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Biomedical subjects

S L Normand

Publications and source records attributed to S L Normand.

At least 19 recordsLinked to original sources
PubMed2001

Impact of underuse, overuse, and discretionary use on geographic variation in the use of coronary angiography after acute myocardial infarction.

BACKGROUND: Geographic variation in the use of medical procedures has been well documented. However, it is not known whether this variation is due to differences in use when procedures are indicated, discretionary, or contraindicated. OBJECTIVES: To examine whether use of coronary angiography after acute myocardial infarction (AMI) according to appropriateness criteria varied across geographic regions and whether underuse, overuse, or discretionary use accounted for variation in overall use. DESIGN: Retrospective cohort study using data from the Cooperative Cardiovascular Project. SETTING: Ninety-five hospital referral regions. PATIENTS: There were 44,294 Medicare patients hospitalized with AMI during 1994 or 1995, classified according to appropriateness for angiography. MAIN OUTCOME MEASURE: Variation in use of angiography, as measured by the difference between high and low rates of use across regions. RESULTS: Across regions, variation in the use of angiography was similar for indications judged necessary; appropriate, but not necessary; or uncertain. Variation was lowest for indications judged unsuitable (difference between high rate and low rate across regions = 16.3%; 95% CI = 12.6%; 20.6%). The primary cause of variation in the overall rate of angiography was due to use for indications judged appropriate, but not necessary or uncertain. When variation associated with these indications was accounted for, the difference between the resulting high and low overall rates was 10.8% (9.4%, 12.4%). In contrast, variation in the overall rate remained high when underuse in necessary situations or overuse in unsuitable situations was accounted for. CONCLUSIONS: Across regions, practice was more similar for patients categorized unsuitable for angiography than for patients with other indications. Variation in overall use of angiography appeared to be driven by utilization for discretionary indications rather than by underuse or overuse. If equivalent rates across geographic areas are judged desirable, then greater effort must be directed toward defining care for patients with discretionary indications.

Aged↗
PubMed2001

Partial versus full hospitalization for adults in psychiatric distress: a systematic review of the published literature (1957-1997).

OBJECTIVE: The authors reviewed published research that compared partial and full hospitalization as alternative programs for the care of mentally ill adults, with the goal of both systematizing the knowledge base and providing directions for future research. METHOD: Studies published since 1950 were obtained through manual and electronic searches. Results were stratified by outcome domain, type of measure used to report between-group differences (global, partial, or rate-based), and time of assessment. Effect sizes were computed and combined within a random-effects framework. RESULTS: Eighteen investigations published between 1957 and 1997 were systematically reviewed. Over half of eligible patients were excluded a priori; diagnostic severity of enrollees varied widely. On measures of psychopathology, social functioning, family burden, and service utilization, the authors found no evidence of differential outcome in the selected patient population admitted to the studies reviewed. Rates of satisfaction with services suggested an advantage for partial hospitalization within 1 year of discharge, with the gap being largest at 7-12 months. CONCLUSIONS: Although partial hospitalization is not an option for all patients requiring intensive services, outcomes of partial hospitalization patients in these studies were no different from those of inpatients. Further, patients and families were more satisfied with partial hospitalization in the short term. Weaknesses of the studies limited the scope of our inquiry and the generalizability of findings. Positive findings require replication under the present circumstances of mental health care, and more research is needed to identify predictors of differential outcome and successful partial hospitalization. A clearer definition of partial hospitalization will help consolidate its role in the continuum of mental health services.

Adult↗
PubMed2001

Managed care and children's behavioral health services in Massachusetts.

OBJECTIVE: The authors investigated changes in treatment patterns and costs of care for children after the implementation of the Massachusetts Medicaid carve-out managed care plan. METHODS: The authors hypothesized that after the introduction of managed care, per-child expenditures would be reduced, continuity of care would not improve, and per-child mental health expenditures would undergo larger reductions for disabled children, compared with children enrolled in the Aid to Families With Dependent Children program. Using data from Medicaid and the Massachusetts Department of Mental Health, the authors studied 16,664 Massachusetts Medicaid beneficiaries aged one to 17 years for whom reimbursement claims were submitted for psychiatric or substance use disorder treatment at least once during the two years before the introduction of managed care (1991 to 1992) or during the two years afterward (1994 to 1995). Multivariate analysis was used to estimate changes in probability of admission, and, among patients admitted, to identify factors accounting for variation in length of stay. To assess the variation in expenditures, we regressed the same variables, using the natural logarithm function to transform total mental health expenditures data and inpatient expenditures data to reduce skewness. RESULTS: After the introduction of managed care, per-child expenditures were lower, especially for disabled children, and the Department of Mental Health was used as a safety net for the most seriously ill children without increasing state expenditures. Continuity of care appeared to decline for disabled children. CONCLUSIONS: It is likely that a combination of factors related to the reported changes in patterns of care and expenditures were responsible for the overall per-child expenditures.

