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Biomedical subjects

C Gatsonis

Publications and source records attributed to C Gatsonis.

At least 37 records · Page 2Linked to original sources
PubMed1994

A controlled prospective study of DSM-III adjustment disorder in childhood. Short-term prognosis and long-term predictive validity.

OBJECTIVES: Using DSM-III criteria for adjustment disorder (AD), further operationalized by requiring at least three clinically significant symptoms, we sought to characterize this diagnosis in terms of presenting features, recovery, and predictive validity among juveniles. DESIGN: The samples included clinically referred, 8- to 13-year-old patients with the research diagnosis of AD (N = 30) and a high rate of comorbid disorders and age-and comorbid disorder-matched psychopathologic controls (N = 26). As part of a naturalistic, longitudinal, nosologic study, patients were repeatedly examined during an average follow-up interval of 7 to 8 years. RESULTS: Adjustment disorder was associated with six symptoms, on average, and 60% of the patients had other, specific psychiatric disorders. Adjustment disorder had a median episode length of 7 months and a 97% recovery rate. Comorbidity had no appreciable effect on recovery. Patients with adjustment disorder and controls had similar rates of new psychiatric disorders and other dysfunctional outcomes during the follow-up. CONCLUSIONS: Among psychiatrically referred youths, the diagnosis of AD has clinical information value and identifies a syndromatic presentation that can be the focus of concern or treatment. It has a reasonably good short-term prognosis, in spite of the fact that patients with this diagnosis typically present with comorbid specific psychiatric disorders. Controlling for the effects of comorbidity, AD does not predict later dysfunction. To achieve a convergence of findings from research and clinical practice, it would be important to ensure a uniform application of specific, operational diagnostic criteria for AD.

Adjustment Disorders↗
PubMed1994

MR imaging and sonography of early prostatic cancer: pathologic and imaging features that influence identification and diagnosis.

OBJECTIVE: The purpose of this study was to correlate findings at MR imaging and transrectal sonography with histopathologic findings after surgery in patients with prostatic cancer, to identify the pathologic characteristics of prostatic cancer that improved detection with MR imaging and transrectal sonography, and to identify the imaging characteristics that correlated with detection of true cancers. MATERIALS AND METHODS: Data from MR imaging in 320 patients and from transrectal sonography in 343 patients who were enrolled in the Radiological Diagnostic Oncology Group multiinstitutional study of imaging in prostatic cancer were correlated with results of radical prostatectomy. Only cancers 5 mm or greater in at least one dimension were evaluated pathologically. The locations of lesions and the linear dimensions and volumes of individual lesions and the prostate gland were evaluated pathologically and with imaging studies. The appearance of lesion margins on images and the degree of differentiation of lesions seen on pathologic examination were also studied. Univariate and multivariate analysis were performed to determine the pathologic findings associated with imaging detection and the imaging characteristics associated with prostatic cancer. RESULTS: MR imaging and transrectal sonography showed 62% and 64% of cancers, respectively, each with a positive predictive value of 68%. Cancers that were larger, moderately or poorly differentiated, or located in the posterior half of the outer gland were easier to detect (p < .0001). The overall size of the prostate did not effect lesion detection. However, abnormalities identified in the posterior half of the outer gland were more likely to be cancers. On transrectal sonograms, larger abnormalities also were more likely to be malignant tumors. The sharpness of the margins of the imaged abnormalities did not predict pathologic status. CONCLUSION: Detection of prostatic cancer with MR imaging or transrectal sonography is affected by cancer size, differentiation, and location; the odds of an imaged lesion's being malignant are related to location and, for transrectal sonography, size. Knowledge of anatomic/pathologic features that enhance lesion detection may help when using imaging tests to detect prostatic carcinoma. That certain imaging characteristics of lesions are associated with true cancers may assist in the interpretation of MR images and transrectal sonograms of the prostate.

