Impact of early death recording on international comparison of acute myocardial infarction mortality - administrative hospital data study using the example of Germany and the United States.

BACKGROUND: In-hospital mortality from acute myocardial infarction (AMI) is widely used in international comparisons as an indicator of health system performance. Because of the high risk of early death after AMI, international comparisons may be biased by differences in the recording of early death cases in hospital inpatient data. This study examined whether differences in the recording of early deaths affect international comparisons of AMI in-hospital mortality by using the example of Germany and the United States, and explored approaches to address this issue. METHODS: The German Diagnosis-Related Groups Statistics (DRG Statistics), the U.S. National Inpatient Sample (NIS) and the U.S. Nationwide Emergency Department Sample (NEDS) were analysed from 2014 to 2019. Cases with treatment for AMI were identified in German and U.S. inpatient data. AMI deaths occurring in the emergency department (ED) without inpatient admission were extracted from NEDS data. 30-day in-hospital mortality figures were calculated according to the OECD indicator definition (unlinked data) and modified by including ED deaths, or excluding all same-day cases. RESULTS: German age-and-sex standardized 30-day in-hospital mortality was substantially higher compared to the U.S. (in 2019, 7.3% vs. 4.6%). The ratio of German vs. U.S. mortality was 1.6. After inclusion of ED deaths in U.S. data this ratio declined to 1.4. Exclusion of same-day cases in German and U.S. data led to a similar ratio. CONCLUSIONS: While short-duration treatments due to early death are generally recorded in German inpatient data, in U.S. inpatient data those cases are partially missing. Excluding cases with short-duration treatment from the calculation of mortality indicators could be a feasible approach to account for differences in the recording of early deaths, that might be existent in other countries as well.

Treatment of Anorectal Malformations in German Hospitals: Analysis of National Hospital Discharge Data from 2016 to 2021.

BACKGROUND: Anorectal malformations (ARMs) are complex congenital anomalies. The corrective operation is demanding and schedulable. Based on complete national data, patterns of care have not been analyzed in Germany yet. METHODS: All cases with ARM were analyzed (1) at the time of birth and (2) during the hospital stay for the corrective operation, based on the national hospital discharge data (DRG statistics). Patient's comorbidities, treatment characteristics, hospital structures, and the outcome of corrective operations were analyzed with respect to the hospitals' caseload. RESULTS: From 2016 to 2021, 1,726 newborns with ARM were treated at the time of birth in 388 hospitals. Of these hospitals, 19% had neither a pediatric nor a pediatric surgical department. At least one additional congenital anomaly was present in 49% of cases and 7% of the newborns had a birthweight below 1,500 g.In all, 2,060 corrective operations for ARM were performed in 113 hospitals in the same time period. In 24.5% of cases, at least one major complication was documented. One-third of the operations were performed in 56 hospitals, one-third in 20 hospitals, and one-third in 10 hospitals with median annual case numbers of 2, 5, and 10, respectively.Hospitals with the highest caseload operated cloacal defects more often than hospitals with the lowest caseload (7 vs. 2%) and had more early complications than hospitals with the lowest caseload (30 vs. 21%). This difference was not statistically significant after risk adjustment. CONCLUSIONS: Children with ARM are multimorbid. Early complications after corrective surgery are common. Considering the large number of hospitals with a very low caseload, centralization of care for the complex and elective corrective surgery for ARM remains a key issue for quality of care.

How did the COVID-19 pandemic affect inpatient care for children in Germany? An exploratory analysis based on national hospital discharge data.

