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Results for “Randomized controlled trials”

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At least 595 records · Page 33Linked to original sources

PubMed2005

Preventing relapse/recurrence in recurrent depression with cognitive therapy: a randomized controlled trial.

This article reports on the outcome of a randomized controlled trial of cognitive group therapy (CT) to prevent relapse/recurrence in a group of high-risk patients diagnosed with recurrent depression. Recurrently depressed patients (N = 187) currently in remission following various types of treatment were randomized to treatment as usual, including continuation of pharmacotherapy, or to treatment as usual augmented with brief CT. Relapse/recurrence to major depression was assessed over 2 years. Augmenting treatment as usual with CT resulted in a significant protective effect, which intensified with the number of previous depressive episodes experienced. For patients with 5 or more previous episodes (41% of the sample), CT reduced relapse/recurrence from 72% to 46%. Our findings extend the accumulating evidence that cognitive interventions following remission can be useful in preventing relapse/recurrence in patients with recurrent depression.

Cognitive Behavioral Therapy↗

PubMed1999

Laser therapy: a randomized, controlled trial of the effects of low-intensity Nd:YAG laser irradiation on musculoskeletal back pain.

OBJECTIVE: To assess the effectiveness of low-intensity laser therapy in the treatment of musculoskeletal low back pain. DESIGN: A double-masked, placebo-controlled, randomized clinical trial. SETTING: A physical medicine and rehabilitation clinic. PARTICIPANTS: Sixty-three ambulatory men and women between the ages of 18 and 70yrs with symptomatic nonradiating low back pain of more than 30 days' duration and normal neurologic examination results. INTERVENTION: Subjects were bloc randomized into two groups with a computer-generated schedule. All underwent irradiation for 90 seconds at eight symmetric points along the lumbosacral spine three times a week for 4 weeks by a masked therapist. The sole difference between the groups was that the probes of a 1.06 microm neodymium:yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for the control subjects. MAIN OUTCOME MEASURES: Subject's perception of benefit, level of function as assessed by the Oswestry Disability Questionnaire, and lumbar mobility. RESULTS: The treated group had a time-dependent improvement in two of the three outcome measures: perception of benefit and level of function. These results were most marked at the midpoint evaluation (p < .005, p < .01) and end of treatment (p < .017, p < .001) but tended to lessen at the 1-month follow-up (p < .10, p < .004). Lumbar mobility did not differ between the groups at any time. All tests were two-sample t tests with unequal variances. CONCLUSIONS: Treatment with low-intensity 1.06 microm laser irradiation produced a moderate reduction in pain and improvement in function in patients with musculoskeletal low back pain. Benefits, however, were limited and decreased with time. Further research is warranted.

Adolescent↗

PubMed1995

The feasibility of a control population for a randomized control trial of seizure prophylaxis in the hypertensive disorders of pregnancy.

OBJECTIVE: To document the feasibility of a control population for a randomized controlled trial, we report our experience in managing hypertensive pregnancies without seizure prophylaxis. STUDY DESIGN: An 8-year cross-sectional study in one institution was performed of all hypertensive patients. RESULTS: Of 467 patients with preeclampsia or superimposed preeclampsia managed without seizure prophylaxis, 18 had seizure activity, 3.9% (95% confidence interval 2.3% to 6.0%). There was no seizure-related maternal mortality or major morbidity, and the perinatal mortality rate after 28 gestational weeks was the same in patients with or without seizures. By logistic regression seizures were 17.4 times more likely in preeclampsia and 8.1 times more likely in chronic hypertension with superimposed preeclampsia, compared with gestational or chronic hypertension alone. CONCLUSION: The rate of seizures in patients with preeclampsia or superimposed preeclampsia managed without seizure prophylaxis was low and unassociated with an increase in maternal or perinatal mortality. A control arm is feasible in a randomized, controlled trial to address the issue of whether antiseizure medication can prevent eclampsia.

Anticonvulsants↗

PubMed1993

Early angiography and angioplasty following thrombolytic therapy of acute myocardial infarction. Metaanalysis of the randomized control trials.

