PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “list randomization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources
PubMed2000

The impact of different response alternatives on responders' reporting of health-related behaviour in a postal survey.

Previous experimental research in other topic areas has shown that the choice of response alternatives can influence respondents' reporting of the frequency of vaguely defined events and that the set of response alternatives is treated as information in the interpretation of the question. The aim of this study was to examine whether such affects would occur in the context of respondents reporting of health-related events using high and medium frequency closed format response categories, which might be used interchangeably by researchers. The study consisted of a postal survey of n = 518 patients aged > or = 18 years randomly selected from the patient list of a diabetes centre and who were equally and randomly allocated to one of three conditions (Condition A: high frequency response alternatives/horizontal orientation; condition B: medium frequency response alternatives/horizontal orientations; condition C: high frequency response alternatives/vertical orientation). Testing for the effect of response alternatives for the combined responses of five vaguely defined questions between conditions A and B was chi 2 = 5.5, p = 0.019, for the difference in proportions, indicating that overall, those respondents presented with response alternatives discriminating at medium frequency, reported significantly fewer target events than those presented with high frequency response alternatives. Testing for the effect of orientation of the combined question responses between conditions A and C, differences in proportions between conditions, did not reach statistical significance (p > 0.05). Findings from this and previous studies indicate that response alternatives provide information on the interpretation of vaguely defined questionnaire items and that their choice should not be left to intuition alone when designing questionnaire items.

Adult↗
PubMedDate not supplied

Binaural and monaural speech discrimination under reverberation.

This study investigated the effects of reverberation upon the speech discrimination performance of 30 normally hearing subjects and 30 persons with bilateral sensorineural hearing loss. Following preliminary tests, the Modified Rhyme Test was administered monaurally and binaurally at reverberation times of 0, 1, 2 and 3 sec. All stimuli were administered under earphones. The lists and conditions were appropriately randomized and counterbalanced so that each subject heard a test list at each reverberation time (RT) monaurally and binaurally. The expected gain due to binaural summation of loudness was simulated in order to test the possibility that any binaural enhancement of intelligibility might be due to binaural loudness summation. For all conditions, the normally hearing subjects performed significantly better than the hearing-impaired group. However, in relative terms, the two groups were remarkably similar. Binaural scores were significantly higher than monaural scores at each RT for both groups (in spite of homophasic conditions). For both groups, monaural and binaural scores decreased with increasing RT. Monaural scores decreased at a significantly faster rate with RT than did the binaural scores (the binaural advantage, however, was larger for the normal group). Increasing the monaural presentation levels to simulate the binaural loudness gain did not result in higher scores. It was concluded that speech discrimination under reverberation is better binaurally than monaurally for both normally hearing and hearing-impaired persons. This is due, at least partly, to the ability of the binaural auditory system to squelch the effects of reverberation. A tentative model is suggested for the binaural squelch of reverberation. The current findings are compared with existing data; and suggestions are offered for clinical application.

Adolescent↗
PubMed1999

Seroprevalence of Helicobacter pylori in the adult population of Christchurch: risk factors and relationship to dyspeptic symptoms and iron studies.

AIM: To determine the prevalence of Helicobacter pylori infection in subjects randomly selected from the Christchurch population and to determine the risk factors and symptoms related to the infection. METHODS: A list of names was randomly generated from the 1996 electoral roll and subjects were sequentially contacted and invited to participate. A questionnaire on dyspeptic symptoms was completed and the subject's serum was analysed for H. pylori antibodies using the Roche method. Equivocal samples were retested by the Meridian method. RESULTS: One thousand and sixty-four subjects participated in the study. In four subjects results for H. pylori were indeterminate and these subjects were excluded from analysis. Of the remaining 1060 subjects, 254 (24.0%) were seropositive for H. pylori. The seropositivity in males (n=444) was 25.9% and in females (n=616) 22.6%. On multivariate analysis age, ethnicity, low income and smoking > 20 cigarettes per day were all independent predictors of H. pylori seropositivity. H. pylori positive subjects had shorter stature compared to those who were seronegative. The symptom scores for dyspepsia were similar in both the seropositive and seronegative subjects. In males the serum iron levels were lower in seropositive subjects but there were no significant differences in serum ferritin in either males or females between seropositive and seronegative subjects. CONCLUSION: H. pylori is a common infection in the Christchurch community with the prevalence increasing significantly with age. H. pylori positive subjects had shorter stature and in males lower serum iron levels were observed. Infection was not associated with an increased risk of dyspeptic symptoms.

