German Rubinstein

Dr. German Rubinstein


Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 October 2019 in The Journal of Clinical Endocrinology & Metabolism
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Journal Article
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GRGerman Rubinstein
German Rubinstein
AOAndrea Osswald
Andrea Osswald
EHEva Hoster
Eva Hoster
MLMarco Losa
Marco Losa
AEAtanaska Elenkova
Atanaska Elenkova
MPMartin Reincke Prof
Martin Reincke Prof
Context: Signs and symptoms of Cushing’s syndrome (CS) overlap with common diseases, such as the metabolic syndrome, obesity, osteoporosis, and depression. Therefore, it can take years to finally diagnose CS, although early diagnosis is important for prevention of complications. Objective: The aim of this study was to assess the time span between first symptoms and diagnosis of CS in different populations to identify factors associated with an early diagnosis. Data Sources: A systematic literature search via PubMed was performed to identify studies reporting on time to diagnosis in CS. In addition, unpublished data from patients of our tertiary care center and 4 other centers were included. Study Selection: Clinical studies reporting on the time to diagnosis of CS were eligible. Corresponding authors were contacted to obtain additional information relevant to the research question. Data Extraction: Data were extracted from the text of the retrieved articles and from additional information provided by authors contacted successfully. From initially 3326 screened studies 44 were included. Data Synthesis: Mean time to diagnosis for patients with CS was 34 months (ectopic CS: 14 months; adrenal CS: 30 months; and pituitary CS: 38 months; P < .001). No difference was found for gender, age (<18 and ≥18 years), and year of diagnosis (before and after 2000). Patients with pituitary CS had a longer time to diagnosis in Germany than elsewhere. Conclusions: Time to diagnosis differs for subtypes of CS but not for gender and age. Time to diagnosis remains to be long and requires to be improved.

3 September 2020 in The Journal of Clinical Endocrinology & Metabolism
Verified
Journal Article
Open access
FVFrederick Vogel
Frederick Vogel
LBLeah T Braun
Leah T Braun
GRGerman Rubinstein
German Rubinstein
SZStephanie Zopp
Stephanie Zopp
HKHeike Künzel
Heike Künzel
MPMartin Reincke Prof
Martin Reincke Prof
Context: Glucocorticoid-induced myopathy is a characteristic symptom of endogenous Cushing’s syndrome (CS). Its long-term outcome is largely unknown. Objective: To evaluate long-term muscle function following the remission of endogenous CS. Study Design: Observational longitudinal cohort study. Setting: Tertiary care hospitals and a specialized outpatient clinic. Patients: As part of the prospective multicenter German Cushing’s Registry, we assessed muscle strength in patients with overt endogenous CS. We studied the patients at the time of diagnosis (n = 88), after 6 months (n = 69), and thereafter annually, following surgical remission over a period of up to 4 years (1 year: n = 55; 2 years: n = 34; 3 years: n = 29; 4 years: n = 22). Muscle function was evaluated by hand grip strength and by chair rising test. Results: Grip strength was decreased to 83% of normal controls (100%) at the time of diagnosis. It further decreased to 71% after 6 months in remission (P ≤ 0.001) and showed no improvement during further follow-up compared with baseline. Chair rising test performance improved initially (8 seconds at baseline vs 7 seconds after 6 months, P = 0.004) but remained at this reduced level thereafter (7 seconds after 3 years vs 5 seconds in controls, P = 0.038). In multivariate analysis, we identified, as predictors for long-term muscle dysfunction, age, waist-to-hip ratio, and hemoglobin A1c at baseline. Furthermore, muscle strength during follow-up was strongly correlated with quality of life. Conclusion: This study shows that CS-associated myopathy does not spontaneously resolve during remission. This calls for action to identify effective interventions to improve muscle dysfunction in this setting.

