Why not to (over)emphasize statistical significance

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.

Prognostic factors and survival in MEN1 patients with gastrinomas: Results from the DutchMEN study group (DMSG)

Background and objectives

Gastrinomas are the most prevalent functioning neuroendocrine tumors (NET) in multiple endocrine neoplasia type 1 (MEN1). Guidelines suggest medical therapy in most patients, but surgery may be considered in a subgroup. Currently, factors to guide management are necessary. This population‐based cohort study assessed prognostic factors of survival in patients with MEN1‐related gastrinomas.

Methods

Patients with MEN1 having gastrinomas were identified in the Dutch MEN1 database from 1990 to 2014 based on fasting serum gastrin (FSG) levels and/or pathology. Predictors of overall survival were assessed using Cox regression.

Results

Sixty‐three patients with gastrinoma (16% of the MEN1 population) were identified. Five‐ and 10‐year overall survival rates were 83% and 65%, respectively. Prognostic factors associated with overall survival were initial FSG levels ≥20x upper limit of normal (ULN) (hazard ratio [HR], 6.2 [95% confidence interval, 1.7‐23.0]), pancreatic NET ≥2 cm (HR 4.5; [1.5‐13.1]), synchronous liver metastases (HR 8.9; [2.1‐36.7]), gastroduodenoscopy suspicious for gastric NETs (HR 12.7; [1.4‐115.6]), and multiple concurrent NETs (HR 5.9; [1.2‐27.7]).

Conclusion

Life expectancy of patients with MEN1 gastrinoma is reduced. FSG levels and pancreatic NETs ≥2 cm are prognostic factors. FSG levels might guide surveillance intensity, step‐up to additional diagnostics, or provide arguments in selecting patients who might benefit from surgery.

The incidence of adrenal crisis in the postoperative period of HPA axis insufficiency after surgical treatment for Cushing's syndrome

BACKGROUND

Adrenal crisis, the most feared complication of adrenal insufficiency, is a potentially life-threatening state of acute glucocorticoid deficiency. After successful surgery for Cushing's syndrome, many patients develop (transient) adrenal insufficiency. The incidence of adrenal crisis in patients treated for hypercortisolism is unknown.

METHODS

Cohort study included consecutive patients with Cushing's syndrome with adrenal insufficiency after surgery from Leiden and Berlin from 2000 to 2015. We summarized the incidence of adrenal crisis, compared patients with and without adrenal crisis regarding potential risk factors for its occurrence and assessed the effect of better education in time on incidence of adrenal crisis.

RESULTS

We included 106 patients, of whom 19 patients had a total of 41 adrenal crises. There were 9.0 crises per 100 patient-years at risk (95% confidence interval (CI): 6.7-12.0). All crises occurred while on hydrocortisone replacement. The risk ratio for a recurrent crisis was 2.3 (95% CI: 1.2-4.6). No clear change in incidence of adrenal crisis due to better education in time was observed. There was no difference in recurrence rate between patients with, and without any crisis, but patients with adrenal crisis had more often pituitary deficiencies.

CONCLUSIONS

The incidence of adrenal crises after treatment for Cushing's syndrome is substantial, and patients who suffered from an adrenal crisis have higher risk for recurrent crisis. Adrenal crisis tends to present early after remission of Cushing's syndrome, which is probably the period of severest HPA axis suppression, despite in general higher hydrocortisone replacement doses for withdrawal complaints in this period. Additional pituitary hormone deficiencies may be a risk marker for increased risk of adrenal crisis. However, further risk factor analysis is needed to identify risks for a first crisis. Effective education methods to prevent adrenal crises should be identified and implemented, including stress instructions by trained nursing staff before hospital discharge.

