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PubMed1997

Current status of the multicenter randomized clinical trial on fetal oxygen saturation monitoring in the United States.

Current clinical methods of intrapartum fetal assessment are sensitive but poorly specific in detecting fetal compromise during labor. These limitations have substantially contributed to the escalating cesarean section rate which occurred in the US during the last several decades. Experimental and clinical research efforts directed towards application of the oxygen saturation monitor (pulse oximeter) to intrapartum fetal assessment have produced encouraging results. If this new method of fetal assessment is to enter the clinical arena, safety and efficacy issues must first be properly evaluated via randomized clinical trials. The purpose of this report is to describe the design of a multicenter randomized clinical trial of intrapartum fetal oxygen saturation monitoring recently begun in the US. Specific aspects of the trial, including purpose, study design, sample size estimates, control and test groups, inclusion and exclusion criteria, fetal heart rate classification, definition of normal fetal arterial oxygen saturation (SpO2), clinical management protocol, and assessment of maternal-fetal outcomes will be addressed.

Female↗

PubMed2004

Australasian experience and trials in sentinel lymph node biopsy: the RACS SNAC trial.

PURPOSE: Sentinel lymph node biopsy (SLNB) has been rapidly adopted by surgical oncologists in the management of invasive breast cancer. This study reviews the Royal Australasian College of Surgeons (RACS) Sentinel Node versus Axillary Clearance (SNAC) trial and reports an interim analysis of the first 150 subjects. Other currently open multi-institutional randomized trials in SLNB are reviewed. METHODS: The SNAC trial is a multicentre, centrally randomized, phase III clinical trial. Subjects are randomized to SLNB alone (with completion axillary clearance, AC, for sentinel node-positive patients) or AC plus SLNB, with stratification according to age (< 50 years, more than or equal to 50 years), primary tumour palpability (palpable vs impalpable), lymphatic mapping technique (blue dye plus scintigraphy vs blue dye alone) and centre. RESULTS: The trial was launched in May 2001 in two centres. Randomization continues currently at the rate of approximately 30 subjects per month (total, 1,012 at the time of writing) from 32 participating centres in Australia and New Zealand. Data from the first 150 subjects have been analysed to assess: compliance with randomized treatment allocation; measures of test performance for SLNB (detection, removal, sensitivity, specificity and false-negative rates); measures of arm volume, function, symptoms and quality of life; and sample size estimates. CONCLUSIONS: The SNAC trial is one of the fastest accruing clinical trials in Australasia. It is on track to determine whether differences in morbidity, with equivalent cancer-related outcomes, exist between SLNB and AC for women with early breast cancer.

Australia↗

PubMed2002

Health status of ICU survivors: a pilot study.

This paper reports on a pilot study that focused on the feasibility of conducting longitudinal research on the health status of intensive care unit (ICU) survivors. Twenty patients completed a short ICU specific health status survey while in ICU and then were invited to complete the same survey--with the addition of the Medical Outcome Study Short Form-36 (SF-36) health status survey--at 6 and 12 months after their hospital discharge. While the patients were in the ICU, 20 family members completed the same survey on the patients' behalf as proxy respondents. Most patients were willing to be in the study for its duration. There was a wide variation in patients' responses to the ICU specific instrument at all data collection points. Patient and proxy responses were very similar for almost all of the physical items but there was a lack of agreement for the more subjective psychosocial items. The SF-36 was found to be more reliable and easier to score and analyse in this small study than the ICU specific health status instrument. The three SF-36 scales ranked lowest at 6 months were physical functioning, role-physical and role-emotional, while at 12 months the three lowest were role-physical, role-emotional and vitality. Total attrition at 12 months was 40 per cent. Using the results of the SF-36, sample size estimates were conducted in preparation for a larger study. It was concluded that it is feasible to conduct longitudinal research on ICU survivors but proxy responses should not be used indiscriminately.

Adult↗

PubMed1995

The randomized clinical trial as a powerful means for understanding treatment efficacy.