22 June 2022 in The Journal of Clinical Endocrinology & Metabolism
Verified
Journal Article
Open access
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LBLeah T Braun
Leah T Braun
FVFrederick Vogel
Frederick Vogel
SZStephanie Zopp
Stephanie Zopp
TSThomas Marchant Seiter
Thomas Marchant Seiter
GRGerman Rubinstein
German Rubinstein
MPMartin Reincke Prof
Martin Reincke Prof
Context Cushing syndrome (CS) is a rare and serious disease with high mortality. Patients are often diagnosed late in the course of the disease. Objective This work investigated whether defined patient populations should be screened outside the at-risk populations defined in current guidelines. Methods As part of the prospective German Cushing registry, we studied 377 patients with suspected CS. The chief complaint for CS referral was documented. Using urinary free cortisol, late-night salivary cortisol, and the 1-mg dexamethasone suppression test as well as long-term clinical observation, CS was confirmed in 93 patients and ruled out for the remaining 284. Results Patients were referred for 18 key symptoms, of which 5 were more common in patients with CS than in those in whom CS was ruled out: osteoporosis (8% vs 2%; P = .02), adrenal incidentaloma (17% vs 8%, P = 0.01), metabolic syndrome (11% vs 4%; P = .02), myopathy (10% vs 2%; P < .001), and presence of multiple symptoms (16% vs 1%; P < .001). Obesity was more common in patients in whom CS was ruled out (30% vs 4%, P < .001), but recent weight gain was prominent in those with CS. A total of 68 of 93 patients with CS (73%) had typical chief complaints, as did 106 of 284 of patients with ruled-out CS status (37%) according to the Endocrine Society practice guideline 2008. Conclusion The 2008 Endocrine Society Practice guideline for screening and diagnosis of CS defined at-risk populations that should undergo testing. These recommendations are still valid in 2022.

27 March 2023 in European Journal of Endocrinology
Verified
Journal Article
Open access
PDF file
FVFrederick Vogel
Frederick Vogel
LBLeah Braun
Leah Braun
SZStephanie Zopp
Stephanie Zopp
ENElisabeth Nowak
Elisabeth Nowak
JSJochen Schreiner
Jochen Schreiner
MPMartin Reincke Prof
Martin Reincke Prof
Endogenous Cushing’s syndrome (CS) leads to profound immunosuppression. Successful surgery induces biochemical remission and reversal of immunosuppression, which is characterized by clinical signs of glucocorticoid withdrawal and associated with increased susceptibility to infections and thromboembolic complications. We hypothesized that the glucocorticoid withdrawal phase is characterized by low-grade inflammation that may be related to patient-relevant outcomes. In this retrospective observational study, we analyzed longitudinal data from 80 patients with CS prospectively enrolled in the German Cushing’s registry between 2012 and 2021. All enrolled patients underwent successful surgery. In a second step, a case control study was performed in 25 of the patients with age-, gender- and BMI-matched control patients in whom hypercortisolism was excluded. Analyses included the inflammatory markers C-reactive protein and interleukin-6, as well as body composition, muscle function testing and quality of life questionnaires. The patients were studied during active CS and in the postoperative remission phase 1, 3, 6, 12 and 24 months after surgery. Compared to the preoperative phase and matched controls, patients with CS had increased systemic inflammatory markers in the early remission phase. One month following surgery, median (IQR) C-reactive protein was 0.48 mg/dL (0.14; 0.90) vs. 0.10 mg/dL (0.06; 0.39) during active CS (p ≤ 0.001). Similarly, interleukin-6 one month after surgery was 7.2 pg/mL (3.3; 11.7) vs. 1.7 pg/mL (1.5; 2.5) during active CS (p ≤ 0.001). Obesity and HbA1c were associated with increased inflammation levels. This proinflammatory state lasted until one year following surgery. Moreover, inflammatory markers during early remission showed an inverse correlation with long-term muscle function. The glucocorticoid withdrawal phase is associated with a low-grade inflammatory state, which is particularly pronounced in obese and hyperglycemic patients and related to lower muscle function.