Use of radiotherapy after pituitary surgery for non-functioning pituitary adenomas

Surgery is the treatment of choice for non-functioning pituitary macroadenomas (NFPAs). In cases of postoperative remnant growth or tumor recurrence, radiotherapy (RT) can be considered. The role of RT in the postoperative management of NFPAs is still debated. The main arguments against routine use of RT are the lack of randomized controlled trials, the use of clinically irrelevant endpoints in most studies on RT, the benign character of the condition, the potential for side effects of RT, and the option to apply RT at a later stage. However, because of its excellent efficacy in inhibiting tumor growth, reducing tumor volume and improving any existing visual defects, and as its side effects seem to be limited compared to the benefits provided, RT keeps a place in the management of NFPAs when a tumor remnant persists, particularly if it is invasive and displays high proliferation markers, if surveillance shows a relevant increase in tumor volume or if the tumor is close to the optic chiasm. The size of the remnant, its vicinity with the optic pathways, and the potential risk to healthy surrounding tissues need to be considered when deciding on an RT procedure.

Comparing Methods for Measurement Error Detection in Serial 24-h Hormonal Data

Measurement errors commonly occur in 24-h hormonal data and may affect the outcomes of such studies. Measurement errors often appear as outliers in such data sets; however, no well-established method is available for their automatic detection. In this study, we aimed to compare performances of different methods for outlier detection in hormonal serial data. Hormones (glucose, insulin, thyroid-stimulating hormone, cortisol, and growth hormone) were measured in blood sampled every 10 min for 24 h in 38 participants of the Leiden Longevity Study. Four methods for detecting outliers were compared: (1) eyeballing, (2) Tukey’s fences, (3) stepwise approach, and (4) the expectation-maximization (EM) algorithm. Eyeballing detects outliers based on experts’ knowledge, and the stepwise approach incorporates physiological knowledge with a statistical algorithm. Tukey’s fences and the EM algorithm are data-driven methods, using interquartile range and a mathematical algorithm to identify the underlying distribution, respectively. The performance of the methods was evaluated based on the number of outliers detected and the change in statistical outcomes after removing detected outliers. Eyeballing resulted in the lowest number of outliers detected (1.0% of all data points), followed by Tukey’s fences (2.3%), the stepwise approach (2.7%), and the EM algorithm (11.0%). In all methods, the mean hormone levels did not change materially after removing outliers. However, their minima were affected by outlier removal. Although removing outliers affected the correlation between glucose and insulin on the individual level, when averaged over all participants, none of the 4 methods influenced the correlation. Based on our results, the EM algorithm is not recommended given the high number of outliers detected, even where data points are physiologically plausible. Since Tukey’s fences is not suitable for all types of data and eyeballing is time-consuming, we recommend the stepwise approach for outlier detection, which combines physiological knowledge and an automated process.

Assessment of the Clinical Benefit of Imaging in Children With Unilateral Sensorineural Hearing Loss: A Systematic Review and Meta-analysis

IMPORTANCE

Imaging used to determine the cause of unilateral sensorineural hearing loss (USNHL) in children is often justified by the high likelihood of detecting abnormalities, which implies that these abnormalities are associated with hearing loss and that imaging has a positive contribution to patient outcome or well-being by providing information on the prognosis, hereditary factors, or cause of hearing loss.

OBJECTIVES

To evaluate the diagnostic yield of computed tomography (CT) and magnetic resonance imaging (MRI) in children with isolated unexplained USNHL and investigate the clinical relevance of these findings.

EVIDENCE REVIEW

Cochrane Library, Embase, PubMed, and Web of Science databases were searched for articles published from 1978 to 2017 on studies of children with USNHL who underwent CT and/or MRI of the temporal bone. Two authors (F.G.R. and E.N.B.P.) independently extracted information on population characteristics, imaging modality, and the prevalence of abnormalities and assessed the studies for risk of bias. Eligibility criteria included studies with 20 or more patients with USNHL who had CT and/or MRI scans, a population younger than 18 years, and those published in English.

MAIN OUTCOMES AND MEASURES

The pooled prevalence with 95% CI of inner ear abnormalities grouped according to finding and imaging modality.

FINDINGS

Of 1562 studies, 18 were included with a total of 1504 participants included in the analysis. Fifteen studies were consecutive case studies and 3 were retrospective cohort studies. The pooled diagnostic yield for pathophysiologic relevant findings in patients with unexplained USNHL was 37% for CT (95% CI, 25%-48%) and 35% for MRI (95% CI, 22%-49%). Cochleovestibular abnormalities were found with a pooled frequency of 19% for CT (95% CI, 14%-25%) and 16% for MRI (95% CI, 7%-25%). Cochlear nerve deficiency and associated cochlear aperture stenosis had a pooled frequency of 16% for MRI (95% CI, 3%-29%) and 44% for CT (95% CI, 36%-53%), respectively. Enlarged vestibular aqueduct (EVA) was detected with a pooled frequency of 7% for CT and 12% for MRI in children with USNHL.

