Trends in caesarean section rates in Europe from 2015 to 2019 using Robson's Ten Group Classification System: A Euro-Peristat study

OBJECTIVE

To assess changes in caesarean section (CS) rates in Europe from 2015 to 2019 and utilise the Robson Ten Group Classification System (TGCS) to evaluate the contribution of different obstetric populations to overall CS rates and trends.

DESIGN

Observational study utilising routine birth registry data.

SETTING

A total of 28 European countries.

POPULATION

Births at ≥22 weeks of gestation in 2015 and 2019.

METHODS

Using a federated model, individual-level data from routine sources in each country were formatted to a common data model and transformed into anonymised, aggregated data.

MAIN OUTCOME MEASURES

By country: overall CS rate. For TGCS groups (by country): CS rate, relative size, relative and absolute contribution to overall CS rate.

RESULTS

Among the 28 European countries, both the CS rates (2015, 16.0%-55.9%; 2019, 16.0%-52.2%) and the trends varied (from -3.7% to +4.7%, with decreased rates in nine countries, maintained rates in seven countries (≤ ± 0.2) and with increasing rates in 12 countries). Using the TGCS (for 17 countries), in most countries labour induction increased (groups 2a and 4a), whereas multiple pregnancies (group 8) decreased. In countries with decreasing overall CS rates, CS tended to decrease across all TGCS groups, whereas in countries with increasing rates, CS tended to increase in most groups. In countries with the greatest increase in CS rates (>1%), the absolute contributions of groups 1 (nulliparous term cephalic singletons, spontaneous labour), 2a and 4a (induction of labour), 2b and 4b (prelabour CS) and 10 (preterm cephalic singletons) to the overall CS rate tended to increase.

CONCLUSIONS

The TGCS shows varying CS trends and rates among countries of Europe. Comparisons between European countries, particularly those with differing trends, could provide insight into strategies to reduce CS without clinical indication.

The Outcome of Laparoscopic Versus Open Appendectomy in Childhood

BACKGROUND

Appendectomy in children is performed either lapa - roscopically (LA) or by open surgery (OA). We studied whether, and how, the outcome is affected by the technique used and by the intraoperative conversion of LA to OA.

METHODS

We analyzed routine data from children and adolescents in three age groups (1-5 years, 6-12 years, and 13-17 years) who were insured by the AOK statutory health insurance carrier in Germany and who underwent appendectomy in the period 2017-2019. General surgical complications and reoperations within 90 days were assessed with relevant indicators. Associations between the surgical technique and these indicators were studied with logistic regression.

RESULTS

Of the 21 541 patients included in the study, general surgical complications were observed in 2.1% and reoperations in 1.8% overall. Broken down by age group, the corresponding figures were 5.4% and 4.4% (age 1 to 5), 2.5% and 1.8% (age 6 to 12), and 1.5% and 1.6% (age 13 to 17). The main risk factors for complications and reoperations were acute complicated appendicitis and conversion from LA to OA. Regression analysis revealed similar outcomes with OA compared to LA in the 1-to-5 age group, (odds ratios and 95% confidence intervals: 1.1 [0.6; 2.1] for general surgical complications and 1.5 [0.8; 2.7] for reoperations), but worse outcomes with OA in the other two age groups (age 6 to 12: 1.9 [1.2; 2.9] and 2.1 [1.5; 2.9]; age 13 to 17: 1.7 [1.0; 2.9] and 2.2 [1.4; 3.6]). When conversions were assigned to the LA group, the odds ratio (OA compared to LA) for reoperation across all age groups was 3.5 [2.8; 4.4] in patients with acute uncomplicated appendicitis and 4.2 [3.4; 5.3] in patients with complicated appendicitis. Complicated appendicitis also increased the rate of general surgical complications and the length of stay in hospital.

CONCLUSION

Among children in the two older age groups, LA was followed by fewer general surgical complications and reoperations than OA. These differences were less pronounced when conversions were counted as belonging to the LA group. Children aged 1-5 appear to benefit the least from the lapa - roscopic technique.

APOBEC mutagenesis, kataegis, chromothripsis in EGFR-mutant osimertinib-resistant lung adenocarcinomas

BACKGROUND

Studies of targeted therapy resistance in lung cancer have primarily focused on single-gene alterations. Based on prior work implicating apolipoprotein b mRNA-editing enzyme, catalytic polypeptide-like (APOBEC) mutagenesis in histological transformation of epidermal growth factor receptor (EGFR)-mutant lung cancers, we hypothesized that mutational signature analysis may help elucidate acquired resistance to targeted therapies.

PATIENTS AND METHODS

APOBEC mutational signatures derived from an Food and Drug Administration-cleared multigene panel [Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT)] using the Signature Multivariate Analysis (SigMA) algorithm were validated against the gold standard of mutational signatures derived from whole-exome sequencing. Mutational signatures were decomposed in 3276 unique lung adenocarcinomas (LUADs), including 93 paired osimertinib-naïve and -resistant EGFR-mutant tumors. Associations between APOBEC and mechanisms of resistance to osimertinib were investigated. Whole-genome sequencing was carried out on available EGFR-mutant lung cancer samples (10 paired, 17 unpaired) to investigate large-scale genomic alterations potentially contributing to osimertinib resistance.

RESULTS

APOBEC mutational signatures were more frequent in receptor tyrosine kinase (RTK)-driven lung cancers (EGFR, ALK, RET, and ROS1; 25%) compared to LUADs at large (20%, P < 0.001); across all subtypes, APOBEC mutational signatures were enriched in subclonal mutations (P < 0.001). In EGFR-mutant lung cancers, osimertinib-resistant samples more frequently displayed an APOBEC-dominant mutational signature compared to osimertinib-naïve samples (28% versus 14%, P = 0.03). Specifically, mutations detected in osimertinib-resistant tumors but not in pre-treatment samples significantly more frequently displayed an APOBEC-dominant mutational signature (44% versus 23%, P < 0.001). EGFR-mutant samples with APOBEC-dominant signatures had enrichment of large-scale genomic rearrangements (P = 0.01) and kataegis (P = 0.03) in areas of APOBEC mutagenesis.

CONCLUSIONS

APOBEC mutational signatures are frequent in RTK-driven LUADs and increase under the selective pressure of osimertinib in EGFR-mutant lung cancer. APOBEC mutational signature enrichment in subclonal mutations, private mutations acquired after osimertinib treatment, and areas of large-scale genomic rearrangements highlights a potentially fundamental role for APOBEC mutagenesis in the development of resistance to targeted therapies, which may be potentially exploited to overcome such resistance.