Adolescent↗
PubMed2000

Outcome of myocardial infarction in Veterans Health Administration patients as compared with medicare patients.

BACKGROUND: Some have the opinion that patients cared for in Veterans Health Administration (VHA) hospitals receive care of poorer quality than those cared for in non-VHA institutions. To assess the quality of care in VHA hospitals, we compared the outcome of acute myocardial infarction among patients in VHA and non-VHA institutions while controlling for potential confounders, including coexisting conditions and severity of illness. METHODS: We studied 2486 veterans discharged from 81 VHA hospitals and 29,249 Medicare patients discharged from 1530 non-VHA hospitals, restricting our samples to men at least 65 years of age who were discharged with confirmed acute myocardial infarction. We compared coexisting conditions, severity of illness, and 30-day and 1-year mortality in the two samples. RESULTS: VHA patients were significantly more likely than Medicare patients to have a recorded history of hypertension (64.3 percent vs. 57.3 percent), chronic obstructive pulmonary disease or asthma (30.9 percent vs. 23.5 percent), diabetes (34.8 percent vs. 29.0 percent), stroke (20.4 percent vs. 14.2 percent), or dementia (7.2 percent vs. 4.8 percent) (P<0.001 for all comparisons). According to both multivariate logistic regression and an analysis using 2265 matched pairs of VHA and Medicare patients, there were no significant differences in 30-day or 1-year mortality. The matched-pairs analysis found that the difference in mortality at 30 days (the mortality rate among Medicare patients minus the mortality rate among VHA patients), averaged over the 5-year age groups, was -0.8 percent (95 percent confidence interval, -2.8 percent to 1.3 percent), and the difference in mortality at 1 year was -1.3 percent (95 percent confidence interval, -3.9 percent to 1.3 percent). CONCLUSIONS: VHA patients had more coexisting conditions than Medicare patients. Nevertheless, we found no significant difference in mortality between VHA and Medicare patients, a result that suggests a similar quality of care for acute myocardial infarction.

Aged↗
PubMed2000

Survival after acute myocardial infarction in patients with end-stage renal disease: results from the cooperative cardiovascular project.

Cardiovascular disease (CVD) is the most common cause of death in patients with end-stage renal disease (ESRD). The optimal management strategy in this population is unknown. We studied 640 patients with ESRD and acute myocardial infarction during 1994 to 1995 as part of the Health Care Financing Administration's Cooperative Cardiovascular Project. The majority of patients were treated with medical therapy alone, 46 patients (7%) were treated with percutaneous transluminal coronary angioplasty (PTCA), and 29 patients (5%) underwent coronary artery bypass grafting (CABG). Patient characteristics and comorbid conditions were similar among the three groups. The overall 1-year mortality rate was 53%. Advanced age, low or high body mass index, history of peripheral vascular disease or stroke, the inability to walk independently, and several indicators of cardiac dysfunction were associated with an increased relative risk (RR) for death. Survival curves differed significantly by treatment modality, with 1-year survival rates of 45%, 54%, and 69% in the medical therapy alone, PTCA, and CABG groups, respectively (P = 0.03). After adjustment for confounding variables, the RR for death was less (but not significantly so) in the CABG group (RR, 0.6; 95% confidence interval, 0.3 to 1.1). There are no randomized clinical trial data to guide therapy of CVD in patients with ESRD. On the basis of these and other available data, CABG may be the optimal therapy for CVD in ESRD. In light of the exceptionally poor outcomes observed for patients treated with medical therapy alone, it may be premature to dismiss PTCA as a therapeutic option in this population.

Age Factors↗
PubMed1999

Meta-analysis: formulating, evaluating, combining, and reporting.

Meta-analysis involves combining summary information from related but independent studies. The objectives of a meta-analysis include increasing power to detect an overall treatment effect, estimation of the degree of benefit associated with a particular study treatment, assessment of the amount of variability between studies, or identification of study characteristics associated with particularly effective treatments. This article presents a tutorial on meta-analysis intended for anyone with a mathematical statistics background. Search strategies and review methods of the literature are discussed. Emphasis is focused on analytic methods for estimation of the parameters of interest. Three modes of inference are discussed: maximum likelihood; restricted maximum likelihood, and Bayesian. Finally, software for performing inference using restricted maximum likelihood and fully Bayesian methods are demonstrated. Methods are illustrated using two examples: an evaluation of mortality from prophylactic use of lidocaine after a heart attack, and a comparison of length of hospital stay for stroke patients under two different management protocols.

