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Results for “Randomized clinical trials (RCTs)”

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PubMed1990

Critical review of the quality and development of randomized clinical trials (RCTs) and their influence on the treatment of advanced epithelial ovarian cancer.

Trials on chemotherapy of advanced ovarian cancer published between 1975-88 were systematically reviewed for quality (according to the method of Chalmers) and consistency of tested hypotheses with a view to a meta-analysis of all published studies in the field. Median overall, internal and external validity scores were 47%, 43% and 53%, respectively. No association was found between scores and key features of trials, such as percentage studies with significant results in response or survival or percentage studies with high or low follow-up retention (withdrawal rates less than or greater than or equal to 15%). Only 21% of trials reported a fully blind randomization procedure and only in 13% were drop-outs accounted for by the intent-to-treat method. Only 4 trials entered more than 150 patients per arm, a sample size consistent with detection of an absolute difference of 11% in mortality. The majority of trials (58%) investigated the role of combination regimens versus a single-agent control arm. The remaining trials tested different polychemotherapies. However, within these two general issues, treatment options were quite heterogeneous: seven subgroups were identified by whether cisplatin was present in either the treatment or the control arm. We conclude that the internal coherence and development of randomized clinical trials in advanced ovarian cancer and their methodologic soundness are quite poor. In this situation meta-analysis cannot go beyond a systematic attempt to answer a very general "treatment effectiveness" question.

Antineoplastic Agents↗

PubMedDate not supplied

Treatment of atopic dermatitis with antihistamines: lessons from a single-patient, randomized clinical trial.

BACKGROUND: Single-patient randomized clinical trials (RCTs) can be utilized to maintain methodologic precision in the analysis of treatment effect in individual patients. We describe the results of a single-patient RCT in a patient with atopic dermatitis and review practical considerations regarding the use of antihistamines. METHODS: Using double-blind, crossover techniques, the patient was randomly allocated to four 2-week treatment periods with the following regimens: chlorpheniramine, 8 mg twice daily; chlorpheniramine, 12 mg twice daily; terfenadine, 120 mg twice daily; and placebo (phase 1). The drug that produced superior results from phase 1 (chlorpheniramine, 8 mg) was subsequently compared with astemizole, 10 mg/d, during phase 2, consisting of four 4-week, double-blind, crossover trial periods with random allocation of study drugs. Daily symptom scores, as well as end of treatment period summary impressions by patient and investigator, were analyzed. RESULTS: In both phases, chlorpheniramine produced the most noticeable positive therapeutic effect on the patient's mild but most disturbing symptoms (pruritus and eye irritation) associated with atopic dermatitis. Drowsiness was reported with chlorpheniramine. Tolerance to this side effect, however, developed quickly. CONCLUSIONS: A single-patient RCT with different antihistamines in a patient with chronic atopic dermatitis was a useful tool in achieving a favorable balance among efficacy, toxicity, and cost of therapy.

Adult↗

PubMed1985

The retrieval of randomized clinical trials in liver disease from the medical literature. A comparison of MEDLARS and manual methods.

Randomized clinical trials (RCTs) provide the most reliable therapeutic information available. Unfortunately, there are no systemic listing of RCTs. We compared a MEDLARS search of 3686 biomedical journals for RCTs with a manual search of the medical literature for the period 1966-1982. For the former search we used subject headings (1) liver disease or (2) biliary tract disease and subheadings (1) drug therapy, (2) surgery, (3) radiotherapy, or (4) therapy, and check tags (1) comparative study or (2) clinical research. For the manual search, the contents of 34 arbitrarily selected, gastroenterologic, hepatologic, surgical, or general journals were perused. The MEDLARS search identified 160 RCTs and 29 others were found in the references of the 160. One hundred fifty-four RCTs were identified by both methods. The manual search identified 208 RCTs and an additional 34 were found in the references of the 208. The MEDLARS search identified only 107 of 208 RCTs found in the references of the 208. The MEDLARS search identified only 107 of 208 RCTs found manually in the 36 journals, an efficiency rate of 51%. We estimate that 330 hepatobiliary RCTs had been published during this 17-year period. Sixty percent of the RCTs found by MEDLARS used the key word "randomized," "double blind," or "controlled" in the title, compared to 36% in those found by the manual search. In order to retrieve RCTs, it is essential that editors require that RCTs be identified in their titles or key words by specific terms such as "controlled," "randomized," and "double blind," that papers be so catalogued and indexed, and that searchers be instructed in appropriate search strategies.