Vaginal Birth at Term - Part 1. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/083, December 2020)

Purpose This guideline aims to summarize the current state of knowledge about vaginal birth at term. The guideline focuses on definitions of the physiological stages of labor as well as differentiating between various pathological developments and conditions. It also assesses the need for intervention and the options to avoid interventions. This first part presents recommendations and statements about patient information and counselling, general patient care, monitoring of patients, pain management and quality control measures for vaginal birth. Methods The German recommendations largely reproduce the recommendations of the National Institute for Health and Care Excellence (NICE) CG 190 guideline "Intrapartum care for healthy women and babies". Other international guidelines were also consulted in specific cases when compiling this guideline. In addition, a systematic search and analysis of the literature was carried out using PICO questions, if this was considered necessary, and other systematic reviews and individual studies were taken into account. For easier comprehension, the assessment tools of the Scottish Intercollegiate Guidelines Network (SIGN) were used to evaluate the quality of the additionally consulted studies. Otherwise, the GRADE system was used for the NICE guideline and the evidence reports of the IQWiG were used to evaluate the quality of the evidence. Recommendations Recommendations and statements were formulated based on identified evidence and/or a structured consensus.

Vaginal Birth at Term - Part 2. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/083, December 2020)

Purpose This guideline aims to summarize the current state of knowledge about vaginal birth at term. The guideline focuses on definitions of the physiological stages of labor as well as differentiating between various pathological developments and conditions. It also assesses the need for intervention and the options to avoid interventions. The second part of this guideline presents recommendations and statements on care during the dilation and expulsion stages as well as during the placental/postnatal stage. Methods The German recommendations largely reproduce the recommendations of the National Institute for Health and Care Excellence (NICE) CG190 guideline "Intrapartum care for healthy women and babies". Other international guidelines were also consulted in individual cases when compiling this guideline. In addition, a systematic search and analysis of the literature was carried out using PICO questions where necessary, and other systematic reviews and individual studies were taken into account. For easier comprehension, the assessment tools of the Scottish Intercollegiate Guidelines Network (SIGN) were used to evaluate the quality of additionally consulted studies. Otherwise, the GRADE system was used for the NICE guideline, and the evidence reports of the IQWiG were used to evaluate the quality of the evidence. Recommendations Recommendations and statements were formulated based on identified evidence and/or a structured consensus.

Setting targets for population health improvements: Trends in perinatal health in Europe over the past five years

Background

The Euro-Peristat network documented disparities in perinatal outcomes between countries in Europe in its reports published every 5 years, but trend analyses were limited because data were not collected annually.

Methods

Using the Euro-Peristat PHIRI protocol, we estimated rates and assessed trends between 2015 and 2019 for preterm birth, stillbirth, neonatal mortality and caesarean delivery. Country-specific relative risks (RR) for year, modelled as a continuous variable, were estimated and random effects meta-analysis used to generate pooled RRs. Heterogeneity was measured with the I2 statistic (percentage of variability in estimates due to heterogeneity rather than sampling error).

Results

Stillbirth rates ≥24 weeks of gestational age (GA) varied in 2019 from &lt;2.5 per 1000 births in Denmark, Estonia, Finland and Slovenia to over 4 per 1000 in Belgium, Cyprus, UK Wales and Lithuania. Preterm birth rates ranged from &lt;6% in Lithuania, Finland, Latvia, Estonia and Denmark to 8% or more in Portugal, Belgium, UK Scotland and Cyprus. Fewer than 20% of births were by caesarean in Norway, the Netherlands, Finland, Estonia in comparison to one-third in Cyprus, Ireland, Italy, UK Scotland. Trends over time differed between countries and were not related to the level of the indicator: the pooled RR by year for preterm birth was 0.99 [0.99; 1.00] with five countries having significant decreases and three countries having increases. Caesarean section rates were stable overall (RR: 1.00 [0.99; 1.01]RR:1.00, 95% CI: 0.99-1.01), but with high heterogeneity (I2=99%); in six countries rates increased significantly, whereas in nine rates decreased between 2015 and 2019.

Conclusions

European countries have varying rates and trends of the principal perinatal health indicators. Investigation of policies in high-performing countries could provide guidance for improvement elsewhere.

OS03.5.A Characterization of the inflammatory tumor microenvironment composition in solid cancer patients with brain metastases after progression to immune checkpoint inhibitor therapy

Background

Immunotherapy (IO) has changed the treatment landscape of metastatic cancer patients, however, treatment resistance is frequent. We aimed to characterize the inflammatory tumor microenvironment in brain metastases (BM) after IO to gain a deeper understanding of immunologic escape mechanisms.

Material and Methods

Solid cancer patients who had BM resection after IO progression (IO cohort) were retrospectively identified. We analyzed tumor-infiltrating immune cell subsets (CD3, CD8, CD45RO, FOXP3) and expression of immune checkpoint molecules (PD-L1, PD-1, LAG-3) by immunohistochemistry. A control cohort of BM tissue samples without prior IO served for comparison (no immunotherapy cohort, NIO).

Results

Twenty-eight IO patients (12/28, 42.9% females; 16/28, 57.1% males; median 61 years; 14/28, 50% lung cancer; 5/28, 17.9% melanoma; 4/28, 14.3% renal cell carcinoma; 1/28, 3.6% breast cancer; 4/28, 14.3% other cancer entities) and 57 NIO patients (28/57, 49.1% females; 29/57, 50.9% males; median 58 years; 35/57, 61.4% lung cancer; 9/57, 15.8% breast cancer; 4/57, 7.0% melanoma; 3/57, 5.3% renal cell carcinoma; 6/57, 10.5% other cancer entities) were included. IO patients had a median of one (range 0-4) systemic therapy line prior to IO. Median time from last IO application until BM resection was 5.6 months (range 0.2-49.8 months). Patients received a median number of 7 (range 1-56) IO applications (14/28, 50% PD-1-targeting IO; 8/28, 28.6% PD-L1; 2/28, 7.1% CTLA4; 4/28, 14.3% CTLA4+PD-1; 3/28, 10.7% IO+chemotherapy). No statistically significant differences in the densities of investigated TILs or PD-L1 expression between the IO and the NIO cohort were observed. Patients of the IO cohort showed higher PD-L1 expression compared to the NIO cohort (57.1 vs. 42.1%, Chi-square, p&gt;0.05). Overall survival (OS) was similar in both cohorts, with a median OS of 11.0 months (range 5.0-17.0) in the IO cohort and 11.0 months (range 5.5-16.5) in the NIO cohort.