Anti-Arrhythmia Agents↗
PubMed1999

Applying Bayesian ideas to the development of medical guidelines.

Measurements of the quality of health care, in particular the underuse and overuse of medical therapies and diagnostic tests, often involve employment of medical practice guidelines to assess the appropriateness of treatments. This paper presents a case study of a Bayesian analysis for the development of medical guidelines based on expert opinion, using ordinal categorical rater data. We develop guidelines for the use of coronary angiography following an acute myocardial infarction (AMI) for 890 clinical indications using statistical models fit to appropriateness ratings obtained from a nine-member expert panel. The main foci of our analyses were on the estimation of an appropriateness score for each of the clinical indications, an associated measure of precision, and functions of the underlying score. We considered two classes of models that assume the ratings are either in the form of grouped normal data or are ungrouped variables arising from a normal distribution, while permitting rater effects and indication heterogeneity in both. We estimated models using Markov chain Monte Carlo methods and constructed indices quantifying appropriateness based on posterior probabilities of selected model parameters. We compared our model-based approach to the standard approach currently employed in medical guideline development and found that the standard approach correctly identified 99 per cent of the appropriate indications while overestimating appropriateness 18 per cent of the time compared to our model-based approach.

Bayes Theorem↗
PubMed1999

Understanding variability in physician ratings of the appropriateness of coronary angiography after acute myocardial infarction.

We examined variability in ratings of the appropriateness of coronary angiography for 890 clinical scenarios (indications) after an acute myocardial infarction (AMI) from a nine-member multispecialty panel as a function of panel characteristics and the attributes of the clinical indications. We documented a substantial degree of reliability in the ratings. However, key differences among the experts in terms of both their overall propensity to score high and their beliefs regarding the impact of clinical factors on appropriateness were identified. Age, cardiac complications, post-AMI angina, and noninvasive test results were the clinical factors most strongly related to appropriateness ratings for coronary angiography. Further research on the effectiveness of coronary angiography in older patients and in patients with shock, pulmonary edema, and silent ischemia is needed to improve our knowledge about the appropriateness of this procedure in these patients.

Aged↗
PubMed1999

Positive predictive value of the diagnosis of acute myocardial infarction in an administrative database.

OBJECTIVE: To determine the positive predictive value of ICD-9-CM coding of acute myocardial infarction and cardiac procedures. METHODS: Using chart-abstracted data as the standard, we examined administrative data from the Veterans Health Administration for a national random sample of 5,151 discharges. MAIN RESULTS: The positive predictive value of acute myocardial infarction coding in the primary position was 96.9%. The sensitivity and specificity of coding were, respectively, 96% and 99% for catheterization, 95.7% and 100% for coronary artery bypass graft surgery, and 90.3% and 99. 7% for percutaneous transluminal coronary angioplasty. CONCLUSIONS: The positive predictive value of acute myocardial infarction and related procedure coding is comparable to or better than previously reported observations of administrative databases.

Aged↗
PubMed1998

Rating the appropriateness of coronary angiography--do practicing physicians agree with an expert panel and with each other?

BACKGROUND: Evaluations of the appropriateness of medical care are important to monitor the quality of care and to contain costs and enhance safety by reducing inappropriate care. Experts' views are usually incorporated into evaluations of appropriateness. However, practicing physicians may not concur with these views, and physicians' clinical backgrounds may influence their beliefs. METHODS: We asked 1058 internists, family practitioners, and cardiologists in California, Florida, New York, Pennsylvania, and Texas to rate the appropriateness of coronary angiography after acute myocardial infarction for 20 common indications. Nine clinical experts also rated these indications using an established consensus method. RESULTS: For 17 of the 20 indications, median ratings of surveyed physicians and the expert panel agreed within 1 unit on a 9-unit scale. Patients' older age had a negative effect on ratings by the expert panel but not on ratings by surveyed physicians. In multivariable analyses of surveyed physicians, cardiologists rated angiography as significantly more appropriate than did primary care physicians for complicated indications, and for uncomplicated indications cardiologists who performed invasive procedures gave higher appropriateness ratings for angiography than did cardiologists who did not perform such procedures and primary care physicians. For uncomplicated indications, physicians from hospitals providing coronary angioplasty and bypass surgery rated angiography as more appropriate than physicians from other hospitals. Physicians from New York and those employed by health maintenance organizations rated angiography as less appropriate than other physicians. CONCLUSIONS: Surveyed physicians agreed with clinical experts about the appropriateness of coronary angiography after myocardial infarction for most indications, indicating that well-designed expert panels can closely reflect the views of practicing physicians. Variations in beliefs among practicing physicians suggest that evaluations of medical practice should incorporate the views of a range of relevant types of physicians.

