital (11.5% versus 4.4%), 1-year (19.3% versus 7.9%), and 3-year mortality rates (28.8% versus 13.1%) after bypass surgery were also significantly higher in patients of age > or = 80 years compared with younger patients. Although their initial surgical risk was high, octogenarians who underwent bypass surgery had a long-term survival rate similar to that of the general US octogenarian population.

CONCLUSIONS

The use of bypass surgery in patients of age > or = 80 years in increasing. These very elderly patients face high surgical risks and accumulate significant hospital expenses. Further research is indicated to determine whether the long-term benefits from bypass surgery in the very elderly outweigh the increased procedural risks.

Measuring hospital mortality rates: are 30-day data enough? Ischemic Heart Disease Patient Outcomes Research Team

OBJECTIVE

We compare 30-day and 180-day postadmission hospital mortality rates for all Medicare patients and those in three categories of cardiac care: coronary artery bypass graft surgery, acute myocardial infarction, and congestive heart failure. DATA SOURCES/COLLECTION: Health Care Financing Administration (HCFA) hospital mortality data for FY 1989.

STUDY DESIGN

Using hospital level public use files of actual and predicted mortality at 30 and 180 days, we constructed residual mortality measures for each hospital. We ranked hospitals and used receiver operating characteristic (ROC) curves to compare 0-30, 31-180, and 0-180-day postadmission mortality.

PRINCIPAL FINDINGS

For the admissions we studied, we found a broad range of hospital performance when we ranked hospitals using the 30-day data; some hospitals had much lower than predicted 30-day mortality rates, while others had much higher than predicted mortality rates. Data from the time period 31-180 days postadmission yield results that corroborate the 0-30 day postadmission data. Moreover, we found evidence that hospital performance on one condition is related to performance on the other conditions, but that the correlation is much weaker in the 31-180-day interval than in the 0-30-day period. Using ROC curves, we found that the 30-day data discriminated the top and bottom fifths of the 180-day data extremely well, especially for AMI outcomes.

CONCLUSIONS

Using data on cumulative hospital mortality from 180 days postadmission does not yield a different perspective from using data from 30 days postadmission for the conditions we studied.

Changes in mortality after myocardial revascularization in the elderly. The national Medicare experience

OBJECTIVE

To examine secular changes in the use and outcome of percutaneous transluminal coronary angioplasty and cardiac bypass graft surgery in the elderly.

DESIGN

A retrospective cohort study based on a longitudinal database created from the administrative files of Medicare.

SETTING

U.S. hospitals that perform myocardial revascularization procedures covered by Medicare.

PATIENTS

225,915 consecutive patients who had angioplasty and 357,885 consecutive patients who had bypass surgery from 1987 to 1990.

MEASUREMENTS

The rates of angioplasty and bypass surgery use; unadjusted 30-day and 1-year mortality rates after revascularization; and adjusted odds ratios for mortality by year of procedure for 1987 to 1990.

RESULTS

From 1987 to 1990, the rates of angioplasty and bypass surgery done in the elderly increased by 55% and 18%, respectively. During this period, 30-day unadjusted mortality rates after angioplasty and bypass surgery decreased by 25% (95% CI, 22% to 28%) and 12% (CI, 10% to 14%), and 1-year mortality rates decreased by 10% (CI, 8% to 11%) and 8% (CI, 7% to 10%), respectively. After adjustment for changes in patient characteristics, 30-day mortality rates after these procedures decreased by 37% (CI, 32% to 41%) and 18% (CI, 14% to 21%), and 1-year mortality rates decreased by 22% (CI, 18% to 25%) and 19% (CI, 16% to 21%), respectively.

CONCLUSIONS

The use of cardiac revascularization procedures in the elderly has steadily increased. Patients who had revascularization are progressively older, have more coded comorbid conditions, and present with more acute diseases. Although elderly patients have apparently higher risk profiles, mortality rates after angioplasty and bypass surgery in the elderly have decreased, suggesting a national improvement in the outcomes of these interventions. Health policy decisions concerning revascularization procedures in the elderly must consider these trends in improved outcome.

The relation between the volume of coronary angioplasty procedures at hospitals treating Medicare beneficiaries and short-term mortality

BACKGROUND

Previous studies have found that hospitals at which more procedures, such as coronary-artery bypass grafting (CABG) and other vascular surgery, are performed have lower rates of mortality related to these procedures than hospitals where fewer such procedures are performed.

