To our knowledge, no publication providing overarching guidance on the conduct of systematic reviews of observational studies of etiology exists.
Conducting Systematic Reviews and Meta-Analyses of ...Observational Studies of Etiology (COSMOS-E) provides guidance on all steps in systematic reviews of observational studies of etiology, from shaping the research question, defining exposure and outcomes, to assessing the risk of bias and statistical analysis. The writing group included researchers experienced in meta-analyses and observational studies of etiology. Standard peer-review was performed. While the structure of systematic reviews of observational studies on etiology may be similar to that for systematic reviews of randomised controlled trials, there are specific tasks within each component that differ. Examples include assessment for confounding, selection bias, and information bias. In systematic reviews of observational studies of etiology, combining studies in meta-analysis may lead to more precise estimates, but such greater precision does not automatically remedy potential bias. Thorough exploration of sources of heterogeneity is key when assessing the validity of estimates and causality.
As many reviews of observational studies on etiology are being performed, this document may provide researchers with guidance on how to conduct and analyse such reviews.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Glucose, insulin and Homeostasis Model Assessment Insulin Resistance (HOMA-IR) are markers of insulin resistance. The objective of this study is to compare fasting glucose, fasting insulin ...concentrations and HOMA-IR in strength of association with incident cardiovascular disease.
We searched the PubMed, MEDLINE, EMBASE, Web of Science, ScienceDirect and Cochrane Library databases from inception to March, 2011, and screened reference lists. Cohort studies or nested case-control studies that investigated the association between fasting glucose, fasting insulin or HOMA-IR and incident cardiovascular disease, were eligible. Two investigators independently performed the article selection, data extraction and risk of bias assessment. Cardiovascular endpoints were coronary heart disease (CHD), stroke or combined cardiovascular disease. We used fixed and random-effect meta-analyses to calculate the pooled relative risk for CHD, stroke and combined cardiovascular disease, comparing high to low concentrations of glucose, insulin or HOMA-IR. Study heterogeneity was calculated with the I(2) statistic. To enable a comparison between cardiovascular disease risks for glucose, insulin and HOMA-IR, we calculated pooled relative risks per increase of one standard deviation.
We included 65 studies (involving 516,325 participants) in this meta-analysis. In a random-effect meta-analysis the pooled relative risk of CHD (95% CI; I(2)) comparing high to low concentrations was 1.52 (1.31, 1.76; 62.4%) for glucose, 1.12 (0.92, 1.37; 41.0%) for insulin and 1.64 (1.35, 2.00; 0%) for HOMA-IR. The pooled relative risk of CHD per one standard deviation increase was 1.21 (1.13, 1.30; 64.9%) for glucose, 1.04 (0.96, 1.12; 43.0%) for insulin and 1.46 (1.26, 1.69; 0.0%) for HOMA-IR.
The relative risk of cardiovascular disease was higher for an increase of one standard deviation in HOMA-IR compared to an increase of one standard deviation in fasting glucose or fasting insulin concentration. It may be useful to add HOMA-IR to a cardiovascular risk prediction model.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Propensity score analysis is a popular method to control for confounding in observational studies. A challenge in propensity methods is missing values in confounders. Several strategies for handling ...missing values exist, but guidance in choosing the best method is needed. In this simulation study, we compared four strategies of handling missing covariate values in propensity matching and propensity weighting. These methods include: complete case analysis, missing indicator method, multiple imputation and combining multiple imputation and missing indicator method. Concurrently, we aimed to provide guidance in choosing the optimal strategy. Simulated scenarios varied regarding missing mechanism, presence of effect modification or unmeasured confounding. Additionally, we demonstrated how missingness graphs help clarifying the missing structure. When no effect modification existed, complete case analysis yielded valid causal treatment effects even when data were missing not at random. In some situations, complete case analysis was also able to partially correct for unmeasured confounding. Multiple imputation worked well if the data were missing (completely) at random, and if the imputation model was correctly specified. In the presence of effect modification, more complex imputation models than default options of commonly used statistical software were required. Multiple imputation may fail when data are missing not at random. Here, combining multiple imputation and the missing indicator method reduced the bias as the missing indicator variable can be a proxy for unobserved confounding. The optimal way to handle missing values in covariates of propensity score models depends on the missing data structure and the presence of effect modification. When effect modification is present, default settings of imputation methods may yield biased results even if data are missing at random.