Clinical Trials as Topic↗

PubMed2026

The clinical value of adding immune checkpoint inhibitors to radiotherapy for cancer: a systematic review and meta-analysis.

BACKGROUND: While several randomized clinical trials (RCTs) have explored the addition of immune checkpoint inhibitor (ICI) treatment for patients undergoing radiotherapy, studies systematically assessing the clinical value of such interventions are lacking. METHODS: PubMed, Embase, and Cochrane Library databases were searched for relevant RCTs of cancers that received ICIs plus radiotherapy or radiotherapy. Eligible studies were those published in English as of 14 April 2024. Two independent reviewers screened the included studies and extracted relevant data, then selected the random or fixed-effects model based on the I2 statistic. The main outcomes were hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS); Odds ratios (ORs) with 95% CIs for objective response rate (ORR), disease control rate (DCR), and adverse events (AEs). Stratified analysis was performed based on cancer type, ICI type, and the timing of ICI addition. The study was registered on PROSPERO (CRD42024551008). RESULTS: 15 RCTs with 7947 patients were included. Pooled HRs were 0.865 (95% CI, 0.730-1.000; I2 = 72.1%) for OS and 0.799 (0.677-0.922; I2 = 82.0%) for PFS in cancer patients. In cancer types, adding immunotherapy to radiotherapy significantly improved patients with non-small-cell lung cancer (OS: 0.544 [0.371-0.717]; PFS: 0.527 [0.438-0.617]) and cervical cancer (OS: 0.722 [0.578-0.867] and PFS: 0.754 [95%CI, 0.621-0.887]). Regarding the ICIs schedule, adjuvant ICI therapy with pooled HRs was 0.742 (0.649-0.834) for OS and 0.638 (0.579-0.697) for PFS. In addition, the pooled ORs for the incidence of grade 3 or higher treatment-related and immune-related adverse events were 1.227 (1.059-1.421; I2 = 71.9%) and 2.217 (1.743-2.821; I2 = 74.0%), respectively. CONCLUSION: Adding immunotherapy to radiotherapy can provide significant clinical benefits for patients with NSCLC and cervical cancer, and the addition of these ICIs in the adjuvant stage is supported.

Humans↗

PubMed1978

Treatment of gastric ulcer. The randomized clinical trials from 1964 to 1974 and their impact.

Twenty-nine randomized clinical trials (RCTs) from the decade 1964-74 evaluating treatments of gastric ulcer have been analyzed. None of them ful-filled all criteria for an ideal RCT. The most frequent shortcomings were: short treatment or follow-up periods, incomplete description of the patients included, small patient samples, suboptimal experimental design, lack of double-blind testing, high number of drop-outs, less precise or less relevant types of evaluation of the treatment effect, uncontrolled ancillary treatment, or lack of statistical evaluation of the results. The most frequently tested drug was carbenoxolone, which has been shown to be clearly effective. Judged by the effect on the recommendations in standard medical textbooks the impact of the best RCTs have been small. This situation emphasizes the need for more well-planned and performed RCTs on treatments of gastric ulcer.

Adult↗

PubMed1992

The efficacy of chiropractic manipulation for back pain: blinded review of relevant randomized clinical trials.

OBJECTIVE: To assess the efficacy of chiropractic for patients with back pain. DATA SOURCES: Randomized clinical trials (RCTs) on spinal manipulation were identified with a Medline search (1966-1990), by citration tracking, and by manual examination of the relevant chiropractic reference systems [Chiropractic Research Archives Collection and Index to Chiropractic Literature]. [Indexing terms, Medline; backache, musculoskeletal diseases, manipulation, osteopathy or chiropractic in combination with evaluation studies, outcome and process assessment, prospective studies, comparative studies, clinical trials or double blind method. Indexing terms, Chiropractic Research Archives Collection: backache therapy-chiropractic clinical trials, cost benefit analysis, evaluation studies--chiropractic, manipulation--spinal, prospective studies, sciatica-therapy. Indexing terms, Index to Chiropractic Literature, backache therapy, clinical trials, cost benefit analysis, intervertebral disc displacement-therapy.] STUDY SELECTION: All RCTs involving chiropractors as therapists. To find additional evidence from nonchiropractic RCTs, chiropractic standards similar to the type of treatment used in nonchiropractic trials were determined by a panel of blinded chiropractors. DATA EXTRACTION: Review by two blinded reviewers independently, using a list of methodological criteria, each of which was attached to a weight. The maximum was set at 100 points. DATA SYNTHESIS: We identified five chiropractic RCTs. No similarity to chiropractic standards could be detected in any of the nonchiropractic RCTs. No chiropractic RCT had a methodological score of more than 50 points. The authors of four of the trials report favorable results for chiropractic, while one refrains from drawing conclusions. The results of the chiropractic RCTs differed on the timing of maximal effect as well as on the subgroups showing the best treatment results. CONCLUSIONS: Although the small number of chiropractic RCTs and the poor general methodological quality precludes the drawing of strong conclusions, chiropractic seems to be an effective treatment of back pain. However, more studies with a better research methodology are clearly still needed.