Algorithms↗
PubMed1993

Discussion of preferences for life-sustaining care by persons with AIDS. Predictors of failure in patient-physician communication.

OBJECTIVES: To assess the determinants of communication about resuscitation between persons with acquired immunodeficiency syndrome (AIDS) and their physician. DESIGN AND SETTING: Structured patient interview at a staff-model health maintenance organization (HMO), an internal medicine group practice at a private teaching hospital, and an AIDS clinic at a public hospital. PATIENTS: 289 persons with AIDS. MAIN RESULTS: Only 38% of patients had discussed their preferences for resuscitation with their physician. Using logistic regression, we found that patients were less likely to have discussed resuscitation with their physician if they were nonwhite (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.24 to 0.99), had never been hospitalized (OR, 0.52; 95% CI, 0.27 to 0.99), or were cared for in the HMO (OR, 0.44 relative to the private teaching hospital; 95% CI, 0.23 to 0.82). Patients were more likely to have discussed their preferences if they were not currently taking zidovudine (OR, 1.76; 95% CI, 1.02 to 3.03) and if they had decided to defer life-sustaining therapy (OR, 2.30; 95% CI, 1.35 to 3.91). Among nonwhites, those with a nonwhite physician were more likely to have discussed resuscitation (OR, 4.38; 95% CI, 1.13 to 16.93). Of patients who had not discussed their preferences for life-sustaining care, 72% wanted to do so. Patient desire for discussion of this issue did not vary by race, severity of illness, hospitalization status, use of zidovudine, or site of care. CONCLUSIONS: A majority of persons with AIDS in this study had not discussed their preferences for life-sustaining care with their physician, despite the desire to do so. Interventions to improve patient-physician communication about resuscitation for nonwhites and other groups at risk of inadequate discussion might lead to clinical decisions that are more consistent with patient preferences.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Zidovudine treatment of the AIDS dementia complex: results of a placebo-controlled trial. AIDS Clinical Trials Group.

The efficacy of two doses of zidovudine was examined for the treatment of the acquired immunodeficiency syndrome (AIDS) dementia complex in a randomized, double-blinded, placebo-controlled trial conducted at nine study centers. For the initial 16 weeks, 40 subjects with mild to moderate AIDS dementia complex were randomized to one of three treatment arms: 400 mg of zidovudine five times daily, 200 mg of zidovudine five times daily, or placebo five times daily. After week 16, patients initially randomized to the placebo group were rerandomized to one of the two zidovudine treatment arms. The primary efficacy end point was improvement in performance on a battery of seven neuropsychological tests; the secondary end point was improvement on a protocol neurological evaluation directed at the cardinal features of the AIDS dementia complex. For the initial 16-week period, average z scores based on the neuropsychological test battery revealed a significant improvement in the combined treatment groups compared to the placebo group; however, when the two treatment groups were compared separately to the placebo group, only the group receiving the higher zidovudine dose exhibited significant improvement. After rerandomization of the placebo patients to one of the two treatment arms at week 16, this group also showed significant improvement in the average neuropsychological z score by week 32. These results extend previous observations that indicate a therapeutic benefit of zidovudine for the treatment of AIDS dementia complex.

AIDS Dementia Complex↗
PubMed1993

Suicidal behaviors and childhood-onset depressive disorders: a longitudinal investigation.

In this longitudinal study, the rates and correlates of suicidal ideation and suicide attempts were determined among outpatient youths with depressive disorders and youths with other psychiatric disorders. At study entry, about 66% of the subjects evidenced suicidal ideation and 9% already attempted suicide. The rate of ideation remained fairly stable over time, whereas the rate of attempts reached 24% by the average age of 17 years. Major depressive and dysthymic disorders were associated with significantly higher rates of suicidal behaviors than were adjustment disorder with depressed mood and nondepressive disorders. In the presence of affective disorders, comorbid conduct and/or substance use disorders further increased the risk of suicide attempts.

Adolescent↗
PubMed1993

Geographic variation of procedure utilization. A hierarchical model approach.