Conclusion

Our findings show an upregulation of PD-L1 in BM occurring after prior IO therapy in the absence of other overt changes in the inflammatory microenvironment. Ongoing analyses in this cohort are investigating possible molecular driver of resistance by analyzing DNA methylation profiles of pre-and post-IO tissue samples of the IO cohort to potentially gain insights on inflammatory IO resistance mechanisms in BM patients.

P11.27.B Whole genome DNA methylation as predictive biomarker in CNS WHO grade 2 and 3 oligodendroglioma patients receiving early postoperative treatment

Background

Oligodendrogliomas are glial tumors with a relatively favorable survival prognosis of &gt;10 years. While immediate postoperative treatment prolongs survival, long-term toxicities of adjuvant radio-chemotherapy remain a concern. Predictive biomarkers guiding postoperative treatment decisions are limited.

Material and Methods

In this retrospective study, we included patients treated for a newly diagnosed oligodendroglioma (isocitrate dehydrogenase (IDH)-mutated, 1p/19q-codeleted, CNS WHO grades 2 and 3) in 1992 - 2019 at the Medical University of Vienna or the Kepler University Hospital Linz (Austria). Early treatment was defined as radiotherapy, chemotherapy, or both within 6 months after resection, whereas benefit from early treatment was defined as progression-free survival (PFS) above the median in the overall cohort. DNA methylation analysis was performed using Illumina MethylationEPIC 850k microarrays.

Results

Of all 201 eligible patients, sufficient tumor tissue for DNA methylation analysis was available in 46 patients. Of these, 25/46 (54.3%) were diagnosed with CNS WHO grade 2 and 21/46 (45.6%) with grade 3 oligodendroglioma. Median age at diagnosis was 41 years (range: 23-70). In total, 21/46 (45.6%) patients received early treatment, of whom 13/21 (61.9%) received radio-chemotherapy, 6/21 (28.6%) radiotherapy only and 2/21 (9.5%) chemotherapy only. Median PFS was 134.0 months (95%CI: 78.3 - not reached) in patients receiving early treatment versus 87.2 months (95%CI: 66.8 - 150) in patients who did not. In patients receiving early treatment, differences in DNA methylation profiles could be detected between patients who drew benefit from postoperative treatment (group 1) versus those who did not (group 2). Based on the top 1000 differentially methylated CpG sites between both groups, two clusters were detected which comprised either patients of group 1 or 2. Clustering was independent from gender, WHO grade, extent of resection, type of postoperative treatment, treating center, and O6-methylguanine-methyltransferease (MGMT) promoter methylation status. Gene set enrichment analysis of the top 1000 differentially methylated gene sites mapped to 694 genes showed differential methylation in genes involved in fibroblast growth receptor 1 (FGFR1) signaling, Wnt signaling, integrin signaling, and actin cytoskeleton regulation. Conversely, in patients not receiving early treatment, PFS did neither correlate with DNA methylation clustering nor with MGMT promoter methylation.

Conclusion

In our cohort, whole genome DNA methylation was associated with PFS in patients who received early postoperative treatment, suggesting a predictive but not prognostic role. As the predictive value of MGMT promoter methylation is limited in oligodendroglioma, whole genome DNA methylation should be considered in future clinical trials.

Prevalence and Infant Mortality of Major Congenital Malformations Stratified by Birthweight

BACKGROUND

Low birthweight and major congenital malformations (MCMs) are key causes of infant mortality.

OBJECTIVES

The aim of this study was to explore the prevalence of MCMs in infants with low and very low birthweight and analyze the impact of MCMs and birthweight on infant mortality.

METHODS

We determined prevalence and infant mortality of 28 life-threatening MCMs in very-low-birthweight (<1,500 g, VLBW), low-birthweight (1,500-2,499 g, LBW), or normal-birthweight (≥2,500 g, NBW) infants in a cohort of 2,727,002 infants born in Germany in 2006-2017, using de-identified administrative data of the largest statutory public health insurance system in Germany.

RESULTS

The rates of VLBW, LBW, and NBW infants studied were 1.3% (34,401), 4.0% (109,558), and 94.7% (2,583,043). MCMs affected 0.5% (13,563) infants, of whom >75% (10,316) had severe congenital heart disease. The prevalence (per 10,000) of any/cardiac MCM was increased in VLBW (286/176) and LBW (244/143), as compared to NBW infants (38/32). Infant mortality rates were significantly higher in infants with an MCM, as opposed to infants without an MCM, in each birthweight group (VLBW 28.5% vs. 11.5%, LBW 16.7% vs. 0.9%, and NBW 8.6% vs. 0.1%). For most MCMs, observed survival rates in VLBW and LBW infants were lower than expected, as calculated from survival rates of VLBW or LBW infants without an MCM, and NBW infants with an MCM.

CONCLUSIONS

Infants with an MCM are more often born with LBW or VLBW, as opposed to infants without an MCM. Many MCMs carry significant excess mortality when occurring in VLBW or LBW infants.

Population-Based Outcome Data of Extremely Preterm Infants in Germany during 2010-2017

BACKGROUND AND OBJECTIVE

Results of five randomized controlled trials (RCT) sequentially published in 2010-2013 suggested that aiming for higher, as opposed to lower oxygen saturation targets, reduces rates of mortality in infants <28 weeks of gestation, while increasing rates of severe retinopathy of prematurity (ROP). Two further RCTs published in 2011 and 2015 demonstrated that avoiding endotracheal intubation by minimally invasive surfactant administration reduces respiratory morbidity. Assuming that such data are likely to affect clinical practice and ultimate outcome, we analyzed population-level results in extremely preterm infants born across Germany during 2010-2017.

METHODS

We used mandatory German quality surveillance data to compare mortality and morbidities in preterm infants born between 24 weeks 0 days and 27 weeks 6 days of gestation in 2010-2013 versus 2014-2017.