Back Pain↗

PubMed1992

Integrating conflicting professional roles: physician participation in randomized clinical trials.

The traditional identification of physicians as either clinician or researcher is challenged by the emergence of randomized clinical trials (RCTs) where research and clinical care are performed simultaneously. A mail survey using a self-administered questionnaire, the Physician Orientation Profile, was conducted of 101 physicians from the Collaborative Ocular Melanoma Study (COMS), a set of trials which compares surgical removal of the eye with radiation in the treatment of medium sized eye cancers. A 95% response rate was obtained; follow-up telephone interviews were conducted with 87% of respondents. Key findings suggest that RCTs challenge traditional definitions of physician's 'core task,' because they participate in a social process that requires them to integrate the formerly disparate and sometimes competing roles of researcher and clinician. Three implications of this integration are discussed: amending the expert reward system, altering customary clinical practice and redefining reference groups for professional interaction.

Adult↗

PubMed1989

Philosophers assess randomized clinical trials: the need for dialogue.

In recent years a growing number of professional philosophers have joined in the controversy over ethical aspects of randomized clinical trials (RCTs). Morally questionable in their utilitarian approach, RCTs are claimed by some to be in direct violation of the second form of Kant's Categorical Imperative. But the arguments used in these critiques at times derive from a lack of insight into basic statistical procedures and the realities of the biomedical research process. Presented to physicians and other nonspecialists, including the lay public, such distortions can be harmful. Given the great complexity of statistical methodology and the anomalous nature of concepts of evidence, more sustained input into the interdisciplinary dialogue is needed from the statistical profession.

Comprehension↗

PubMed1992

Reasons for non-entry in randomized clinical trials for breast cancer: a single institutional study.

Reasons for patient non-entry in randomized clinical trials (RCTs) assessing oncologic treatment modalities are not well documented in the literature. We have prospectively recorded reasons for RCT non-entry in breast cancer patients at St. Michael's Hospital, Toronto. From September 1984 to November 1989, 592 consecutive patients were evaluated through the clinical trials office. One hundred six out of the 592 patients were placed into a RCT (17.9%). Protocol ineligibilities accounted for 273 non-entries (46.1%) and protocol eligible but not entered patients accounted for 213 (36.0%) non-entries. The most common reason for protocol ineligibility was advanced age (94 patients). The most common reason for protocol eligible but not entered patients was patient refusal (148 patients). A total of 272 patients in both non-entered groups were identified as having reasons for non-entry that were potentially correctable. In summary, protocol ineligibilities account for the majority of non-entered patients, but patient refusal accounted for the single largest group of potentially correctable non-entries. More dissemination about the merit of RCTs in the lay press and amongst primary care physicians must take place if we are to expediently and efficiently answer important oncologic questions.

Breast Neoplasms↗

PubMed1987

Clinical evaluation: how does it influence medical practice?

This paper reviews reports of the effects of clinical evaluations on physician awareness and behavior. Among the reviewed papers, there are 28 studies of the effect of specific randomized clinical trials (RCTs) on 19 different medical practices. After analyzing these 28 papers, there remain two (7%) where the RCT has clear implications for practice, where the pattern of practice reported quantitatively over time conforms fully to the RCT findings, where the RCT preceded the change in the pattern of practice, and where findings from the RCT differ from the results of other forms of evaluation. The majority of the reviewed papers do not support an inference that RCTs have a strong, direct influence in changing established clinical practices. Clinical evaluation is one among many factors bearing on changes in medical practices. Improving the care of patients requires both improved methods of evaluation and more effective translation of the results of evaluation into practice. Evaluations are likely to exert a greater impact on medical practices if they are buttressed by attention to other controllable factors, like channels of communication and environmental constraints and incentives, that affect the adoption and abandonment of medical practices.

Awareness↗

PubMed1987

Publication bias and clinical trials.