CONCLUSIONS AND RELEVANCE

Imaging provided insight into the cause of hearing loss in a pooled frequency of about 35% to 37% in children with isolated unexplained USNHL. However, none of these findings had therapeutic consequences, and imaging provided information on prognosis and hereditary factors only in a small proportion of children, namely those with EVA. Thus, there is currently no convincing evidence supporting a strong recommendation for imaging in children who present with USNHL. The advantages of imaging should be carefully balanced against the drawbacks during shared decision making.

Oral sex is associated with reduced incidence of recurrent miscarriage

A possible way of immunomodulation of the maternal immune system before pregnancy would be exposure to paternal antigens via seminal fluid to oral mucosa. We hypothesized that women with recurrent miscarriage have had less oral sex compared to women with uneventful pregnancy. In a matched case control study, 97 women with at least three unexplained consecutive miscarriages prior to the 20^th week of gestation with the same partner were included. Cases were younger than 36 years at time of the third miscarriage. The control group included 137 matched women with an uneventful pregnancy. The association between oral sex and recurrent miscarriage was assessed with conditional logistic regression, odds ratios (ORs) were estimated. Missing data were imputed using Imputation by Chained Equations. In the matched analysis, 41 out of 72 women with recurrent miscarriage had have oral sex, whereas 70 out of 96 matched controls answered positive to this question (56.9% vs. 72.9%, OR 0.50 95%CI 0.25-0.97, p = 0.04). After imputation of missing exposure data (51.7%), the association became weaker (OR 0.67, 95%CI 0.36-1.24, p = 0.21). In conclusion, this study suggests a possible protective role of oral sex in the occurrence of recurrent miscarriage in a proportion of the cases. Future studies in women with recurrent miscarriage explained by immune abnormalities should reveal whether oral exposure to seminal plasma indeed modifies the maternal immune system, resulting in more live births.

Hypothyroidism and the risk of breast cancer recurrence and all-cause mortality - a Danish population-based study

Background

Hypothyroidism may occur as a late effect of breast cancer-directed treatment, particularly after radiotherapy, but little is known whether hypothyroidism affects the prognosis after breast cancer. We investigated the association between hypothyroidism and breast cancer recurrence, and all-cause mortality.

Methods

In this population-based cohort study, we used national medical registries to identify all Danish women 35 years or older diagnosed with stage I–III, operable breast cancer between 1996 and 2009. Hypothyroidism was defined as hospital diagnoses ascertained via diagnostic codes, or as prescriptions for levothyroxine. Two analytic models were used: (i) hypothyroidism present at the time of the breast cancer diagnosis (prevalent) and (ii) hypothyroidism diagnosed during follow-up as a time-varying exposure lagged by 1 year (incident). Breast cancer recurrence was defined as any local, regional, or distant recurrence or contralateral breast cancer. All-cause mortality included death from any cause in any setting. We used Cox regression models accounting for competing risks to compute adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer recurrence and all-cause mortality.

Results

The study cohort included 35,463 women with breast cancer with 212,641 person-years of follow-up. At diagnosis, 1272 women had hypothyroidism and 859 women developed hypothyroidism during follow-up. In total, 5810 patients developed recurrent breast cancer. Neither prevalent nor incident hypothyroidism was associated with breast cancer recurrence (adjusted HR_prevalent 1.01, 95% CI 0.87–1.19; adjusted HR_incident 0.93, 95% CI 0.75–1.16, respectively). Furthermore, no differences were seen for all-cause mortality for prevalent or incident hypothyroidism (adjusted HR_prevalent 1.02, 95% CI 0.92–1.14, and HR_incident 1.08, 95% CI 0.95–1.23, respectively). Stratification by menopausal status, oestrogen receptor status, chemotherapy, or radiotherapy did not alter the estimates.