RESULTS

Mortality decreased from 15.1% (1,366/9,058) in 2010-2013 to 12.7% (1,385/10,924) in 2014-2017, risk ratio (RR) 0.845 (95% confidence interval [CI], 0.784-0.901). Rates of severe ROP (≥grade 3) per survivor increased from 12.1% (930/7,692) to 13.3% (1.269/9,539), RR 1.100 (95% CI: 1.017-1.191). The lowest mortality and highest ROP rates were found in infants born in 2014. There was no change in rates of necrotizing enterocolitis, while those of bronchopulmonary dysplasia (BPD) decreased steadily between 2010 and 2017, alongside the increased proportion of infants who were never intubated.

CONCLUSIONS

There was a moderate decline in mortality, an insignificant increase in severe ROP, and a steady decline of BPD in Germany during 2010-2017. Avoiding endotracheal intubation may have contributed to lowered BPD rates.

Core-binding factor leukemia hijacks the T-cell-prone PU.1 antisense promoter

The blood system serves as a key model for cell differentiation and cancer. It is orchestrated by precise spatiotemporal expression of crucial transcription factors. One of the key master regulators in the hematopoietic systems is PU.1. Reduced levels of PU.1 are characteristic for human acute myeloid leukemia (AML) and are known to induce AML in mouse models. Here, we show that transcriptional downregulation of PU.1 is an active process involving an alternative promoter in intron 3 that is induced by RUNX transcription factors driving noncoding antisense transcription. Core-binding factor (CBF) fusions RUNX1-ETO and CBFβ-MYH11 in t(8;21) and inv(16) AML, respectively, activate the PU.1 antisense promoter that results in a shift from sense toward antisense transcription and myeloid differentiation blockade. In patients with CBF-AML, we found that an elevated antisense/sense transcript and promoter accessibility ratio represents a hallmark compared with normal karyotype AML or healthy CD34+ cells. Competitive interaction of an enhancer with the proximal or the antisense promoter forms a binary on/off switch for either myeloid or T-cell development. Leukemic CBF fusions thus use a physiological mechanism used by T cells to decrease sense transcription. Our study is the first example of a sense/antisense promoter competition as a crucial functional switch for gene expression perturbation by oncogenes. Hence, this disease mechanism reveals a previously unknown Achilles heel for future precise therapeutic targeting of oncogene-induced chromatin remodeling.

Zum Beitrag: Qualität der Versorgung sehr kleiner Frühgeborener in Deutschland – Auswertung öffentlich verfügbarer Daten der Perinatalzentren von 2014 bis 2018

Wir begrüßen den Beitrag von Prof. Trotter 1 mit Blick auf Volume-Outcome-Effekte in der Versorgung von sehr kleinen Frühgeborenen, insbesondere auch unter Berücksichtigung des von uns einführten Konzeptes der risikoadjustieren Fallzahlen 2, im Sinne eines wissenschaftlich offenen Diskurses. Wir freuen uns ausdrücklich über das anhaltende Interesse an dieser Thematik wie auch über die Tatsache, dass auch Prof. Trotter grundsätzlich ähnliche Volume-Outcome-Zusammenhänge wie wir beschreibt. Dabei hatte Prof. Trotter (von geringfügigen unterjährigen Veränderungen abgesehen) in Teilen die gleiche Datenbasis wie wir genutzt 3. So kann konstatiert werden, dass dort wo die Analysen vergleichbar sind, sich erfreulicherweise nahezu identische Ergebnisse darstellen 4. Zwar können wir nur spekulieren, aufgrund welcher Analyse bzw. Beobachtung sich in der Arbeit von Prof. Trotter die Aussage ableitet, dass Volume-Outcome-Effekte maßgeblich nur durch größere Perinatalzentren getrieben werden, ungeachtet dessen passt diese Aussage zu der von uns beschriebenen hohen „optimalen Mindestmenge“ 3.

Caesarean Section. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/084, June 2020)

Purpose This is an official S3-guideline of the German Society of Gynaecology and Obstetrics (DGGG), the Austrian Society of Gynaecology and Obstetrics (ÖGGG) and the Swiss Society of Gynaecology and Obstetrics (SGGG). The guideline contains evidence-based information and recommendations on indications, complications, methods and care associated with delivery by caesarean section for all medical specialties involved as well as for pregnant women. Methods This guideline has adapted information and recommendations issued in the NICE Caesarean Birth guideline. This guideline also considers additional issues prioritised by the Cochrane Institute and the Institute for Research in Operative Medicine (IFOM). The evaluation of evidence was based on the system developed by the Scottish Intercollegiate Guidelines Network (SIGN). A multi-part nominal group process moderated by the AWMF was used to compile this S3-level guideline. Recommendations Recommendations on consultations, indications and the process of performing a caesarean section as well as the care provided to the mother and neonate were drawn up.

Tumor mutational burden and immune infiltrates in renal cell carcinoma and matched brain metastases

BACKGROUND

Tumor mutational burden (TMB) and density of tumor-infiltrating lymphocytes (TIL) have been postulated as predictive biomarkers for immunotherapy. Therefore, we investigated the concordance of TMB and TIL of primary/extracranial renal cell carcinoma (RCC) specimens and matched brain metastases (BM).

PATIENTS AND METHODS

Twenty specimens from 10 patients were retrieved from the Vienna Brain Metastasis Registry (6/10 primary tumor, 4/10 lung metastasis, 10/10 matched BM). TMB was assessed using the TruSight Oncology 500 gene panel with libraries sequenced on a NextSeq instrument. TIL subsets (CD3+, CD8+, CD45RO+, FOXP3+, PD-L1+) were investigated using immunohistochemistry (Ventana Benchmark Ultra system) and automated tissue analysis (Definiens software).

RESULTS

No significant difference in TMB, CD3+, CD8+, CD45RO+, FOXP3+ or PD-L1+ expression was observed between extracranial and matched intracranial specimens (P > 0.05). Higher CD8+ TIL (P = 0.053) and CD45RO+ TIL (P = 0.030) densities in the primary tumor compared with the intracranial samples were observed in specimens collected after exposure to systemic treatment. Neither extracranial sample origin (lung metastasis versus primary RCC) nor extracranial disease status at BM diagnosis (progressive versus stable disease) were significantly associated with TMB or TIL densities in extracranial and intracranial samples (P > 0.05). No significant correlation was found between the median differences of TMB or TIL densities from extracranial to intracranial samples and BM-free survival.

CONCLUSION

The comparable immunological microenvironment of extra- and intracranial tumor samples in our study underscores the immunological activation also in BM from RCC, and therefore, supports the development of immune modulatory treatments also in patients with brain metastatic RCC.