Adult↗
PubMed1996

Methodology citations and the quality of randomized controlled trials in obstetrics and gynecology.

OBJECTIVES: Randomized controlled trials offer the best chance for valid treatment comparisons, yet most trials are of poor quality. This may reflect a lack of awareness of the requirements for conducting and reporting this type of research. If so, then citation of methodology references might indicate knowledge of how to conduct these studies and vice versa. Our study tests the hypothesis that the methodologic quality of published trials is related to citation of methodology references. STUDY DESIGN: We performed a hand search of the American Journal of Obstetrics and Gynecology, the British Journal of Obstetrics and Gynaecology, the Journal of Obstetrics and Gynaecology, and Obstetrics and Gynecology to identify all randomized controlled trials published in 1990 and 1991 (N = 206). We reviewed the reference lists of all reports of randomized controlled trials and evaluated the adequacy of randomization methods by accepted criteria. RESULTS: Most reports (81.6%) cited no methodology text or article. Although lack of any methodology reference was not significantly related to failure to report an adequate random method of sequence generation, this was highly related (p < 0.001) to failure to report adequate allocation concealment. Scanning the reference list of reports took a mean of 16 seconds and identified most poorly done trials. CONCLUSIONS: Investigators who conduct randomized controlled trials should be thoroughly familiar with this type of research or should get expert help. Poorly done trials are wasteful and often misleading.

Bibliographies as Topic↗
PubMed1978

Concurrent validity of the Depression Adjective Check List in a normal population.

A random sample of 309 employees of a state mental hospital completed form E of the Depression Adjective Check List (DACL), the Beck Depression Inventory, the Zung Self-Rating Depression Scale, and the Crowne-Marlowe Social Desirability Scale. Two psychiatrists then interviewed and independently rated all subjects on a 5-point scale. Most of the correlations between the DACL and the other measurements were significant and of sufficient magnitude to warrant interpretation as support for the concurrent validity of the DACL.

Adult↗
PubMed2006

A survey validation of generic objectives for community-based education in undergraduate medical training.

INTRODUCTION: A framework for the definition of generic objectives for community-based education (CBE) was developed for undergraduate medical programmes, particularly for developing countries. To probe the validity of the set of CBE objectives generated by this approach, opinions from a wider audience were sought. METHOD: Questionnaires were sent to 72 medical schools in 36 developing countries. Half of the addressees were randomly drawn from the list of institutional members of The Network: Toward Unity For Health (TUFH) and stratified according to developing countries. Another 36 medical schools were randomly drawn from non-Network: TUFH schools from the same country where the selected Network: TUFH addressee was located, or from a neighbouring country. RESULTS: A total of 43 medical schools responded to the questionnaire (60% response rate), 31 out of the 36 addressed Network: TUFH members (86%) and 12 out of 36 addressed non-Network: TUFH schools (33%). Out of all 43 respondents 39 (91%) had implemented CBE in their curricula. Opinions of Network: TUFH and non-Network: TUFH schools on the framework and the generic objectives were not significantly different. Out of the 21 proposed objectives, 17 were scored as relevant by 75% or over of all responders and one out of the four objectives considered to be less relevant by the responders was deleted. CONCLUSION: A framework to develop generic CBE objectives and a derived set of 21 objectives were modified based on input by 43 medical schools residing in developing countries distributed all over the globe. The outcome is a validated set of 20 generic objectives for CBE programmes in developing countries.

Chi-Square Distribution↗
PubMed2005

Utilization of indigenous systems of medicine & homoeopathy in India.