Aged↗
PubMed1998

Eliciting expert opinion using the Delphi technique: identifying performance indicators for cardiovascular disease.

Combining opinion from expert panels is becoming a more common method of selecting criteria to define quality of health care. The Rand Corporation pioneered this method is the 1950s and 1960s in the context of forecasting technological events. Since then, numerous organizations have adopted the methodology to develop local and national policy. In the context of quality of care, opinion is typically elicited from a sample of experts regarding the appropriateness or importance of a medical treatment for several well-defined clinical cohorts. The information from the experts is then combined in order to create a standard or performance measure of care. This article describes how to use the panel process to elicit information from diverse panels of experts. Methods are demonstrated using the data from five distinct panels convened as part of the Harvard Q-SPAN-CD study, a nationally-funded project whose goal is to identify a set of cardiovascular-related performance measures.

Boston↗
PubMed1997

Use of cardiac procedures and outcomes in elderly patients with myocardial infarction in the United States and Canada.

BACKGROUND: Acute myocardial infarction is a leading cause of morbidity and mortality in the United States and Canada. We performed a population-based study to compare the use of cardiac procedures and outcomes after acute myocardial infarction in elderly patients in the two countries. METHODS: We compared the use of invasive cardiac procedures and the mortality rates among 224,258 elderly Medicare beneficiaries in the United States and 9444 elderly patients in Ontario, Canada, each of whom had a new acute myocardial infarction in 1991. RESULTS: The U.S. patients were significantly more likely than the Canadian patients to undergo coronary angiography (34.9 percent vs. 6.7 percent, P< 0.001), percutaneous transluminal coronary angioplasty (11.7 percent vs. 1.5 percent, P<0.001), and coronary-artery bypass surgery (10.6 percent vs. 1.4 percent, P<0.001) during the first 30 days after the index infarction. These differences in the use of cardiac procedures narrowed but persisted through 180 days of follow-up. The 30-day mortality rates were slightly but significantly lower for the U.S. patients than for the Canadian patients (21.4 percent vs. 22.3 percent, P=0.03). However, the one-year mortality rates were virtually identical (34.3 percent in the United States vs. 34.4 percent in Ontario, P= 0.94). CONCLUSIONS: Short-term mortality after an acute myocardial infarction was slightly lower in the United States than in Ontario, but these differences did not persist through one year of follow-up. The strikingly higher rates of use of cardiac procedures in the United States, as compared with Canada, do not appear to result in better long-term survival rates for elderly U.S. patients with acute myocardial infarction.

Aged↗
PubMed1997

Computed tomography of complications of lung transplantation.

In spite of improvements in single or double lung transplantation (LT) technique, complications after LT are not uncommon; the most frequent ale anastomotic complications, infections and rejection (acute or chronic). Early detection of complications of LT allows the optimal therapeutic option to be taken, yielding decreased morbidity and mortality. In some cases, CT plays a key role in early detection of several complications of LT that may not be depicted with other diagnostic modalities, so that knowledge of their CT features is important. In this pictorial review, the authors describe the spectrum of CT features of the complications of LT (including reimplantation response, mechanical problems, acute and chronic rejection, infection, lymphoproliferative disorders, recurrence of the initial disease and complications involving the pleura and the anastomotic sites). In addition, the authors analyze the value of CT compared to that of the other available modalities for the detection of complications of LT.

Adult↗
PubMed1996

Managing the care of schizophrenia. Lessons from a 4-year Massachusetts Medicaid study.

BACKGROUND: In 1992, Massachusetts launched a state-wide managed care plan for all Medicaid beneficiaries. METHODS: This retrospective, multi-year, cross-sectional study used administrative data from the Massachusetts Division of Medical Assistance and Department of Mental Health, consisting of claims for 16,400 disabled adult patients insured by Medicaid in Massachusetts between July 1, 1990, and June 30, 1994. The main outcome measures include annual rates of hospitalization, emergency department utilization, and follow-up care 30 days after discharge; length of inpatient stay; and per-person inpatient and outpatient expenditures. RESULTS: Between 1991 and 1994, the likelihood of an inpatient admission decreased from 29% to 24% and was accompanied by a slight reduction in length of stay (median number of bed-days per admission dropped by 3.3 days). There was a slight decrease in the number of patients who sought care in general hospital emergency department utilization. However, there was a small increase in the fraction of patients readmitted within 30 days of discharge. Medicaid and Department of Mental Health expenditures for mental health per treated beneficiary decreased slightly, from $11,060 to $10,640, during the 4-year study period. CONCLUSION: Although per-person expenditures dropped and most patient patterns of care remained the same, longer-term study is recommended to asses whether the trends can be maintained.