STUDY OBJECTIVE: There have been at least 10 randomized control trials (RCTs) of early intervention in patients with acute myocardial infarction published, and all are inconclusive with regard to impact on mortality. Metaanalysis offers an opportunity to assess the efficacy of an early intervention following thrombolytic therapy in the treatment of acute myocardial infarction. DESIGN: Data on the number of patients who died in the hospital, and the total number of patients randomized to aggressive versus conservative therapies, were drawn from 9 publications and combined using both a fixed and a random-effects metaanalysis model. Quality of the trials was assessed under blinded conditions. SETTING: The 10 RCTs to be combined were each carried out in individual institutions. PATIENTS: A total of 5882 patients have been randomized, with 305 deaths (5.2%), indicating that this group of patients had a relatively low mortality rate compared to patients in general with acute myocardial infarction. COMPARISON OF TREATMENTS: No matter how the 10 trials were combined for analysis, there was no evidence that aggressive intervention was trending towards saving lives. Data on other endpoints such as need for repeat percutaneous transluminal coronary angioplasty (PTCA), coronary artery bypass grafting (CABG), or recurrent myocardial infarction were sparse, but the same adverse trend was apparent. CONCLUSION: In spite of the fact that early angiography and PTCA when indicated have been advocated for more than a decade, there is still no evidence that they reduce overall mortality after fibrinolysis in a specific subgroup. Further studies of early intervention should be done in an effort to answer subgroup questions which include the search for appropriate timing and patient selection for PTCA after fibrinolysis. As more RCTs with mortality data are published they will be added to these metaanalyses in The Online Journal of Current Clinical Trials.

Angioplasty, Balloon, Coronary↗

PubMed1992

[Reappraisal of Zelen's method in randomized controlled trials].

This paper discusses Zelen's method (a study design with pre-randomization) in randomized controlled trials from the following aspects: 1) compliance of patients with a randomly assigned treatment; 2) infringement of patients' right to choose treatments; and 3) unfairness that only patients assigned to a new treatment are allowed a choice of treatments. The reason Zelen's method is rarely used in the United States or European countries seems to be the lower compliance of treatments in Zelen's method than in the conventional design of randomized controlled trials. Considering the present study practice in Japan, where study subjects are not completely informed by randomized assignment of treatments, Zelen's method is thought to be more practical, and not inferior to the conventional design in terms of compliance.

Humans↗

PubMed2007

The Personality Disorders Institute/Borderline Personality Disorder Research Foundation Randomized Control Trial for Borderline Personality Disorder: reliability of Axis I and II diagnoses.

The Personality Disorder Institute/Borderline Personality Disorder Research Foundation randomized control trial (PDI/BPDRF RCT) is a randomized control trial comparing three treatments for borderline personality disorder (BPD). An important issue for any RCT is diagnostic reliability, demonstration of which is necessary to evaluate claims of a treatment's efficacy for a given population. The present paper examines the interrater reliability of Axis I and II disorders in the context of a high base rate of BPD features for participants referred for inclusion in the RCT. Our results indicate good to excellent levels of interrater reliability for all Axis I and II disorders in this context. Assessors were able to reliably diagnose BPD, exclusionary criteria, and comorbid diagnoses. This data is important for comparing findings and sample composition across different studies using similar sampling strategies, especially as treatments are increasingly being developed and tested for BPD.

Adult↗

PubMed2005

Another look at observational studies in rehabilitation research: going beyond the holy grail of the randomized controlled trial.

Horn SD, DeJong G, Ryser DK, Veazie PJ, Teraoka J. Another look at observational studies in rehabilitation research: going beyond the holy grail of the randomized controlled trial. This commentary compares randomized controlled trials (RCTs) and clinical practice improvement (CPI) approaches to study design, evaluates their relative advantages and disadvantages, and discusses their implications for rehabilitation research and evidence-based practice. Many argue that observational cohort studies are not sufficient as scientific evidence for practice change. We challenge this assertion by introducing the concept of a CPI study: a comprehensive observational paradigm structured to decrease biases generally associated with observational research. One strength of CPI studies is their attention to defining and characterizing the "black box" of clinical practice. CPI studies require demanding data collection, but by using bivariate and multivariate associations among patient characteristics, process steps, and outcomes, they can uncover best practices more quickly while achieving many of the presumed advantages of RCTs.

Clinical Trials as Topic↗

PubMed2002

Is ureteral stenting necessary after uncomplicated ureteroscopic lithotripsy? A prospective, randomized controlled trial.

