RESUMO
Trial registration has a great potential to increase research transparency and public access to research results. This study examined the availability of results either in journal publications or in the trial registry from all studies registered atClinicalTrials.gov. All 137,612 records from ClinicalTrials.gov in December 2012 were merged with all 19,158 PubMed records containing registration numbers in the indexing field or in the abstracts. A multivariate analysis was conducted to examine the association between the availability of the results with study and participant characteristics available in registration records. Fewer than 10% of the registered studies and 15% of the registered and completed studies had published results. The highest publication rate of 22.4% was for randomized trials completed between 2005 [starting year for structured indexing in PubMed of study registration] and 2010. For 86% of overall and 78% of completed registered studies, no results were available in ClinicalTrials.gov or in journal publications. Studies funded by industry vs. other funding sources and drug studies vs. all studies of other interventions were published less often after adjustment for study type, subject characteristics, or posting of results in ClinicalTrials.gov. Existing policy does not ensure availability of results from clinical research. International policy revisions should charge principal investigators with ensuring that the approved protocols and posted data elements are aligned and that results are available from all conducted studies
RESUMO
We conducted a meta-analysis using results from the Korean literature to determine whether prostate-specific antigen (PSA) or digital rectal examination (DRE) or transrectal ultrasonography (TRUS) provides a better diagnostic outcome for possible prostate cancer patients. An extensive literature search of MedRIC database et al. (1980 to 2003) was performed using the medical subject headings "PSA", "DRE", "TRUS" and "prostate cancer". Of the 108 articles that we retrieved, 13 studies (2, 029 subjects) were selected for this meta-analysis. The criteria for quality evaluation were as follows: the study subjects must have been compared clinically for suspected prostate cancer, and the articles must have included individual data about sensitivity and specificity for this diagnostic triad based on the biopsy results as a reference standard. For the quantitative meta-analysis process the Hasselblad method was utilized. The pooled sensitivity and specificity for a PSA level greater than 4ng/mL were 91.3% and 35.9%, respectively; and those for a PSA level greater than 10ng/mL were 77.3% and 67.5%, respectively; and those for DRE were 68.4% and 71.5%, respectively; and those for TRUS were 73.6% and 61.3%, respectively. According to the results in a fixed effect model for PSA criteria, the estimates of d for PSA4 and PSA10 were 0.8517 [95% confidence interval (CI) : 0.6694, 1.0340] and 1.0996 (95% CI: 0.9459, 1.2534), respectively. Also, according to the results using a random effect model for both DRE and TRUS criteria, the estimates of d for DRE and TRUS were 0.8398 (95% CI: 0.7169, 0.9627) and 0.8002 (95% CI: 0.6714, 0.9289), respectively. The detection rate for combination testing of PSA, DRE and TRUS for the diagnosis of prostate cancer jumped further to 68.3% or to 76.8%. In conclusion, this study suggests that this diagnostic triad for prostate cancer was noneffective when they were used separately. Therefore, we recommend that the urologists should use PSA together with DRE and TRUS for the primary diagnosis of prostate cancer in men with lower urological symptoms.