In this study, an abbreviated introduction to hierarchical statistical models for quantifying and explaining variations in the utilization of medical care is presented. The illustrative example was derived from an analysis of interstate variation in coronary angiography utilization for Medicare patients with a recent acute myocardial infarction. The hierarchical model distinguished within-from between-states variation: the former was modeled via a separate logistic regression for each state, with age and sex as the independent variables, while the latter was modeled via a multivariate normal distribution for the coefficients of the state-specific logistic models. Alternative computation approaches were compared and model fit was assessed. Estimates of the distribution of state rates of angiography for an average patient and for age-by-sex strata were obtained. The results showed substantial interstate variation in angiography utilization, but only moderate interstate variation in the effects of age and sex on the decision to perform angiography. This analytic approach allows substantially more detailed results than those by standardization, and accounts for sample size differences between units of aggregation. The next major step in the analysis would be to derive smoothed estimates of the individual state logistic models by pooling data across states. The analysis can also be extended to incorporate other patient characteristics, such as race and comorbidity, and state characteristics, such as geographic location and availability of the procedure.

Aged↗
PubMed1993

Health-related quality of life in persons with acquired immune deficiency syndrome.

Assessing health-related quality of life in persons infected with human immunodeficiency virus (HIV) is extremely important, but most available scales are too long, contain items that are not relevant for such persons, or do not assess important signs and symptoms of HIV infection. This study presents a new set of scales for assessing the symptoms and functioning of persons infected with HIV and reports data on their reliability and validity collected in face-to-face interviews with 189 patients receiving primary care. This study also assesses the associations among systems, functional impairment, and global health assessments. The scales are easy to administer, are reliable, and serve as valid measures of quality of life. Fatigue, functional status, and average severity of all symptoms were the best predictors of overall perceived health status. Psychological well-being and perceived health status were the best predictors of overall perceived health status. Psychological well-being and perceived health status were the strongest correlates of life satisfaction. When assessing the health-related quality of life of persons infected with HIV, this study recommends utilizing a comprehensive set of measures that allows one to examine both discrete symptoms and the more diffuse impact of illness on functioning, mental health, and quality of life.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Acute myocardial infarction in the Medicare population. Process of care and clinical outcomes.

OBJECTIVE: To describe the process of care and clinical outcomes associated with acute myocardial infarction (AMI) in the Medicare population, and to examine differences in process of care and outcome of care as a function of patient age, gender, and race. DESIGN: Retrospective cohort study using a longitudinal database created from Medicare utilization and administrative files. PATIENT POPULATIONS: A cohort of AMI patients covered by Medicare in 1987 and a random sample of Medicare patients without AMI. MAIN PROCESS AND OUTCOME MEASUREMENTS: (1) The use of coronary angiography, coronary artery bypass graft surgery, and percutaneous transluminal coronary angioplasty during the first 90 days after a new AMI; (2) mortality at 30 days, 1 year, and 2 years; (3) reinfarction rates; and (4) reoperation rates for coronary artery bypass graft surgery and percutaneous transluminal coronary angioplasty. MAIN RESULTS: Mortality rates were high: 26% at 30 days, 40% at 1 year, and 47% at 2 years. They varied greatly by age, less so by gender and race, and were high even among patients who survived the first 30 days. Compared with mortality, reinfarction was uncommon, occurring in 7.3% of patients. During the first 90 days, 23% of all patients underwent angiography and 13% underwent coronary revascularization (coronary artery bypass graft surgery, 8%; percutaneous transluminal coronary angioplasty, 5%). The use of all three procedures decreased with age and was less common among women and blacks than among men and whites. Differential use by age and race was greater for angiography than for revascularization procedures. CONCLUSIONS: The prognosis following AMI in patients aged 65 years and above is much worse than is commonly realized. Procedure use in these patients varies as a function of gender and race, even though mortality does not. Further research is needed to reduce the mortality of elderly patients with AMI and to understand the significance of differences in procedure use on the basis of sociodemographic characteristics.

