PubMed Health⌕ Search

Biomedical subjects

C Gatsonis

Publications and source records attributed to C Gatsonis.

At least 19 recordsLinked to original sources
PubMed2001

Racial differences in cardiac revascularization rates: does "overuse" explain higher rates among white patients?

BACKGROUND: Coronary artery bypass graft (CABG) surgery and percutaneous transluminal coronary angioplasty (PTCA) are well-established treatments for symptomatic coronary artery disease. Previous studies have documented racial differences in rates of use of these cardiac revascularization procedures. Other studies suggest that these procedures are overused: that is, they are done for patients with clinically inappropriate indications. OBJECTIVE: To test the hypothesis that the higher rate of cardiac revascularization among white patients is associated with a higher prevalence of overuse (revascularization for clinically inappropriate indications) among white patients than among African-American patients. DESIGN: Observational cohort study using Medicare claims and medical record review. SETTING: 173 hospitals in five U.S. states. PARTICIPANTS: A stratified, weighted, random sample of 3960 Medicare beneficiaries who underwent coronary angiography during 1991 and 1992; 1692 of these patients underwent 1711 revascularization procedures within 90 days. MEASUREMENTS: The proportion of CABG and PTCA procedures rated appropriate, uncertain, and inappropriate according to RAND criteria, and the multivariate odds of undergoing inappropriate revascularization among African-American patients and white patients. RESULTS: After angiography, rates of PTCA (23% vs. 19%) and CABG surgery (29% vs. 17%) were significantly higher among white patients than among African-American patients. The respective rates of inappropriate PTCA and CABG surgery were 14% and 10%. Among the study states, rates of inappropriate use ranged from 4% to 24% for PTCA and 0% to 14% for CABG surgery. White patients were more likely than African-American patients to receive inappropriate PTCA (15% vs. 9%; difference, 6 percentage points [95% CI, -0.4 to 12.7 percentage points]), and difference by race was statistically significant among men (20% vs. 8%; difference, 12 percentage points [CI, 1.2 to 21.7 percentage points]). Rates of inappropriate CABG surgery did not differ by race (10% in both groups). CONCLUSIONS: Among a large and diverse sample of Medicare beneficiaries in five U.S. states, overuse of PTCA was greater among white men than among other groups, but this difference did not fully account for racial disparities in revascularization. Overuse of cardiac revascularization varied significantly by geographic region.

Aged↗
PubMed2000

Effects of angiotensin-converting enzyme inhibitors and digoxin on health outcomes of very old patients with heart failure. SAGE Study Group. Systematic Assessment of Geriatric drug use via Epidemiology.

BACKGROUND: Randomized trials have shown that angiotensin-converting enzyme (ACE) inhibitors reduce mortality and morbidity, and improve symptoms and exercise tolerance in selected patients with congestive heart failure (CHF). There is, however, no evidence on the effectiveness of ACE inhibitors in the typical, very old and frail patients with CHF. OBJECTIVE: To compare the effects of ACE inhibitors and digoxin on 1-year mortality, morbidity, and physical function among patients aged 85 years. METHODS: We conducted a retrospective cohort study using the SAGE database, a long-term care database linking patient information with drug utilization data. Among 64637 patients with CHF admitted to all nursing homes in 5 states between 1992 and 1995, we identified 19492 patients taking either an ACE inhibitor (n = 4911) or digoxin (n = 14890). Record of date of death was derived from Medicare enrollment files, and we used the part A Medicare files to identify hospital admissions and discharge diagnoses. As a measure of physical function, we used a scale for activities of daily living performance. The effect of ACE inhibitors was estimated using Cox proportional hazards models with digoxin users as the reference group. RESULTS: The overall mortality rate among ACE inhibitor recipients was more than 10% less than that of digoxin users (relative rate, 0.89; 95% confidence interval, 0.83-0.95). Mortality was equally reduced regardless of concomitant cardiovascular conditions and baseline physical function. Treatment with ACE inhibitors was associated with a tendency toward reduced hospital admissions that was more evident among patients with greater functional impairment. The adjusted relative rate for hospitalization for any reason was 0.96 (95% confidence interval, 0.91-1.01). The rate of functional decline was greatly reduced among ACE inhibitor recipients (relative rate, 0.74; 95% confidence interval, 0.69-0.80), and this effect was consistent and independent of background comorbidity and baseline physical function. CONCLUSIONS: These data suggest that survival and functional benefits of ACE inhibitor therapy extend to patients with CHF 85 years and older, and mostly women, both systematically underrepresented in randomized trials. Alternatively, digoxin has a detrimental effect in this population.

