Biomedical subjects

C Gatsonis

Publications and source records attributed to C Gatsonis.

44 records · Page 3Linked to original sources

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↗

PubMed1989

Multiple correlation: exact power and sample size calculations.

This article discusses power and sample size calculations for observational studies in which the values of the independent variables cannot be fixed in advance but are themselves outcomes of the study. It reviews the mathematical framework applicable when a multivariate normal distribution can be assumed and describes a method for calculating exact power and sample sizes using a series expansion for the distribution of the multiple correlation coefficient. A table of exact sample sizes for level .05 tests is provided. Approximations to the exact power are discussed, most notably those of Cohen (1977). A rigorous justification of Cohen's approximations is given. Comparisons with exact answers show that the approximations are quite accurate in many situations of practical interest. More extensive tables and a computer program for exact calculations can be obtained from the authors.

Computer Simulation↗

PubMedDate not supplied

Secular trends in age at onset of major depressive disorder in a clinical sample of children.

Using a psychiatrically referred, depressed, school-age sample, we sought to cross-validate the clinically pertinent epidemiologic finding that the distribution of age at onset of first episode of major depressive disorder (MDD) is subject to birth-cohort and period effects. Demographic and historical variables also were considered in attempting to explain the variability in age-at-onset. The results indicated a birth-cohort effect, but no discernable period effect on age at onset of MDD; successive birth cohorts were younger when they first developed MDD even after stringent analyses were conducted that corrected for structural sampling biases in the sample. In view of the relatively small size and clinical nature of the sample and the restricted birth-year span that characterizes children, the results are presented to stimulate further discussion of this topical area.

Adolescent↗

PubMedDate not supplied

Depressive disorders in childhood. III. A longitudinal study of comorbidity with and risk for conduct disorders.

As part of a longitudinal nosologic study of major depressive disorder (MDD), dysthymic disorder, and adjustment disorder with depressed mood in 104 school-aged probands, the prevalence and consequences of comorbid conduct disorders (CD) were examined. During the index depressive episodes, 16% of the patients had comorbid CD; during the full study observation 23% had CD; and the estimated time-dependent risk of conduct disorder developing was 36% by age 19. For most cases, comorbid CD developed as a complication of the depression and persisted after the depression remitted. Comorbid CD was not differentially associated with the type of depression at study entry, did not affect depressive symptom presentation, was similarly distributed among boys and girls, and was unrelated to demographic factors. Additionally, comorbid CD did not affect recovery from the index depressive episodes and did not influence the symptom-free interval before a recurrent depression among cases with MDD. The risk of CD developing was not altered by chronologically earlier family variables or demographic factors. But girls who had attention deficit disorder, compared to those who did not, seemed to be at higher risk for CD during study observation. Finally, in this depressed cohort, having CD any time was associated with an increased rate of long-term functional problems.

Adjustment Disorders↗

PubMedDate not supplied

Interobserver variability in CT and MR staging of lung cancer.

OBJECTIVE: Our goal was to assess the interobserver variability in staging non-small cell lung cancer using CT and MRI. MATERIALS AND METHODS: As part of the Radiologic Diagnostic Oncology Group (RDOG) study of lung cancer staging, the CT and MR examinations of 40 patients suspected of having non-small cell bronchogenic carcinoma were blindly interpreted by four expert observers. The primary tumor and lymph node stages in the 40 study subjects were similar to the final proportions reported in the RDOG study. Assessed abnormalities included the presence of a lung nodule, chest wall invasion, mediastinal invasion, bronchial involvement, lymph node metastasis in specific node stations, and T and N classifications. Percent agreement and kappa-values were calculated for each of these determinations. RESULTS: Depending on the finding assessed and the method of analysis, average agreement rates ranged from 58 to 90% for CT and from 61 to 96% for MRI. Average kappa-values were largely between 0.40 and 0.60 when dichotomous analysis was used; weighted kappa-values were similar. With a single exception, no significant differences were found for kappa-values calculated for CT and MRI. CONCLUSION: Although interobserver agreement rates are good for determining T and N classification in patients with lung cancer, variability in image interpretation is frequent, even among experienced observers.

Carcinoma, Bronchogenic↗

PubMedDate not supplied

Relaxation therapy for hypertension: setting-specific effects.