The comparison of technologies, ie, alternative ways to accomplish the same aim, is inherently difficult. In orthodontics, technology covers a wide spectrum of areas: variations in treatment approach, appliances, wires, diagnostic procedures, and patient management techniques. Clinical trial methodology has been developed to minimize the effect of bias and to provide more objective answers to questions of comparative efficacy and benefits of particular treatments or procedures. The randomized controlled clinical trial (RCT) is now generally considered the strongest research design for the comparison of treatments. This report reviews four issues that should be addressed in planning an RCT: defining the study cohort, selecting the treatment allocation technique, estimating sample size, and performing the trial.

Data Interpretation, Statistical↗

PubMed2000

Prerequisites for human papillomavirus vaccine trial: results of feasibility studies.

BACKGROUND AND AIMS: Oncogenic human papillomaviruses (HPVs) are the major cause of cervical cancer and associated cancers. First generation preventive vaccines against HPVs are entering clinical trials. Therefore, it is time to consider prerequisites of field trials in Finland. RESULTS: Incidence of cervical cancer is increasing in young women which is not unexpected since risk taking behavior among young women has also increased. In the developed countries up to 44% of cervical cancer cases are attributable to HPV16 infection alone. However, high risk HPV types other than HPV16 and HPV18 are emerging in the population based on HPV DNA pilot screening studies. Annual attack rates among young women less than 25 years of age is 2.3% for HPV16 infection, and 0.03% for CIN3 invasive cervic cancer. Thus, sample size estimates for HPV vaccine efficacy trial are approximately 1000 when the endpoint is HPV16 infection, and approximately 15000 when the endpoint is >/=CIN3 or worse assuming that the vaccine efficacy is 70%. Both HPV vaccine trial acceptability and compliance rates at routine visits of the general Finnish female population are going to be high based on a pilot study. CONCLUSION: Prerequisites for large scale field trials on HPV vaccination are fulfilled in Finland.

Adult↗

PubMed2004

Escherichia coli sampling reliability at a frequently closed Chicago Beach: monitoring and management implications.

Monitoring beaches for recreational water quality is becoming more common, but few sampling designs or policy approaches have evaluated the efficacy of monitoring programs. The authors intensively sampled water for E. coli (N=1770) at 63rd Street Beach, Chicago for 6 months in 2000 in order to (1) characterize spatial-temporal trends, (2) determine between and within transect variation, and (3) estimate sample size requirements and determine sampling reliability. E. coli counts were highly variable within and between sampling sites but spatially and diurnally autocorrelated. Variation in counts decreased with water depth and time of day. Required number of samples was high for 70% precision around the critical closure level (i.e., 6 within or 24 between transect replicates). Since spatial replication may be cost prohibitive, composite sampling is an alternative once sources of error have been well defined. The results suggest that beach monitoring programs may be requiring too few samples to fulfill management objectives desired. As the recreational water quality national database is developed, it is important that sampling strategies are empirically derived from a thorough understanding of the sources of variation and the reliability of collected data. Greater monitoring efficacy will yield better policy decisions, risk assessments, programmatic goals, and future usefulness of the information.

Chicago↗

PubMed2002

How to study postoperative nausea and vomiting.

Anesthesiological journals are flooded by innumerable studies of postoperative nausea and vomiting (PONV). Nevertheless, PONV remains a continuing problem with an average incidence of 20-30%. This paper should provide essential information for the design, conduct, and presentation of these studies. It should also increase comparability among future studies and help clinicians in assessing and reading the literature on PONV. First, future studies should address new and relevant questions instead of repeatedly investigating prophylactically given antiemetics whose main results are predictable (e.g. already proven by meta-analysis). Second, group comparability should be based on well-proven risk factors and a simplified risk score for predicting PONV. Endless listings of doubtful risk factors should be avoided. Third, a realistic sample size estimation should be performed, i.e. in most cases at least 100 patients per group are necessary. Fourth, nausea, vomiting and rescue medication should be recorded and reported separately with the corresponding incidences (and number of patients with these separate symptoms), and the main end-point should be PONV. The entire observation period should cover 24 h. Additional reporting of the early (0-2 h) and delayed (2-24 h) postoperative period is desirable and should consider single and cumulative incidences. Lastly, interpretation of results should take into account the study hypothesis, sources of potential bias or imprecision, and the difficulties associated with multiplicity of analysis and outcomes.