BACKGROUND: The delivery of health services around the world faced considerable disruptions during the COVID-19 pandemic. While this has been discussed for a number of conditions in the adult population, related patterns have been studied less for children. In light of the detrimental effects of the pandemic, particularly for children and young people under the age of 18, it is pivotal to explore this issue further. METHODS: Based on complete national hospital discharge data available via the German National Institute for the Reimbursement of Hospitals (InEK) data browser, we compare the top 30 diagnoses for which children were hospitalised in 2019, 2020, 2021 and 2022. We analyse the development of monthly admissions between January 2019 and December 2022 for three tracers of variable time-sensitivity: acute lymphoblastic leukaemia (ALL), appendicitis/appendectomy and tonsillectomy/adenoidectomy. RESULTS: Compared to 2019, total admissions were approximately 20% lower in 2020 and 2021, and 13% lower in 2022. The composition of the most frequent principal diagnoses remained similar across years, although changes in rank were observed. Decreases were observed in 2020 for respiratory and gastrointestinal infections, with cases increasing again in 2021. The number of ALL admissions showed an upward trend and a periodicity prima vista unrelated to pandemic factors. Appendicitis admissions decreased by about 9% in 2020 and a further 8% in 2021 and 4% in 2022, while tonsillectomies/adenoidectomies decreased by more than 40% in 2020 and a further 32% in 2021 before increasing in 2022; for these tracers, monthly changes are in line with pandemic waves. CONCLUSIONS: Hospital care for critical and urgent conditions among patients under the age of 18 was largely upheld in Germany during the COVID-19 pandemic, potentially at the expense of elective treatments. There is an alignment between observed variations in hospitalisations and pandemic mitigation measures, possibly also reflecting changes in demand. This study highlights the need for comprehensive, intersectoral data that would be necessary to better understand changing demand, unmet need/foregone care and shifts from inpatient to outpatient care, as well as their link to patient outcomes and health care efficiency.

Health and Care Data: Approaches to data linkage for evidence-informed policy.

An indispensable prerequisite for answering research questions in health services research is the availability and accessibility of comprehensive, high-quality data. It can be assumed that health services research in the coming years will be increasingly based on data linkage, i.e., the linking, or connecting, of several data sources based on suitable common key variables. A range of approaches to data collection, storage, linkage and availability exists across countries, particularly for secondary research purposes (i.e., the use of data initially collected for other purposes), such as health systems research. The main goal of this review is to develop an overview of, and gain insights into, current approaches to linking data sources in the context of health services research, with the view to inform policy, based on existing practices in high-income countries in Europe and beyond. In doing so, another objective is to provide lessons for countries looking for possible or alternative approaches to data linkage. Thirteen country case studies of data linkage approaches were selected and analysed. Rather than being comprehensive, this review aimed to identify varied and potentially useful case studies to showcase different approaches to data linkage worldwide. A conceptual framework was developed to guide the selection and description of case studies. Information was first identified and collected from publicly available sources and a profile was then created for each country and each case study; these profiles were forwarded to appropriate country experts for validation and completion. The report presents an overview of the included countries and their case studies (Chapter 2), with key data per country and case study in the appendices. This is followed by a closer look at the possibilities of using routine data (Chapter 3); the different approaches to linkage (Chapter 4); the different access routes for researchers (Chapter 5); the use of data for research from electronic patient or health records (Chapter 6); foundational considerations related to data safety, privacy and governance (Chapter 7); recent developments in cross-border data sharing and the European Health Data Space (Chapter 8); and considerations of changes and responses catalysed by the COVID-19 pandemic as related to the generation and secondary use of data (Chapter 9). The review ends with overall conclusions on the necessary characteristics of data to inform research relevant for policy and highlights some insights to inspire possible future solutions - less or more disruptive - for countries looking to expand their use of data (Chapter 10). It emphasises that investing in data linkage for secondary use will not only contribute to the strengthening of national health systems, but also promote international cooperation and contribute to the international visibility of scientific excellence.

Health and care data: approaches to data linkage for evidence-informed policy

An indispensable prerequisite for answering research questions in health services research is the availability and accessibility of comprehensive, high quality data. It can be assumed that health services research in the comingyears will be increasingly based on data linkage, i.e., the linking, or connecting, of several data sources based on suitable common key variables. A range of approaches to data collection, storage, linkage and availability exists across countries, particularly for secondary research purposes (i.e., the use of data initially collected for other purposes), such as health systems research. The main goal of this review is to develop an overview of, and gain insights into, current approaches to linking data sources in the context of health services research, with the view to inform policy, based on existing practices in high-income countries in Europe and beyond. In doing so, another objective is to provide lessons for countries looking for possible or alternative approaches to data linkage. Thirteen country case studies of data linkage approaches were selected and analyzed. Rather than being comprehensive, this review aimed to identify varied and potentially useful case studies to showcase different approaches to data linkage worldwide. A conceptual framework was developed to guide the selection and description of case studies. Information was first identified and collected from publicly available sources and a profile was then created for each country and each case study; these profiles were forwarded to appropriate country experts for validation and completion.