BACKGROUND & OBJECTIVE: Very little information is available on the utilization of Indian systems of medicine and homoeopathy (ISM&H) in India. A study was undertaken on the usage and acceptability of indigenous systems of medicine to provide estimate of utilization of different indigenous systems of medicine in the country along with the reasons for preferences as well as the cost of treatment. METHODS: The study covered 35 districts spreading over 19 States of the country. From 16 major States, two districts each were selected randomly one from the list of districts with high utilization level and another with low level of utilization. From other 3 States, one district each was selected randomly. From each selected district, 1000 households with at least one sick person were covered. This was achieved by selecting 50 Urban Frame Surveys (UFS)/villages and 20 sick persons each per village/UFS. Allocation of 50 First Stage Units (FSUs) among rural and urban sectors was made in proportion to rural-urban population of the district. From selected FSUs, 20 households with at least one sick person was selected randomly. The data were collected on the health seeking behaviour of persons who were sick (with common or serious ailments) in the last three months before survey including at the time of survey. RESULTS: About 45,000 sick persons from 33,666 households from 35 districts of the country were covered. The preference of ISM&H for common ailment was about 33 per cent while only 18 per cent preferred to use these systems in case of serious ailments in the country. The sick persons actually availing ISM&H treatment were about 14 per cent. Of those who preferred ISM&H, the reasons were mainly "no side effect" and low cost of treatment. Slow progress was the main reason for not preferring the indigenous systems. INTERPRETATION & CONCLUSION: The findings of this study showed that about 14 per cent sick persons utilizing indigenous system of medicine. Slow progress and non availability of practitioners were the main reasons for not preferring the ISM & H treatment.

Delivery of Health Care↗
PubMed2006

Risk of breast cancer for women living in rural areas from adult exposure to atrazine from well water in Wisconsin.

Research has suggested possible human health effects from low-level widespread exposure to environmental contaminants. We employed a novel exposure estimation technique using a publicly available data set to examine atrazine exposure, a suspected endocrine disruptor, in relation to breast cancer risk for women living in rural areas of Wisconsin. Incident breast cancer cases who were 20-79 years of age from 1987 to 2000 (n=3,275) and living in rural areas of Wisconsin at the time of interview were identified from Wisconsin's statewide cancer registry. Female controls of similar age and living in rural areas of Wisconsin were randomly selected from population lists (n=3,669). The addresses at diagnosis or reference year of study participants were assigned latitude/longitude coordinates (geocoded). The results from three statewide random studies of atrazine levels in well water in 1994, 1996, and 2001 were obtained from the Wisconsin Department of Agriculture, Trade, and Consumer Protection. Natural neighbor interpolation was used to estimate atrazine exposure levels separately for each of the 3 years. The mean atrazine exposure level was assigned to each participant based on her geocode. After adjustment for established breast cancer risk factors, compared to women in the lowest category of atrazine exposure (<0.15 ppb), the odds ratio of breast cancer for women exposed to atrazine concentrations of 1.0-2.9 ppb was 1.1 (95% CI 0.9-1.4). Results from this large population-based study do not suggest an increased risk of breast cancer from adult exposure to atrazine in drinking water. The possible risk for women exposed to levels of atrazine at or above statutory action levels of >or=3 ppb (OR 1.3, 95% CI 0.3-6.5) could not be ruled out due to small numbers in this category.

Adult↗
PubMed2005

Precautionary regulation in Europe and the United States: a quantitative comparison.

Much attention has been addressed to the question of whether Europe or the United States adopts a more precautionary stance to the regulation of potential environmental, health, and safety risks. Some commentators suggest that Europe is more risk-averse and precautionary, whereas the United States is seen as more risk-taking and optimistic about the prospects for new technology. Others suggest that the United States is more precautionary because its regulatory process is more legalistic and adversarial, while Europe is more lax and corporatist in its regulations. The flip-flop hypothesis claims that the United States was more precautionary than Europe in the 1970s and early 1980s, and that Europe has become more precautionary since then. We examine the levels and trends in regulation of environmental, health, and safety risks since 1970. Unlike previous research, which has studied only a small set of prominent cases selected nonrandomly, we develop a comprehensive list of almost 3,000 risks and code the relative stringency of regulation in Europe and the United States for each of 100 risks randomly selected from that list for each year from 1970 through 2004. Our results suggest that: (a) averaging over risks, there is no significant difference in relative precaution over the period, (b) weakly consistent with the flip-flop hypothesis, there is some evidence of a modest shift toward greater relative precaution of European regulation since about 1990, although (c) there is a diversity of trends across risks, of which the most common is no change in relative precaution (including cases where Europe and the United States are equally precautionary and where Europe or the United States has been consistently more precautionary). The overall finding is of a mixed and diverse pattern of relative transatlantic precaution over the period.