Antwort: Erwiderung auf den Leserbrief von Prof. Dr. Pohlandt

Wir danken Herrn Prof. Pohlandt für seinen Leserbrief und die darin gestellten Fragen zu unserem Artikel „Wie hoch ist die optimale Mindestmenge für die Behandlung Frühgeborener mit einem Geburtsgewicht unter 1250 g in Deutschland?“ 1 und möchten im Folgenden auf die einzelnen Punkte eingehen:

Using Robson's Ten-Group Classification System for comparing caesarean section rates in Europe: an analysis of routine data from the Euro-Peristat study

Objective

Robson's Ten Group Classification System (TGCS) creates clinically relevant sub‐groups for monitoring caesarean birth rates. This study assesses whether this classification can be derived from routine data in Europe and uses it to analyse national caesarean rates.

Design

Observational study using routine data.

Setting

Twenty‐seven EU member states plus Iceland, Norway, Switzerland and the UK.

Population

All births at ≥22 weeks of gestational age in 2015.

Methods

National statistical offices and medical birth registers derived numbers of caesarean births in TGCS groups.

Main outcome measures

Overall caesarean rate, prevalence and caesarean rates in each of the TGCS groups.

Results

Of 31 countries, 18 were able to provide data on the TGCS groups, with UK data available only from Northern Ireland. Caesarean birth rates ranged from 16.1 to 56.9%. Countries providing TGCS data had lower caesarean rates than countries without data (25.8% versus 32.9%, P = 0.04). Countries with higher caesarean rates tended to have higher rates in all TGCS groups. Substantial heterogeneity was observed, however, especially for groups 5 (previous caesarean section), 6, 7 (nulliparous/multiparous breech) and 10 (singleton cephalic preterm). The differences in percentages of abnormal lies, group 9, illustrate potential misclassification arising from unstandardised definitions.

Conclusions

Although further validation of data quality is needed, using TGCS in Europe provides valuable comparator and baseline data for benchmarking and surveillance. Higher caesarean rates in countries unable to construct the TGCS suggest that effective routine information systems may be an indicator of a country's investment in implementing evidence‐based caesarean policies.

Tweetable abstract

Many European countries can provide Robson's Ten‐Group Classification to improve caesarean rate comparisons.

Many European countries can provide Robson's Ten‐Group Classification to improve caesarean rate comparisons.

Rates of Complications After Appendectomy in Children and Adolescents: Pediatric Surgical Compared to General Surgical Hospitals

BACKGROUND

Appendectomies in children and adolescents are performed in Germany in pediatric surgical (PS) or general surgical hospitals (GS). The aim of this study is to evaluate whether the surgery in a PS or GS hospital has an influence on the postoperative course after appendectomy in children and adolescents.

MATERIALS AND METHODS

Nationwide routine data from children and adolescents aged 1-17 y insured by the Local Health Insurance Fund who underwent appendectomy between 2014 and 2016 were analyzed (cohort study). Descriptive statistics were calculated both overall and in the two groups (PS and GS). Patients were additionally examined by age (1-5, 6-12, and 13-17 y), treatment (laparoscopic, open surgical, and conversion), and appendicitis type (nonacute: K36/K37/K38/R10, acute simple: K35.30/K35.8, and acute complex: K35.2/K35.31/K35.32). The influence of surgeon specialization on 90-d secondary surgery and 90-d general complications was assessed by multiple logistic regression.

RESULTS

Altogether, 25,065 patients who underwent surgery in 83 PS and 906 GS hospitals were included. Logistic regression analysis revealed that PS was associated with a reduced risk of interventions in the 1-5- and 6-12-y age groups (odds ratio: 0.44, 0.62). Acute complex appendicitis, comorbidities, and open surgery significantly increased the risk for reintervention. PS was associated with an increased risk for complications in the 13-17-y age group (odds ratio: 1.66).

CONCLUSIONS

PS and GS hospitals provided safe appendectomies in children and adolescents with low reintervention and complication rates. PS hospitals demonstrated advantages for patients in the 1-5- and 6-12-y age groups and GS hospitals for patients 13-17 y.

[What is the Optimal Minimum Provider Volume in the Provision of Care for Preterm Infants with a Birth Weight below 1250 g in Germany?]

INTRODUCTION

Numerous studies have investigated volume-outcome relationships in the treatment of very low birth weight infants. However, studies addressing the identification of optimal thresholds when introducing minimum provider volumes for treatment of these infants do not exist.

METHODS

Publicly available data (www.perinatalzentren.org) of more than 56,000 infants weighing less than 1250 g at birth (NB<1250) and treated in level-1 perinatal centers (highest level in Germany) between 2010 and 2018 was used for statistical analysis. Potentially avoidable deaths after the introduction of minimum provider volumes were calculated by deducting observed deaths from estimated deaths based on logistic regression models for every existing empirical provider volume. Various smoothing functions were used to ascertain optimal thresholds for minimum provider volumes.

RESULTS

Independent of the observation period or smoothing technique, the highest number of potentially avoidable deaths was observed for minimum provider volumes of 50-60 NB<1250 per year. Introducing a minimum provider volume of 50 without a transition period would reduce the number of level-1 perinatal centers to a quarter of the current number in Germany. Approximately 60% of NB<1250 would have to be reallocated.

CONCLUSION

Analyses of resulting geographical distances are needed in the preparation of minimum provider volumes for treatment of NB<1250 in Germany. Such analyses should include perinatal centers expected to reach minimum provider volumes after subsequent reallocation in the future.

Hospital volume and outcome in inguinal hernia repair: analysis of routine data of 133,449 patients

Introduction

Inguinal hernias are repaired using either open or minimally invasive surgical techniques. For both types of surgery it has been demonstrated that a higher annual surgeon volume is associated with a lower risk of recurrence. This present study investigated the volume-outcome implications for recurrence operations, surgical complications, rate of chronic pain requiring treatment, and 30-day mortality based on the hospital volume.

Materials and methods

The data basis used was the routine data collected throughout the Federal Republic of Germany for persons insured by the Local General Sickness Fund “AOK” who had undergone inpatient inguinal hernia repair between 2013 and 2015. Complications were recorded by means of indicators. Hospitals were divided into five groups on the basis of the annual caseload volume: 1–50, 51–75, 76–100, 101–125, and ≥ 126 inguinal hernia repairs per year. The effect of the hospital volume on the indicators was assessed using multiple logistic regression.