Clinical Trials as Topic↗

PubMed2005

Methods and the baseline situation in the field trial of home-based neonatal care in Gadchiroli, India.

In this paper, we describe the planning of the field trial and the methods used for collecting baseline health and ethnographic data in a rural field study site. We describe the study hypotheses, specific objectives, study design, sample size estimates, selection of study area, community consent, the organization of study teams, review mechanism, financial support and baseline data collection. Baseline population characteristics and vital statistics are presented. The qualitative information on traditional beliefs and practices prevalent in the study area revealed that parents felt powerless about newborn health and sickness. There was an enormous unmet need to reach the home-delivered neonates and their care-givers with the correct knowledge and health-care practices.

Home Care Services↗

PubMed2006

Linking the PANSS, BPRS, and CGI: clinical implications.

To understand what given scores of the Brief Psychiatric Rating Scale (BPRS) and the Positive and Negative Syndrome Scale (PANSS) mean from a clinical point of view is important for the translation of research results into practice. We therefore (a) compared the absolute change of the BPRS/PANSS with the Clinical Global Impressions Ratings (CGI) -improvement score and the change of the CGI severity score, (b) analyzed whether the severity of illness at baseline had an impact on the latter association, and (c) attempted to replicate previous BPRS findings using a completely different data set based upon the PANSS-derived BPRS. The method used was equipercentile linking of BPRS and CGI ratings from 14 drug trials in acutely ill patients with schizophrenia (n=5970). An absolute reduction of the BPRS/PANSS by approximately 10/15 points corresponded to a CGI change of 'minimally improved' and to a change of the CGI severity score by one severity step. However, the latter associations depended on the severity of symptoms at baseline. Less severely ill patients required less BPRS/PANSS total score reduction to achieve the same CGI-improvement score than more severely ill patients. This effect of initial severity was attenuated using percentage rather than absolute BPRS/PANSS reduction scores. The linking analysis between the absolute BPRS/PANSS reduction and the CGI may have an implication for the interpretation of efficacy differences found in clinical trials, and for sample size estimations. Clinicians seem to base CGI ratings on relative change rather than on absolute change of symptoms.

Adult↗

PubMed2000

Amitriptyline treatment of chronic pain in patients with temporomandibular disorders.

Randomized clinical trials of amitriptyline will require data from pilot studies to be used for sample size estimates, but such data are lacking. This study investigated the 6-week and 1-year effectiveness of low dose amitriptyline (10-30 mg) for the treatment of patients with chronic temporomandibular disorder (TMD) pain. Based on clinical examination, patients were divided into two groups: myofascial and mixed (myofascial and temporomandibular joint disorders). Baseline pain was assessed by a Visual Analogue Scale (VAS) for pain intensity and by the McGill Pain Questionnaire (MPQ). Depression was assessed by the Beck Depression Inventory (BDI) short form. Patient assessment of global treatment effectiveness was obtained after 6 weeks and 1 year of treatment by using a five-point ordinal scale: (1) worse, (2) unchanged, (3) minimally improved, (4) moderately improved, (5) markedly improved. The results showed a significant reduction for all pain scores after 6 weeks and 1 year post-treatment. The depression scores changed in depressed but not in non-depressed patients. Global treatment effectiveness showed significant improvement 6 weeks and 1 year post-treatment. However, pain and global treatment effectiveness were less improved at 1 year than at 6 weeks.

Adult↗

PubMed2003

Prevalence of undetected ocular conditions in a pilot sample of school children.

Parents of 134 children (age 5-18 years; 84% participation) attending a private school gave informed consent for their child's participation in a pilot study to demonstrate the feasibility and estimate sample size for a larger study of myopia prevalence, the Sydney Myopia Study. LogMAR visual acuity and other ocular assessments, including cycloplegic autorefraction (tropicamide 1%) and examination of the media and fundus, were performed. The prevalence of significant ocular conditions was 28.2%. Eleven children (8.4%) wore glasses. Five were referred for a change in their correction. Previously undetected ocular conditions (19.8%) included one child with ocular pathology and four children with strabismus. Uncorrected refractive error (16.8%) was the most common reason for referral and was more predominant in the senior students (25%), corresponding with an age-related shift in mean spherical equivalent refraction towards myopia (less than 7 years: +0.40 +/- 0.60 D; more than 15 years: -1.15 +/- 1.18 D). Three senior students were classified as having socially significant correctable vision impairment. These findings suggest that reliance on ad hoc referrals could result in delayed referral and that vision screening in both early and later school years may be desirable.

