Primary versus secondary source of data in observational studies and heterogeneity in meta-analyses of drug effects: a survey of major medical journals

The data from individual observational studies included in meta-analyses of drug effects are collected either from ad hoc methods (i.e. "primary data") or databases that were established for non-research purposes (i.e. "secondary data"). The use of secondary sources may be prone to measurement bias and confounding due to over-the-counter and out-of-pocket drug consumption, or non-adherence to treatment. In fact, it has been noted that failing to consider the origin of the data as a potential cause of heterogeneity may change the conclusions of a meta-analysis. We aimed to assess to what extent the origin of data is explored as a source of heterogeneity in meta-analyses of observational studies.publishe

Prognostic factors in prostate cancer

Prognostic factors in organ confined prostate cancer will reflect survival after surgical radical prostatectomy. Gleason score, tumour volume, surgical margins and Ki-67 index have the most significant prognosticators. Also the origins from the transitional zone, p53 status in cancer tissue, stage, and aneuploidy have shown prognostic significance. Progression-associated features include Gleason score, stage, and capsular invasion, but PSA is also highly significant. Progression can also be predicted with biological markers (E-cadherin, microvessel density, and aneuploidy) with high level of significance. Other prognostic features of clinical or PSA-associated progression include age, IGF-1, p27, and Ki-67. In patients who were treated with radiotherapy the survival was potentially predictable with age, race and p53, but available research on other markers is limited. The most significant published survival-associated prognosticators of prostate cancer with extension outside prostate are microvessel density and total blood PSA. However, survival can potentially be predicted by other markers like androgen receptor, and Ki-67-positive cell fraction. In advanced prostate cancer nuclear morphometry and Gleason score are the most highly significant progression-associated prognosticators. In conclusion, Gleason score, capsular invasion, blood PSA, stage, and aneuploidy are the best markers of progression in organ confined disease. Other biological markers are less important. In advanced disease Gleason score and nuclear morphometry can be used as predictors of progression. Compound prognostic factors based on combinations of single prognosticators, or on gene expression profiles (tested by DNA arrays) are promising, but clinically relevant data is still lacking

Is the routine pressure dressing after thyroidectomy necessary? A prospective randomized controlled study

<p>Abstract</p> <p>Background</p> <p>An acute complication of thyroidectomy is fatal hematoma, which can produce an upper airway obstruction needing immediate intubation or tracheostomy. After neck surgery, we usually apply a pressure dressing with a non-woven, adhesive fabric to reduce bleeding and fluid collection at the operative bed. We conducted a prospective, randomized, controlled study to evaluate a pressure <it>vs</it>. a non-pressure dressing after thyroid surgery by monitoring blood and serum in the operative bed.</p> <p>Methods</p> <p>We studied 108 patients who underwent 116 thyroid surgeries at Srinagarind Hospital, Khon Kaen University, between December 2006 and September 2007. The patients were randomized to either the pressure dressing or non-pressure dressing group. Ultrasound of the neck was performed 24 ± 3 hours after surgery. The volume of fluid collection in the operative bed was calculated. All patients were observed for any post-operative respiratory distress, wound complications, tingling sensation or tetany.</p> <p>Results</p> <p>The distributions of age, sex, surgical indications and approaches were similar between the two groups. There was no statistically significant difference in the volume of fluid collection in the operative bed (<it>p </it>= 0.150) and the collected drained content (<it>p </it>= 0.798). The average time a drain was retained was 3 days. One patient in the pressure dressing group suffered cutaneous bruising while one patient in the non-pressure dressing group developed immediate hemorrhage after the skin sutures.</p> <p>Conclusion</p> <p>Pressure dressing after thyroidectomy does not have any significant impact on decreasing fluid collection at the operative bed. The use of pressure dressing after thyroidectomy may not therefore be justified.</p> <p>Trial Registration</p> <p>NCT00400465, ISRCTN52660978</p