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Biomedical subjects

S Klawansky

Publications and source records attributed to S Klawansky.

13 recordsLinked to original sources
PubMed1997

Methadone vs. L-alpha-acetylmethadol (LAAM) in the treatment of opiate addiction. A meta-analysis of the randomized, controlled trials.

The authors conducted a meta-analysis of the reported randomized, controlled trials comparing methadone to L-alpha-acetylmethadol (LAAM) to assess the efficacy of LAAM relative to methadone in the treatment of opiate addiction. All studies were conducted in standard outpatient opiate addiction treatment clinics. Most patients were men from lower socioeconomic strata. A statistically significant risk difference favoring methadone was detected for retention-in-treatment and discontinuation of treatment because of side effects. The risk difference for illicit drug use favored LAAM, but was not significant. A small treatment difference in favor of methadone was noted. LAAM does appear to be a relatively effective alternative in the treatment of opiate addiction, more so in certain select situations.

Adult↗
PubMed1996

A joint hazard and time scaling model to compare survival curves.

To provide a more general method for comparing survival experience, we propose a model that independently scales both hazard and time dimensions. To test the curve shape similarity of two time-dependent hazards, h1(t) and h2(t), we apply the proposed hazard relationship, h12(tKt)/ h1(t) = Kh, to h1. This relationship doubly scales h1 by the constant hazard and time scale factors, Kh and Kt, producing a transformed hazard, h12, with the same underlying curve shape as h1. We optimize the match of h12 to h2 by adjusting Kh and Kt. The corresponding survival relationship S12(tKt) = [S1(t)]KtKh transforms S1 into a new curve S12 of the same underlying shape that can be matched to the original S2. We apply this model to the curves for regional and local breast cancer contained in the National Cancer Institute's End Results Registry (1950-1973). Scaling the original regional curves, h1 and S1 with Kt = 1.769 and Kh = 0.263 produces transformed curves h12 and S12 that display congruence with the respective local curves, h2 and S2. This similarity of curve shapes suggests the application of the more complete curve shapes for regional disease as templates to predict the long-term survival pattern for local disease. By extension, this similarity raises the possibility of scaling early data for clinical trial curves according to templates of registry or previous trial curves, projecting long-term outcomes and reducing costs. The proposed model includes as special cases the widely used proportional hazards (Kt = 1) and accelerated life (KtKh = 1) models.

Breast Neoplasms↗
PubMed1996

Functional electrostimulation in poststroke rehabilitation: a meta-analysis of the randomized controlled trials.

OBJECTIVE: To assess the efficacy of functional electrical stimulation (FES) in the rehabilitation of hemiparesis in stroke. DESIGN: A meta-analysis combined the reported randomized controlled trials of FES in stroke, using the effect size method of Glass, and the DerSimonian-Laird Random Effects Method for pooling studies. SETTING: The included studies were published between 1978 and 1992. They were conducted in academic rehabilitation medicine settings. PATIENTS: In all included studies, patients were in poststroke rehabilitation. The mean time after stroke varied from 1.5 to 29.2 months. INTERVENTION: FES applied to a muscle or associated nerve in a hemiparetic extremity was compared to No FES. MAIN OUTCOME MEASURE: Change in paretic muscle force of contraction following FES was compared to change without FES. RESULTS: For the four included studies, the mean effect size was .63 (95% CI: .29, .98). This result was statistically significant (p < .05). CONCLUSION: Pooling from randomized trials supports FES as promoting recovery of muscle strength after stroke. This effect is statistically significant. There is a reasonable likelihood of clinical significance as well.

Aged↗
PubMed1995

Biofeedback therapy in poststroke rehabilitation: a meta-analysis of the randomized controlled trials.

OBJECTIVE: To assess the efficacy of biofeedback therapy in poststroke rehabilitation. DESIGN: A meta-analysis of the reported randomized control trials of biofeedback therapy in poststroke rehabilitation was performed. Data were analyzed using the effect size method and pooled using the Der Simonian-Laird Random Effects Model. Study quality was assessed according to the method of Chalmers. SETTING: All included studies were conducted in academically based rehabilitation settings. PATIENTS: Patients were in the rehabilitative phase of their illness. The timing of the intervention from the acute event did vary greatly between and within studies. INTERVENTION: Biofeedback therapy was applied to a paretic limb of patients in the study group. Both treatment and control groups received standard physical therapy. MAIN OUTCOME MEASURE: Change in range of motion of a joint of a paretic limb as a result of treatment was examined. This measure was chosen after the eligible studies were evaluated for combinable end points. RESULTS: A total of eight studies were included in the analysis. The mean effect size for change in lower extremity range of motion as a result of biofeedback therapy was 1.50 (95% confidence interval [CI]: -0.59, 3.59). For the upper extremity the effect size was 2.30 (95% CI: -1.06, 5.66). Both results were not significant at the p < .05 level. Statistical tests showed significant heterogeneity among studies, validating the use of the Random Effects Model. CONCLUSION: Results of pooling available randomized control trials do not support the efficacy of biofeedback in restoring the range of motion of hemiparetic joints. Nevertheless, because the calculated mean effect sizes were large, with associated wide confidence intervals, the possibility of a type II error masking an important clinical benefit needs to be considered in evaluating this result.