Aged↗
PubMed1992

Rates of avoidable hospitalization by insurance status in Massachusetts and Maryland.

OBJECTIVE: To determine whether uninsured and Medicaid patients have higher rates of avoidable hospitalizations than do insured patients. DESIGN: We used 1987 computerized hospital discharge data to select a cross-sectional sample of hospitalized patients. Population estimates from the Current Population Survey were used to estimate rates of admission, standardized for age and sex. SETTING: Nonfederal acute care hospitals in Massachusetts and Maryland. PATIENTS: All patients under 65 years of age who were uninsured, privately insured, or insured by Medicaid. Hospitalizations for obstetric and psychiatric conditions were excluded. MAIN OUTCOME MEASURES: Relative risk of admission for 12 avoidable hospital conditions (AHCs) identified by a physician panel. RESULTS: Uninsured and Medicaid patients were more likely than insured patients to be hospitalized for AHCs. Rates for uninsured patients were significantly greater than for privately insured patients in Massachusetts for 10 of 12 individual AHCs, and in Maryland for five of 12 AHCs. After adjustment for baseline utilization, the results were statistically significant for 10 of 12 AHCs in Massachusetts and seven of 12 AHCs in Maryland. For Medicaid patients, rates were significantly greater than for privately insured patients for all AHCs in each state before adjustment, and for nine of 12 and seven of 12 AHCs in each state, respectively, after adjustment for baseline utilization. CONCLUSION: Our findings suggest that patients who are uninsured or who have Medicaid coverage have higher rates of hospitalization for conditions that can often be treated out of hospital or avoided altogether. Our approach is potentially useful for routine monitoring of access and quality of care for selected groups of patients.

Adult↗
PubMed1992

Bayesian methods for phase I clinical trials.

Phase I clinical trials are conducted to determine the dose-response curve of a new drug with respect to toxic side effects and, in particular, to estimate the maximum tolerated dose (MTD). In this paper we take a Bayesian approach to the problem of making inferences about the MTD. Working with broad classes of priors, we obtain the posterior distribution of the MTD and study its properties. We also address the question of providing updated assessments of the risk of toxicity for new patients entering the study at a specific dose level. These assessments would be useful in deciding issues of study management and ethics. Our analysis pays particular attention to the sensitivity of the inferences and risk assessments to the choice of prior and the choice of model for the dose-response relationship.

Algorithms↗
PubMed1992

Prognostic significance of tumor proliferative fraction and DNA content in stage I non-small cell lung cancer.

Analyses of tumor DNA content and proliferative fraction by flow cytometry have been useful as prognostic determinants in a variety of solid tumors. The significance of this analysis in Stage I (T1N0M0 and T2N0M0) non-small cell lung carcinoma (NSCC) is unestablished. We determined DNA content (ploidy) and proliferative fraction (percentage S phase) on 44 surgically resected Stage I NSCC specimens obtained between 1977 and 1982. All cases had a minimum follow-up of 5 yr. Of the 44 cases, 27 were adenocarcinomas, 15 squamous cell carcinomas, and 2 large cell carcinomas. Of these, 32 (73%) had T1N0M0 lesions and 12 (27%) had T2N0M0 lesions. Overall 5-yr survival was 70%. All patients surviving 5 yr were free of detectable tumor. Patients with T1N0M0 lesions had an 81% 5-yr survival, but those with T2N0M0 lesions had a 42% 5-yr survival (p = 0.009). Analysis of tumor DNA content revealed 35 diploid tumors (79%) and 9 aneuploid tumors (21%). The 5-yr survival for diploid tumors was 77% compared with a 44% 5-yr survival in aneuploid lesions (p = 0.048). The median proliferative fraction was 6%. All patients with a percentage S phase less than 6% survived 5 yr, and 41% (9 of 22) of those greater than 6% survived 5 yr (p less than 0.001). When 8% S phase was used as a cutoff, 93% (28 of 30) below the cutoff survived 5 yr but only 21% (3 of 14) above the cutoff survived 5 yr (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Current issues in profiling quality of care.