METHODS

We examined the relation between the number of percutaneous transluminal coronary angioplasty (PTCA) procedures performed at hospitals (volume) and short-term mortality in a population of 217,836 Medicare beneficiaries 65 years of age or older who underwent angioplasty in the United States from 1987 through 1990.

RESULTS

The unadjusted in-hospital mortality among patients who underwent PTCA increased from 2.5 percent among the 10 percent of patients treated in hospitals with the highest volume of such procedures to 3.9 percent among the 10 percent of patients treated in hospitals with the lowest volume. The rate of bypass surgery after PTCA also increased, from 2.8 percent among patients in the highest-volume hospitals to 5.3 percent among those in the lowest-volume hospitals. Higher rates of mortality and CABG persisted in all the groups of patients treated in hospitals that performed fewer than 100 angioplasty procedures per year in Medicare beneficiaries; this volume in Medicare beneficiaries can be extrapolated to an overall annual volume of 200 to 400 angioplasty procedures. In a logistic-regression model, the volume of PTCA procedures at a hospital was found to be a highly significant predictor of in-hospital mortality (P < 0.001). These results suggest that if the hospitals with the lowest volume had achieved the experience and technical results of the highest-volume hospitals, 381 fewer patients would have undergone CABG and there would have been 300 fewer in-hospital deaths in the population we studied.

CONCLUSIONS

Hospitals that perform more PTCA procedures have lower short-term mortality rates after the procedure. These data provide evidence in support of the regionalization of angioplasty services.

Absence of sex bias in the referral of patients for cardiac catheterization

BACKGROUND

It has been suggested that women with clinical evidence of coronary artery disease are less often referred for cardiac catheterization than are men. To determine whether there is sex-related bias in referral for cardiac catheterization, we prospectively studied a cohort of 410 symptomatic outpatients (280 men and 130 women) who were being evaluated with exercise testing for possible-coronary artery disease.

METHODS

Before the patients underwent exercise testing, 15 cardiologists from an academic medical center were asked to predict the probability that the patients they saw in the cardiology clinic would have angiographic evidence of any obstructive coronary disease (stenosis of 75 percent or more); the probability of severe coronary disease (three-vessel or left main coronary artery disease); the probability of left main coronary artery disease; and the probability of survival one, three, and five years after the evaluation. Similar predictions were generated by previously validated statistical models with use of data collected before exercise testing from the history, physical examination, and 12-lead electrocardiography with the patient at rest.

RESULTS

Overall, women were referred for cardiac catheterization significantly less often than men (18 percent vs. 27 percent, P = 0.03). As compared with men, women had a significantly lower pretest probability of coronary disease (as estimated by their physicians) and a lower rate of positive exercise-test results. After accounting for differences in these two factors, sex was not an independent predictor of referral for catheterization. Comparing physicians' estimates of outcome with those generated by the statistical models revealed no evidence that the physicians were underestimating the risk of coronary disease in women. Furthermore, physicians' predictions did not underestimate the probability of any obstructive coronary disease in men and women who subsequently underwent catheterization.

CONCLUSIONS

Academic cardiologists made appropriately lower pretest predictions of categories of disease in women with possible coronary artery disease than in men, and these assessments, along with women's lower rate of positive exercise tests, rather than bias based on sex, accounted for the lower rate of catheterization among women.

Programmed Outcome Research Teams (PORTs) and implications for clinical practice

The spiraling cost of health care has created a health care crisis. Concerns about the appropriate use of expensive medical technologies have been heightened by health services research studies that demonstrate widespread and dramatic geographic variability in the use of tests and procedures. The Agency for Health Care Policy and Research has funded 14 Programmed Outcome Research Teams (PORTs) targeted at specific disease entities. The PORT in ischemic heart disease is examining 2 principal decisions--which patients should undergo cardiac catheterization and, following catheterization, how patients should be treated. The PORT in ischemic heart disease combines information from the literature, 18 databases, and patient preference studies in models examining these 2 decisions. The databases have also been used to develop statistical models that estimate outcomes with different therapies. The benefit of a therapy in a population can be illustrated using an empirically derived, marginal value curve that describes the expected improvement in outcome (e.g., survival) that accrues with additional procedures performed in patients who are most likely to benefit.

Discordance of databases designed for claims payment versus clinical information systems. Implications for outcomes research

OBJECTIVE

To determine the suitability of insurance claims information for use in clinical outcomes research in ischemic heart disease.