A study was performed to evaluate the extent to which the medical literature may be misleading as a result of selective publication of randomized clinical trials (RCTs) with results showing a statistically significant treatment effect. Three hundred eighteen authors of published trials were asked whether they had participated in any unpublished RCTs. The 156 respondents reported 271 unpublished and 1041 published trials. Of the 178 completed unpublished RCTs with a trend specified, 26 (14%) favored the new therapy compared to 423 of 767 (55%) published reports (p less than 0.001). For trials that were completed but not published, the major reasons for nonpublication were "negative" results and lack of interest. From the data provided, it appears that nonpublication was primarily a result of failure to write up and submit the trial results rather than rejection of submitted manuscripts. The results of this study imply the existence of a publication bias of importance both to meta-analysis and the interpretation of statistically significant positive trials.

Clinical Trials as Topic↗

PubMed1986

The conflict between randomized clinical trials and the therapeutic obligation.

The central dilemma concerning randomized clinical trials (RCTs) arises out of some simple facts about causal methodology (RCTs are the best way to generate the reliable causal knowledge necessary for optimally-informed action) and a prima facie plausible principle concerning how physicians should treat their patients (always do what it is most reasonable to believe will be best for the patient). A number of arguments related to this in the literature are considered. Attempts to avoid the dilemma fail. Appeals to informed consent and mechanisms for minimizing the resulting harm are important for policy, but informed consent is problematic and mechanisms for minimization of harm do not address the dilemma. Appeals to some sort of contract model of justification are promising and illuminating.

Clinical Trials as Topic↗

PubMed1992

The efficacy of laser therapy for musculoskeletal and skin disorders: a criteria-based meta-analysis of randomized clinical trials.

The efficacy of laser therapy for musculoskeletal and skin disorders has been assessed on the basis of the results of 36 randomized clinical trials (RCTs) involving 1,704 patients. For this purpose, a criteria-based meta-analysis that took into account the methodological quality of the individual trials was used. The studies with a positive outcome were generally of a better quality than the studies with a negative outcome. No clear relationship could be demonstrated between the laser dosage applied and the efficacy of laser therapy, or between the dosage and the methodological score. In general, the methodological quality of these studies appeared to be rather low. Consequently, no definite conclusions can be drawn about the efficacy of laser therapy for skin disorders. The efficacy of laser therapy for musculoskeletal disorders seems, on average, to be larger than the efficacy of a placebo treatment. More specifically, for rheumatoid arthritis, posttraumatic joint disorders, and myofascial pain, laser therapy seems to have a substantial specific therapeutic effect. Further RCTs, avoiding the most prevalent methodological errors, are needed in order to enable the benefits of laser therapy to be more precisely and validly evaluated.

Dose-Response Relationship, Radiation↗

PubMed1987

Recruitment in NHLBI population-based studies and randomized clinical trials: data analysis and survey results.

Data on screening and recruitment from current and previous NHLBI population-based studies (PBSs) and randomized clinical trials (RCTs) were examined. In only two of the studies examined was the projected recruitment completed within the planned recruitment period. The shape of the graph of the relation between enrollment of participants and time varies by study. A single summary statistic for measuring the efficiency of recruitment in RCTs and PBSs is proposed and applied to the examined studies. In addition to providing summary data on recruitment for several studies, this article reports the survey results of a questionnaire sent to the coordinating centers of currently and previously funded National Heart, Lung, and Blood Institute and Veteran's Administration studies. The purpose was to ascertain the desirability of recommending that a generic core of information be collected on recruitment and screening in future studies. Most respondents believed that comparing data collected uniformly and prospectively might be helpful in designing further studies. The variables most respondents believed to be potentially useful are described.

Clinical Trials as Topic↗

PubMed2026

Efficacy, tolerability, and threshold effect of atropine eye drops for myopia control: A systematic review and dose-response meta-analysis.