Profiling provider performance for the assessment of quality involves a number of issues related to selection of appropriate quality measures, subsequent data collection and analysis, and selection of standards of comparison. This article emphasizes the limitations of current data systems for this purpose and discusses hierarchical modeling as the optimal analytic approach for analyzing resulting data. Mention is made of the difficulties of achieving large enough sample sizes for statistical significance at the individual provider level. Finally, the article discusses feasible options for profiling quality.

Data Collection↗
PubMed1991

CT and MR imaging in staging non-small cell bronchogenic carcinoma: report of the Radiologic Diagnostic Oncology Group.

The accuracies of magnetic resonance (MR) imaging and computed tomography (CT) in determining tumor classification and assessing mediastinal node metastases were compared in a prospective cooperative study of 170 patients with non-small cell bronchogenic carcinoma. The sensitivity of CT in distinguishing T3-T4 tumors from T0-T2 tumors was 63%; specificity was 84%. These values for MR imaging were not significantly different (56% and 80%). With receiver operating characteristic (ROC) analysis, no difference existed between the accuracies of CT and MR imaging in diagnosis of bronchial involvement or chest wall invasion, but MR imaging was significantly more accurate than CT (P = .047) in diagnosis of mediastinal invasion. Lymph node sampling was performed in 155 patients (642 node stations). Cancerous nodes were found in 14% of stations in 21% of patients. There was no significant difference between the accuracies of CT and MR imaging in detecting mediastinal node metastases (N2 or N3); the sensitivities were 52% and 48%, respectively, and specificities were 69% and 64%. ROC analysis also showed no difference between CT and MR imaging.

Carcinoma, Non-Small-Cell Lung↗
PubMed1990

Collaborative evaluations of diagnostic tests: experience of the Radiology Diagnostic Oncology Group.

Multicenter, collaborative studies offer an effective way to meet the growing need for timely and generalizable clinical evaluations of imaging technologies. This article discusses issues of study design, statistical analysis, organization, and day-to-day group operation for collaborative prospective clinical evaluations. It draws significantly on the authors' experience with the Radiology Diagnostic Oncology Group, a cooperative group funded by the National Cancer Institute, which conducts comparative studies of the ability of diagnostic imaging modalities to enable the staging of various types of cancer including that of the prostate gland, lung, pancreas, colon, and rectum. The results from 2 1/2 years of the experience of this group hold promise for the importance of this approach to the future growth of radiologic research.

Diagnostic Imaging↗
PubMed1989

Depressive disorders in childhood. IV. A longitudinal study of comorbidity with and risk for anxiety disorders.

As part of a longitudinal nosologic study of major depressive disorder (MDD), dysthymic disorder (DD), and adjustment disorder with depressed mood (ADDM) in a school-age cohort, we examined the prevalence and clinical consequences of comorbid anxiety disorders. We also estimated the risk of a first anxiety disorder and examined its predictors. Of 104 cases, 41% had anxiety disorders in conjunction with their index depression, which was more likely with MDD and DD than with ADDM. The age-corrected risk of a first anxiety disorder was 0.47 up to age 18 years. Separation-anxiety disorder was the most frequent diagnosis of anxiety, followed by overanxious disorder of childhood. Among the MDD cases with comorbidity, the anxiety disorder preceded the depression about two thirds of the time and often persisted after the depression remitted. The effect of comorbid anxiety disorder on the length of index MDD depended on the presence of other clinical features, but it did not seem to affect the risk of subsequent MDD or the course of DD or ADDM. Concurrent maternal psychopathology and poor physical health increased the risk of anxiety disorder in the children, but a history of prior separation from parental figures did not seem to have an effect.

Adjustment Disorders↗