Adolescent↗
PubMed1995

Permanent pacemaker selection and subsequent survival in elderly Medicare pacemaker recipients.

BACKGROUND: Dual-chamber pacemakers have been in use for more than 15 years. Although they may confer a physiological advantage over single-chamber ventricular pacemakers, they are more expensive and have a generally shorter service life than single-chamber devices. We carried out the present study to identify patient subgroups who were preferentially receiving greater or lesser proportions of dual-chamber devices and to determine whether the selection of different types of pacemakers was associated with differences in mortality. METHODS AND RESULTS: We analyzed a 20% random national sample of all Medicare beneficiaries aged 65 years or older who underwent initial placement of a permanent pacemaker and were discharged in 1988, 1989, or 1990 (n = 36,312). The minimum follow-up for vital status was 1 year. The relation of pacemaker type to patient and provider characteristics was determined using logistic regression analysis. The relation between pacemaker type and mortality was determined using the Cox proportional hazards method. The proportion of dual-chamber systems that were received increased from 27.2% in 1988 to 37.0% in 1990 (P < .001). Dual-chamber pacemaker recipients were younger (P < .001) than ventricular pacemaker recipients. Other independent correlates of dual-chamber pacemaker selection included male sex (odds ratio and 95% confidence intervals, 1.18 and 1.12 to 1.24, respectively), atrioventricular block (1.59 and 1.51 to 1.67), congestive heart failure (1.14 and 1.08 to 1.20), atrial fibrillation (0.36 and 0.34 to 0.39), and the presence of a major noncardiac diagnosis (0.86 and 0.83 to 0.89). Nonmedical predictors of dual-chamber pacemaker selection included Medicaid eligibility (0.78 and 0.71 to 0.86), implantation in the western United States (1.19 and 1.10 to 1.29), implantation by a rural provider (0.70 and 0.65 to 0.76), hospitalization in a 500-bed-or-larger hospital (1.20 and 1.13 to 1.28), hospitalization in a private hospital (1.19 and 1.10 to 1.28), or hospitalization in a hospital with a catheterization laboratory (1.47 and 1.38 to 1.56). Dual-chamber pacemaker selection was an independent predictor of survival at 1 year (0.82 and 0.77 to 0.87) and at 2 years (0.82 and 0.77 to 0.87) after controlling for potentially confounding patient-level and hospital-level characteristics. CONCLUSIONS: The present study describes important variations in the clinical practice of cardiac pacing, many of which are not based on clinical characteristics. Furthermore, the selection of a dual-chamber pacemaker is associated with increased survival. These results underscore the need for prospective, outcome-based clinical trials of pacemaker mode selection.

Aged↗
PubMed1995

Statistical prediction of the optimal site for thalamotomy in parkinsonian tremor.

Stereotactic lesions in the thalamus for treatment of parkinsonian tremor are often made at the location where neurons fire at approximately tremor frequency (tremor cells). Some of these cells show a large amount of activity at tremor frequency and are significantly correlated with electromyographic activity (EMG) during tremor. Our analysis of cellular location identifies a cluster of neurons showing activity characterized both by concentration of power at tremor frequency and by significant correlation with EMG. In a retrospective analysis of results in 15 patients, lesions placed within 2 mm of the center of this cluster were uniformly effective in relieving tremor. Therefore, a small lesion targeting this cluster is effective in treatment of parkinsonian tremor.

Brain Mapping↗
PubMed1995

Gaussian models for degradation processes-Part I: Methods for the analysis of biomarker data.

We present two stochastic models that describe the relationship between biomarker process values at random time points, event times, and a vector of covariates. In both models the biomarker processes are degradation processes that represent the decay of systems over time. In the first model the biomarker process is a Wiener process whose drift is a function of the covariate vector. In the second model the biomarker process is taken to be the difference between a stationary Gaussian process and a time drift whose drift parameter is a function of the covariates. For both models we present statistical methods for estimation of the regression coefficients. The first model is useful for predicting the residual time from study entry to the time a critical boundary is reached while the second model is useful for predicting the latency time from the infection until the time the presence of the infection is detected. We present our methods principally in the context of conducting inference in a population of HIV infected individuals.

Biomarkers↗