Background Pituitary tumours are common and easily treated by surgery or medical treatment in most cases. However, a small subset of pituitary tumours does not respond to standard medical treatment ...and presents with multiple local recurrences (aggressive pituitary tumours) and in rare occasion with metastases (pituitary carcinoma). The present European Society of Endocrinology (ESE) guideline aims to provide clinical guidance on diagnosis, treatment and follow-up in aggressive pituitary tumours and carcinomas. Methods We decided upfront, while acknowledging that literature on aggressive pituitary tumours and carcinomas is scarce, to systematically review the literature according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The review focused primarily on first- and second-line treatment in aggressive pituitary tumours and carcinomas. We included 14 single-arm cohort studies (total number of patients = 116) most on temozolomide treatment (n = 11 studies, total number of patients = 106). A positive treatment effect was seen in 47% (95% CI: 36–58%) of temozolomide treated. Data from the recently performed ESE survey on aggressive pituitary tumours and carcinomas (165 patients) were also used as backbone for the guideline. Selected recommendation (i) Patients with aggressive pituitary tumours should be managed by a multidisciplinary expert team. (ii) Histopathological analyses including pituitary hormones and proliferative markers are needed for correct tumour classification. (iii) Temozolomide monotherapy is the first-line chemotherapy for aggressive pituitary tumours and pituitary carcinomas after failure of standard therapies; treatment evaluation after 3 cycles allows identification of responder and non-responder patients. (iv) In patients responding to first-line temozolomide, we suggest continuing treatment for at least 6 months in total. Furthermore, the guideline offers recommendations for patients who recurred after temozolomide treatment, for those who did not respond to temozolomide and for patients with systemic metastasis.
By definition, an adrenal incidentaloma is an asymptomatic adrenal mass detected on imaging not performed for suspected adrenal disease. In most cases, adrenal incidentalomas are nonfunctioning ...adrenocortical adenomas, but may also represent conditions requiring therapeutic intervention (e.g. adrenocortical carcinoma, pheochromocytoma, hormone-producing adenoma or metastasis). The purpose of this guideline is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with adrenal incidentalomas based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions crucial for the management of adrenal incidentaloma patients, addressing these four with systematic literature searches: (A) How to assess risk of malignancy?; (B) How to define and manage low-level autonomous cortisol secretion, formerly called ‘subclinical’ Cushing’s syndrome?; (C) Who should have surgical treatment and how should it be performed?; (D) What follow-up is indicated if the adrenal incidentaloma is not surgically removed? Selected recommendations: (i) At the time of initial detection of an adrenal mass establishing whether the mass is benign or malignant is an important aim to avoid cumbersome and expensive follow-up imaging in those with benign disease. (ii) To exclude cortisol excess, a 1mg overnight dexamethasone suppression test should be performed (applying a cut-off value of serum cortisol ≤50nmol/L (1.8µg/dL)). (iii) For patients without clinical signs of overt Cushing’s syndrome but serum cortisol levels post 1mg dexamethasone >138nmol/L (>5µg/dL), we propose the term ‘autonomous cortisol secretion’. (iv) All patients with ‘(possible) autonomous cortisol’ secretion should be screened for hypertension and type 2 diabetes mellitus, to ensure these are appropriately treated. (v) Surgical treatment should be considered in an individualized approach in patients with ‘autonomous cortisol secretion’ who also have comorbidities that are potentially related to cortisol excess. (vi) In principle, the appropriateness of surgical intervention should be guided by the likelihood of malignancy, the presence and degree of hormone excess, age, general health and patient preference. (vii) Surgery is not usually indicated in patients with an asymptomatic, nonfunctioning unilateral adrenal mass and obvious benign features on imaging studies. We provide guidance on which surgical approach should be considered for adrenal masses with radiological findings suspicious of malignancy. Furthermore, we offer recommendations for the follow-up of patients with adrenal incidentaloma who do not undergo adrenal surgery, for those with bilateral incidentalomas, for patients with extra-adrenal malignancy and adrenal masses and for young and elderly patients with adrenal incidentalomas