Conclusions

Hypothyroidism present at diagnosis or during follow-up was not associated with breast cancer recurrence or all-cause mortality in women with breast cancer. Our findings provide reassurance to patients and their physicians that hypothyroidism is unlikely to impact on the clinical course of breast cancer or survival.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1122-3) contains supplementary material, which is available to authorized users.

Microscopic versus endoscopic transsphenoidal surgery in the Leiden cohort treated for Cushing's disease: surgical outcome, mortality, and complications

BACKGROUND

First-choice treatment for Cushing's disease is transsphenoidal adenomectomy. Since its introduction in the 1970s, many centers have now switched from microscopic to endoscopic surgery. We compared both techniques for the treatment of Cushing's disease at the Leiden University Medical Center, a European reference center for pituitary diseases.

METHODS

Cohort study with inclusion and follow-up of consecutive Cushing's disease patients primarily treated by transsphenoidal surgery at the Leiden University Medical Center between 1978 and 2016. We compared remission rates (primary endpoint), mortality, and complications between microscopic (performed up to 2005) and endoscopic (performed from 2003 onwards) surgery. Subgroup analyses were performed by tumor size, surgical experience, and preoperative imaging techniques. Additionally, surgeons' intraoperative findings regarding presence and removal of the adenoma were related to surgical outcome.

RESULTS

Of 137 included patients, 87 were treated microscopically and 50 endoscopically. Three months after microscopic surgery, 74 patients (86%) were in remission. Five-year recurrence-free survival was 89% (95% confidence interval [CI]: 82-96%), and ten-year recurrence free survival was 84% (95% CI: 75-93%). After endoscopic surgery, 39 patients (83%) were in remission. Both five-year and ten-year recurrence-free survival were 71% (95% CI: 55-87%). Hazard ratio for recurrence was 0.47 (95% CI: 0.19-1.14), and for mortality 2.79 (95% CI: 0.35-22.51), for microscopic versus endoscopic surgery. No learning curve was found for endoscopy, nor an influence of preoperative imaging technique for microscopy. In addition, we did not find a clear relation between the surgeons' intraoperative findings and surgical outcomes.

CONCLUSIONS

This study did not identify a clear advantage of microscopic or endoscopic transsphenoidal surgery for the treatment of Cushing's disease based on clinical outcome. The transition to endoscopic surgery at our center was not accompanied by transient worsening of outcomes, which may be reassuring for those considering transitioning.

Metastasis of cutaneous squamous cell carcinoma in organ transplant recipients and the immunocompetent population: is there a difference? a systematic review and meta-analysis

BACKGROUND

Organ transplant recipients (OTR) have a higher risk of developing cutaneous squamous cell carcinoma (cSCC) compared to the immunocompetent population. Immunosuppression is often stated as a risk factor for metastasis. However, evidence for this is scarce.

OBJECTIVES

To investigate the cSCC metastasis risk in OTR and the immunocompetent population by systematically reviewing the literature.

METHODS

A systematic review of the literature was performed up to January 2018 using: Medline; Embase; Web of Science and ISI Science Citation Index. Studies assessing cSCC metastasis risk in ORT or immunocompetent cohorts were considered. A pooled risk estimate for metastasis was calculated for the immunocompetent population and OTR separately.

RESULTS

The pooled metastasis risk estimate for OTR was, respectively, 7.3% (95% CI 6.2-8.4) for cSCC on total body, and 11.0% (95% CI 7.7-14.8) for cSCC of the head neck area. For the immunocompetent population reported risk estimate analysis showed a pooled metastatic risk of 3.1% (95% CI 2.8-3.4) in total body cSCC and of 8.5% (95% CI 7.3-9.8) in cSCC of the head and neck area. Pooled risk estimate per single cSCC in OTR was 1.3% (95% CI 1.0-1.7) in total body cSCC and 4.0% (95% CI 2.7-5.5) in cSCC of the head and neck area. In the immunocompetent population, these pooled risk estimates were, respectively, 2.4% (95% CI 2.1-2.6) and 6.7% (95% CI 5.7-7.8).

