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PubMed2004

Predicting methadone maintenance treatment outcomes using the Addiction Severity Index and the MMPI-2 Content Scales (Negative Treatment Indicators and Cynism scales).

We studied the ability of the Minnesota Multiphasic Personality Inventory-2 Content Scales (Negative Treatment Indicators [TRT] and Cynicism [CYN]) and the domain scales of the Addiction Severity Index (ASI) in predicting outcome from a methadone maintenance program. Participants were 108 African American males treated in a VA health care outpatient methadone maintenance treatment program and followed for up to 1 year after admission. Dependent variables were 1) length of stay and the percentage of 2) missed medication days, 3) toxicology urine samples free from illicit drugs, 4) full-time employment, 5) attendance at scheduled counseling sessions, and 6) counselor ratings of patient progress. A stepwise linear regression equation indicated that low drug severity scores on the ASI and low scores on percentage of missed medication predicted patients who were clean 1 year later; low scores on the psychological domain of the ASI predicted attendance at counseling sessions; a discriminant function analysis (consisting of percent of missed medication, percentage of clean urines, and ratings of patient progress) successfully predicted patient status (i.e., dropouts vs. "active patients") with 85% accuracy. Although the TRT and CYN were related to some ASI domains, they were not associated with any outcome variable. Results suggest that some ASI scores serve as important indicators of patient progress in methadone maintenance treatment.

Adult↗
PubMed2004

Estimation of the treatment difference in multicenter trials.

The three fixed effects estimators of a treatment,difference are compared under conditions of random enrollment in a multicenter clinical trial. These comparisons are performed by assuming five different enrollment schemes. The estimators are compared via simulation using their expected mean squared errors. Unlike previous discussions of these three estimators, we take explicit account of the effect of centers that fail to enroll patients to one or both treatment arms. Within each center, we assume enrollment follows a Poisson process and consider the two situations in which the mean rate of this process is the same in every center and in which the mean rates are sampled from a gamma distribution. The effect of patient dropout is studied as well as the effect of increasing the number of centers. Simulations show that for many sound scenarios, the simpler estimator corresponding to the simplest model works better, even for the cases when data are generated by more complex models.

Algorithms↗
PubMed2006

An open-label randomized comparison of olanzapine versus risperidone in the treatment of childhood-onset schizophrenia.

BACKGROUND AND PURPOSE: Childhood-onset schizophrenia (COS) is a clinically severe form of schizophrenia, which causes severe impairment to cognitive, linguistic, and social development. There are few prospective and retrospective open clinical trials of risperidone and olanzapine in COS. In this open-label, randomized, prospective study, we compared the tolerability and effectiveness of risperidone versus olanzapine in the treatment of COS patients. METHODS: The study population consisted of 25 children with COS (mean age 11.09 +/- 1.55 years). After an evaluation, patients received risperidone (0.25-4.5 mg/day, mean dose 1.62 +/- 1.02 mg/day) or olanzapine (2.5-20 mg/day, mean dose 8.18 +/- 4.41 mg/day) for 12 weeks, with weekly evaluations. RESULTS: Both groups showed comparable significant (p < 0.001) within-group improvement from baseline to endpoint (LOCF) in Positive and Negative Symptoms Scale (PANSS) total and subscale scores. Of the olanzapine-treated children, 11 (91.7%) completed the 12 weeks of the study, whereas in the risperidone-treated children only 9 (69.2%) did. No significant differences between risperidone-treated children and olanzapine-treated children were observed on Barnes Akathisia Rating Scale (BAS) and Simpson-Angus Scale (SAS) rating scales. Both treatment groups showed significant (p < 0.001) increase in weight from baseline to endpoint. CONCLUSION: Our open-label, small-scale comparative study suggests that both risperidone and olanzapine appear to be efficacious antipsychotic medications in COS, with a slight nonsignificant advantage of olanzapine in the dropout rate.

Adolescent↗
PubMed2005

Directly parameterized regression conditioning on being alive: analysis of longitudinal data truncated by deaths.