Results

133,449 inguinal hernia repairs were included. The incidence for recurrence operations was 0.95%, for surgical complications 4.22%, for chronic pain requiring treatment 2.87%, and for the 30-day mortality 0.28%. Low volume hospitals (1–50 and 51–75 inguinal hernia repairs per year) showed a significantly increased recurrence risk compared to high volume hospitals with ≥ 126 inguinal hernia repairs per year (odds ratio: 1.53 and 1.24). No significant correlations were found for the other results.

Conclusions

The study gives a detailed picture of hospital care for inguinal hernia repair in Germany. Furthermore, it was noted that the risk of hernia recurrence decreases in line with a rising caseload of the treating hospital.

Zum Beitrag: Frühgeburtenrate in 6 Perinatalzentren in Baden-Württemberg – Potenzial zur Reduktion der Frühgeborenenzahl

Frühgeburtenrate in 6 Perinatalzentren in Baden-Württemberg – Potential zur Reduktion der Frühgeborenenzahl

Sehr geehrte Damen und Herren,

mit großem Interesse haben wir die Arbeit von Trotter et al. 1 gelesen und teilen die Auffassung, dass eine Vermeidung von Frühgeburten und eine Reduzierung der Frühgeburtenrate unbedingt anzustreben ist, wie dies auch vom Bundesgesundheitsministerium als Nationales Gesundheitsziel „Gesundheit rund um die Geburt” gefordert wird 2.

Qualitätssicherung mit Routinedaten bei Cholelithiasis – Veränderungen und aktueller Stand

Qualitätssicherung mit Routinedaten (QSR) ist ein relativ neues Verfahren zur Bewertung der Ergebnisqualität, das sich von der externen Qualitätssicherung und der Qualitätssicherung über Registerdaten im methodischen Ansatz unterscheidet. Seitens des Wissenschaftlichen Instituts der AOK (WIdO) wird QSR seit 2011 für den Bereich Cholelithiasis bei AOK-Patienten vorgehalten. Nach Einführung eines Expertenpanels im Jahr 2013 wurden zahlreiche Veränderungen vorgenommen, die die Indikatorraten für „Transfusion/Blutung“, „Sonstige Komplikationen“ sowie den Gesamtindikator verringert, aber die risikoadjustierten Qualitätsunterschiede zwischen Kliniken keineswegs aufgehoben haben.

Decision-to-Delivery Time and Perinatal Complications in Emergency Cesarean Section

BACKGROUND

A decision-to-delivery interval (DDI) of no more than 20 minutes has long been considered a requirement for cesarean sections, even though there have hardly been any studies on this topic. We retrospectively investigated data relevant to DDI for emergency cesarean sections performed for the most common indications, namely, suspected and documented fetal asphyxia.

METHODS

We analyzed data on emergency in-hospital cesarean sections in the period 2008-2015. Low 5- and 10-minute Apgar scores (a scheme with points awarded for breathing, heart rate, muscle tone, skin coloration, and the elicitability of reflexes) were the primary endpoints; acid-base status in arterial cord blood and in-hospital neonatal death were the secondary endpoints. The raw analysis was supplemented by an analysis adjusted for various factors including gestational age, maternal age, and obstetrical presentation.

RESULTS

Data from 39 291 neonates were included. The DDI was up to 10 minutes in 64.6% of cases, from 11 to 20 minutes in 34.3%, and over 20 minutes in 1.1%. Low Apgar scores were less common in children whose emergency cesarean sections were performed within 10 minutes or within 20 minutes. For example, the adjusted odds ratio for a 10-minute Apgar score below 4 was 0.49 (95% confidence interval [0.25; 0.96] when a DDI of more than 20 minutes was used as the reference criterion.

CONCLUSION

This is the largest population-based, risk-adjusted analysis to be carried out on this topic to date. It reveals, for the first time, an association between DDI of 20 minutes or less and the avoidance of outcomes that are dangerous to the child. As it is not possible to predict such obstetrical emergencies in advance, it seems reasonable to ensure the availability of caredelivery structures that make it possible for emergency cesarean sections to be performed within 20 minutes of the decision to do so.

DNVF-Memorandum III „Methoden für die Versorgungsforschung“, Teil 3: Methoden der Qualitäts- und Patientensicherheitsforschung

Das Deutsche Netzwerk Versorgungsforschung e.V. (DNVF) fördert seit Jahren die methodische Qualität von Versorgungsforschungsstudien auf der Basis von Memoranden und anderen Initiativen. Die Qualitäts- und Patientensicherheitsforschung (QPSF) gilt als Kerngebiet der Gesundheitsversorgungsforschung. Das vorliegende Memorandum erläutert wesentliche etablierte Fragestellungen und Methoden der QPSF. Vor dem Hintergrund der besonderen gesundheitspolitischen Bedeutung des Themas werden Methoden der Messgrößenentwicklung und -prüfung, die Risikoadjustierung, Methoden zur Erhebung von Patientensicherheitsdaten, Instrumente zur Analyse sicherheitsrelevanter Ereignisse und Methoden zur Evaluation der meist multiplen und komplexen QPSF-Interventionen behandelt. Zudem werden vordringliche Forschungsthemen benannt.

Case Numbers and Process Quality in Breast Surgery in Germany: A Retrospective Analysis of Over 150,000 Patients From 2013 to 2014

BACKGROUND

Numerous studies from around the world have shown a positive association between case numbers and the quality of medical care. The evidence to date suggests that conformity to guidelines for the treatment of patients with breast cancer is better in German hospitals that have higher case numbers.

METHODS

We used data obtained by an external program for quality assurance in inpatient care (externe stationäre Qualitätssicherung, esQS) for the years 2013 and 2014 to investigate seven process indicators in the area of breast surgery, including histologic confirmation of the diagnosis before definitive treatment, axillary dissection as recommended by the guidelines, and an appropriate temporal interval between diagnosis and operation. Case numbers were categorized with the aid of various threshold values. Moreover, subgroup analyses were carried out for patients under age 65, patients in good general health, patients without lymph-node involvement, and patients with a tumor size pT0 or pT1 or an overall tumor size less than 5 cm.

RESULTS

Data on 153,475 patients from 939 hospitals were analyzed. Six of seven indicators had values that were better overall, to a statistically significant extent, in hospitals with higher case numbers. Although this relationship was not consistently seen, the worst results were generally found in the category with the lowest case numbers. Similar though less striking results were obtained in the subgroup analyses. An exception to the general finding was that, in hospitals with higher case numbers, the interval between diagnosis and operation was more often longer than three weeks.