DESIGN

Concordance study of two databases.

SETTING

Tertiary care referral center.

PATIENTS

A total of 12,937 consecutive patients hospitalized for cardiac catheterization for suspected ischemic heart disease between July 1985 and May 1990.

INTERVENTIONS

Two-by-two tables were used to compute overall and kappa measures of agreement comparing clinical versus claims data for 12 important predictors of prognosis in patients with ischemic heart disease.

MEASUREMENTS

Kappa statistics (agreement adjusted for chance agreement) were used to quantify agreement rates.

RESULTS

Agreement rates between the clinical and claims databases ranged from 0.83 for the diagnosis of diabetes to 0.09 for the diagnosis of unstable angina (kappa values). Claims data failed to identify more than one half of the patients with prognostically important conditions, including mitral insufficiency, congestive heart failure, peripheral vascular disease, old myocardial infarction, hyperlipidemia, cerebrovascular disease, tobacco use, angina, and unstable angina, when compared with the clinical information system.

CONCLUSIONS

Our results suggest that insurance claims data lack important diagnostic and prognostic information when compared with concurrently collected clinical data in the study of ischemic heart disease. Thus, insurance claims data are not as useful as clinical data for identifying clinically relevant patient groups and for adjusting for risk in outcome studies, such as analyses of hospital mortality.

Impact of glucose self-monitoring on non-insulin-treated patients with type II diabetes mellitus. Randomized controlled trial comparing blood and urine testing

The goal of this study was to compare the relative efficacy and cost of self-monitoring of blood glucose (SMBG) with routine urine testing in the management of patients with type II (non-insulin-dependent) diabetes mellitus not treated with insulin. Fifty-four patients with type II diabetes mellitus, not treated with insulin, who had inadequate glucose control on diet alone or diet and oral hypoglycemic agents were studied. Patients performed SMBG or urine glucose testing as part of a standardized treatment program that also included diet and exercise counseling. During the 6-mo study, both the urine-testing and SMBG groups showed similar improvement in glycemic control; within each group, there were significant improvements in fasting plasma glucose (reduction of 1.4 +/- 3.2 mM, P less than 0.03) and glycosylated hemoglobin (reduction of 2.0 +/- 3.4%, P less than 0.01) levels. Seventeen (31%) of 54 patients actually normalized their glycosylated hemoglobin values, 9 in the urine-testing group and 8 in the SMBG group. Comparisons between the urine-testing and SMBG groups showed no significant differences in mean fasting plasma glucose (P greater than 0.86), glycosylated hemoglobin (P greater than 0.95), or weight (P greater than 0.19). In patients with type II diabetes mellitus not treated with insulin, SMBG is no more effective, but is 8-12 times more expensive, than urine testing in facilitating improved glycemic control. Our results do not support widespread use of SMBG in diabetic patients not treated with insulin.

Randomized, double-blind, placebo-controlled, patient-initiated study of topical high- and low-dose interferon-alpha with nonoxynol-9 in the treatment of recurrent genital herpes

To explore further topical antiviral therapy for recurrent genital herpes, 188 culture-proven patients were randomized to receive treatment with topical interferon-alpha in high-dose (10(6) IU/g with 1% nonoxynol-9 in 3.5% methylcellulose) or low-dose (10(3) IU/g with 0.1% nonoxynol-9 in 3.5% methylcellulose) treatments or placebo (3.5% methylcellulose, alone), applied three times daily for 5 days. Of these, 105 experienced prodromal symptoms within the study period and applied the medication, of whom 99 could be evaluated for efficacy. Patients were followed with daily clinical assessments and cultures until reepithelialization. The median time to negative virus culture in high-dose recipients was 2.5 days compared with 3.9 days for placebo recipients (P = .023), and a significant dose response was observed (P = .016). Antiviral effects were more prominent in men than women. High-dose recipients also had reduced median duration of symptoms to 2.7 days from 3.7 days for placebo recipients (P = .03), with a significant dose-response relationship (P = .047). Effects on duration of symptoms were more prominent in women. Times to complete reepithelialization in those who applied the drug during the prodromal phase were 5.8 days for high-dose recipients compared with 6.5 days for placebo recipients (P = .053). A multivariate ranked linear model analysis of four efficacy variables (crusting, healing, virus shedding, symptom duration) also favored the high-dose gel (P = .015). High-dose topical interferon-alpha preparation is effective for patients with recurrent genital herpes. Applied early in the course of a recurrent episode, this treatment is safe and may provide a topical alternative to other types of therapy in the future.