For observational longitudinal studies of geriatric populations, outcomes such as disability or cognitive functioning are often censored by death. Statistical analysis of such data may explicitly condition on either vital status or survival time when summarizing the longitudinal response. For example a pattern-mixture model characterizes the mean response at time t conditional on death at time S = s (for s > t), and thus uses future status as a predictor for the time t response. As an alternative, we define regression conditioning on being alive as a regression model that conditions on survival status, rather than a specific survival time. Such models may be referred to as partly conditional since the mean at time t is specified conditional on being alive (S > t), rather than using finer stratification (S = s for s > t). We show that naive use of standard likelihood-based longitudinal methods and generalized estimating equations with non-independence weights may lead to biased estimation of the partly conditional mean model. We develop a taxonomy for accommodation of both dropout and death, and describe estimation for binary longitudinal data that applies selection weights to estimating equations with independence working correlation. Simulation studies and an analysis of monthly disability status illustrate potential bias in regression methods that do not explicitly condition on survival.

Activities of Daily Living↗
PubMed2006

A marginalized pattern-mixture model for longitudinal binary data when nonresponse depends on unobserved responses.

This paper proposes a method for modeling longitudinal binary data when nonresponse depends on unobserved responses. The proposed method presumes that the target of inference is the marginal distribution of the response at each occasion and its dependence on covariates, and can accommodate both monotone and non-monotone missingness. The approach involves a marginally specified pattern-mixture model that directly parameterizes both the marginal means at each occasion and the dependence of each response on indicators of nonresponse pattern. This formulation readily incorporates a variety of nonresponse processes assumed within a sensitivity analysis. Once identifying restrictions have been made, estimation of model parameters proceeds via solution to a set of modified generalized estimating equations. The proposed method provides an alternative to standard selection and pattern-mixture modeling frameworks, while featuring certain advantages of each. The paper concludes with application of the method to data from a contraceptive clinical trial with substantial dropout.

Amenorrhea↗
PubMed1988

The relationship between prior functioning on cognitive and personality dimensions and subject attrition in longitudinal research.

This study compared the intellectual and personality functioning of continuing participants in a longitudinal study with individuals who were lost from the panel after at least 7 years of involvement. Based on their reason for discontinuation, participants who were lost to the panel were categorized into three attrition groups: deceased, ill, and voluntary dropouts. When the performance of these groups prior to leaving the study was compared with that of the continuing participants, no general differences were found. However, specific differences were revealed, particularly on crystallized-type intellectual abilities and the personality factors. Participants who were lost due to illness or death had functioned at the lowest levels of the four groups prior to attrition. These effects varied by age. In late middle age, ill participants functioned at the lowest levels, whereas in old age, participants who subsequently died scored lowest of the four groups prior to attrition. Individuals who had voluntarily discontinued participation in the study most closely resembled the continuing participants, particularly in late middle age. The results indicate that performance effects associated with continued participation vary by age, the intelligence or personality factor being considered, and the reason for loss of the participant. Furthermore, they suggest that loss of participants from a longitudinal panel does not inevitably bias the validity of developmental findings.

Adult↗
PubMed1994

Therapy termination and persistence patterns of elderly clients in a community mental health center.

Analyses were conducted on 180 community and nursing home clients, ages 60 to 98, who received psychotherapy as part of a community mental health center program. Case records were reviewed to identify factors associated with persistence in therapy and dropout patterns. Very few (less than 12%) terminated therapy appropriately (as judged by the therapist), about 59% completed at least 10 sessions, and a majority of the community residents themselves initiated termination. Persistence in treatment was associated with nursing home residence, religious beliefs, and receiving the therapy at home. Contrary to predictions, persistence was not associated with self-referral, type of psychiatric diagnosis, age, or gender.

Aged↗
PubMed2004

Innovative techniques to address retention in a behavioral weight-loss trial.

Given that retention rates for weight-loss trials have not significantly improved in the past 20 years, identifying effective techniques to enhance retention is critical. This paper describes a conceptual and practical advance that may have improved retention in a behavioral weight-loss trial-the novel application of motivational interviewing techniques to diffuse ambivalence during interactive group-based orientation sessions prior to randomization. These orientation sessions addressed ambivalence about making eating and exercise behavior changes, ambivalence about joining a randomized controlled trial, and unrealistic weight-loss expectations. During these sessions, overweight and obese men and women learned about the health benefits of modest weight loss as well as trial design, the importance of a control condition, random assignment and the impact of dropouts. Participants were then divided into groups of three or four, and asked to generate two pros and two cons of being assigned to a control condition and an active condition. Participants shared their pros and cons with the larger group, while the investigator asked open-ended questions, engaged in reflective listening and avoided taking a 'pro-change' position. Retention was high, with 96% of the participants (N = 162) completing 18-month clinic visits.