10 March 2022 in Endocrine
Verified
Journal Article
Open access
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GRGerman Rubinstein
German Rubinstein
AOAndrea Osswald
Andrea Osswald
LBLeah Theresa Braun
Leah Theresa Braun
FVFrederick Vogel
Frederick Vogel
MKMatthias Kroiss
Matthias Kroiss
MPMartin Reincke Prof
Martin Reincke Prof
Objective: Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) is a rare cause of ACTH-independent Cushing’s syndrome. Current guidelines recommend bilateral adrenalectomy for PBMAH, but several studies showed clinical effectiveness of unilateral adrenalectomy despite bilateral disease in selected patients. Our aim was to evaluate the gain of information which can be obtained through adrenal venous sampling (AVS) based cortisol lateralization ratios for guidance of unilateral adrenalectomy.Design: We performed a retrospective analysis of 16 patients with PBMAH and clinical overt cortisol secretion in three centersMethods: Selectivity of adrenal vein sampling during AVS was defined as a gradient of cortisol or a reference adrenal hormone ≥2.0 between adrenal and peripheral vein. Lateralization was assumed if the dominant to non-dominant ratio of cortisol to reference hormone was ≥4.0.Results: AVS was technically successful in all patients based on absolute cortisol levels and in 13 of 16 patients (81%) based on reference hormone levels. Lateralization was documented in 8 of 16 patients. In patients with lateralization, in 5 of 8 cases this occurred toward morphologically larger adrenals, while in 3 patients lateralization was present in bilaterally identical adrenals. The combined volume of adrenals correlated positively with urinary free cortisol, suggesting that adrenal size is the dominant determinant of cortisol secretion.Conclusions: In this study the gain of information through AVS for unilateral adrenalectomy was limited in patients with PBMAH and marked adrenal asymmetry.

30 September 2024 in European Journal of Endocrinology
Verified
Journal Article
Closed access
LBLeah T Braun
Leah T Braun
FVFrederick Vogel
Frederick Vogel
ENElisabeth Nowak
Elisabeth Nowak
GRGerman Rubinstein
German Rubinstein
SZStephanie Zopp
Stephanie Zopp
MPMartin Reincke Prof
Martin Reincke Prof
Background: Cushing's syndrome (CS) can be difficult to diagnose. A timely diagnosis, however, is the cornerstone for targeted treatment, to reduce morbidity and mortality. One reason for the difficulties to identify early on patients with CS might be the presence of a mild phenotype. The aim of the study was to classify the phenotypic landscape of CS. We studied patients with overt CS and mild autonomous cortisol secretion (MACS). Method: The study was part of the German Cushing's registry. Patients were prospectively included at time of diagnosis and the number of comorbidities and clinical signs and symptoms were assessed in a standardized fashion. One hundred twenty-nine patients with CS (pituitary CS, n = 85, adrenal CS, n = 32, ectopic CS, n = 12, respectively) and 48 patients with MACS were included. Patients with clinical signs and/or comorbidities typical for CS and at least 2 pathological screening tests were classified as having CS. Patients with a 1 mg low-dose-dexamethasone-suppression test above 1.8 µg/dL without being clinically overt CS were classified as having MACS. Results: On average, patients with CS had 2 comorbidities (range 1-3) at time of diagnosis (pituitary CS: 2 [1-3], adrenal CS: 3 [2-4], ectopic CS: 3 [2-4]). Patients with MACS, however, had 3 comorbidities (range 2-3). Hypertension was the most common comorbidity in all subtypes of CS (78%-92%) and in patients with MACS (87%). Of a total of 11 clinical signs, patients with CS had on average 5 with 28% of patients having between 0 and 3 clinical signs, 50% 4-7 signs, and 22% more than 7 clinical signs. Patients with MACS had on average 2 clinical signs (range 1-3) at time of diagnosis. Conclusion: The phenotypic landscape of CS is quite variable. The frequency of comorbidities is similar between patients with CS and MACS. A relevant number of patients with overt CS have just a few clinical signs. There is also an overlap in frequency of symptoms and clinical signs between patients with CS and MACS. According to the current guidelines, 96% of our patients with MACS fall into the category “consideration of adrenalectomy”. This should be kept in mind when making treatment decisions in the latter group of patients.