Five-year follow-up of men with androgenetic alopecia treated with topical minoxidil

Thirty-one men with androgenetic alopecia completed 4 1/2 to 5 years of therapy with 2% and 3% topical minoxidil. Hair regrowth with topical minoxidil tended to peak at 1 year with a slow decline in regrowth over subsequent years. However, at 4 1/2 to 5 years, maintenance of nonvellus hairs beyond that seen at baseline was still evident. Topical minoxidil appears to be effective in helping to maintain nonvellus hair growth in men with androgenetic alopecia.

Comparing the areas under two or more correlated receiver operating characteristic curves: a nonparametric approach

Methods of evaluating and comparing the performance of diagnostic tests are of increasing importance as new tests are developed and marketed. When a test is based on an observed variable that lies on a continuous or graded scale, an assessment of the overall value of the test can be made through the use of a receiver operating characteristic (ROC) curve. The curve is constructed by varying the cutpoint used to determine which values of the observed variable will be considered abnormal and then plotting the resulting sensitivities against the corresponding false positive rates. When two or more empirical curves are constructed based on tests performed on the same individuals, statistical analysis on differences between curves must take into account the correlated nature of the data. This paper presents a nonparametric approach to the analysis of areas under correlated ROC curves, by using the theory on generalized U-statistics to generate an estimated covariance matrix.

Erythrocyte anisocytosis. Visual inspection of blood films vs automated analysis of red blood cell distribution width

An improved anemia classification may be available by combining measures of red blood cell size variability with mean corpuscular volume. Visual inspection of the peripheral blood film allows semiquantitative description of anisocytosis while quantitative measures are determined from electronic cell counter analyzers' red blood cell distribution width. We evaluated correlations between semiquantitative and quantitative measures of anisocytosis for different groups of observers. Hematologists', medical students', and medical residents' semiquantitative assessment of anisocytosis correlated with the quantitative red blood cell distribution width. The interobserver variability demonstrated that all observers correlated with each other, while the intraobserver variability of semiquantitative anisocytosis demonstrated that observers were more precise than could be predicted by chance. However, the extreme precision of the red blood cell distribution width strongly suggests that it should be the "gold standard" for measuring red blood cell size variability.

Intestinal obstruction in patients with ovarian cancer. Variables associated with surgical complications and survival

Intestinal obstruction is frequently encountered in patients with ovarian cancer. Surgical correction of intestinal obstruction may allow the prolonged survival of some patients. We identified prognostic factors associated with operative complications and postoperative survival. Multiple preoperative, intraoperative, and postoperative variables were considered. In addition, a previously published prognostic index was evaluated. Statistical assessment developed a model that demonstrated that the clinical assessment of tumor status, the serum albumin level, and the nutrition score were variables significantly associated with postoperative survival. The amount of residual ovarian cancer at the completion of bowel obstruction surgery was also significantly associated with postoperative survival. This information may aid in the preoperative selection of patients who might benefit from surgical correction of intestinal obstruction.

Intermediate, indeterminate, and uninterpretable diagnostic test results

Diagnostic tests do not always yield positive or negative results; sometimes the results are intermediate, indeterminate, or uninterpretable. No consensus exists for the incorporation of such results into data assessment. Conventional Bayesian analysis leads investigators to either exclude patients with non-positive, non-negative results from their studies or categorize such results into inappropriate cells of the standard four-cell decision matrix. The authors propose a standardized method for reporting results in studies dealing with diagnostic test use and discuss how researchers should expand the four-cell matrix to six cells when non-positive, non-negative results occur. They suggest that the six-cell matrix with new operational definitions of sensitivity, specificity, likelihood ratios, and test yield should be adopted routinely. In addition, they define the different types of non-positive, non-negative results and demonstrate how clinicians can use tree-structured decision analysis from the six-cell matrix. While their method does not solve all problems posed by non-positive, non-negative results, it does suggest a standard method for reporting these results and utilizing all the data in decision making.