CONCLUSIONS

Organ transplant recipients show a higher overall risk of cSCC metastasis compared to the immunocompetent population. Metastasis risks per single cSCC were substantially lower in both groups. However, due to heterogeneity and differences between studies, comparisons are difficult. Comprehensive follow-up studies with defined cohorts are necessary to adequately asses the risk for cSCC metastasis.

10-Year Outcomes After Left Ventricular Reconstruction: Rethinking the Impact of Mitral Regurgitation

BACKGROUND

Heart failure with reduced ejection fraction due to a post-infarction anteroseptal aneurysm carries a poor prognosis. Patients with refractory heart failure may be considered for advanced surgery, including left ventricular assist device implantation, heart transplantation and left ventricular reconstruction. The aim of this study was to evaluate outcomes after an integrated approach of left ventricular reconstruction with concomitant procedures (mitral/tricuspid valve repair, coronary revascularization), and assess risk factors for event-free survival, focusing on left ventricular geometry/function and presence of functional mitral regurgitation (MR).

METHODS

A total of 159 consecutive heart failure patients who underwent left ventricular reconstruction between 2002 and 2011 were included. Mid-term echocardiographic and long-term clinical outcomes were evaluated. Preoperative risk factors were correlated to event-free survival (freedom from mortality, left ventricular assist device implantation, and heart transplantation).

RESULTS

Mid-term echocardiography demonstrated decreased indexed left ventricular end-systolic volumes (89 ± 42 mL/m² preoperatively; 51 ± 18 at mid-term, p < 0.001), and absence of MR ≥ grade 2. Event-free survival was 83% ± 3% at 1-year, 68% ± 4% at 5-year, and 46% ± 4% at 10-year follow-up. Preoperative wall motion score index (WMSI; hazard ratio [HR] 3.1, 95% confidence interval [CI] 1.7-5.8, p < 0.001) and presence of MR ≥ grade 2 (HR 1.9, 95% CI 1.1-3.1, p = 0.014) were independently associated with adverse event-free survival.

CONCLUSIONS

Event-free survival is favorable in patients with WMSI < 2.5 and significantly worse when WMSI is ≥ 2.5. In both groups, the presence of preoperative MR ≥ grade 2 negatively affects event-free survival, despite successful correction of MR. Risk stratification by preoperative WMSI and MR grade supports the Heart team in choosing the optimal surgical strategy for patients with refractory heart failure.

COSMOS-E: Guidance on conducting systematic reviews and meta-analyses of observational studies of etiology

BACKGROUND

To our knowledge, no publication providing overarching guidance on the conduct of systematic reviews of observational studies of etiology exists.

METHODS AND FINDINGS

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.

CONCLUSION

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.

Associated auto-immune disease in type 1 diabetes patients: a systematic review and meta-analysis

Introduction The association between type 1 diabetes (T1D) and other auto-immune diseases is well known. However, a quantitative overview of all associated auto-immune diseases and their prevalence in T1D is lacking. Methods We searched PubMed, Web of Science, EMBASE and Cochrane library in September 2018 to identify relevant articles about the prevalence of the following associated auto-immune diseases in T1D cohorts: auto-immune thyroid disease, celiac disease, gastric autoimmunity including pernicious anemia, vitiligo and adrenal gland insufficiency. A meta-analysis was performed to estimate pooled prevalence using a random-effects model. Furthermore, random-effects meta-regression analysis was performed to assess the association between prevalence and mean age or diabetes duration. Results One hundred eighty articles were eligible including a total of 293 889 type 1 diabetes patients. Hypothyroidism (65 studies) was prevalent in 9.8% (95% CI: 7.5-12.3) of patients. Meta-regression showed that for every 10-year age increase, hypothyroidism prevalence increased 4.6% (95% CI: 2.6-6.6, P < 0.000, 54 studies). Weighted prevalence of celiac disease was 4.5% (95% CI: 4.0-5.5, 87 studies). Gastric autoimmunity was found in 4.3% of patients (95% CI: 1.6-8.2, 8 studies) and vitiligo in 2.4% (95% CI: 1.2-3.9, 14 studies) of patients. The prevalence of adrenal insufficiency was 0.2% (95% CI: 0.0-0.4, 14 studies) and hyperthyroidism was found in 1.3 percent (95% CI: 0.9-1.8, 45 studies) of type 1 diabetes patients. For all analyses, statistical heterogeneity between studies was moderate to high. Conclusions The prevalence of antibody-mediated auto-immune disease is high among type 1 diabetes patients. Especially hypothyroidism and celiac disease are frequently found.

