The effects of metformin on endogenous androgens and SHBG in women : a systematic review and meta-analysis

Objectives Elevated circulating androgens are risk factors for several chronic, metabolic and reproductive disorders. Metformin is an insulin-sensitizing agent that may lower androgen levels. To evaluate the effects of metformin on endogenous androgens and SHBG levels in women, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing metformin with placebo or no treatment. Data source We used OVID to search MEDLINE, EMBASE and CENTRAL until March 2007. Review methods Two reviewers independently extracted data on methodological quality, participants, interventions and outcomes of interest. Our a priori primary outcome was post-treatment measurements. In a secondary analysis, we evaluated the difference between the pre- and post-treatment levels. We computed the weighted mean difference (WMD) as a measure of effect for each outcome using the DerSimonian-Laird random effects method. We used the I2 statistic to assess heterogeneity and explored its causes in subgroup analyses of features related to participants' characteristics and study design. Based on a regression model, we conducted sensitivity analyses by investigating the use of placebo as a predictor of effect size. Results Twenty RCTs fulfilled the inclusion criteria. Pooled WMDs in post-treatment levels between the metformin and control group were -0\ub731 nmol/l (95% CI -0\ub765 to 0\ub703) for total testosterone (TT), 0\ub710 pmol/l (95% CI -0\ub789 to 1\ub710) for free testosterone (FT), 0\ub714 \u3bcmol/l (95% CI -0\ub734 to 0\ub762) for dehydroepiandrosteronesulfate (DHEAS), -0\ub760 nmol/l (95% CI -1\ub767 to 0\ub746) for androstenedione (AND) and 5\ub788 nmol/l (95% CI 2\ub701-9\ub775) for SHBG. Pooled WMDs of the pre- to post-treatment differences (i.e. with adjustment for baseline hormone levels) were -0\ub738 (95% CI -0\ub751 to -0\ub725) for TT, -2\ub771 (95% CI -10\ub735 to 4\ub793) for FT, -0\ub750 (95% CI -0\ub783 to -0\ub716) for DHEAS, -1\ub739 (95% CI -2\ub730 to -0\ub749) for AND and 6\ub763 (95% CI 2\ub732-10\ub794) for SHBG. In subgroup analyses, features related to the administered treatment (i.e. metformin as a single agent or as part of combined regimens) partly explained the heterogeneity. Sensitivity analyses of studies using placebo showed similar results to those not using placebo. Conclusions Our systematic review and meta-analysis provides evidence of metformin-induced changes in circulating androgens and SHBG levels in women but the quality of evidence is not high. However, there are no data from RCTs regarding these effects in postmenopausal women or healthy premenopausal women. High-quality RCTs are required to evaluate whether metformin has effects on surrogate markers and patient-important outcomes in these patient groups

Effects of assessing the productivity of faculty in academic medical centres : a systematic review

Background: Many academic medical centres have introduced strategies to assess the productivity of faculty as part of compensation schemes. We conducted a systematic review of the effects of such strategies on faculty productivity. Methods: We searched the MEDLINE, Healthstar, Embase and PsycInfo databases from their date of inception up to October 2011. We included studies that assessed academic productivity in clinical, research, teaching and administrative activities, as well as compensation, promotion processes and satisfaction. Results: Of 531 full-text articles assessed for eligibility, we in cluded 9 articles reporting on eight studies. The introduction of strategies for assessing academic productivity as part of compensation schemes resulted in increases in clinical productivity (in six of six studies) in terms of clinical revenue, the work component of relative-value units (these units are nonmonetary standard units of measure used to indicate the value of services provided), patient satisfaction and other departmentally used standards. Increases in research productivity were noted (in five of six studies) in terms of funding and publications. There was no change in teaching productivity (in two of five studies) in terms of educational output. Such strategies also resulted in increases in compensation at both individual and group levels (in three studies), with two studies re - porting a change in distribution of compensation in favour of junior faculty. None of the studies assessed effects on administrative productivity or promotion processes. The overall quality of evidence was low. Interpretation: Strategies introduced to assess productivity as part of a compensation scheme appeared to improve productivity in research activities and possibly improved clinical productivity, but they had no effect in the area of teaching. Compensation increased at both group and individual levels, particularly among junior faculty. Higher quality evidence about the benefits and harms of such assessment strategies is needed