Phase II diaziquone-based chemotherapy trials in patients with anaplastic supratentorial astrocytic neoplasms

We treated 103 patients with histologically confirmed anaplastic supratentorial astrocytic neoplasms with either diaziquone (AZQ) and carmustine (BCNU) or AZQ and procarbazine. There were 74 patients with glioblastoma multiforme (GBM) and 29 patients with anaplastic astrocytoma (AA). AZQ plus BCNU produced partial (PR) or unequivocal responses in seven of 32 (21.9%) patients with GBMs and three of ten (30%) patients with AAs. Two patients with GBMs (6.3%) and five patients with AAs (50%) showed stable disease (SD). AZQ plus procarbazine produced PRs or unequivocal responses in five of 42 (11.9%) patients with GBMs and nine of 19 (47.4%) patients with AAs. Eight patients with GBMs (19%) and one patient with an AA (5.2%) showed SD. In addition to histologic diagnosis, only the Karnofsky performance-status (KPS) rating independently influenced response and survival. Differences in response rates between the two regimens were not significant, although estimated median survival after adjusting for performance status was slightly better with AZQ plus BCNU than with AZQ plus procarbazine (P = .031). Neither age nor prior chemotherapy were significant independent risk factors. Toxicity was mild and primarily hematologic. We conclude that these AZQ-based regimens have activity in patients with recurrent anaplastic gliomas, but that they are not clearly superior to other agents in current use. The histologic diagnosis of GBM is associated with a significantly worse prognosis than AA, and we believe that this important distinction must be recognized in phase II as well as phase III trials.

Long-term follow-up of men with male pattern baldness treated with topical minoxidil

Forty-one men with male pattern baldness completed 132 study weeks (2 years 9 months) with topical minoxidil and had follow-up 1-inch target-area vertex scalp hair counts. Initially these men were treated with either twice-daily 2% topical minoxidil for 12 months or 3% topical minoxidil for 8 to 12 months (one third of the subjects received placebo for the first 4 months). After 12 months all subjects continued to apply 3% topical minoxidil twice daily for 1 more year, after which they were randomized to once- versus twice-daily topical minoxidil for an additional 9 months. Those subjects who changed to once-daily application of topical minoxidil at 2 years had a mean change from baseline nonvellus hair count at 1 year of 291.2 (range of hairs four to 553) and at 2 years 9 months of 235 (two to 592 hairs). Those subjects who continued with twice-daily application of topical minoxidil throughout the study had a mean change from baseline nonvellus hair count at 1 year of 323 (15 to 589 hairs) and 335 (13 to 808 hairs) at 2 years 9 months with maintenance topical minoxidil. There were subjects on both maintenance schedules of topical minoxidil who lost some of the nonvellus hair they had initially gained with topical minoxidil; however, there was a greater mean loss in those patients following the once-daily versus twice-daily topical minoxidil regimen (p = 0.05). No subject lost nonvellus target hair as compared with baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

A quantitative analysis of palliative care decisions in acute nonlymphocytic leukemia

With the increasing incidence of cancer in elderly patients, decisions to adopt palliative care become particularly relevant to this patient population. In order to define characteristics of decisions to adopt palliative care, including those factors influencing whether a particular patient received palliation, the frequency of this therapeutic posture, and the duration of this treatment period, we performed a retrospective analytical survey of all patients with acute nonlymphocytic leukemia (ANLL) treated at Duke University Medical Center over the past ten years. Logistic regression analysis identified several potentially significant variables influencing the decision to adopt palliative care. Using a stepwise logistic model, the only independent variable associated with adoption of palliative therapy was initial treatment off a research protocol (P = 0.0001). Initial treatment off a research protocol was itself associated with older age (P = 0.0002), nonspontaneous onset of leukemia (P = 0.005), female sex (P = 0.003), and the absence of dependent children (P = 0.01) when examined by multivariate logistic regression. The palliative treatment interval was defined as the time between the discontinuation of aggressive treatment and the patient's death. Fifty-one percent, 119 of 235 patients, received palliative care; of these, 47% were palliated from the time of diagnosis and 53% were palliated only after receiving remission induction therapy. The median duration for the palliative care period was 46 days (50 days for the initially palliated group, 24 days for the group receiving aggressive therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Variables associated with postoperative deep venous thrombosis: a prospective study of 411 gynecology patients and creation of a prognostic model