Adrenocortical carcinoma (ACC) is a rare and in most cases steroid hormone-producing tumor with variable prognosis. The purpose of these guidelines is to provide clinicians with best possible ...evidence-based recommendations for clinical management of patients with ACC based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions, which we judged as particularly important for the management of ACC patients and performed systematic literature searches: (A) What is needed to diagnose an ACC by histopathology? (B) Which are the best prognostic markers in ACC? (C) Is adjuvant therapy able to prevent recurrent disease or reduce mortality after radical resection? (D) What is the best treatment option for macroscopically incompletely resected, recurrent or metastatic disease? Other relevant questions were discussed within the group. Selected Recommendations: (i) We recommend that all patients with suspected and proven ACC are discussed in a multidisciplinary expert team meeting. (ii) We recommend that every patient with (suspected) ACC should undergo careful clinical assessment, detailed endocrine work-up to identify autonomous hormone excess and adrenal-focused imaging. (iii) We recommend that adrenal surgery for (suspected) ACC should be performed only by surgeons experienced in adrenal and oncological surgery aiming at a complete en bloc resection (including resection of oligo-metastatic disease). (iv) We suggest that all suspected ACC should be reviewed by an expert adrenal pathologist using the Weiss score and providing Ki67 index. (v) We suggest adjuvant mitotane treatment in patients after radical surgery that have a perceived high risk of recurrence (ENSAT stage III, or R1 resection, or Ki67 >10%). (vi) For advanced ACC not amenable to complete surgical resection, local therapeutic measures (e.g. radiation therapy, radiofrequency ablation, chemoembolization) are of particular value. However, we suggest against the routine use of adrenal surgery in case of widespread metastatic disease. In these patients, we recommend either mitotane monotherapy or mitotane, etoposide, doxorubicin and cisplatin depending on prognostic parameters. In selected patients with a good response, surgery may be subsequently considered. (vii) In patients with recurrent disease and a disease-free interval of at least 12 months, in whom a complete resection/ablation seems feasible, we recommend surgery or alternatively other local therapies. Furthermore, we offer detailed recommendations about the management of mitotane treatment and other supportive therapies. Finally, we suggest directions for future research.
Patients with pituitary tumours, ensuing hormonal abnormalities and mass effects are usually followed in multidisciplinary pituitary clinics and can represent a management challenge even during the ...times of non-pandemic. The COVID-19 pandemic has put on hold routine medical care for hundreds of millions of patients around the globe, while many pituitary patients’ evaluations cannot be delayed for too long. Furthermore, the majority of patients with pituitary tumours have co-morbidities potentially impacting the course and management of COVID-19 (e.g. hypopituitarism, diabetes mellitus, hypertension, obesity and cardiovascular disease). Here, we summarize some of the diagnostic and management dilemmas encountered, and provide guidance on safe and as effective as possible delivery of care in the COVID-19 era. We also attempt to address how pituitary services should be remodelled in the event of similar crises, while maintaining or even improving patient outcomes. Regular review of these recommendations and further adjustments are needed, depending on the evolution of the COVID-19 pandemic status. We consider that the utilization of successful models of pituitary multidisciplinary care implemented during the COVID-19 pandemic should continue after the crisis is over by using the valuable and exceptional experience gained during these challenging times.
Objective:
We aimed to estimate pooled percentages of patients with adrenal insufficiency after treatment with corticosteroids for various conditions in a meta-analysis. Secondly, we aimed to ...stratify the results by route of administration, disease, treatment dose, and duration.
Methods:
We searched seven electronic databases (PubMed, MEDLINE, EMBASE, COCHRANE, CENTRAL, Web of Science, and CINAHL/Academic Search Premier) in February 2014 to identify potentially relevant studies. Original articles testing adult corticosteroid users for adrenal insufficiency were eligible.
Results:
We included 74 articles with a total of 3753 participants. Stratified by administration form, percentages of patients with adrenal insufficiency ranged from 4.2% for nasal administration (95% confidence interval CI, 0.5–28.9) to 52.2% for intra-articular administration (95% CI, 40.5–63.6). Stratified by disease, percentages ranged from 6.8% for asthma with inhalation corticosteroids only (95% CI, 3.8–12.0) to 60.0% for hematological malignancies (95% CI, 38.0–78.6). The risk also varied according to dose from 2.4% (95% CI, 0.6–9.3) (low dose) to 21.5% (95% CI, 12.0–35.5) (high dose), and according to treatment duration from 1.4% (95% CI, 0.3–7.4) (<28 d) to 27.4% (95% CI, 17.7–39.8) (>1 year) in asthma patients.
Conclusions:
1) Adrenal insufficiency after discontinuation of glucocorticoid occurs frequently; 2) there is no administration form, dosing, treatment duration, or underlying disease for which adrenal insufficiency can be excluded with certainty, although higher dose and longer use give the highest risk; 3) the threshold to test corticosteroid users for adrenal insufficiency should be low in clinical practice, especially for those patients with nonspecific symptoms after cessation.
P values should not merely be used to categorize results into significant and non-significant. This practice disregards clinical relevance, confounds non-significance with no effect and ...underestimates the likelihood of false-positive results. Better than to use the P value as a dichotomizing instrument, the P values and the confidence intervals around effect estimates can be used to put research findings in a context, thereby taking clinical relevance but also uncertainty genuinely into account.
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