Activities of Daily Living↗
PubMed1999

Characteristics of the SAGE database: a new resource for research on outcomes in long-term care. SAGE (Systematic Assessment of Geriatric drug use via Epidemiology) Study Group.

BACKGROUND: Because there is a lack of databases specific to long-term care, standardized assessments of nursing home residents are seen as a potential new resource for studying an important but neglected population. We describe the design and principal population characteristics of the first integrated database combining detailed clinical information and administrative claims data. METHODS: We studied nearly 300,000 residents admitted between 1992 and 1994 to all Medicare/Medicaid certified nursing homes of five U.S. states (Kansas, Maine, Mississippi, New York, and South Dakota). The database crosslinks: (a) Resident Data: over 350 items (demographic, diagnostic, clinical, and treatments) collected with the Minimum Data Set; (b) Drug Data: brand name, dosage route, and frequency of administration for all drugs consumed by each resident; (c) Medicare Data: eligibility and inpatient hospital claims; (d) Facilities Data: structural and staffing information on nursing homes; and (e) Country Data: information on population, health professions and facility data, and economic parameters. RESULTS: Ninety-two percent of the residents were aged 65 years and older. Residents were predominantly white (85%) and female (72%). The average number of medical diagnoses was above three, and residents were receiving an average of six medications. Sixty-five percent of residents had at least one hospital claim following the initial assessment, most commonly related to cardiovascular diseases and metabolic disorders. Fifty-five percent of the facilities were for-profit and 33% were of small size. Quality indicators and staffing level varied significantly by state. CONCLUSIONS: The SAGE (Systematic Assessment of Geriatric drug use via Epidemiology) database provides a unique resource to study the relation between treatments received and outcomes experienced, particularly functional and health services outcomes, that have not been possible before in very old, frail people.

Activities of Daily Living↗
PubMed1999

Generalized estimating equations for ordinal categorical data: arbitrary patterns of missing responses and missingness in a key covariate.

We propose methods for regression analysis of repeatedly measured ordinal categorical data when there is nonmonotone missingness in these responses and when a key covariate is missing depending on observables. The methods use ordinal regression models in conjunction with generalized estimating equations (GEEs). We extend the GEE methodology to accommodate arbitrary patterns of missingness in the responses when this missingness is independent of the unobserved responses. We further extend the methodology to provide correction for possible bias when missingness in knowledge of a key covariate may depend on observables. The approach is illustrated with the analysis of data from a study in diagnostic oncology in which multiple correlated receiver operating characteristic curves are estimated and corrected for possible verification bias when the true disease status is missing depending on observables.

Biometry↗
PubMed1998

Management of pain in elderly patients with cancer. SAGE Study Group. Systematic Assessment of Geriatric Drug Use via Epidemiology.