Deep venous thrombosis is a major complication following gynecologic surgery. Assessing a patient's risk of developing deep venous thrombosis is important for patient selection and in choosing appropriate prophylactic methods. Four hundred eleven patients undergoing major gynecologic surgery were evaluated prospectively. All known variables associated with deep venous thrombosis were recorded. Deep venous thrombosis was diagnosed by 125I fibrinogen leg counting of all patients. Univariate analysis of all variables identified the following to be significantly related (P less than .05) to postoperative deep venous thrombosis: a prior history of deep venous thrombosis, leg edema or venous stasis changes, venous varicosities, degree of preoperative ambulation, type of surgery, nonwhite race, recurrent malignancy, prior pelvic radiation therapy, age above 45 years, excessive body weight, intraoperative blood loss, and duration of anesthesia. A stepwise logistic regression analysis of these variables was performed. The following preoperative prognostic factors remained significant: type of surgery, age, leg edema, nonwhite patients, severity of venous varicosities, prior radiation therapy, and prior history of deep venous thrombosis. Duration of anesthesia was also important when intraoperative factors were considered in the analysis. Using these factors, a prognostic model was created and tested. The model resulted in a degree of concordance of 0.82 and allows one to evaluate the risks of postoperative deep venous thrombosis for an individual patient.

Surgical management of intestinal obstruction in ovarian cancer. I. Clinical features, postoperative complications, and survival

The results of surgery to relieve intestinal obstruction in 49 patients who were known to have ovarian cancer were studied. All patients had received adjunctive chemotherapy and/or radiation therapy prior to bowel obstruction. Thirty patients had small bowel obstruction, 16 patients had colonic obstruction, and 3 patients had concurrent small and large bowel obstruction. Clinical status, nutritional parameters, and radiographic findings were analyzed. Progressive ovarian cancer was ultimately found to be the cause of obstruction in 86% of patients. Major postoperative complications occurred in 49% of patients and were encountered significantly more frequently in those patients with small bowel obstruction (P less than 0.04). Complications most frequently encountered included wound infection, enterocutaneous fistulae, and other septic sequelae. Median postoperative survival was 140 days, with 73% surviving at 60 days postoperatively. A total of 14.3% of patients were alive 12 months postoperatively. These results are similar to prior reports and emphasize the need for clearer preoperative selection criteria.

A comparison of methods for the estimation of plasma low- and very low-density lipoprotein cholesterol. The Lipid Research Clinics Prevalence Study

Using data from over 10 000 men, women, and children who participated in the Lipid Research Clinics prevalence studies, we have examined the formula adopted by Friedewald et al for estimating plasma or serum concentrations of low-density lipoprotein cholesterol (LDL-C) when (for economy, or in the absence of an ultracentrifuge) only fasting total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) concentrations are measured in milligrams per liter, ie, LDL-C = TC-(HDL-C + 0.20 X TG). Values for LDL-C obtained by use of the Friedewald formula were compared with values derived from the Lipid Research Clinics ultracentrifugal procedure for LDL-C, which was used as a reference. Participants who were pregnant, who had not fasted, or whose plasma contained chylomicrons or floating beta-lipoproteins were excluded. We concluded that a better estimator for LDL-C was provided by the equation LDL-C = TC-(HDL-C + 0.16 X TG), since it produced an error (relative to the reference method) of lesser magnitude than the previous formula. The expression 0.16 X TG (0.37 X TG when measurements are reported in millimoles per liter) also produced a more accurate estimate of very low-density lipoprotein cholesterol relative to values obtained by the standard Lipid Research Clinics procedure for this component. The proposed formula is more precise for plasmas or sera with a TG concentration within the normal range.

Dose-response study of topical minoxidil in male pattern baldness

Eighty-nine healthy men with male pattern baldness completed a 6-month double-blind, placebo-controlled study of 0.01%, 0.1%, 1%, and 2% topical minoxidil. Subjects on 2% topical minoxidil had a statistically significant increase in mean total target area hair count over baseline compared to the placebo, 0.01%, and 0.1% topical minoxidil groups (p = 0.04). Changes from baseline were more impressive with the 2% topical minoxidil group but not significantly different from the 1% topical minoxidil group in all parameters of objective response to treatment. The investigator, however, rated more subjects as having at least a moderate cosmetic response to treatment in the 2% versus 1% topical minoxidil treatment group. These results indicate that 1% topical minoxidil is the lowest effective concentration of topical minoxidil for male pattern baldness of those tested. Because of the more impressive changes in hair counts and the cosmetic preference for the 2% versus 1% topical minoxidil, 2% topical minoxidil may be the standard preferred treatment for male pattern baldness.