Journal Article↗
PubMed2005

A short-term cognitive group treatment program gives substantial weight reduction up to 18 months from the end of treatment. A randomized controlled trial.

OBJECTIVE: To describe and evaluate long-term efficacy (18 months from the end of treatment) of a new cognitive short-term weight reducing treatment program for obese patients. SUBJECTS: One hundred and five obese [Body Mass Index (BMI) > or = 30] patients participated in the study. Of these, 62 took part in the treatment program and 43 served as controls. METHOD: From an obesity unit's waiting list, the patients were randomly assigned to either a treatment group or remained in the waiting list to serve as a control group. The treatment group participated in a 10-week (30 hours) cognitive group treatment program. All participants were weighed at the outset of the study, directly after treatment and at a 6-, 12- and 18-month post-treatment follow-up without any booster treatment after the 10-week program. RESULTS: Fifty-seven (92%) patients completed treatment. For the 34 (60%) patients who participated in the study 18 months after treatment was terminated, the mean weight loss at treatment's end was 8.5 kg (SD=16.1). Eighteen months later their mean weight loss was 10.4 kg (SD=10.8). The control patients (n=31.72%) that participated in the study during the same period increased in weight by 2.3 kg (SD=7.0). The weight difference between the treatment and control group at the 18-month follow-up was highly significant (p<0.001). CONCLUSION: The cognitive group treatment program was highly acceptable among the participants and was completed by nearly all the patients. The 10-week treatment program resulted in satisfactory weight loss. The weight difference between the treatment group and controls was nearly the same at 18 months after end of treatment as at six months. The study, therefore, does not provide support for the contention that a lengthy therapy for obesity is necessary if treatment results are lasting.

Cognitive Behavioral Therapy↗
PubMed1979

Development of a distinctive feature discrimination test.

Construction and standardization is described of a distinctive feature discrimination test (DFDT) incorporating a modified Miller-Nicely system of distinctive features. The test is a rhyme-type where error responses in a closed set were chosen to be one, two, and three distinctive features removed from the stimulus word. Performance-intensity (P.I) functions were established with 6 normal-hearing young women (12 ears) at SPLs or 20, 25, 30, 35, and 40 db under each of three filter bandpass conditions: .2-6, .2-1.2, and .2-.6 kc/s. P-I functions were presented for unweighted scores and for scores where error responses were weighted in terms of distinctive feature differences from stimulus items. The 4 DFDT lists generated, and their 3 randomizations each, appear to have a reasonable degree of inter-list reliability and it is felt that the 12 resultant list may be used interchangeably, This preliminary study indicated that the DFDT test may provide more diagnostic information than currently-used discrimination test.

Adult↗
PubMed1999

Differences in stakeholder expectations in the outcome of physiotherapy management of acute low back pain.

OBJECTIVE: To compare stakeholder expectations of outcome of physiotherapy management of acute low back pain. DESIGN: Observational design using interviews and questionnaires. SETTING: Practice/workplace. STUDY PARTICIPANTS: The study sample was from South Australia. It comprised 74 physiotherapists randomly selected from professional association listings (49.3% response rate), 121 physiotherapy patients (recruited by participating physiotherapists when attending their first physiotherapy treatment for acute low back pain), 21 general practitioners randomly selected from medical practitioner listings in the metropolitan telephone book (36.2% response rate) and 13 third party payers of a total of 16 available insurers in the metropolitan area (82% response rate). MAIN OUTCOME MEASUREMENTS: Stakeholders reported expectations of outcome at the end of the first treatment session and at the completion of the episode of care. RESULTS: There were differences in expectations between stakeholders, as well as between naive and experienced patients. Overall, patients expected symptom relief at the end of the first treatment. Naive patients decided to return for further treatment based on the relationship established with the therapist, whereas experienced patients also expected some advice on their condition during the first contact. Physiotherapists and referrers expected symptom relief and then long-term management strategies to be provided, and third party payers expected cost-efficient management of the condition and patient satisfaction. CONCLUSION: Physiotherapists need to address potential imbalance of consumer knowledge and foster a quality partnership with their patients on the first visit to physiotherapy. Patients who are in pain may not derive full value from information provided in an untimely manner.