Adult↗
PubMed1995

The Multicenter AIDS Cohort Study: retention after 9 1/2 years.

In a longitudinal, multicenter study of 4,954 men at risk for human immunodeficiency virus infection and acquired immunodeficiency syndrome, data from the first 9.5 years of follow-up (April 1984 through September 1993) were used to determine differences between those who remained in the study and those who dropped out. Demographic variables (age, race, education, employment, and study center), health status (human immunodeficiency virus type 1 serostatus and depression), and behavioral characteristics (alcohol drinking, drug use, and anal-receptive intercourse) were analyzed. Strategies for promoting retention included having frequent contact with participants, generating trust, keeping participants well-informed, utilizing multiple resources for follow-up, and providing flexible methods of participation. After 9.5 years of follow-up, vital status was known for 4,385 (88.5%) of the participants. Results from multiple logistic regression showed that race, age, education, and smoking were each significantly associated with nonparticipation (p < 0.001). A high level of retention was maintained in this well-educated and highly motivated cohort of homosexual/bisexual men. Extensive follow-up methods may improve case-finding. Nonwhite race, younger age, less education, and smoking were important predictors of dropping out. These findings identify specific groups for targeting follow-up efforts to reduce potential bias due to dropout.

Acquired Immunodeficiency Syndrome↗
PubMed2004

Efficacy of alendronate, a bisphosphonate, in the treatment of AVN of the hip. A prospective open-label study.

OBJECTIVE: To study the efficacy of alendronate, in the treatment of avascular necrosis (AVN) of the hip. METHODS: Sixty patients with AVN of the hip (100 hips with AVN) were studied. The follow-up period ranged from 3 months to 5 yr. The most common cause of AVN was steroids. Parameters studied were walking time, standing time, pain and disability on a visual analogue scale (VAS), range of motion of the hip, X-ray and MRI of the hip. All patients were treated with alendronate 10 mg/day (or 70 mg/week) along with 500-1000 mg of daily calcium and vitamin D supplements, and were advised to avoid weight-bearing. NSAIDs and analgesics were permitted as needed and were recorded. RESULTS: Forty-one patients (71 AVN hips) with AVN have been followed up for a minimum of 1 yr, 24 patients (42 AVN hips) for 2 yr and 21 patients (37 AVN hips) for more than 2 yr (average 37 month). Fourteen patients have been followed up for less than 1 yr (3-9 months). Significant reduction in pain and disability scores (P < 0.001) and significant increase in standing and walking time (P < 0.001) were observed. All hip movements improved at 1 yr (P value 0.000-0.009) with an insignificant decline after that (P > 0.001). Radiologically, the hips either stabilized in the same grade or progressed by one grade. MRI showed a decrease in marrow oedema in most cases at the 1-yr follow-up. Six patients (10 hips) required surgery and there were two (three hips) dropouts. The drug was well tolerated and there was a reduction in NSAID requirement. CONCLUSION: Alendronate reduces pain, improves function and retards AVN progression. Early surgical intervention can be avoided in most patients.

Adolescent↗
PubMed1997

Youths and communities: toward comprehensive strategies for youth development.

Society's conventional response to problems of young people--such as teenage pregnancy, school dropout, substance abuse, juvenile delinquency, and violence--is to target a specific problem and develop intervention or prevention programs for individuals who manifest the problem or are at high risk of it. Research shows that overlapping risk and protective factors affect the occurrence of all of these problems and that prevention strategies aimed at enhancing youths' development, reducing communities' specific risks, and strengthening protective factors are likely to be more successful than programs addressing the problem behaviors themselves. Among such strategies deserving wider consideration are "comprehensive community initiatives" that create collaborative partnerships among public officials, service providers, primary institutions, and citizens to promote the well-being of children, youths, and families.

Adolescent↗
PubMed1990

Restructuring education and its impact on medical education.