CONTEXT: Cancer pain can be relieved with pharmacological agents as indicated by the World Health Organization (WHO). All too frequently pain management is reported to be poor. OBJECTIVE: To evaluate the adequacy of pain management in elderly and minority cancer patients admitted to nursing homes. DESIGN: Retrospective, cross-sectional study. SETTING: A total of 1492 Medicare-certified and/or Medicaid-certified nursing homes in 5 states participating in the Health Care Financing Administration's demonstration project, which evaluated the implementation of the Resident Assessment Instrument and its Minimum Data Set. STUDY POPULATION: A group of 13 625 cancer patients aged 65 years and older discharged from the hospital to any of the facilities from 1992 to 1995. Data were from the multilinked Systematic Assessment of Geriatric Drug Use via Epidemiology (SAGE) database. MAIN OUTCOME MEASURES: Prevalence and predictors of daily pain and of analgesic treatment. Pain assessment was based on patients' report and was completed by a multidisciplinary team of nursing home personnel that observed, over a 7-day period, whether each resident complained or showed evidence of pain daily. RESULTS: A total of 4003 patients (24%, 29%, and 38% of those aged > or =85 years, 75 to 84 years, and 65 to 74 years, respectively) reported daily pain. Age, gender, race, marital status, physical function, depression, and cognitive status were all independently associated with the presence of pain. Of patients with daily pain, 16% received a WHO level 1 drug, 32% a WHO level 2 drug, and only 26% received morphine. Patients aged 85 years and older were less likely to receive morphine or other strong opiates [corrected] than those aged 65 to 74 years (13% vs 38%, respectively). More than a quarter of patients (26%) in daily pain did not receive any analgesic agent. Patients older than 85 years in daily pain were also more likely to receive no analgesia (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.13-1.73). Other independent predictors of failing to receive any analgesic agent were minority race (OR, 1.63; 95% CI, 1.18-2.26 for African Americans), low cognitive performance (OR, 1.23; 95% CI, 1.05-1.44), and the number of other medications received (OR, 0.65; 95% CI, 0.5-0.84 for 11 or more medications). CONCLUSIONS: Daily pain is prevalent among nursing home residents with cancer and is often untreated, particularly among older and minority patients.

Aged↗
PubMed1997

Hierarchical polytomous regression models with applications to health services research.

The analysis of variations is an important area of interest in health services and outcomes research and has two main goals: to identify and quantify variability across units, such as geographic regions or health care providers, in terms of procedure utilization and outcomes, and to explore the links between process, such as regional or hospital practice patterns, and outcomes, such as patient mortality and functional status. Hierarchical regression models are well suited for this type of analysis. In this paper we formulate a hierarchical polytomous regression model and apply it to the analysis of variations in the utilization of alternative cardiac procedures in a national cohort of elderly Medicare patients who had an acute myocardial infarction during 1987. The model is designed to accommodate clustered multinomial data with covariate vectors available on individual cases and on clusters. We present a Bayesian approach to fitting and checking the model using simulated values from the posterior distribution of the parameters. The simulation algorithms are based on Gibbs sampling in combination with Metropolis steps. Using the hierarchical polytomous regression model, we examine how the rates of cardiac procedures depend on patient-level characteristics, including age, gender and race, and whether there exist interstate differences and regional patterns in the use of these procedures.

Aged↗
PubMed1997

First-episode major depressive and dysthymic disorder in childhood: clinical and sociodemographic factors in recovery.

OBJECTIVE: To characterize the temporal pattern of depressive disorder in childhood, the first episode of depression was examined, focusing on recovery and its baseline predictors. METHOD: The sample includes 112 clinically referred 8- to 13-year-olds with first-episode major depressive or dysthymic disorder participating in a naturalistic follow-up study. Psychiatric diagnoses were based on standardized interviews and operational criteria. Recovery was modeled by multivariate procedures using baseline clinical and demographic predictors. RESULTS: Recovery rates were 86% and 7% for major depression and dysthymia, respectively, 2 years after onset. Median duration of major depression was 9 months and was predicted only by underlying dysthymia. Median duration of dysthymic disorder was 3.9 years and was predicted only by comorbid externalizing disorder. In post hoc analyses, no positive treatment effects were detected. CONCLUSIONS: First-episode depression in youths is persistent, it generally appears to run its own course, and its naturalistic treatment requires scrutiny. However, because comorbid externalizing disorder apparently affects duration of dysthymia, intervention for behavior problems may shorten this type of depression.

Adolescent↗
PubMed1997

CT and MR imaging in the local staging of primary malignant musculoskeletal neoplasms: Report of the Radiology Diagnostic Oncology Group.