PURPOSE: We conducted a prospective, randomized controlled study to investigate the advantages and disadvantages of ureteral stenting after ureteroscopic lithotripsy. MATERIALS AND METHODS: A total of 60 patients who underwent ureteroscopic lithotripsy were equally randomized into a stented or a nonstented group. The inclusion criteria were stone 6 to 10 mm., absence of polyp or stricture in the ureter and no mucosal injury during ureteroscopy. The operation was performed with a 6Fr rigid ureteroscope without ureteral dilation and stones were fragmented with a 1.9Fr electrohydraulic lithotriptor without extraction. A 7Fr double pigtail stent was placed in the stented group for 3 days after ureteroscopy. Urinalysis, plain x-ray and renosonography were performed before and after lithotripsy in each patient. Subjective symptoms and pain score were recorded on admission to the hospital and 3 days postoperatively. RESULTS: The stone-free rate was 100% in each group and preoperative hydronephrosis equally resolved in both groups. Mean pain score plus or minus standard deviation improved significantly in the nonstented (6.33 +/- 1.81 preoperatively to 2.30 +/- 1.93 postoperatively, paired Student's t test p <0.0001) and stented (7.10 +/- 1.03 to 2.30 +/- 2.22, p < 0.0001) group. There was no statistical difference in pain reduction between the 2 groups (p = 0.18). The amount of extra parenteral analgesic used was similar in both groups. One patient in the nonstented group visited the emergency room for postoperative renal colic, 25 (83.3%) patients in the stented group complained of at least 1 irritative bladder symptom and only 4 (13.3%) in the nonstented group experienced bladder discomfort. CONCLUSIONS: After uncomplicated ureteroscopic electrohydraulic lithotripsy patients without ureteral stenting tend to have similar renal function recovery and satisfactory pain reduction with less irritative symptoms compared to those treated with a ureteral stent. We suggest that it is not necessary to place a ureteral stent routinely after uncomplicated ureteroscopic electrohydraulic lithotripsy for stones smaller than 1 cm.

Adult↗

PubMed2006

How to identify randomized controlled trials in MEDLINE: ten years on.

OBJECTIVE: The researchers sought to assess whether the widely used 1994 Cochrane Highly Sensitive Search Strategy (HSSS) for randomized controlled trials (RCTs) in MEDLINE could be improved in terms of sensitivity, precision, or parsimony. METHODS: A gold standard of 1,347 RCT records and a comparison group of 2,400 non-trials were randomly selected from MEDLINE. Terms occurring in at least 1% of RCT records were identified. Fifty percent of the RCT and comparison group records were randomly selected, and the ability of the terms to discriminate RCTs from non-trial records was determined using logistic regression. The best performing combinations of terms were tested on the remaining records and in MEDLINE. RESULTS: The best discriminating term was "Clinical Trial" (Publication Type). In years where the Cochrane assessment of MEDLINE records had taken place, the strategies identified few additional unindexed records of trials. In years where Cochrane assessment has yet to take place, "Randomized Controlled Trial" (Publication Type) proved highly sensitive and precise. Adding six more search terms identified further, unindexed trials at reasonable levels of precision and with sensitivity almost equal to the Cochrane HSSS. CONCLUSIONS: Most reports of RCTs in MEDLINE can now be identified easily using "Randomized Controlled Trial" (Publication Type). More sensitive searches can be achieved by a brief strategy, the Centre for Reviews and Dissemination/Cochrane Highly Sensitive Search Strategy (2005 revision).

Abstracting and Indexing↗

PubMed2006

Using the symptom monitor in a randomized controlled trial: the effect on symptom prevalence and severity.

This randomized controlled trial investigated the effect of reporting physical symptoms by using a systematic symptom monitoring instrument, the Symptom Monitor, on symptom prevalence and severity among patients with cancer in the palliative phase. The overall objective was to achieve symptom relief through systematic and regular symptom reporting by patients themselves. One hundred forty-six patients with cancer in the palliative phase were randomized to either the intervention group (n = 69 with Symptom Monitor) or the control group (n = 77 without Symptom Monitor). Ten physical symptoms with regard to prevalence and severity were monitored. After 2 months, the prevalence of symptoms was lower in the intervention group compared to the control group (prevalent differences 2.1-24.3%) for 9 out of 10 symptoms (except coughing). The intervention group scored a statistically significantly lower prevalence in constipation and vomiting (prevalence differences 24.3% and 18.0%, respectively). In four symptoms (fatigue, lack of appetite, shortness of breath, and nausea), the intervention group had a lower, although not statistically significant, severity score (median differences 0.5-1). In four symptoms (pain, coughing, sleeplessness, and diarrhea), the severity score was the same in both groups (medians 2-4). In two symptoms (constipation and vomiting), the severity score was lower in the control group (median differences -1 and -2). A comparison between the study groups on improved, deteriorated, or steady-state cases showed that the severity score had deteriorated less for 8 out of 10 symptoms in a larger proportion of patients in the intervention group. Although statistical significance was not reached, the prevalence as well as severity of symptoms in the palliative phase of cancer can be influenced by using the Symptom Monitor.