Adolescent↗

PubMed2006

[Design and method of clinical trials of drugs used in the therapy of stable peripheral arterial occlusive disease].

To prove the efficacy of the treatment of atherosclerotic stable peripheral arterial occlusive disease with drugs certain criteria are to be considered in the context of the design and performance of clinical trials. These criteria refer to the design of the study, randomisation, blinding, inclusion and exclusion criteria, definition of outcomes, methods of examination, sample size estimation, and evaluation of the results. If these criteria and conditions are not taken into consideration, false positive and negative results can arise. In the present study, the criteria to prove the efficacy of vasoactive substances in the treatment of atherosclerotic peripheral occlusive arterial diseases are presented.

Arterial Occlusive Diseases↗

PubMed2003

[Guidelines and methods for clinical investigation of drugs for treatment of stable angina pectoris].

To prove the antianginal efficacy of drugs in patients with stable angina pectoris the notice of certain criteria is necessary for the planning and performance for the clinical investigation of medicinal products. They consist of the study design, the randomization, blinding, inclusion and exclusion criteria, definition of endpoints, the performance of the study, the doses and dosing scheme, the methods of investigation, the sample size estimation and the evaluation of the results. If there will be not paid enough attention to these criteria and conditions false positive but also false negative results can arise. The criteria necessary for proving the antianginal efficacy in patients with stable angina pectoris will be presented.

Angina Pectoris↗

PubMed2001

Are there hangover-effects on physical performance when melatonin is ingested by athletes before nocturnal sleep?

Athletes ingest melatonin in an attempt to improve sleep quality or alleviate symptoms of jet lag after transmeridian travel. It is not known whether there are residual effects of this hormone on physical performance in fit subjects. After a sample size estimation involving a meaningful effect on performance of 5%, five milligrams of melatonin or placebo were ingested by twelve physically-active subjects before sleep in a double-blind experiment. The following morning, subjective sleep quality (latency and maintenance) were measured together with intra-aural temperature, grip strength of the left and right hands, and time to complete a 4 km time trial on a cycle ergometer. The subjects also rated perceived exertion during the latter test. The null hypothesis of no effect of melatonin on either subjective sleep quality or physical performance measured the morning after administration could not be rejected on the basis of our observations (P > 0.30). The mean differences between treatments were less than 1% for the strength tests and time trial performance. The confidence intervals for these differences for left and right grip strength and the cycling test were - 2.1 to 2.8 kg, - 3.1 to 2.7 kg and -3.0 to 4.5 s, respectively. In conclusion, it is unlikely that 5 mg of melatonin would have any meaningful effects on physical performance in the morning after fit subjects ingest the hormone. There was also little evidence that it improves sleep quality in this population. Further research is needed concerning the effects of daytime and nighttime admistration of melatonin on performance, in both situations of normal and disturbed sleep.

Adult↗

PubMed2000

Statistical methods in epidemiology. v. Towards an understanding of the kappa coefficient.

PURPOSE: This paper introduces readers to the problem of measuring interrater agreement in observer variation studies. The most usual statistic to quote is the kappa coefficient which measures agreement having corrected for chance. METHOD: The kappa coefficient for measuring agreement between two observers is introduced. Some pointers are given to determining sample size estimation. RESULTS: Some properties of the kappa coefficient are illustrated by taking examples from the author's teaching experiences. CONCLUSION: The kappa coefficient is recommended for measuring agreement in observer variation studies.

Epidemiology↗

PubMed2000

Lower extremity function and subsequent disability: consistency across studies, predictive models, and value of gait speed alone compared with the short physical performance battery.