Acute Disease↗
PubMed1998

[Smoking associated with alcoholism: introduction to the major human dependencies].

OBJECTIVE: To establish the existence of an association between smoking and alcoholism in a general population sample and to compare two samples of alcoholics and non alcoholics matched by age and sex. MATERIAL AND METHOD: Health Teaching Unit Murialdo-State Health Department-RS-Brazil in a limited area of 65,000 predicted population a cross-sectional study was undertaken in which adults of 35 y.o. or more were sampled. Of this sample, the alcoholics were selected by applying the CAGE Scale. A non alcoholic random sample was compared with the alcoholic one. It was identified 129 alcoholics among 1,387 adults of 35 y.o. or more. From the general list of adults a random sample of 129 non alcoholics were selected and matched to the alcoholics by age and sex. Both groups were compared. Data were obtained from a 19 item questionnaire. Answers to generic questions were obtained from all family members, such as: income and smoking habit. Specific data were obtained from the interviewed person of 35 y.o. or more, such as: schooling grade, occupation, diseases and respiratory symptoms, smoking habit, Peak Expiratory Flow and alcoholism. RESULTS: Of 129 alcoholics, 109 (84.5%) were male and 20 (15.5%) were female. The smoking prevalence among alcoholics (67%) was greater than among non alcoholics (43%) (p < .002). The kind of occupation distinguished both groups. Among alcoholics unemployment and elementary levels of occupation are more usual while among the abstemious intermediate and superior levels are more frequent (p < .003). The family as well as the personal income are higher among the abstemious (p < .001). There is an increased non significant number of non whites, illiterate people and family smokers among the alcoholics (p < .06). The tendency to start smoking earlier in life and to smoke more cigarettes for a longer period of time was noticed among alcoholics. CONCLUSIONS: There is a statistical association between smoking and alcoholism in the sample studied. Alcoholism in this sample is more prevalent among people who fulfil the following conditions: smokers, low income, rudimentary cultural and professional levels.

Adult↗
PubMed1988

The effects of orientation and maintenance of attention on hemispheric asymmetry for speech perception.

The contributions of orientation and maintenance of attention to the measurement of ear asymmetry was investigated in 20 right handed subjects. The subject listened to dichotic lists and had to respond to a target word in either the male or the female voice only (focused attention), or both voices (divided attention). At random positions throughout the lists the voices changed ears. A switch in voices from one side of space to the other interfered with speech processing during focused attention, but facilitated the detection of targets during divided attention. The interference was greater for the left than the right ear during focused attention. Likewise, facilitation during divided attention was asymmetrical, with right targets receiving faster processing. The qualitative differences of attention strategy on ear asymmetry during dichotic listening may be due to hemispheric differences in preferred attentional modes.

Adult↗
PubMed2000

The effectiveness of omeprazole, clarithromycin and tinidazole in eradicating Helicobacter pylori in a community screen and treat programme. Leeds Help Study Group.

INTRODUCTION: Helicobacter pylori screening and treatment has been proposed as a cost-effective method of preventing gastric cancer. AIM: To assess, in a randomized controlled trial, the efficacy of therapy in eradicating H. pylori as part of a screening programme, and to report the adverse events associated with this strategy. METHODS: Subjects between the ages of 40-49 years were randomly selected from the lists of 36 primary care centres. Participants attended their local practice and H. pylori status was determined by 13C-urea breath test. Infected subjects were randomized to receive omeprazole 20 mg b.d., clarithromycin 250 mg b.d. and tinidazole 500 mg b.d. for 7 days (OCT) or identical placebos. Eradication was determined by a 13C-urea breath test 6 months and 2 years after the first visit. Successful eradication was defined as two negative 13C-urea breath tests or one negative and one missing test. Adverse events and compliance were assessed at the 6-month visit. RESULTS: A total of 32 929 subjects were invited to attend, 8407 were evaluable, and 2329 (28%) of these were H. pylori-positive. A total of 1161 subjects were randomized to OCT and 1163 to placebo; over 80% returned for a repeat 13C-urea breath test on at least one occasion. The eradication rates in those allocated to OCT were as follows: intention-to-treat, 710 out of 1161 (61%; 95% confidence interval: 58-64%); evaluable 710 out of 967 (73%; 95% CI: 71-76%); took all medication 645 out of 769 (84%; 95% CI: 81-87%). Adverse events occurred in 45% of the treatment group and in 18% of the placebo group (relative risk 2.5; 95% CI: 2.1-2.9). Compliance, male gender, no antibiotic prescription in the subsequent 2 years and experiencing a bitter taste with the medication were independently associated with treatment success. CONCLUSIONS: The OCT regimen has an eradication rate of 61% in intention-to-treat analysis and is therefore less successful in treating H. pylori as part of a screening programme compared with hospital studies in dyspeptic patients.