Urinary 6-sulphatoxymelatonin levels and risk of breast cancer in premenopausal women : the ORDET cohort

Background: Lower urinary melatonin levels are associated with a higher risk of breast cancer in postmenopausal women. Literature for premenopausal women is scant and inconsistent. Methods: In a prospective case-control study, we measured the concentration of 6-sulphatoxymelatonin (aMT6s) in the 12-hour overnight urine of 180 premenopausal women with incident breast cancer and 683 matched controls. Results: In logistic regression models, the multivariate odds ratio (OR) of invasive breast cancer for women in the highest quartile of total overnight aMT6s output compared with the lowest was 1.43 [95% confidence interval (CI), 0.83-2.45; Ptrend = 0.03]. Among current nonsmokers, no association was existent (OR, 1.00; 95% CI, 0.52-1.94; Ptrend = 0.29). We observed an OR of 0.68 between overnight urinary aMT6s level and breast cancer risk in women with invasive breast cancer diagnosed >2 years after urine collection and a significant inverse association in women with a breast cancer diagnosis >8 years after urine collection (OR, 0.17; 95% CI, 0.04-0.71; Ptrend = 0.01). There were no important variations in ORs by tumor stage or hormone receptor status of breast tumors. Conclusion: Overall, we observed a positive association between aMT6s and risk of breast cancer. However, there was some evidence to suggest that this might be driven by the influence of subclinical disease on melatonin levels, with a possible inverse association among women diagnosed further from recruitment. Thus, the influence of lag time on the association between melatonin and breast cancer risk needs to be evaluated in further studies

American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19: May 2021 update on the use of intermediate-intensity anticoagulation in critically ill patients

Background: COVID-19-related critical illness is associated with an increased risk of venous thromboembolism (VTE). Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in making decisions about the use of anticoagulation for thromboprophylaxis in patients with COVID-19-related critical illness who do not have confirmed or suspected VTE.Methods: ASH formed a multidisciplinary guideline panel that included 3 patient representatives and applied strategies to minimize potential bias from conflicts of interest. The McMaster University Grading of Recommendations Assessment, Development and Evaluation (GRADE) Centre supported the guideline development process by performing systematic evidence reviews (up to 5 March 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the GRADE approach to assess evidence and make recommendations, which were subject to public comment. This is an update on guidelines published in February 2021.Results: The panel agreed on 1 additional recommendation. The panel issued a conditional recommendation in favor of prophylactic-intensity over intermediate-intensity anticoagulation in patients with COVID-19-related critical illness who do not have confirmed or suspected VTE.Conclusions: This recommendation was based on low certainty in the evidence, which underscores the need for additional high-quality, randomized, controlled trials comparing different intensities of anticoagulation in critically ill patients. Other key research priorities include better evidence regarding predictors of thrombosis and bleeding risk in critically ill patients with COVID-19 and the impact of nonanticoagulant therapies (eg, antiviral agents, corticosteroids) on thrombotic risk.Thrombosis and Hemostasi

Misconceptions, challenges, uncertainty, and progress in guideline recommendations

Although the quality of clinical practice guidelines has improved over the last decade, current guideline systems have limitations that reduce their validity and limit their acceptance. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) working group, a worldwide collaboration of guideline developers, methodologists, and clinicians, has constructed a system for developing guidelines that addresses these shortcomings. The system includes a transparent and rigorous methodology for rating the quality of evidence, an explicit balancing of benefits and harms of healthcare interventions, an explicit acknowledgement of the values and preferences that underlie the recommendations, and whether the intervention represents a wise use of resources. These four elements determine whether a recommendation is strong or weak. A guideline panel offers strong recommendations when virtually all informed patients would choose the same management strategy. Weak recommendations imply that choices will differ across the range of patient values and preferences. The GRADE system has been tested in multiple practice settings and for a large spectrum of questions, refined and re-evaluated to ensure that it captures the complex issues involved in evidence assessment and grading recommendations while maintaining simplicity and practicality. Many guideline organizations and medical societies have endorsed the system and adopted it for their guideline processes

A practical guide for using a survey about attitudes and behaviors to inform health care decisions