BACKGROUND: Although it has been demonstrated that physical performance measures predict incident disability in previously nondisabled older persons, the available data have not been fully developed to create usable methods for determining risk profiles in community-dwelling populations. Using several populations and different follow-up periods, this study replicates previous findings by using the Established Populations for the Epidemiologic Study of the Elderly (EPESE) performance battery and provides equations for the prediction of disability risk according to age, sex, and level of performance. METHODS: Tests of balance, time to walk 8 ft, and time to rise from a chair 5 times were administered to 4,588 initially nondisabled persons in the four sites of the EPESE and to 1,946 initially nondisabled persons in the Hispanic EPESE. Follow-up assessment for activity of daily living (ADL) and mobility-related disability occurred from 1 to 6 years later. RESULTS: In the EPESE, compared with those with the best performance (EPESE summary performance score of 10-12), the relative risks of mobility-related disability for those with scores of 4-6 ranged from 2.9 to 4.9 and the relative risk of disability for those with scores of 7-9 ranged from 1.5 to 2.1, with similar consistent results for ADL disability. The observed rates of incident disability according to performance level in the Hispanic EPESE agreed closely with rates predicted from models developed from the EPESE sites. Receiver operating characteristic curves showed that gait speed alone performed almost as well as the full battery in predicting incident disability. CONCLUSIONS: Performance tests of lower extremity function accurately predict disability across diverse populations. Equations derived from models using both the summary score and the gait speed alone allow for the estimation of risk of disability in community-dwelling populations and provide valuable information for estimating sample size for clinical trials of disability prevention.

Activities of Daily Living↗

PubMed1995

Human immunodeficiency virus type 1 quantitative cell microculture as a measure of antiviral efficacy in a multicenter clinical trial.

A quantitative cell microculture assay (QMC) was used to measure the human immunodeficiency virus type 1 (HIV-1) peripheral blood mononuclear cell (PBMC)-associated titer in 109 subjects rolled in an open-label phase I/II study of didanosine monotherapy or combination therapy with zidovudine. The titer was inversely correlated with CD4+ cell count at baseline (r = .37, P = .001). After 12 weeks of therapy, subjects showed a significant decreases in virus titer and those with the highest baseline virus titers had the greatest increase in CD4+ cell number (r = .430, P = .002). The QMC assay was more sensitive (98%) for assessing the antiretroviral effect of therapy than was immune complex-dissociated HIV p24 antigen (32%) or plasma culture (3.4%). Estimated sample sizes for phase I/II clinical trials were derived using the within-subject QMC SD of .72 log10 infectious units per 10(6) PMBC.

CD4 Lymphocyte Count↗

PubMed2000

Development and initial validation of the back pain functional scale.

STUDY DESIGN: A prospective repeated-measures design was applied. OBJECTIVES: To examine the measurement properties of the Back Pain Functional Scale (BPFS) and the Roland-Morris Questionnaire (RMQ) and to formulate hypotheses and sample size estimates for a subsequent comparison study. SUMMARY OF BACKGROUND DATA: Although there are numerous functional status measures for patients with low back pain, most have been conceived of and validated with a group rather than an individual patient as the unit of interest. Also, little has been done to formally compare-this includes the generation of a priori hypotheses, followed by statistical hypotheses testing-the many competing measures. METHODS: Subjects were 77 patients with low back pain who were referred by physicians to 10 outpatient physical therapy clinics located in Canada and the United States. The questionnaires were administered at patients' initial visits, within 48 hours of the initial visit, and at 1-, 2-, and 3-week follow-up visits. Reliability, cross-sectional validity, and longitudinal validity (sensitivity to change) coefficients were calculated. RESULTS: Test-retest reliability estimates of 0.81 and 0. 88 were obtained for the RMQ and BPFS, respectively. The measures demonstrated similar levels of cross-sectional validity. Correlations of 0.56 and 0.65 were noted between a prognostic rating of change and the RMQ and BPFS, respectively. The RMQ demonstrated a ceiling effect. Approximately 180 patients are needed for a subsequent head-to-head comparison study of the measures. CONCLUSIONS: The BPFS appears to have sound measurement properties, and a formal head-to-head comparison study with the RMQ is warranted.

Adolescent↗