Sex Differences in Presentation but Not in Outcome for ACTH-Dependent Cushing's Syndrome

Background: Sex differences in clinical picture of ACTH-dependent Cushing's syndrome are controversial, except for the known higher prevalence in females. We compared a broad range of potential differences to enable a more accurate understanding of the clinical picture of sex-specific ACTH-dependent Cushing's syndrome. Methods: Cohort study including consecutive patients with ACTH-dependent Cushing's syndrome from Leiden and Berlin diagnosed between 2000 and 2016. We compared clinical presentation, biochemical parameters, diagnostic tests, surgical outcome, and comorbidities between men and women. Results: We included 130 patients: 37 males and 93 females. With similar cortisol concentrations, ACTH concentrations were higher in males than females at time of diagnosis (median: 116 vs. 57 ng/L). The prevalence of osteoporosis was higher in males than in females (48.6 vs. 25.0%), persisting after surgery, with more vertebral fractures (16.2 vs. 5.4%) before surgery. Males showed more anemia (75.9 vs. 36.8%) after surgery. There were no differences in etiology, pituitary tumor size, diagnostic and therapeutic strategy, or surgical outcome between sexes. Conclusions: Based on this study, males and females with ACTH-dependent Cushing's syndrome present different clinical patterns. However, these differences do not justify different diagnostic strategies or treatment based on sex, considering the similar surgical outcome. Clinicians should be alert to diagnose accompanying osteoporosis (with fractures) in male patients with ACTH-dependent Cushing's syndrome.

Hypercortisolism in Newly Diagnosed Type 2 Diabetes: A Prospective Study of 384 Newly Diagnosed Patients

Cross-sectional studies in small and selected populations report a high prevalence of hypercortisolism in patients with type 2 diabetes (T2D), which could have therapeutic implications, if confirmed. We therefore estimated the prevalence of hypercortisolism in a large and unselected cohort of recently diagnosed T2D patients. Consecutive patients with recently diagnosed T2D first underwent an overnight dexamethasone (1 mg) suppression test (OD). Patients not suppressing serum cortisol ≤50 nmol/l proceeded with a 48-h low dose dexamethasone suppression test (LDDST) and 24-h urinary free cortisol collection (UFC). Patients with elevated cortisol levels according to LDDST and/or UFC underwent imaging guided by plasma ACTH levels, and assessment of bone mineral density. A total of 384 T2D patients (232male/152 females) with a mean age of 60±10 years were included. Eighty-five (22%) patients suppressed incompletely to OD of whom 20 (5%) failed to suppress after LDDST and/or had elevated UFC (=hypercortisolism). Patients with hypercortisolism did not differ as regards age, BMI, HbA1c, T-score or blood pressure, but a higher proportion of them received antihypertensive treatment (100% vs. 64%, p=0.001). Imaging revealed adrenal adenoma(s) in 9 cases and a pituitary macroadenoma in 1 case. We found a 5% prevalence of hypercortisolism in unselected, recently diagnosed T2D, which was not associated with a persuasive cushingoid phenotype. The clinical implications are therefore uncertain.

The current landscape of European registries for rare endocrine conditions

Objective To identify cross-border international registries for rare endocrine conditions that are led from Europe and to understand the extent of engagement with these registries within a network of reference centres (RCs) for rare endocrine conditions. Methods Database search of international registries and a survey of RCs in the European Reference Network for rare endocrine conditions (Endo-ERN) with an overall response rate of 82%. Results Of the 42 conditions with orphacodes currently covered within Endo-ERN, international registries exist for 32 (76%). Of 27 registries identified in the Orphanet and RD-Connect databases, Endo-ERN RCs were aware of 11 (41%). Of 21 registries identified by the RC, RD-Connect and Orphanet did not have a record of 10 (48%). Of the 29 glucose RCs, the awareness and participation rate in an international registry was highest for rare diabetes at 75 and 56% respectively. Of the 37 sex development RCs, the corresponding rates were highest for disorders of sex development at 70 and 52%. Of the 33 adrenal RCs, the rates were highest for adrenocortical tumours at 68 and 43%. Of the 43 pituitary RCs, the rates were highest for pituitary adenomas at 43 and 29%. Of the 31 genetic tumour RCs, the rates were highest for MEN1 at 26 and 9%. For the remaining conditions, awareness and participation in registries was less than 25%. Conclusion Although there is a need to develop new registries for rare endocrine conditions, there is a more immediate need to improve the awareness and participation in existing registries.