Atropine is an emerging therapy for myopia, yet the optimal concentration for prescription remains uncertain. We searched PubMed, Embase, Web of Science, Cochrane Library, World Health Organization International Clinical Trials, and ClinicalTrials.gov registry platforms. We included the randomized clinical trials (RCTs) that compared any dose of atropine against a placebo in myopic children. Among 3566 studies assessed, we identified 33 eligible RCTs involving 6301 children aged 4-18 years, with 10 different concentrations and a mean follow-up time of 19.5 ± 12.3 months. A nonlinear relationship was observed between atropine dosage and treatment efficacy (P < 0.001). Compared to placebo groups, the mean differences in reducing annual spherical equivalent refraction progression for atropine concentrations of 0.01%, 0.02%, 0.03%, 0.04%, and 0.05% were 0.21 diopters (D) (95% CI, 0.13-0.28), 0.35 D (95% CI, 0.23-0.46), 0.42 D (95% CI, 0.28-0.56), 0.45 D (95% CI, 0.30-0.60), and 0.46 D (95% CI, 0.32-0.61) respectively For higher concentrations, the estimates were 0.49 D (95% CI, 0.34-0.63) for 0.1% and 0.99 D (95% CI, 0.66-1.31) for 1%, although these were based on fewer and smaller trials. Higher doses of atropine were associated with decreased amplitude of accommodation (P = 0.02), increased pupil diameters (P = 0.01) and a higher frequency of photophobia (P = 0.02). Our findings suggest that the increase in treatment efficacy with higher concentrations may plateau beyond a certain range, and that the current practice of increasing atropine concentrations for children who show inadequate responses to lower doses should be confined to a specific concentration range. This analysis is limited by the number, design heterogeneity, and sample sizes of available trials for higher concentrations, and by the frequent lack of pre-intervention refractive history in included studies. Therefore, estimates-particularly for doses exceeding 0.1%-should be interpreted with caution.

Humans↗

PubMed1992

Prevention of upper gastrointestinal bleeding from portal hypertension in cirrhosis: rationale for medical treatment.

We updated meta-analysis and critical descriptive analysis of randomized clinical trials (RCTs) assessing the value of beta-blockers in preventing first bleeding (prophylactic) or rebleeding (therapeutic) and on survival of patients with cirrhosis. Both the methods of Peto-Mantel-Haenszel and DerSimonian-Laird were used to assess the heterogeneity and obtain cumulative estimates of treatment effects; the L'Abbé plot was also used for a visual assessment of heterogeneity in the direction of treatment effect. Seven prophylactic and nine therapeutic RCTs were analysed. beta-Blockers uniformly reduced the bleeding risk and revealed a trend toward improved survival in non-ascitic, well-compensated patients in both the prophylactic and therapeutic sets of RCTs. Discordant results were found in patients with ascites or in poor functional condition.

Adrenergic beta-Antagonists↗

PubMed2026

Timeliness of publication of randomized controlled trials in rheumatology: A systematic review.

OBJECTIVE: To systematically review the (1) timeliness of publication of randomized controlled trials (RCTs) in rheumatology, (2) impact of the COVID-19 pandemic on time to publication, and (3) factors associated with publication delays. METHODS: We searched Medline, Embase, EBM Reviews, Cochrane Central Register of Controlled Trials, and Scopus from January 1, 2018, to June 30, 2023 for Phase 3, superiority, parallel-design RCTs that evaluated any treatment for a rheumatologic illness or a rheumatologic treatment for COVID-19 and reported clinical primary efficacy outcome. Outcomes of interest were time to publication after trial completion and publication delay of >2 years after trial completion. RESULTS: 448 RCTs were included in this systematic review. Median time from completion to publication was 549 days and 65.9 % RCTs were published within 2 years of completion. Compared with RCTs on rheumatologic diseases, RCTs on COVID-19 were published sooner (253 vs. 549 days; p < 0.001) and were more likely to be published within 2 years (adjusted OR 9.49, 95 % CI 2.07 to 43.61). Compared with RCTs completed before March 1, 2020, RCTs completed after March 1, 2020, were published sooner (327 vs. 724 days; p < 0.001) and were more likely to be published within 2 years (adjusted OR 9.40, 95 % CI 5.14 to 17.21). Time from RCT completion to submission accounted for most (67 %) of the time to publication. CONCLUSIONS: Publication delay continues to be an important concern in dissemination of clinical research. Most of the delays in publication were attributable to delays in submission to journals after trial completion.

Humans↗

PubMed1990

The evaluation of different approaches to randomized clinical trials. Report on the 1987 MacArthur Foundation Network I Methodology Workshop.

The second annual MacArthur Foundation Network I Methodology Workshop focused on the different approaches to implementing randomized controlled clinical trials (RCTs) and the situations in which each approach seems to be most appropriate. We reviewed the advantages and disadvantages of various approaches (single-site RCTs, multisite collaborative RCTs, multiple single-site RCTs, and meta-analysis of existing RCTs), and we make recommendations based on these considerations proposed.

Cost-Benefit Analysis↗