Aged↗

PubMed2003

Reliability of the PEDro scale for rating quality of randomized controlled trials.

BACKGROUND AND PURPOSE: Assessment of the quality of randomized controlled trials (RCTs) is common practice in systematic reviews. However, the reliability of data obtained with most quality assessment scales has not been established. This report describes 2 studies designed to investigate the reliability of data obtained with the Physiotherapy Evidence Database (PEDro) scale developed to rate the quality of RCTs evaluating physical therapist interventions. METHOD: In the first study, 11 raters independently rated 25 RCTs randomly selected from the PEDro database. In the second study, 2 raters rated 120 RCTs randomly selected from the PEDro database, and disagreements were resolved by a third rater; this generated a set of individual rater and consensus ratings. The process was repeated by independent raters to create a second set of individual and consensus ratings. Reliability of ratings of PEDro scale items was calculated using multirater kappas, and reliability of the total (summed) score was calculated using intraclass correlation coefficients (ICC [1,1]). RESULTS: The kappa value for each of the 11 items ranged from.36 to.80 for individual assessors and from.50 to.79 for consensus ratings generated by groups of 2 or 3 raters. The ICC for the total score was.56 (95% confidence interval=.47-.65) for ratings by individuals, and the ICC for consensus ratings was.68 (95% confidence interval=.57-.76). DISCUSSION AND CONCLUSION: The reliability of ratings of PEDro scale items varied from "fair" to "substantial," and the reliability of the total PEDro score was "fair" to "good."

Databases, Bibliographic↗

PubMed2006

Redefining the randomized controlled trial in the context of acupuncture research.

BACKGROUND: The randomized controlled trial (RCT) is considered the 'gold standard' methodology for evaluating efficacy of an intervention. It has been argued that RCTs cannot be used to examine the effectiveness of acupuncture. PURPOSE: The purpose of this paper is to examine the applicability of an RCT study design for acupuncture research. FINDINGS: RCTs would be more effective in studying acupuncture if study participants were randomized to groups based on the acupuncture diagnosis and not solely on the Western diagnostic criteria. Treatments must also be standardized somewhat to ensure replicability of the study and the information it provides. Blinding is not absolutely necessary for a good-quality RCT; however, if used, control groups need to be standardized and sham techniques evaluated to ensure accurate interpretation of results. CONCLUSIONS: With these factors combined, it is possible to greatly increase internal and external validity in acupuncture RCTs.

Acupuncture Therapy↗

PubMed2000

Evaluation of ethical conflicts associated with randomized, controlled trials in critically ill children.

OBJECTIVE: To determine whether randomized, controlled trials (RCTS) of potentially life-sustaining therapies in critically ill infants and children cause an ethical conflict for physician investigators and if ethical conflicts affect protocol implementation. DESIGN: Descriptive survey. SUBJECTS: A convenience sample of 1,050 physicians from a national pediatric critical care meeting mailing list. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The survey return rate was 41% (n = 415). Of the returned surveys, 81% (n = 331) were answered by pediatric intensivists and fellows. The remaining 19% (n = 84) were completed by other physician subspecialists. Overall, 74% had experience with RCTs involving a potentially life-saving therapy (25% had experience with three or more trials, and 26% had never participated in this type of study). The vast majority of the respondents (96%) indicated that they believe RCTs of potentially life-sustaining therapies are ethical; however, only 10% stated that they never experienced an ethical conflict with these types of studies. Most respondents (84%) indicated that published data from uncontrolled trials may bias them toward an investigational therapy. Furthermore, only 35% of the respondents indicated that they always maintain strict protocol adherence when the condition of a control patient deteriorates and parents request the experimental treatment. There was a significant association between physicians who experienced an ethical conflict and the likelihood that they would do the following if the condition of a control patient deteriorated: fail to maintain strict protocol adherence (p = .05); alter the protocol in response to parental requests for the experimental treatment (p < .01); or seek compassionate use of the experimental treatment (p < .01). CONCLUSIONS: Although physicians consider RCTs of potentially life-sustaining therapies ethical, they acknowledge that this type of study sometimes creates an ethical conflict. Published results of uncontrolled trials lead to investigator bias in randomized trials and preclude equipoise. Our results indicate that RCTs involving life-sustaining therapies may be biased, lack consistent protocol implementation, and raise concern that data from these studies are potentially flawed.