Effectiveness of medical treatment for Cushing's syndrome: a systematic review and meta-analysis

PURPOSE

To systematically review the effectiveness of medical treatment for Cushing's syndrome in clinical practice, regarding cortisol secretion, clinical symptom improvement, and quality of life. To assess the occurrence of side effects of these medical therapies.

METHODS

Eight electronic databases were searched in March 2017 to identify potentially relevant articles. Randomized controlled trials and cohort studies assessing the effectiveness of medical treatment in patients with Cushing's syndrome, were eligible. Pooled proportions were reported including 95% confidence intervals.

RESULTS

We included 35 articles with in total 1520 patients in this meta-analysis. Most included patients had Cushing's disease. Pooled reported percentage of patients with normalization of cortisol ranged from 35.7% for cabergoline to 81.8% for mitotane in Cushing's disease. Patients using medication monotherapy showed a lower percentage of cortisol normalization compared to use of multiple medical agents (49.4 vs. 65.7%); this was even higher for patients with concurrent or previous radiotherapy (83.6%). Mild side effects were reported in 39.9%, and severe side effects were seen in 15.2% of patients after medical treatment. No meta-analyses were performed for clinical symptom improvement or quality of life due to lack of sufficient data.

CONCLUSIONS

This meta-analysis shows that medication induces cortisol normalization effectively in a large percentage of patients. Medical treatment for Cushing's disease patients is thus a reasonable option in case of a contraindication for surgery, a recurrence, or in patients choosing not to have surgery. When experiencing side effects or no treatment effect, an alternate medical therapy or combination therapy can be considered.

Influence of hormonal functional status on survival in adrenocortical carcinoma: systematic review and meta-analysis

Objective Adrenocortical carcinoma (ACC) is a malignancy with a poor prognosis. Many publications in ACC report on risk factors for a poor outcome; one risk factor studied is hormonal hypersecretion (cortisol, sex-hormones, steroid precursors or aldosterone). The aim of this systematic review was to study the association between hormonal secretion and recurrence or mortality in ACC. Design Systematic review and meta-analysis. We searched PubMed, EMBASE and The Cochrane library (January 2018) for cohort studies examining the association between hormonal secretion on overall or recurrence-free survival in ACC. Methods A random-effects model meta-analysis was performed to obtain a weighted relative risk comparing cortisol-secreting and/or androgen-secreting ACCs to non-secreting tumours regarding overall and recurrence-free survival. Risk of bias assessment was performed for all studies included. Results Nineteen publications were included representing a total of 3814 patients. Most studies were generally considered low/intermediate risk of bias. Meta-analysis showed higher mortality risk for cortisol-secreting ACCs, weighted relative risk 1.71 (95% CI: 1.18-2.47) combining studies that adjusted for tumour stage; also a higher recurrence risk was found for cortisol producing ACCs, relative risk 1.43 (95% CI: 1.18-1.73). Androgen secretion was not clearly associated with survival (RR: 0.82, 95% CI: 0.60-1.12). Conclusion This systematic review and meta-analysis show that cortisol-secreting ACCs are associated with a worse overall survival; future research is needed to establish whether this association points to negative effects of cortisol action, whether it signifies a more aggressive ACC subtype or whether cortisol is merely a prognostic marker.

A comparison of different methods to handle missing data in the context of propensity score analysis

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.

Association of Thyroid Hormone Therapy With Quality of Life and Thyroid-Related Symptoms in Patients With Subclinical Hypothyroidism: A Systematic Review and Meta-analysis

IMPORTANCE

The benefit of thyroid hormone therapy for subclinical hypothyroidism is uncertain. New evidence from recent large randomized clinical trials warrants an update of previous meta-analyses.