Arm↗
PubMed1995

Meta-analysis of randomized controlled trials of cranial electrostimulation. Efficacy in treating selected psychological and physiological conditions.

To clarify the diverse published results of cranial electrostimulation (CES) efficacy, we conducted an extensive literature review that identified 18 of the most carefully conducted randomized controlled trials of CES versus sham treatment. For the 14 trials that had sufficient data, we used the techniques of meta-analysis to pool the published results of treating each of four conditions: anxiety (eight trials), brain dysfunction (two trials), headache (two trials), and insomnia (two trials). Because studies utilized different outcome measures, we used an effect size method to normalize measures which we then pooled across studies within each condition. The meta-analysis of anxiety showed CES to be significantly more effective than sham treatment (p < .05). Pooling did not affect results that were individually positive (headache and pain under anesthesia) or negative (brain dysfunction and insomnia). Most studies failed to report all data necessary for meta-analysis. Moreover, in all but two trials, the therapist was not blinded and knew which patients were receiving CES or sham treatment. We strongly recommend that future trials of CES report complete data and incorporate therapist blinding to avoid possible bias.

Anxiety Disorders↗
PubMed1993

Survival from localized breast cancer. Variability across trials and registries.

Age-specific (< 50, 50-69 years) 10-year survival proportions in four European trials for node-negative, Stage I and II breast cancer patients differ significantly. These patients, identified as having the same stage as localized-breast cancer patients in the End Results Registry of the U.S. National Cancer Institute, had pooled survival proportions for the two age groups (0.713, 0.579) close to those of the registry (0.713, 0.607).

Adult↗
PubMed1991

Use of the SEER Cancer Registry for technology assessment.

The Surveillance, Epidemiology, and End Results (SEER) cancer registry contributed to technology assessment by providing population-based samples for detailed case-control studies, by serving as the control group in comparisons with various experimental groups, by allowing an assessment of selection bias in clinical trials, and by facilitating evaluations of classification and coding systems.

Databases, Factual↗
PubMed1991

Technology assessment in the Normative Aging Study.

This review of publications based on data from the Veterans Affairs Normative Aging Study identified four articles that were considered assessments of health care technologies. Three evaluated methods for research on body composition, the fourth studied ventricular size in patient with presenile dementia. Several additional articles are discussed that provided data on baseline values or risk factors for disease that might be useful in generating hypotheses to be tested in later assessments of technologies.

Aging↗
PubMed1984

A growth rate distribution model for the age dependence of human cancer incidence: a proposed role for promotion in cancer of the lung and breast.

A biological model is proposed to account for the steep rise of human cancer incidence with age. The model casts in mathematical terms the assumptions that each clone destined to give rise to a detectable tumor displays a characteristic net growth rate and that the assembly of such clones displays a distribution of growth rates. Incidence is introduced as the rate of appearance of clones whose size permits detection. While the cancer formation process may involve a series of stages, we assume that the overall kinetics of tumor detection reflect one stage of development whose duration spans the major portion of the latent period between initial cell alteration and final detection. We further assume that the net growth rates of tumor-forming clones increase in the presence of promotors and resume their original growth rates when the promoting substance is removed. Assuming that cigarette smoke has promoting activity, we show how the model could account for the abrupt impact of cessation of smoking on subsequent lung cancer incidence. If we assume that clones destined to be detected as breast cancers experience promotional activity during the period of a woman's fertility, the model predicts that as a consequence of the slowing down of the clones a discontinuous decline in incidence would follow menopause. Since women experience menopause over a range of ages, we show how aggregating the contributions from these menopausal ages results in an overall age dependence of incidence with no discontinuities and with the observed change in the incidence rate for breast cancer near the age range of menopause.

Age Factors↗