Bias↗

PubMed2001

Effect of early patient enrollment on the time to completion and publication of randomized controlled trials.

The authors evaluated whether early enrollment affects the significance of the results and the time to completion and publication of randomized controlled trials. Seventy-seven efficacy randomized controlled trials (total enrollment, 28,992 patients) initiated by the Acquired Immunodeficiency Syndrome Clinical Trials Group between 1986 and 1996 were evaluated. After adjustment for target sample size, for each 10-fold increase in the first-month accrual, the odds of a trial reaching statistically significant results increased 2.8-fold (p = 0.040). The relative enrollment during the first month over target sample size (hazard ratio (HR) = 1.40 per 10 percent increase, p = 0.004) and masking (HR = 1.78 for double-blind vs. single or unblinded studies, p = 0.031) were the major predictors of faster completion. Rapid early accrual (HR = 1.09 per 10 additional patients accrued the first month, p = 0.011) and statistical significance in favor of an experimental arm (HR = 2.47, p = 0.004) independently predicted faster publication. Early enrollment is a strong predictor of whether a study will reach formal statistical significance, and it can offer predictive information on the time needed to complete the study and publish its findings. Ongoing unpublished studies and their enrollment rates may need to be considered when interpreting the accumulated evidence.

Acquired Immunodeficiency Syndrome↗

PubMed2004

The Personality Disorders Institute/Borderline Personality Disorder Research Foundation randomized control trial for borderline personality disorder: rationale, methods, and patient characteristics.

The Personality Disorder Institute/Borderline Personality Disorder Research Foundation randomized control trial (PDI/BPDRF RCT) is a controlled outcome study for borderline personality disorder (BPD), in which 90 participants were randomized to one of three manualized and monitored, active psychosocial treatment conditions. These treatments are: (a) Transference-Focused Psychotherapy (TFP; Clarkin, Yeomans, & Kernberg, 1999), a treatment for BPD based on object-relational and psychoanalytic principles first applied to BPD by Kernberg (1996), notable for its particular emphasis on interpretation of object relations activated in the ongoing therapeutic relationship; (b) Dialectical Behavior Therapy (DBT; Linehan, 1993), a popular treatment for BPD, with evidence of efficacy (Linehan, Armstrong, Suarez, Allmon, & Heard, 1991) that emphasizes a balance between acceptance and change in its combination of cognitive-behavioral and Zen principles; and (c) supportive psychotherapy (Rockland, 1992), another object-relational and psychoanalytically based treatment for BPD which, in contrast to TFP, eschews transference interpretation and places primary emphasis on development of a collaborative engagement with the patient to foster identity development. Patients received medication, if clearly indicated, according to the treatment algorithm developed by Soloff (2000). This article describes the significance and rationale of the study and the overall design, methods, plan of analysis, and demographic characteristics of the recruited sample of patients.

Adult↗

PubMedDate not supplied

Effects of multimicronutrient supplementation on helminth reinfection: a randomized, controlled trial in Kenyan schoolchildren.

A randomized, placebo-controlled, double-blind, two-by-two factorial trial was carried out among 977 schoolchildren from 19 primary schools in Nyanza Province, Kenya from February 1995 to February 1996. The interventions were multimicronutrient supplementation (vitamin A, 1000 micrograms; vitamin B1, 1.4 mg; vitamin B2, 1.6 mg; vitamin B6, 1.7 mg; vitamin B12, 2.0 micrograms; folate, 150 micrograms; niacin, 16 mg; vitamin C, 50 mg; vitamin D, 5 micrograms; vitamin E, 8 mg; iron, 18 mg; zinc, 20 mg; copper, 2.0 mg; iodine, 150 micrograms; selenium, 40 micrograms) and multihelminth chemotherapy (albendazole 600 mg in a single dose and/or praziquantel 40 mg/kg in a single dose). This paper reports the effects of the supplementation given on all school days on reinfection with hookworm, Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni after 11 months. Baseline prevalence and geometric mean intensity for hookworm, A. lumbricoides, T. trichiura and S. mansoni in all children investigated were 54.7%, 13.8%, 45.6% and 70.0%, respectively and 8.6, 2.7, 5.9 and 19.4 eggs per gram (epg), respectively. Children received a mean of 2.3 multimicronutrient/placebo tablets per school week, giving a compliance rate of 46%. Children given multimicronutrients had a slightly, but significantly, lower intensity of S. mansoni reinfection compared with children given placebo (5.5 epg vs. 7.7 epg, P = 0.047). Multiple linear regression analyses controlling for baseline infection status confirmed this, as children who received micronutrients were reinfected with S. mansoni at only 69% of the intensity of those who received placebo. Multiple logistic regression analyses revealed that micronutrient supplementation was associated with a lower S. mansoni reinfection rate (odds ratio = 0.7) although this was only of borderline significance (P = 0.090). There were no significant differences in reinfection rates or intensities of hookworm, A. lumbricoides and T. trichiura. The effect on S. mansoni infection intensity is particularly interesting given the low compliance, suggesting that full micronutrient supplementation might have a role to play in S. mansoni control programmes.