[Research Data Center on Health - Vision for Further Development from the Research Perspective]. / Forschungsdatenzentrum Gesundheit ­ Vision für eine Weiterentwicklung aus Sicht der Forschung.

The German research data center for health will provide claims data of statutory health insurances. The data center was set up at the medical regulatory body BfArM pursuant to the German data transparency regulation (DaTraV). The data provided by the center will cover about 90% of the German population, supporting research on healthcare issues, including questions of care supply, demand and the (mis-)match of both. These data support the development of recommendations for evidence-based healthcare. The legal framework for the center (including §§ 303a-f of Book V of the Social Security Code and two subsequent ordinances) leaves a considerable degree of freedom when it comes to organisational and procedural aspects of the center's operation. The present paper addresses these degrees of freedom. From the point of view of researchers, ten statements show the potential of the data center and provide ideas for its further and sustainable development.

Recording early deaths following emergency department visits in inpatient data: An observational study using data of 16 German hospitals.

OBJECTIVE: In German hospital emergency departments (EDs), no definite reimbursement rules exist for patients who die within 24 hours after arrival. Our study aimed to assess whether these cases were recorded and billed as inpatient stays. Furthermore, characteristics of patients who die within 24 hours following arrival at the ED were investigated for all ED visits, as well as for the subgroup of ED visits with an ED diagnosis or inpatient principal diagnosis of acute myocardial infarction. METHODS: This study was part of the INDEED project, which aimed to explore utilization and trans-sectoral patterns of care for patients treated in EDs in Germany. The study population includes ED visits of adult patients in 2016 in 16 German hospitals participating in the project. In the data set of combined ED, inpatient, and outpatient treatment information early deaths were classified as patients who died in the ED or in the hospital within 24 hours after arrival. Characteristics of visits followed by early death were analyzed descriptively. Mode of billing as inpatient or outpatient was validated by identifying corresponding billing information using linked inpatient and outpatient data. RESULTS: In 2016, 454,747 ED visits of adult patients occurred in the participating hospitals and 42.8% resulted in inpatient admission. Among these inpatients 8,317 (4.3%) died during the overall hospital stay, and 1,302 (0.7%) died within 24 hours following arrival. The proportion of early deaths among all deaths in patients with a diagnosis of acute myocardial infarction was higher (27%) compared to the overall patient population (16%). Although all cases of early death were classified as inpatients the corresponding inpatient data was missing in 1.9% of all early deaths and in 3.4% of early deaths with a diagnosis of acute myocardial infarction. Outpatient billing information suggesting that these cases were billed as outpatients, was found in 0.3% of all early deaths and in 0.8 to 1.7% of early deaths with a diagnosis of acute myocardial infarction, respectively. CONCLUSION: In-hospital mortality might be biased by incomplete recording of early deaths in inpatient data. However, the proportion of patients with early death who were billed as outpatients was marginal in the investigated study population of 16 hospitals. Although the study results are limited by restricted generalizability and subpar data quality, this finding indicates that early deaths might be almost completely recorded in German inpatient data. Nevertheless, data quality should be enhanced by establishing general billing rules for cases with a short treatment duration due to early death.

[Methodological Challenges and Lessons Learned in the Scientific Use of Data from a Private Health Insurance Company within the IPHA Project]. / Methodische Herausforderungen und Lessons Learned bei der wissenschaftlichen Nutzung von Daten eines privaten Krankenversicherungsunternehmens im Rahmen des Projekts IPHA.

The 11% of people with private health insurance (PHI) in Germany have so far been underrepresented in health services research. The scientific use of PHI data is rare. The aim of this research was to examine the scientific usability of PHI data and to highlight challenges and lessons learned in the process of data preparation and analysis using a linked dataset (n=3,109) of survey and claims data of one PHI company. Challenges were identified in the terminology of the PHI insurance, in the processing and validity of the data, and regarding insured persons without submitted billing receipts. With thorough preparation of the data and presentation of the limitations, PHI data can be used for health services research.

[Recording Trauma Care in German Hospital Discharge Data: Services Provided by Hospitals Owned by Workers' Compensation Funds and Financed through Statutory Accidental Insurance]. / Erfassung der Verletztenversorgung in Krankenhausabrechnungsdaten: Leistungen der BG Kliniken zu Lasten der Gesetzlichen Unfallversicherung.