Administration, Oral↗
PubMed2005

Dopexamine and its role in the protection of hepatosplanchnic and renal perfusion in high-risk surgical and critically ill patients.

BACKGROUND: Dopexamine is increasingly being used in high-risk surgical and critically ill patients to preserve hepatosplanchnic and renal perfusion. This systematic review of randomized controlled trials was undertaken to investigate the clinical evidence for using dopexamine in this role. METHODS: Data sources included Medline, Cochrane Library, EMBASE and CINAHL and reference lists of relevant articles. Randomized controlled trials which compared dopexamine treatment with a control group, in high-risk surgical and critically ill adult patients and with primary outcome measures designed to assess hepatosplanchnic and renal perfusion were included. Articles not published in English were excluded. RESULTS: Twenty-one trials were selected from the literature search. The results suggest that dopexamine may protect against colonic mucosal damage in patients undergoing abdominal aortic surgery and may improve gastric mucosal pHi in general surgical patients, especially those with preoperative gastric mucosal pHi measurements <7.35 and those undergoing pancreatico-duodenectomy surgery. Dopexamine may have beneficial effects on renal perfusion in patients undergoing cardiac surgery but appears to have little or no benefit on gastric mucosal pHi in the same patient population. In critically ill patients none of the studies demonstrated a beneficial effect of dopexamine on either hepatosplanchnic or renal perfusion. CONCLUSION: The evidence provided by the existing studies is both inadequate and inconsistent. There is insufficient evidence to offer reliable recommendations on the clinical use of dopexamine for the protection of either hepatosplanchnic or renal perfusion in high-risk surgical patients. Furthermore, there is no current evidence to support a role for dopexamine in protecting either hepatosplanchnic or renal perfusion in critically ill patients.

Critical Illness↗
PubMed2004

Correlation between thrombus regression and recurrent venous thromboembolism. Examining venographic and clinical effects of low-molecular-weight heparins: a meta-analysis.

We analyzed the correlation between thrombus regression on control venography performed after discontinuation of heparin therapy and recurrent venous thromboembolism (VTE) detected during clinical follow-up in randomized trials comparing low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) in patients with deep vein thrombosis (DVT). Data were abstracted from MEDLINE, conference abstracts and reference lists of previous reviews. Randomized, controlled trials comparing LMWH and UFH for the treatment of DVT using a combined venographic and clinical assessment and with at least 2 months of follow-up were selected. The proportions of patients with thrombus regression on control venography performed soon after discontinuation of heparin therapy and recurrent VTE at 2-6 months were independently collected by two researchers. Thirteen studies met the inclusion criteria. There was a strong inverse correlation between thrombus regression and recurrent VTE (r =- 0.70; P =0.008). The venographic effect varied between the different LMWHs (P = 0.013). A very strong correlation was found when the results were pooled by the type of LMWH used (r = - 0.84; P=0.037). No influence of the dose interval used on the venographic effect (P=0.156) or on recurrent VTE (P=0.218) was shown. The lack of thrombus regression in venography, performed soon after heparin discontinuation, was correlated with clinical recurrence. Non-invasive imaging techniques should be relevant to identify non-responders and to assess the optimal duration of initial heparin treatment in daily clinical practice.

Heparin, Low-Molecular-Weight↗