Sensitivity and specificity of a monitoring test

The usefulness of a diagnostic test is generally assessed by calculating the sensitivity and specificity, or the predictive value positive and predictive value negative of the test. When subjects are monitored periodically for evidence of disease, these calculations must incorporate the varying amounts of information per individual. If in addition, the test results lie on a continuous scale, these quantities vary with the cutoff value (cutpoint) used to define a positive test. They are usually calculated for a spectrum of potential cutpoints in order to produce receiver-operator characteristic curves. In this paper we use a partial likelihood solution to the discrete logistic model in order to obtain estimates of the diagnostic test indices and to provide a significance test when the diagnostic test is administered repeatedly to individuals.

Multiple myeloma and family history of cancer. A case-control study

A hospital-based case-control study was done to examine the hypothesis that persons with a family history of multiple myeloma (MM) or other cancers are at increased risk of multiple myeloma. Study members were 439 cases of multiple myeloma and 1317 matched controls seen at the Duke University Medical Center. Only 3 cases and 4 controls reported multiple myeloma in their families. The relative risk (RR) was 2.3, but the 95% confidence interval (CI) was 0.5-10.1, allowing no firm conclusion about the risk associated with familial MM. A family history of cancer of any type resulted in a relative risk of MM of 1.4 (CI: 1.1-1.8). This association was strongest (RR = 2.5, CI: 1.1-5.3) among young study members (age less than or equal to 49). A family history of hematologic malignancy (ICD 200-208) resulted in a RR of 2.4 (95% CI: 1.4-4.0). The data also suggested that a family history of lung cancer, breast cancer, and genitourinary cancer may be associated with increased risk of myeloma in older persons.

Complications of low-dose heparin prophylaxis in gynecologic oncology surgery

The clinical and laboratory effects of low-dose heparin prophylaxis was prospectively studied in a controlled trial of 182 patients undergoing major surgery for gynecologic malignancy. Low-dose heparin was given in 5000 U subcutaneously two hours preoperatively and every 12 hours for seven days postoperatively. Low-dose heparin-treated patients had a significantly increased daily retroperitoneal hemovac drainage. Although not statistically significant, low-dose heparin was associated with increased estimated intraoperative blood loss, transfusion requirements, and wound hematomas. Fifteen percent of patients receiving low-dose heparin were found to have an activated partial thromboplastin time greater than 1.5 times the control value. In these patients, all clinical bleeding parameters were significantly increased. Low-dose heparin-treated patients also had significantly prolonged activated partial thromboplastin time and lower final platelet counts as compared with the control patients. When using low-dose heparin for thromboembolism prophylaxis, patients should be closely observed for clinical hemorrhagic complications. Activated partial thromboplastin times and platelet counts should be monitored throughout therapy.

Climate, socioeconomic status and Hodgkin's disease mortality in the United States

This study examines the relative effects of climate and socioeconomic status (SES) on standard mortality ratios (SMR) from both young adult and older adult Hodgkin's disease (HD) in the United States. Climate variables explain a greater percentage of the variation in the SMR for HD than do SES variables. After adjusting for SES, indicators of climate exhibit a strong correlation with the young adult SMR, but not with the older adult SMR. These findings suggest that environmental factors play an important role in the etiology of young adult HD and support the hypothesis that young adult HD is a different disease from the older adult form.

Secular trends in ischemic heart disease mortality: regional variation

We compared secular trends in ischemic heart disease (IHD) mortality in four southeastern states (North Carolina, Georgia, South Carolina, and Virginia) with those in three selected other states (California, New York, and Utah). Mortality data were obtained from U.S. vital statistics and population information from the U.S. Census Bureau. Age-adjusted IHD mortality increased until 1968 in the southeastern states and then declined and declines were greatest in the nonwhite female population. In contrast, IHD mortality in all groups in California and in the female population in New York and Utah began to decline in the early 1950s, with accelerated declines since 1968. In all states the decline in rates in nonwhite populations have been greatest in the younger age groups. This has not been true in the white populations. Declining IHD mortality correlated moderately well with the decline in death from all cardiovascular disease and from all causes, but not with the declining cerebrovascular disease mortality. Respiratory cancer mortality increased in similar proportions in California and South Carolina, two states with dissimilar IHD trends. These findings suggest that improved control of hypertension and changing patterns of cigarette smoking may not be responsible for the recent decline in IHD mortality.