Objectives: Surveys can provide important information about what people think or do. There is little guidance about how to use surveys in decision-making. This article provides guidance for how to appraise and use a survey to answer health care questions. Study Design and Setting: A guidance article about the use a survey of a selected sample of people, who completed a self-report tool about their knowledge, beliefs and opinions, behaviors and experiences, or personal attributes. We use survey examples, one scenario, and a specific survey for illustration. Results: Decision makers should consider the credibility and applicability of the results of a survey. Key threats to credibility depend on the representativeness of the population and likelihood that it provides an accurate picture of the population's knowledge, attitudes, or self-reported practices. If survey investigators do not use rigorous strategies to develop or pretest questions, there is a greater risk that results will be misleading. Decision makers may want to consider the precision of estimates and whether it would change their decisions. Finally, they need to decide how similar the surveyed population is to their specific population before applying results. Conclusions: Decision makers can follow this guidance to critically appraise, interpret, and apply the results of surveys to health care questions

Prospective study on the role of glucose metabolism in breast cancer occurrence

High circulating glucose, insulin resistance and obesity appear to be associated with increased risk of breast cancer (BC). We sought further insight into the relation of these variables to BC. We assessed associations of BC risk with serum fasting glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR) index and sex-binding hormone globulin (SHBG) in women recruited to the ORDET cohort who gave blood samples in 1987-1992. After a median 13.5 years of follow-up, 356 women developed BC. Four matched controls per case were selected by incidence density sampling, and rate ratios (RR) were estimated by conditional logistic regression. Women in the highest glucose quartile had a significantly greater risk of BC than those in the lowest glucose quartile (RR 1.63; 95% CI: 1.14-2.32; p for trend of 0.003). The association was significant in pre and post menopausal women separately and in women diagnosed after 55 years. Women in the highest HOMA-IR quartile had higher BC risk than the lowest quartile (RR 1.44; 95% CI: 1.03-2.02). Significantly increased BC risk in women diagnosed after 55 years was also present in the highest HOMA-IR quartile; in the same group decreased BC risk was significantly associated with high SHBG. The results of this study add to the existing epidemiological evidence that hyperglycemia and insulin resistance increase BC risk

Observaciones ecológicas sobre el pez capitán, eremophilus mutisii humboldt 1805 (pisces : trichomycteridae) en los departamentos de cundinamarca y boyacá, colombia

Para varias poblaciones de EremophUus mutisii Humboldt 1805. en los Departamentos de Cundinamarca y Boyacá, se proporciona información acerca del habítat, la distribución altitudinal. la temperatura del agua, la tolerancia de oxigeno. las tallas y relaciones de peso y longitud la fecundidad y la relación del número de huevos y peso de la gónada. así como lasrelaciones de los índices de reproducción, el peso del t-süculo y el peso total del ejemplar, el factor de condición para juveniles y adultos, las tallas por sexo y épocas de desove.Information of the population for several Eremophilus muusu Humboldt 1805 were provided at the Cundinamarca and Boyacá regíons. The main ínformatíon were concerning the habitat, dístrtbunon of altitude. water temperature, oxygen tolerance, sizes and relation of weight/lenght. The fertíltty and relation of eggs number, weíght of the gonade as well the relation of reproduction index wight of testicle, the complete weíght werealso gíved. On the other side conditions factor for young and adults, sex for male and female in different time of spawning were also provided

American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19: July 2021 update on postdischarge thromboprophylaxis

Background: COVID-19-related acute illness is associated with an increased risk of venous thromboembolism (VTE).Objective: These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about the use of anticoagulation for thromboprophylaxis in patients with COVID-19 who do not have confirmed or suspected VTE.Methods: ASH formed a multidisciplinary guideline panel, including 3 patient representatives, and applied strategies to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including performing systematic evidence reviews (up to March 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the grading of recommendations assessment, development, and evaluation (GRADE) approach to assess evidence and make recommendations, which were subject to public comment.Results: The panel agreed on 1 additional recommendation. The panel issued a conditional recommendation against the use of outpatient anticoagulant prophylaxis in patients with COVID-19 who are discharged from the hospital and who do not have suspected or confirmed VTE or another indication for anticoagulation.Conclsions: This recommendation was based on very low certainty in the evidence, underscoring the need for high-quality randomized controlled trials assessing the role of postdischarge thromboprophylaxis. Other key research priorities include better evidence on assessing risk of thrombosis and bleeding outcomes in patients with COVID-19 after hospital discharge.Thrombosis and Hemostasi