OBJECTIVE

To conduct a meta-analysis of the association of thyroid hormone therapy with quality of life and thyroid-related symptoms in adults with subclinical hypothyroidism.

DATA SOURCES

PubMed, EMBASE, ClinicalTrials.gov, Web of Science, Cochrane Library, CENTRAL, Emcare, and Academic Search Premier from inception until July 4, 2018.

STUDY SELECTION

Randomized clinical trials that compared thyroid hormone therapy with placebo or no therapy in nonpregnant adults with subclinical hypothyroidism were eligible. Two reviewers independently evaluated eligibility based on titles and abstracts of all retrieved studies. Studies not excluded in this first step were independently assessed for inclusion after full-text evaluation by 2 reviewers.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data, assessed risk of bias (Cochrane risk-of-bias tool), and evaluated the quality of evidence (GRADE tool). For synthesis, differences in clinical scores were transformed (eg, quality of life) into standardized mean differences (SMDs; positive values indicate benefit of thyroid hormone therapy; 0.2, 0.5, and 0.8 correspond to small, moderate, and large effects, respectively). Random-effects models for meta-analyses were applied.

MAIN OUTCOMES AND MEASURES

General quality of life and thyroid-related symptoms after a minimum follow-up of 3 months.

RESULTS

Overall, 21 of 3088 initially identified publications met the inclusion criteria, with 2192 adults randomized. After treatment (range, 3-18 months), thyroid hormone therapy was associated with lowering the mean thyrotropin value into the normal reference range compared with placebo (range, 0.5-3.7 mIU/L vs 4.6 to 14.7 mIU/L) but was not associated with benefit regarding general quality of life (n = 796; SMD, -0.11; 95% CI, -0.25 to 0.03; I2=66.7%) or thyroid-related symptoms (n = 858; SMD, 0.01; 95% CI, -0.12 to 0.14; I2=0.0%). Overall, risk of bias was low and the quality of evidence assessed with the GRADE tool was judged moderate to high.

CONCLUSIONS AND RELEVANCE

Among nonpregnant adults with subclinical hypothyroidism, the use of thyroid hormone therapy was not associated with improvements in general quality of life or thyroid-related symptoms. These findings do not support the routine use of thyroid hormone therapy in adults with subclinical hypothyroidism.

Endoscopic vs. microscopic transsphenoidal surgery for Cushing's disease: a systematic review and meta-analysis

PURPOSE

Systematic review and meta-analysis comparing endoscopic and microscopic transsphenoidal surgery for Cushing's disease regarding surgical outcomes (remission, recurrence, and mortality) and complication rates. To stratify the results by tumor size.

METHODS

Nine electronic databases were searched in February 2017 to identify potentially relevant articles. Cohort studies assessing surgical outcomes or complication rates after endoscopic or microscopic transsphenoidal surgery for Cushing's disease were eligible. Pooled proportions were reported including 95% confidence intervals.

RESULTS

We included 97 articles with 6695 patients in total (5711 microscopically and 984 endoscopically operated). Overall, remission was achieved in 5177 patients (80%), with no clear difference between both techniques. Recurrence was around 10% and short term mortality < 0.5% for both techniques. Cerebrospinal fluid leak occurred more often in endoscopic surgery (12.9 vs. 4.0%), whereas transient diabetes insipidus occurred less often (11.3 vs. 21.7%). For microadenomas, results were comparable between both techniques. For macroadenomas, the percentage of patients in remission was higher after endoscopic surgery (76.3 vs. 59.9%), and the percentage recurrence lower after endoscopic surgery (1.5 vs. 17.0%).

CONCLUSIONS

Endoscopic surgery for patients with Cushing's disease reaches comparable results for microadenomas, and probably better results for macroadenomas than microscopic surgery. This is present despite the presumed learning curve of the newer endoscopic technique, although confounding cannot be excluded. Based on this study, endoscopic surgery may thus be considered the current standard of care. Microscopic surgery can be used based on neurosurgeon's preference. Endocrinologists and neurosurgeons in pituitary centers performing the microscopic technique should at least consider referring Cushing's disease patients with a macroadenoma.