PURPOSE: To assess the relative accuracies of computed tomography (CT) and magnetic resonance (MR) imaging in the local staging of primary malignant bone and soft-tissue tumors. MATERIALS AND METHODS: At four institutions, 367 eligible patients (aged 6-89 years) with malignant bone or soft-tissue neoplasms in selected anatomic sites were enrolled. Patients underwent both CT and MR imaging within 4 weeks before surgery. In each patient, CT scans were interpreted independently by two radiologists and MR images by two other radiologists at the enrolling institution. The CT and MR images were then interpreted together by two of those radiologists and subsequently reread at the other institutions. Imaging and histopathologic findings were compared and were supplemented when needed with surgical findings. Receiver operating characteristic curve analysis and descriptive statistical analysis were performed. RESULTS: Cases were analyzable in 316 patients: 183 had primary bone tumors; 133 had primary soft-tissue tumors. There was no statistically significant difference between CT and MR imaging in determining tumor involvement of muscle, bone, joints, or neurovascular structures. The combined interpretation of CT and MR images did not statistically significantly improve accuracy. Interreader variability was similar for both modalities. CONCLUSION: CT and MR imaging are equally accurate in the local staging of malignant bone and soft-tissue neoplasms in the specific anatomic sites studied.

Adolescent↗
PubMed1997

The Boston AIDS Survival Score (BASS): a multidimensional AIDS severity instrument.

OBJECTIVES: This study developed a new acquired immunodeficiency syndrome (AIDS) severity system by including diagnostic, physiological, functional, and sociodemographic factors predictive of survival. METHODS: Three-hundred five persons with AIDS in Boston were interviewed; their medical records were reviewed and vital status ascertained. RESULTS: Overall median (+/- SD) survival for the cohort from the first interview until death was 560 +/- 14.4 days. The best model for predicting survival, the Boston AIDS Survival Score, included the Justice score (stage 2 relative hazard [RH] = 1.25, 95% confidence interval [CI] = 0.80, 1.96; stage 3 RH = 1.76, 95% CI = 1.15, 2.70), a newly developed opportunistic disease score (Boston Opportunistic Disease Survival Score; stage 2 RH = 1.35, 95% CI = 0.90, 2.02; stage 3 RH = 2.10, 95% CI = 1.38, 3.18), and measures of activities of daily living (any intermediate limitations, RH = 1.84, 95% CI = 1.05, 3.21; any basic limitations, RH = 2.60, 95% CI = 1.44, 4.69). This model had substantially greater predictive power (R2 = .17, C statistic = .68) than the Justice score alone (R2 = .09, C statistic = .61). CONCLUSIONS: Incorporating data on clinically important events and functional status into a physiologically based system can improve the prediction of survival with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Ordinal regression methodology for ROC curves derived from correlated data.

We present an approach for the analysis of correlated ROC data, using ordinal regression models in conjunction with generalized estimating equations. The approach applies to the analysis of degree-of-suspicion data derived from multiple interpretations of the same diagnostic study and from the examination of the same patients with multiple diagnostic modalities. The regression models make it possible to incorporate patient and reader characteristics into the analysis, without having to resort to stratification. We illustrate the potential of the approach with analysis of data from two studies in diagnostic oncology.

Diagnosis↗
PubMed1996

The influence of health-related quality of life and social characteristics on hospital use by patients with AIDS in the Boston Health Study.