CONCLUSION

Guideline adherence is higher in hospitals that treat more cases. The present study does not address the question whether this, in turn, affects morbidity or mortality. To improve process quality in peripheral hospitals, the quality assurance program should be continued.

Common Femoral Artery — Uncommon Aneurysms

Background and Aims:

Femoral artery aneurysms are rare. Their natural history, tendency to embolize or rupture are not well known.

Material and Methods:

Data of all patients seen 1996–2002 with femoral artery aneurysms at the Swiss Cardiovascular Center were analysed. Nine patients with 13 aneurysms of the common femoral artery (CFA) were identified. Only true aneurysms with a diameter of at least 2.5 cm were included. All patients were male, mean age 70 years (range: 57–85 years). Four patients had bilateral femoral aneurysms. Risk factors included hypertension (9/9), smoking (7/9). One of the aneurysms was palpable in 5/9. Four patients were asymptomatic, 5 had Fontaine class II claudication. Five patients also had an aortic aneurysm (AAA), one a thoracic aneurysm; and 6/9 popliteal aneurysms. In all patients, diagnosis was confirmed with duplex scan. Angiography was performed preoperatively.

Results:

The aneurysms were operated on electively using aneurysm secclusion and interposition grafting. There were no significant perioperative complications. Median hospital stay was 8 days.

Conclusion:

CFA aneurysms are rare. They are palpable in nearly half of the cases. They rarely cause thrombotic or embolic complications, but are almost always connected to other aneurysms. Patients with CFA aneurysms should be screened with duplex scan. Operative therapy is straightforward, few complications can be expected. Postoperative follow-up with annual duplex scans is suggested.

Soluble and membrane-bound interleukin (IL)-15 Rα/IL-15 complexes mediate proliferation of high-avidity central memory CD8+ T cells for adoptive immunotherapy of cancer and infections

The lack of persistence of infused T cells is a principal limitation of adoptive immunotherapy in man. Interleukin (IL)-15 can sustain memory T cell expansion when presented in complex with IL-15Rα (15Rα/15). We developed a novel in-vitro system for generation of stable 15Rα/15 complexes. Immunologically quantifiable amounts of IL-15 were obtained when both IL-15Rα and IL-15 genes were co-transduced in NIH 3T3 fibroblast-based artificial antigen-presenting cells expressing human leucocyte antigen (HLA) A:0201, β₂ microglobulin, CD80, CD58 and CD54 [A2-artificial antigen presenting cell (AAPC)] and a murine pro-B cell line (Baf-3) (A2-AAPC^15Rα/15 and Baf-3^15Rα/15 ). Transduction of cells with IL-15 alone resulted in only transient expression of IL-15, with minimal amounts of immunologically detectable IL-15. In comparison, cells transduced with IL-15Rα alone (A2-AAPC^Rα ) demonstrated stable expression of IL-15Rα; however, when loaded with soluble IL-15 (sIL-15), these cells sequestered 15Rα/15 intracellularly and also demonstrated minimal amounts of IL-15. Human T cells stimulated in vitro against a viral antigen (CMVpp65) in the presence of 15Rα/15 generated superior yields of high-avidity CMVpp65 epitope-specific T cells [cytomegalovirus-cytotoxic T lymphocytes (CMV-CTLs)] responding to ≤ 10^{- 13} M peptide concentrations, and lysing targets cells at lower effector : target ratios (1 : 10 and 1 : 100), where sIL-15, sIL-2 or sIL-7 CMV-CTLs demonstrated minimal or no activity. Both soluble and surface presented 15Rα/15, but not sIL-15, sustained in-vitro expansion of CD62L⁺ and CCR7⁺ central memory phenotype CMV-CTLs (T_CM ). 15Rα/15 complexes represent a potent adjuvant for augmenting the efficacy of adoptive immunotherapy. Such cell-bound or soluble 15Rα/15 complexes could be developed for use in combination immunotherapy approaches.

Spontaneous Dissection of Common Iliac Artery

Spontaneous dissection of the iliac artery is very rare but known as a complication of highenergy traumatic injuries and has been reported in connection with pregnancy, collagen diseases, and alpha-1-antitrypsin deficiency. The authors report a 42-year-old man with an acute dissection of the common iliac artery during exercise. Groin pain and claudication were the early symptoms. Computerized angiotomography was diagnostic. Operative iliac artery reconstruction was performed. A prerelease control computed tomography examination showed a dissection of the distal aorta and left iliac artery. To their knowledge, the combination of the 2 dissections has not been previously published.

Fetal Monitoring of Patients Diagnosed with Systemic Lupus Erythematosus - A Case Report

We report a case of pathological foetal Doppler velocity, specifically the absence of end diastolic flow in the umbilical artery (AEDV/REDV), suspected diabetic pregnancy and mesangioproliferative glomerulonephritis, at 32 weeks of gestation. The foetal heart rate tracings were evaluated using a computerised cardiotocogram (Oxford Sonicaid system 8002 Chichester, England) 1 for 20-30 min parallel to the routine cardiotocogram. The ultrasound control at 33 weeks of gestation showed oligohydramnion, foetal centralisation and reduced interval foetal growth. Due to small gestational age (SGA) and oligohydramnion, labour was induced at 36 weeks gestation with vaginal prostaglandin and an amniotomy. Due to cephalopelvic disproportion, a Caesarean section was performed. Signs and symptoms of neonatal lupus were not found.

Mortality and Major Morbidity of Very-Low-Birth-Weight Infants in Germany 2008-2012: A Report Based on Administrative Data

BACKGROUND

Expectant parents of very preterm infants, physicians, and policy makers require estimates for chances of survival and survival without morbidity. Such estimates should derive from a large, reliable, and contemporary data base of easily available items known at birth.

OBJECTIVE

To determine short-term outcome and risk factors in very-low-birth-weight preterm infants based on administrative data.

METHODS

Anonymized routine data sets transmitted from hospital administrations to statutory health insurance companies were used to assess survival and survival free of major morbidities in a large cohort of preterm infants in Germany.