Adolescent↗

PubMed1999

Developing a register for randomized controlled trials in prosthodontics: results of a search from prosthodontic journals published in the United States.

STATEMENT OF PROBLEM: Treatment decisions are often made despite absence of evidence from well-conducted clinical trials. Conclusions about treatment efficacy derived from nonexperimental approaches often overestimate treatment effect. Randomized controlled trials (RCTs) provide the most reliable basis for evaluating effectiveness of treatment interventions. PURPOSE: This study attempted to identify and catalog RCTs in prosthodontic journals published in the United States as an initial step in creating a register of clinical trials that would be a resource in setting up systemic overviews of prosthodontic literature. METHODS: The International Journal of Prosthodontics, The Journal of Prosthetic Dentistry, and The Journal of Prosthodontics published between 1988 and 1997 were searched manually to identify clinical trials. Clinical trials had to meet the following criteria for inclusion in the register: the trial must involve human subjects, must include at least 2 treatment groups, and treatment group allocation must be randomized. RESULTS: A total of 3,631 articles in 196 journal issues were screened. Sixty-two articles (1.7%) met the minimum criteria for inclusion in the RCT register. CONCLUSION: Given the lack of randomized controlled trials in prosthodontic journals, a concerted effort by the organized prosthodontic community should be made to screen national and international journals and contribute to the development of a register of randomized controlled trials relevant to prosthodontics.

Dental Research↗

PubMed2006

Prevalence and factors associated with use of placebo control groups in randomized controlled trials in psoriasis: a cross-sectional study.

BACKGROUND: The ethics and science of using placebo control groups in clinical trials have been widely debated. Few studies, however, have examined factors associated with choice of control group. OBJECTIVE: Our aim was to assess the prevalence of use of placebo controls in randomized controlled trials in psoriasis and to identify factors associated with use of placebo controls in these trials. METHODS: This is a cross-sectional study of randomized controlled trials in psoriasis published from January 1, 2001 to December 20, 2005 and indexed in the Cochrane Central Register of Controlled Trials. We extracted data on types of control groups used, design issues (number of patients enrolled, primary end point), disease characteristics (psoriasis type and severity), and extrascientific issues (trial location, funding source, and year of publication). We used bivariable and multivariable logistic regression to determine factors associated with use of a placebo control group. RESULTS: Of 194 citations, 187 were available for review. One hundred thirty-five trials from 134 articles in 38 journals met inclusion criteria. Eighty-three trials (61.5%) enrolling 8171 subjects (41.7%) used active controls only, and 52 trials (38.5%) enrolling 11,406 subjects (58.3%) used placebo controls. Adjusted for trial location and funding source, trials significantly more likely to have used placebo controls included those conducted in the United States (odds ratio [OR], 5.79; 95% confidence interval [CI], 2.45-13.68; P < .001) and those funded by pharmaceutical companies (OR, 2.61; 95% CI, 1.19-5.73; P = .02). Predicted frequencies of placebo use ranged from 77.6% (industry-funded, conducted trials in the United States) to 18.6% (non-industry-funded trials not conducted in the United States). LIMITATIONS: Our searches may not have identified all published trials, and we did not have access to data from unpublished trials. CONCLUSIONS: Use of placebo controls has been more common in psoriasis trials conducted in the United States and funded by pharmaceutical companies. The findings suggest that ethical and scientific issues related to choice of control group in psoriasis trials are interpreted markedly differently depending on trial location and funding source.

Cross-Sectional Studies↗