The United States has an education deficit that in the long term may be more harmful to the country than the serious budget and trade deficits. U.S. students are far less prepared in mathematics, chemistry, and physics than are their counterparts in Western Europe and Japan. The dropout rate among high school students, and the high and increasing rate of functional illiteracy, blight lives and represent an enormous economic loss to the nation. American education must be restructured at all levels so that local and federal funds can be used flexibly to pursue revised educational goals. Students and their families should be allowed to choose their elementary and secondary schools, and school management should be decentralized and more rooted in the community. The medical profession must become involved in elementary and secondary education, and medical faculty must be involved in their communities. Further, medical faculty must encourage minority students at all educational levels, must recruit minority medical students, and must increase the number of minority faculty members.

Education↗
PubMed2001

The challenges of conducting clinical research: one research team's experiences.

Conducting clinical research is an exciting and a rewarding endeavor. Each project is unique and, because of this uniqueness, research studies require considerable planning. Regardless of all the upfront planning, challenges will occur throughout the life of the study. Clinical research projects are rife with obstacles that range from the lack of administrative and physician support to subject attrition. Some of the challenges, such as subject dropout, are not unexpected, whereas other unanticipated issues can blindside a research team. This case study examines several such challenges experienced in one longitudinal study and presents the solutions engineered by the research team to keep the project on track.

Cardiac Output, Low↗
PubMed1999

Gay, lesbian, and bisexual youth risks for emotional, physical, and social problems: results from a community-based survey.

OBJECTIVE: Health problems of gay, lesbian, and bisexual (GLB) youth are reported as differing from those of heterosexual youth. Increased depression, suicide, substance use, homelessness, and school dropout have been reported. Most studies of GLB youth use clinical or convenience samples. The authors conducted a community school-based health survey that included an opportunity to self-identify as GLB. METHOD: An anonymous self-report health care questionnaire was used during a community-based survey in 2 high schools in an upper middle class district. RESULTS: Significantly increased health risks for self-identified GLB youth were found in mental health, sexual risk-taking, and general health risks compared with self-identified heterosexuals, but not in health domains associated with substance abuse, homelessness, or truancy. CONCLUSIONS: Self-identified GLB youth in community settings are at greater risk for mental health, sexual risk-taking, and poorer general health maintenance than their heterosexual peers.

Adolescent↗
PubMed1996

Fluvoxamine in prevention of relapse in bulimia nervosa: effects on eating-specific psychopathology.

In a double-blind, placebo-controlled study of 72 patients with bulimia nervosa treated successfully with inpatient psychotherapy, the efficacy of fluvoxamine in maintaining improvement was tested. Fluvoxamine and placebo, respectively, were given over a period of about 15 weeks (2-3 weeks inpatient titration phase, 12 weeks outpatient relapse-prevention [maintenance] phase). The variables assessed concerned bulimic behavior and other aspects of eating disorders, global status, depression, anxieties, obsessive-compulsive behavior, and other aspects of psychopathology. Because the dropout rate was relatively high (N = 27 [33%]) and because it was considerably higher in the fluvoxamine group (19 out of 37 subjects), analyses were performed on the intent-to-treat sample (ideally including all 72 subjects). Results of the completer sample analyses (including only those subjects who finished the study) are briefly presented for comparison. In both the intent-to-treat and the completer analyses, the following scales showed fluvoxamine to have a significant effect in reducing the return of bulimic behavior: (1) self-ratings: Eating Disorder Inventory (EDI)-bulimia, urges to binge in previous week and the number of actual binges in the previous week; (2) expert ratings: Psychiatric Status Rating Scales for Bulimia nervosa, Structured Interview for Anorexia and Bulimia nervosa (SIAB)-"total score," SIAB-subscale "fasting," and SIAB-subscale "vomiting." Two further variables (EDI-total score and SIAB-subscale "bulimia") showed the superior relapse prevention effects of fluvoxamine compared with placebo for the completer sample, while they did not reach significance for group-by-time interactions in the intent-to-treat sample. During a final, short (4-week) off-medication phase, no effect of the discontinuation of medication was observed.

Adolescent↗
PubMed2000

Effects of risperidone on affective symptoms in patients with schizophrenia.