OBJECTIVES: The authors examine whether health-related quality of life (HRQL) and social factors were independent predictors of future hospital use for persons with acquired immunodeficiency syndrome (AIDS). METHODS: A panel of 305 patients with AIDS treated at three provider settings in the Boston, Massachusetts area were enrolled during 1990 and 1991. Data were collected at baseline study enrollment and again 4 months later. Patient interviews, hospital bills, and medical charts were used to measure hospital use (admissions and days during the 4 months after enrollment), sociodemographic characteristics (age, gender, race, education, insurance, homelessness, alcohol use, and AIDS risk factors), disease burden (patient severity and a three-level opportunistic diseases and complications score), HRQL (patient-reported symptoms, activities of daily living, neuropsychological status, and global health assessment), system of care, and use of prophylactic drugs. Logistic regression was used to estimate the odds of admission. Total days of hospital care by patients with at least one admission were analyzed using multiple linear regression. Clinical models of hospital use were developed first from the variables measuring disease burden and system of care. Models estimating the associations between hospital use and all other predictor variables measured at baseline then were estimated using stepwise techniques, controlling for variables in the core model. RESULTS: Patients were more likely than their reference groups to be hospitalized if they had serious opportunistic diseases (adjusted odds ratio [OR] = 2.7), had poorer neuropsychological status (OR = 1.9), were non-white (OR = 2.0), or were homeless (OR = 3.3) (all P < or = 0.05). Activities of daily living were associated moderately (OR = 1.3; P = 0.07). Only system of care and neuropsychological status predicted total hospital days. CONCLUSIONS: The results indicate that future hospital use by persons with AIDS may be influenced by social and other health-related factors in addition to the more clinically related characteristics that are recorded in a medical chart. It therefore may be appropriate to assess these factors when considering options for intervention or when comparing patterns of use among patient groups or settings.

Acquired Immunodeficiency Syndrome↗
PubMed1996

CT and MR imaging in the staging of colorectal carcinoma: report of the Radiology Diagnostic Oncology Group II.

PURPOSE: To prospectively evaluate the relative accuracy of computed tomography (CT) and magnetic resonance (MR) imaging in the staging of colorectal carcinoma. MATERIALS AND METHODS: CT and MR studies were independently interpreted in a group of 478 patients with colorectal carcinoma in a study conducted from 1989 to 1993. The accuracy of each modality was assessed in a subset of 365 patients with primary tumors with respect to staging of local extent of tumor, status of local-regional lymph nodes, and the presence of liver metastases. RESULTS: In the staging of local extent of tumor, CT is more accurate than MR imaging, particularly in the definition of penetration of the muscularis propria by rectal cancer (74% vs 58%). Accuracies of CT and MR imaging were equivalent in depiction of transmural extent in colon cancers. CT and MR imaging exhibited accuracies of 62% and 64% in assessment of lymph node involvement with sensitivities of 48% and 22%, respectively. The accuracy of MR imaging and of CT (85% for each) are better for evaluation of liver metastases; lower sensitivities (62% and 70%, respectively) than specificities (97% and 94%, respectively) were demonstrated for both modalities. CONCLUSION: CT was more accurate than MR imaging in detection and characterization of transmural penetration of rectal tumors. Recent technologic advances in MR imaging may affect these results.

Aged↗
PubMed1995

[Management of myocardial infarction in the Rhone-Alps area. Are there many variations in practice?].

The aim of this study was to determine the diagnostic and therapeutic strategies after myocardial infarction and to examine variations in medical and surgical practice with respect to the severity of disease, status of the hospital and patients' characteristics. The method used was a prospective study with follow-up at 30 days and 18 months. The subjects came from an exhaustive cohort of all patients admitted to hospital for myocardial infarction during the month of April 1991 in 57 public and private hospitals in the Rhone-Alps region (n = 311). The patients were identified after admission by consulting physicians of the Department of Social Security. The study included all patients with acute myocardial infarction with at least two of the three usual diagnostic criteria (prolonged, constrictive chest pain, enzyme increases and electrocardiographic changes). The study excluded patients who were dead before arrival at hospital. The parameters analysed included the clinical management, use of echocardiography, exercise stress testing, myocardial scintigraphy, coronary angiography, thrombolysis, angioplasty and coronary bypass surgery in the first 30 days after admission. The severity of infarction was assessed by seven clinical, enzymatic and electrocardiographic criteria by physicians from the Department of Social Security (pain, syncope, shock, left ventricular dysfunction, elevation of CPK > 1000 IU, anterior or extensive necrosis, arrhythmias). The mortality rate of this cohort was calculated from hospital statistics and then by enquiring in the town halls of the region. The demographic features of the cohort were marked by a predominance of men (69.5%) and a relatively high mean age (69 years; 23% over 80 years). Complementary investigations were used with the following frequencies: echocardiography, 61.1%; coronary angiography, 26.4%; exercise stress testing 22.8%; myocardial scintigraphy, 5.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Costs of medical care and out-of-pocket expenditures for persons with AIDS in the Boston Health Study.