BACKGROUND: In Germany, the Diagnosis-Related Group Statistics (DRG Statistics) represent an almost complete discharge data-based registry of inpatient services in acute care hospitals. However, services of hospitals owned by workers' compensation funds and financed through the statutory insurance for occupational accidents are excluded from the obligation of submitting hospital discharge data. Hence, the DRG statistics might be incomplete regarding inpatient services for trauma care. METHODS: In order to illustrate trauma and post-trauma care in acute care hospitals, groups of specific inpatient services were defined. Numbers of cases according to these groups were identified in the microdata of the DRG statistics, as well as in the inpatient data of all nine workers' compensation funds hospitals in Germany. By dividing cases financed through the statutory insurance for occupational accidents from cases financed through other payers, the overlap of both databases as well as the share of cases not recorded in the DRG statistics were quantified. The analysis comprised data of 2016-2018. RESULTS: Depending on the type of service, the share of cases not recorded in the DRG statistics varied between 0.1% and more than 60% (accumulated 2016 to 2018). There was under-recording of early-stage rehabilitation for traumatic brain injury (61%), treatment for traumatic paraplegia (14% for initial treatment and 23% for subsequent treatment), treatment for amputation injury (13%) and treatment for severe hand injury (5%). CONCLUSION: Regarding inpatient services that are not covered by the statutory insurance for occupational accidents, the microdata of the DRG statistics can be considered as virtually complete. However, inpatient services for trauma care are not completely recorded because discharge data are not submitted by hospitals run by workers' compensation funds when services are financed through the statutory insurance for occupational accidents. Analyses of trauma care can only be complete if data of hospitals financed by workers' compensation funds are included.

Health care patterns and policies in 18 European countries during the first wave of the COVID-19 pandemic: an observational study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has developed into an unprecedented global challenge. Differences between countries in testing strategies, hospitalization protocols as well as ensuring and managing ICU capacities can illustrate initial responses to a major health system shock, and steer future preparedness activities. METHODS: Publicly available daily data for 18 European countries were retrieved manually from official sources and documented in an Excel table (March-July 2020). The ratio of tests to cases, the share of hospitalizations out of all cases and the share of ICU admissions out of all hospitalizations were computed using 7-day rolling averages per 100 000 population. Information on country policies was collected from the COVID-19 Health System Response Monitor of the European Observatory on Health Systems and Policies. Information on health care capacities, expenditure and utilization was extracted from the Eurostat health database. RESULTS: There was substantial variation across countries for all studied variables. In all countries, the ratio of tests to cases increased over time, albeit to varying degrees, while the shares of hospitalizations and ICU admissions stabilized, reflecting the evolution of testing strategies and the adaptation of COVID-19 health care delivery pathways, respectively. Health care patterns for COVID-19 at the outset of the pandemic did not necessarily follow the usual health service delivery pattern of each health system. CONCLUSIONS: This study enables a general understanding of how the early evolution of the pandemic influenced and was influenced by country responses and clearly demonstrates the immense potential for cross-country learning.

A country-level analysis comparing hospital capacity and utilisation during the first COVID-19 wave across Europe.

BACKGROUND: The exponential increase in SARS-CoV-2 infections during the first wave of the pandemic created an extraordinary overload and demand on hospitals, especially intensive care units (ICUs), across Europe. European countries have implemented different measures to address the surge ICU capacity, but little is known about the extent. The aim of this paper is to compare the rates of hospitalised COVID-19 patients in acute and ICU care and the levels of national surge capacity for intensive care beds across 16 European countries and Lombardy region during the first wave of the pandemic (28 February to 31 July). METHODS: For this country level analysis, we used data on SARS-CoV-2 cases, current and/or cumulative hospitalised COVID-19 patients and current and/or cumulative COVID-19 patients in ICU care. To analyse whether capacities were exceeded, we also retrieved information on the numbers of hospital beds, and on (surge) capacity of ICU beds during the first wave of the COVID-19 pandemic from the COVID-19 Health System Response Monitor (HSRM). Treatment days and mean length of hospital stay were calculated to assess hospital utilisation. RESULTS: Hospital and ICU capacity varied widely across countries. Our results show that utilisation of acute care bed capacity by patients with COVID-19 did not exceed 38.3% in any studied country. However, the Netherlands, Sweden, and Lombardy would not have been able to treat all patients with COVID-19 requiring intensive care during the first wave without an ICU surge capacity. Indicators of hospital utilisation were not consistently related to the number of SARS-CoV-2 infections. The mean number of hospital days associated with one SARS-CoV-2 case ranged from 1.3 (Norway) to 11.8 (France). CONCLUSION: In many countries, the increase in ICU capacity was important to accommodate the high demand for intensive care during the first COVID-19 wave.