We determined the effect of relaxation therapy for hypertension in patients whose blood pressure remained elevated despite the use of antihypertensive medication. The effect was assessed in multiple settings, including the relaxation therapist's office, the Hypertension Clinic, and the patient's natural environment, the latter using 24-hour automated ambulatory blood pressure measures. Nineteen patients were randomized either to temperature biofeedback-assisted relaxation or to an attention control, "stress education." Antihypertensive medication was kept constant. In the behavioral therapist's office, blood pressure decreased in equivalent amounts with both treatments. Hypertension Clinic nurse blood pressure remained stable or increased with both treatments, but again there was no difference between treatments. Ambulatory blood pressure increased with relaxation therapy and decreased with stress education, the effect being significant for diastolic pressure. The effects on ambulatory blood pressure were limited to the waking hours. The only variable that showed superior effects for relaxation therapy was physician-determined blood pressure. These results call into question the generalizability of the effects of relaxation therapy from one setting to another.

Adult↗

PubMedDate not supplied

Ambulatory blood pressure responses and the circumplex model of mood: a 4-day study.

BACKGROUND: The relation between mood or emotions and concurrent ambulatory blood pressure responses holds both fundamental and clinical interest. METHODS: The primary sample consisted of 69 normotensive or borderline hypertensive but otherwise healthy adult males. The validation sample consisted of 85 healthy male undergraduate college students. Both samples underwent half-hourly 24-hour ambulatory blood pressure measurements on four separate workdays, 1 week apart. At each ambulatory measurement, subjects recorded their behavior, environment, and mood. The circular mood scale, a circular visual analogue scale based on the circumplex model of mood, was used to reflect the totality of a participant's affective state space. Longitudinal random effects regression models were applied in the data analysis. RESULTS: The results for both samples were quite similar. Sleep and posture had the greatest influence on ambulatory blood pressure and heart rate. The effects of the environmental setting, social setting, and consumption were modest but statistically significant. Independent of these covariates, mood exerted a significant effect on blood pressure and heart rate. Relative to the "mellow" default category, blood pressure increased both for "anxious/annoyed" and "elated/happy" and decreased during "disengaged/sleepy" mood. The range of mood-related blood pressure estimates was 6.0/3.7 mm Hg. CONCLUSIONS: The pattern of blood pressure responses suggests that they were related to the degree of engagement of a mood rather than the degree of unpleasantness. The hypothesis that posits that negative affect-related cardiovascular reactivity mediates the observed correlation between negative affect and disease risk should be reconsidered.

Adolescent↗

PubMedDate not supplied

The stability of preferences for life-sustaining care among persons with AIDS in the Boston Health Study.

BACKGROUND: Clinicians recognize the importance of eliciting patient preferences for life-sustaining care, yet little is known about the stability of those preferences for patients with serious disease. OBJECTIVES: To examine the stability of preferences for life-sustaining care among persons with AIDS and to assess factors associated with changes in preferences. DESIGN: Two patient surveys and medical record reviews, administered four months apart in 1990-1991. SETTING: Three health care settings in Boston. PATIENTS: 252 of 505 eligible persons with AIDS who participated in both baseline and follow-up surveys. MAIN OUTCOME MEASURES: A single question assessing desire for cardiac resuscitation and a scale of preferences for life-extending treatment conditional on hypothetical health states. RESULTS: Approximately one-fourth of the respondents changed their minds about life-sustaining care during a four-month period. Of patients who initially desired cardiac resuscitation, 23% decided to forego it four months later, and of those who initially said they would decline care, 34% later said they would accept it. Of those who initially desired any of the life-extending treatments, 25% decided to forego them four months later, and of those who initially said they would decline life-extending care, 24% later said they would accept some treatment. Patients reporting changes in physical function, pain, or suicide ideation were more likely to modify their desires to be resuscitated (all p< or =0.05). Patients lacking an advance directive, not completing high school, or becoming more severely ill were more likely to change their preferences on the Life Extension scale (p< or =0.05). Patients who discussed their preferences with at least one physician were just as likely as others to change desires for cardiac resuscitation. Age, gender, race, emotional health, clinical severity, social support, and site of care were not significant correlates of change for either measure. CONCLUSIONS: Health care providers should periodically reassess preferences for life-sustaining care, particularly for patients with progressive disease, given the instability in patient preferences. However, predictors of instability may vary with how preferences are measured. In particular, changes in health status may be related to instability of preferences for certain types of treatments.

Acquired Immunodeficiency Syndrome↗