The effects of risperidone on affective symptoms were determined by an analysis of pooled data from six double-blind trials of risperidone versus haloperidol in 1254 patients with chronic schizophrenia. Symptoms indicating mania were assessed by the Positive and Negative Syndrome Scale (PANSS) excitement and grandiosity items and by the excited cluster (excitement, hostility, uncooperativeness, and poor impulse control); anxious / depressive symptoms were assessed by the PANSS anxious / depressive cluster (somatic concern, anxiety, guilt feelings, and depression). Mean change scores from baseline to endpoint were compared in patients receiving risperidone, haloperidol or placebo by analysis of variance with factors for trial and baseline score included in the model. In all patients, change scores on excitement and grandiosity items and excited and anxious / depressive clusters were significantly greater for risperidone than for haloperidol or placebo. Dropouts due to inefficacy were less frequent with risperidone (5 of 59; 8%) than with haloperidol (7 of 38; 18%) or placebo (8 of 10; 80%). In patients with anxious / depressive symptoms at baseline (anxiety / depression cluster score > or = the median), anxiety / depression scores decreased significantly more with risperidone than with haloperidol, and symptom reduction occurred faster with risperidone. These results are consistent with previous reports and suggest that risperidone is more efficacious than haloperidol for affective symptoms in patients with schizophrenia.

Adolescent↗
PubMed2002

Somatization as a predictor of medication discontinuation due to adverse events.

Medication discontinuation due to intolerable side-effects remains a significant clinical problem in the treatment of depression. We were unable to locate studies which found predictors of medication cessation due to side-effects. We posited that an identifiable subgroup of medically healthy, depressed adults who discontinued medication because of adverse events would have higher pre-treatment somatic symptoms than patients who completed a course of treatment. The sample (n =940) was drawn from a series of double-blind, placebo-controlled studies of antidepressants (imipramine, phenelelzine, L-deprenyl, mianserin and desipramine). Within the medication group, side-effect dropouts had more somatic symptoms than study completers and those who discontinued treatment for miscellaneous reasons. Within the placebo-treated group, the small number of subject who discontinued treated because of side-effects precluded valid statistical analyses, but the findings were in the same direction as those in the medication group. Clearly, further research is required to determine whether these results, obtained from a series of university-based clinical trials with healthy subjects, are generalizable to patients with significant comorbid medical and/or psychiatric disorders, treated with newer antidepressants agents in a general clinical practice setting.

Adult↗
PubMed2003

Moxonidine treatment of hypertensive patients with advanced renal failure.

OBJECTIVES: To compare safety and tolerability of moxonidine versus nitrendipine in hypertensive patients with renal failure. A secondary endpoint was to test whether the sympatholytic drug moxonidine slows decline of renal function when added to standard therapy with an angiotensin-converting enzyme inhibitor or AT(1) receptor antagonist plus loop diuretic. DESIGN: This prospective, randomized, double-blind, multicenter study recruited 177 patients with advanced renal failure receiving antihypertensive standard therapy at outpatient clinics in Germany and Hungary. Following a 2 week run-in, patients were randomized to 24 weeks of add-on treatment with 0.3 mg/day moxonidine or 20 mg/day nitrendipine. RESULTS: The incidence of pre-defined specific adverse events was 42% in the moxonidine (37/89 patients) and 46% in the nitrendipine group (38/82 patients) in intention-to-treat analysis. Intensity and multiplicity were comparable. The dropout rate due to adverse events was 12.4% in the moxonidine and 9.8% in the nitrendipine group. Creatinine clearance according to Cockcroft and Gault decreased by 0.5 +/- 4.3 ml/min (mean +/- standard deviation) in the moxonidine group and 2.3 +/- 4.0 ml/min in the nitrendipine group. Serum creatinine increased by 12.7 +/- 49.2 micromol/l in the moxonidine group and by 43.4 +/- 71.3 micromol/l in the nitrendipine group. These differences were statistically significant (P < 0.05). CONCLUSION: Add-on treatment with 0.3 mg/day moxonidine in hypertensive patients with renal failure is well tolerated and not inferior to 20 mg/day nitrendipine with respect to the incidence of specific adverse events. The idea of a sympatholytic drug to be renoprotective is appealing but needs further evaluation.

Adult↗