[ST-elevation Myocardial Infarction and Percutaneous Coronary Intervention: Analysis of Time Stamps in Hospital Administrative Data]. / Analyse der Zeitangaben in Krankenhausabrechnungsdaten bei ST-Streckenhebungs-Herzinfarkt und Linksherzkatheterintervention.

BACKGROUND: German hospital administrative data contain demographic, medical, and administrative information on inpatients, as well as time stamps, such as time of admission or when a medical procedure was carried out. Time stamps allow the calculation of important process indicators which may help to assess quality of care. However, regarding the plausibility of time stamps in German hospital administrative data, no information is as yet available. This study investigates time stamps through the example of ST-elevation myocardial infarction and percutaneous coronary intervention aiming to provide first indications on the plausibility of time stamp documentation. METHODS: Based on complete national German hospital administrative data (DRG statistics) from 2014 to 2017, all inpatient cases with ST-elevation myocardial infarction in the first admitting hospital were identified. Date and time of admission and date and time of percutaneous coronary intervention were analyzed. Time intervals were calculated as difference between time of admission and time of percutaneous coronary intervention and were categorized in groups. RESULTS: The analysis of time of admission of inpatient cases with ST-elevation myocardial infarction (n=254,719) showed a pattern with highest frequencies between 9 a.m. and 1 p.m. on working days. The pattern of time of percutaneous coronary interventions (n=206,079) was similar but revealed frequency peaks at noon and midnight. The share of inpatient cases with implausible time intervals between time of admission and time of percutaneous coronary intervention declined from 9.5% in 2014 to 7.8% in 2017 and showed high variation on the hospital level. CONCLUSION: Analyzing time stamps in hospital administrative data may provide valuable information on treatment processes while clinical staff may be released from separate documentation tasks. However, the results of this study indicate that the reliability of time stamps is affected by implausible entries and several uncertainties. The quality of time stamp documentation in German hospital administrative data might be improved by setting incentives for correct documentation and by setting out definite specifications of time points, such as time of admission.

Acute Appendicitis: Trends in Surgical Treatment­A Population-Based Study of Over 800 000 Patients.

BACKGROUND: Appendectomy is the gold standard for treatment of acute appendicitis. However, recent studies favor primary antibiotic therapy. The aim of this observational study was to explore changes in the numbers of operations for acute appendicitis in the period 2010-2017, paying special attention to disease severity. METHODS: Data from diagnosis-related group statistics were used to analyze the trends, mortality, and complication rates in the surgical treatment of appendicitis in Germany between 2010 and 2017. All cases of appendectomy after a diagnosis of appendicitis were included. RESULTS: Altogether, 865 688 inpatient cases were analyzed. The number of appendectomies went down by 9,8%, from 113 614 in 2010 to 102 464 in 2017, while the incidence fell from 139/100 000 in 2010 to 123/100 000 in 2017 (standardized by age group). This decrease is due to the lower number of operations for uncomplicated appendicitis (79 906 in 2017 versus 93 135 in 2010). Hospital mortality decreased both in patients who underwent surgical treatment of complicated appendicitis (0.62% in 2010 versus 0.42% in 2017) and in those with a complicated clinical course (5.4% in 2010 versus 3.4% in 2017). CONCLUSION: Decisions on the treatment of acute appendicitis in German hospitals follow the current trend towards non-surgical management in selected patients. At the same time, the care of acute appendicitis has improved with regard to overall hospital morbidity and hospital mortality.

[Opportunities and limitations of risk adjustment of quality indicators based on inpatient administrative health data - a workshop report]. / Möglichkeiten und Grenzen der Risikoadjustierung von Qualitätsindikatoren aus Krankenhausabrechnungsdaten - ein Werkstattbericht.