We examined the cost of health care and out-of-pocket medical expenditures for 189 persons with AIDS at three sites in Massachusetts: an HMO; a public hospital immunodeficiency clinic; and a group practice at a major teaching hospital. The mean cost of care during a four-month reference period was $9,093 +/- $12,683 (mean +/- standard deviation) per patient. Thirty-six percent of the cost was due to hospital care and 40% was due to home health care. Mean out-of-pocket expenditures were $429 +/- $991 (mean +/- standard deviation). Studies that focus on the cost of hospital care may seriously underestimate the medical costs of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Guidelines for meta-analyses evaluating diagnostic tests.

OBJECTIVES: To introduce guidelines for the conduct, reporting, and critical appraisal of meta-analyses evaluating diagnostic tests and to apply these guidelines to recently published meta-analyses of diagnostic tests. DATA SOURCES: Based on current concepts of how to assess diagnostic tests and conduct meta-analyses. They are applied to all meta-analyses evaluating diagnostic tests published in English-language journals from January 1990 through December 1991, identified through MEDLINE searching and by experts in the field. STUDY SELECTION: Meta-analyses were included if at least two of three independent readers regarded their main purpose as the evaluation of diagnostic tests against a concurrent reference standard. DATA EXTRACTION: By three independent readers on the extent to which meta-analyses fulfilled each guideline, with consensus defined as agreement by at least two readers. DATA SYNTHESIS: The guidelines are concerned with determining the objective of the meta-analysis, identifying the relevant literature and extracting the data, estimating diagnostic accuracy, and identifying the extent to which variability is explained by study design characteristics and characteristics of the patients and diagnostic test. In general, the guidelines were only partially fulfilled. CONCLUSION: Meta-analysis is potentially important in the assessment of diagnostic tests. Those reading meta-analyses evaluating diagnostic tests should critically appraise them; those doing meta-analyses should apply recently developed methods. The conduct and reporting of primary studies on which meta-analyses are based require improvement.

Bias↗
PubMed1994

Childhood-onset dysthymic disorder. Clinical features and prospective naturalistic outcome.

OBJECTIVES: To characterize the clinical presentation, course, and outcome of childhood-onset dysthymic disorder and assess the predictive validity of this diagnosis. DESIGN: As part of a longitudinal prospective study, school-age, clinically referred youngsters (n = 55) whose first depression was dysthymic disorder and a comparison group of youngsters (n = 60) whose first affective episode was major depressive disorder (MDD) were repeatedly examined during a 3- to 12-year interval. The diagnoses were based on DSM-III criteria. RESULTS: Dysthymic disorder was associated with earlier age at onset than MDD, similarly frequent symptoms of affective dysregulation, but low rates of anhedonia and neurovegetative symptoms and greater overall risk of any subsequent affective disorder. The affective disorders that dysthymic children developed, including first-episode MDD (76%) and bipolar disorder (13%), far outnumbered nonaffective conditions. After the first episode of MDD, the clinical course of the initially dysthymic youths was similar to the course of the comparison patients with regard to rates of recurrent major depression, bipolar disorder, and certain nonaffective disorders. CONCLUSIONS: Childhood-onset dysthymic disorder is an early marker of recurrent affective illness. Although on long-term follow-up, dysthymic disorder and MDD are associated with similar rates of certain outcomes, there exist sufficient differences to warrant diagnosis of each disorder. Dysthymic children who have subsequent mood disorders are most likely first to have an episode of MDD, and that episode appears to be the "gateway" to recurrent affective illness. The interval between the onset of dysthymia and the first major depression provides a window of opportunity for intervention and possible prevention of later episodes.

Adolescent↗