RESULTS

After exclusion of infants with lethal malformations, there were 13,147 infants with a birth weight below 1,500 g admitted to neonatal care 2008-2012, of whom 1,432 infants (10.9%) died within 180 days. Estimated 180 days survival probabilities were 0.632 (95% confidence interval 0.583-0.677) for infants with 250-499 g birth weight, 0.817 (0.799-0.834) for 500-749 g, 0.931 (0.920-0.940) for 750-999 g, 0.973 (0.967-0.979) for 1,000-1,249 g, and 0.985 (0.981-0.988) for 1,250-1,499 g. Estimated probabilities for survival without major morbidity (surgically treated intraventricular hemorrhage, necrotizing enterocolitis, intestinal perforation, or retinopathy) were 0.433 (0.384-0.481) for 250-499 g, 0.622 (0.600-0.643) for 500-749 g, 0.836 (0.821-0.849) for 750-999 g, 0.938 (0.928-0.946) for 1,000-1,249 g, and 0.969 (0.964-0.974) for 1,250-1,499 g, respectively. Prediction of survival and survival without major morbidities was moderately improved by adding sex, small for gestational age, and severe or moderate congenital malformation, increasing receiver operating characteristic areas under the curve from 0.839 (0.827-0.850) to 0.862 (0.852-0.874) (survival) and from 0.827 (0.822-0.842) to 0.852 (0.846-0.863) (survival without major morbidities), respectively.

CONCLUSION

The present analysis encourages attempts to use administrative data to investigate the association between risk factors and outcome in preterm infants.

Statistical controversies in clinical research: an initial evaluation of a surrogate end point using a single randomized clinical trial and the Prentice criteria

Surrogate end point research has grown in recent years with the increasing development and usage of biomarkers in clinical research. Surrogacy analysis is derived through randomized clinical trial data and it is carried out at the individual level and at the trial level. A common surrogate analysis at the individual level is the application of the Prentice criteria. An approach for the evaluation of the Prentice criteria is discussed, with a focus on its most difficult component, the determination of whether the treatment effect is captured by the surrogate. An interpretation of this criterion is illustrated using data from a randomized clinical trial in prostate cancer.

The prognostic significance of respiratory rate in patients with pneumonia: a retrospective analysis of data from 705,928 hospitalized patients in Germany from 2010-2012

BACKGROUND

Measurement of the respiratory rate is an important instrument for assessing the severity of acute disease. The respiratory rate is often not measured in routine practice because its clinical utility is inadequately appreciated. In Germany, documentation of the respiratory rate is obligatory when a patient with pneumonia is hospitalized. This fact has enabled us to study the prognostic significance of the respiratory rate in reference to a large medical database.

METHOD

We retrospectively analyzed data from the external quality-assurance program for community-acquired pneumonia for the years 2010-2012. All patients aged 18 years or older who were not mechanically ventilated on admission were included in the analysis. Logistic regression was used to determine the significance of the respiratory rate as a risk factor for in-hospital mortality.

RESULTS

705,928 patients were admitted to the hospital with community-acquired pneumonia (incidence: 3.5 cases per 1000 adults per year). The in-hospital mortality of these patients was 13.1% (92 227 persons). The plot of mortality as a function of respiratory rate on admission was U-shaped and slanted to the right, with the lowest mortality at a respiratory rate of 20/min on admission. If patients with a respiratory rate of 12-20/min are used as a baseline for comparison, patients with a respiratory rate of 27-33/min had an odds ratio (OR) of 1.72 for in-hospital death, and those with a respiratory rate above 33/min had an OR of 2.55. Further independent risk factors for in-hospital death were age, admission from a nursing home, hospital, or rehabilitation facility, chronic bedridden state, disorientation, systolic blood pressure, and pulse pressure.

CONCLUSION

Respiratory rate is an independent risk marker for in-hospital mortality in community-acquired pneumonia. It should be measured when patients are admitted to the hospital with pneumonia and other acute conditions.

[Quality measurement using administrative data in mandatory quality assurance]

For several years, the use of administrative data in mandatory quality measurement has been requested by several stakeholders in Germany. Main advantages of using administrative data include the reduction of documentary expenditures and the possibility to perform longitudinal quality analyses across different healthcare units. After a short introduction, a brief overview of the current use of administrative data for mandatory quality assurance as well as current developments is given, which will then be further exemplified by decubital ulcer prophylaxis. By using administrative data coding expenditures in this clinical area could be reduced by nine million data fields. At the same time the population analysed was expanded resulting in a more than tenfold increase in potentially quality-relevant events. Finally, perspectives, further developments, possibilities as well as limits of quality measurement with administrative data are discussed.

[Joint replacement quality index: the perspective of resident physicians]

BACKGROUND AND AIM

Joint replacement is an established therapy for arthrosis. The quality index for joint replacement (knee and hip) should include screening for quality of patient-centred care in hospitals providing replacements, on the basis of administrative data. The quality index summarizes 16 inpatient and posthospital complications (indicators). The aim of the study was to evaluate this quality index from the medical practitioner's viewpoint.

METHODS

Four semistructured focus groups with 11 family physicians and 8 orthopaedic/trauma surgeons were conducted. The discussions were recorded, transcribed and analysed qualitatively according to Mayring.

RESULTS

Infections and the revision of a total joint arthroplasty have been weighted as the most important indicators from the existing quality indicators. Between the participants some differences regarding the relevance of the indicators thrombosis and pulmonary embolism occurred. These indicators were weighted as more important by family physicians than orthopedic/trauma surgeons. For eight of the indicators, imprecision in words/meaning was criticized. In an open-ended second section, 20 new indicators within the areas complications, management and overall sector communication were identified.

CONCLUSION

Major amendments of the quality index for the joint replacement are necessary. The knowledge gained from this study may serve as a basis for this development.

Die Hydrolyse einiger Borsäureester unter Base-Einfluß in nichtwäßrigen Lösungsmitteln / The Hydrolysis of Some Tris(organyloxy)boranes under Alkaline Influence in Non-aqueous Solvents

The hydrolysis of tris(organyloxy)boranes (boric acid esters) in organic solvents in the presence of KOH leading to potassium polyborates (free from water of crystallization) is studied as to the influences of (a) the reaction medium (ethanol or ligroine/ethanol), (b) the concentration of water, (c) the organyl group of the boric acid ester (methyl, isopropyl, or phenyl), (d) the time of stay of the precipitated insoluble polyborates under the mother liquor (15 to 61850 s), and (e) the temperature during precipitation and the time of stay (—18 to + 60°C).

In the first stage of the reaction, during precipitation time, ester hydrolysis is followed by condensation, while aggregation and desorption processes occur between the time of precipitation and filtration.