INTRODUCTION: The quality indicators of the Initiative Qualitätsmedizin e. V. (IQM) have been developed as triggers to examine treatment processes for opportunities for improvement. Published quality results have partly been used for external quality comparisons in the media. Therefore, member hospitals of IQM demanded to investigate if methods of risk adjustment should be applied in the calculation of the quality indicators. After a hearing of experts had been held, a task force was founded to conduct test calculations on risk adjustment methods. METHODS: Specific risk adjustment models for mortality in myocardial infarction, heart failure, stroke, pneumonia, and colectomy in colorectal cancer were developed in the database of national German DRG data of the year 2016. These models were used to calculate standardized mortality ratios (SMR) per indicator in a sample of 172 member hospitals of IQM based on the data of the year 2018. Median SMR per indicator were compared to median SMR based on a standardization by age and gender, which is the standard procedure in IQM. Correlations between the different SMR were calculated. Quality of care was judged by two different approaches: a) a descriptive discrepancy of |0.1| from the SMR value of 1, and b) a significant discrepancy from 1 using the 95% confidence limits. The effect of using the specific risk adjustment in relation to the standard procedure was investigated for both approaches (a and b). RESULTS: The specific risk adjustment methods showed an area under the curve between 0.72 and 0.84. The median differences between the SMR based on standardization by age and gender and the SMR based on specific risk adjustment were small (between 0 and 0.4); Spearman's correlations were between 0.90 and 0.99. Changes in the judgement of quality of care in comparison to the national average occurred in 3.9% (mortality from pneumonia) to 20.6% of the hospitals (mortality from heart failure) in descriptive comparisons. When the judgement was based on confidence limits changes were observed in 1.6% (mortality after colectomy) to 17.4% of the hospitals (mortality from heart failure). DISCUSSION: Implementing specific risk adjustment models had only minor effects on the distribution of risk-adjusted mortality compared to the standard procedure, but the judgement of quality of care could change for a fifth of the hospitals in individual indicators. Concerning methodological and practical reasons, the task force recommends further development of risk adjustment methods for selected indicators. This should be accompanied by studies on the validity of inpatient administrative data for quality management as well as by efforts to improve the usefulness of these data for such purposes.

In-hospital mortality and failure to rescue following hepatobiliary surgery in Germany - a nationwide analysis.

BACKGROUND: Recent observational studies on volume-outcome associations in hepatobiliary surgery were not designed to account for the varying extent of hepatobiliary resections and the consequential risk of perioperative morbidity and mortality. Therefore, this study aimed to determine the risk-adjusted in-hospital mortality for minor and major hepatobiliary resections at the national level in Germany and to examine the effect of hospital volume on in-hospital mortality, and failure to rescue. METHODS: All inpatient cases of hepatobiliary surgery (n = 31,114) in Germany from 2009 to 2015 were studied using national hospital discharge data. After ranking hospitals according to increasing hospital volumes, five volume categories were established based on all hepatobiliary resections. The association between hospital volume and in-hospital mortality following minor and major hepatobiliary resections was evaluated by multivariable regression methods. RESULTS: Minor hepatobiliary resections were associated with an overall mortality rate of 3.9% and showed no significant volume-outcome associations. In contrast, overall mortality rate of major hepatobiliary resections was 10.3%. In this cohort, risk-adjusted in-hospital mortality following major resections varied widely across hospital volume categories, from 11.4% (95% CI 10.4-12.5) in very low volume hospitals to 7.4% (95% CI 6.6-8.2) in very high volume hospitals (risk-adjusted OR 0.59, 95% CI 0.41-0.54). Moreover, rates of failure to rescue decreased from 29.38% (95% CI 26.7-32.2) in very low volume hospitals to 21.38% (95% CI 19.2-23.8) in very high volume hospitals. CONCLUSIONS: In Germany, patients who are undergoing major hepatobiliary resections have improved outcomes, if they are admitted to higher volume hospitals. However, such associations are not evident following minor hepatobiliary resections. Following major hepatobiliary resections, 70-80% of the excess mortality in very low volume hospitals was estimated to be attributable to failure to rescue.

Evaluating the consequences of health policy decisions.

Uncertainty about intended and possible unintended side effects makes it important to evaluate changes following health policy decisions. A recent IJHPR article by Greenberg et al. evaluated changes in emergency department care following a directive of the Israeli Ministry of Health to limit occupancy in internal medicine wards. Over a six-year observation period, they found that one-month mortality and one-week readmissions after ED visits remained unchanged, while increases in average ED visit length, as well as increased delay time from ED admission to ward were observed. These findings help to assess the impact of the occupancy limit directive and may support future health policy decisions.However, the study by Greenberg et al. was limited by the unavailability of diagnostic data, and this illustrates a significant issue that transcends this particular study. In many countries, policy-relevant administrative data are not sufficiently available on a timely basis. Data availability is the prerequisite for monitoring developments in patterns of care following health policy changes. Besides conducting retrospective studies, timely availability of data makes it possible to establish monitoring systems which may help decision makers assess the impact of policy changes, identify undesired developments early, and recognize changes in need or demand of health services within the population.

[Health Care Provision and Volume-Outcome Relationship for Acute Myocardial Infarction: Long-Term Analysis of German Nationwide Hospital Discharge Data 2005-2015]. / Versorgungsstrukturen und Mengen-Ergebnis-Beziehung beim akuten Herzinfarkt ­ Verlaufsbetrachtung der deutschlandweiten Krankenhausabrechnungsdaten von 2005 bis 2015.

BACKGROUND: Studies on acute myocardial infarction have reported that higher hospital volume is associated with better outcomes. In this context, changes of acute hospital care for myocardial infarction and of the volume-outcome relationship were analysed. The aim of this study was to assess developments of hospital care in order to derive approaches for improving care for acute myocardial infarction in German hospitals. METHODS: Inpatient cases of acute myocardial infarction in the first admitting hospital were identified from the complete national hospital discharge data (DRG statistics) 2005-2015. These cases were assigned to quintiles according to the annual myocardial infarction case volume of the treating hospital. RESULTS: From 2005 to 2015, there was an increase in the proportion of patients with myocardial infarction treated with a coronary intervention. In-hospital mortality in first treating hospitals declined from 12.1 to 8.7%. In all the years of observation, mortality was lower in higher volume hospitals quintiles than in the very-low volume quintile. In 2015, the risk of in-hospital death in hospitals with medium, high, or very high volume was 20% lower (adjusted OR 0.8 [95% KI 0.7-0.9] respectively), compared to very-low volume hospitals. More than 40% of very-low volume hospitals were located in urban areas. CONCLUSION: Hospital care for acute myocardial infarction in Germany can be improved further, if patients with heart attack symptoms were primarily allocated to hospitals with high volumes. For reasons of medical quality and economic efficiency, such a targeted referral is essential particularly in urban regions.

[Definition of Variables in Hospital Discharge Data: Pitfalls and Proposed Solutions]. / Variablendefinition in fallbezogenen Krankenhausabrechnungsdaten ­ Fallstricke und Lösungsmöglichkeiten.

In Germany, the Diagnosis-Related Group Statistics (DRG Statistics) supply full coverage of inpatient episodes in acute care hospitals. The Research Data Centres of the Federal Statistical Office and the Statistical Offices of the Federal States provide the microdata of the DRG Statistics, namely hospital discharge files of each inpatient case, for scientific research. Hospital discharge data are generated for administrative purposes. As well as other data sources, they have specific features and characteristics, which should be considered in planning and designing research studies. A key challenge is the appropriate and sophisticated operationalization of units of analysis, targets variables, and other study variables. The methodological approach should consider, among other factors, differing coding behaviour between hospitals in order to minimize the risk of bias. This contribution shows by practical examples what should be incorporated in variable definition to ensure that the risk of bias by coding behaviour or other factors is minimized to the greatest possible degree. First of all, the features and characteristics of the German hospital discharge data are outlined. Based on the authors' experiences, basic steps and challenges in observational health services research studies are described. Examples are illustrated by our own calculations, derived from previous studies based on the microdata of the DRG Statistics. The reliability and validity of analyses based on hospital discharge data are crucially dependent on the appropriateness of variable definition. To minimize the risk of bias and misinterpretation, extensive preliminary considerations are required which involve clinical aspects, as well as the context of data collection and technical classification opportunities. Hopefully, there will be greater acceptance of research based on hospital discharge data, so that these valuable data will be used more frequently for research purposes in the future.

Correction to: Amputation rates of the lower limb by amputation level - observational study using German national hospital discharge data from 2005 to 2015.

In the original publication of this article [1], some numbers in the below sentence errors in the Results section of the Abstract.