In-hospital mortality, comorbidities, and costs of one million mechanically ventilated patients in Germany: a nationwide observational study before, during, and after the COVID-19 pandemic.

Background: Even more than hospital care in general, intensive care and mechanical ventilation capacities and its utilization in terms of rates, indications, ventilation types and outcomes vary largely among countries. We analyzed complete and nationwide data for Germany, a country with a large intensive care sector, before, during and after the COVID-19 pandemic. Methods: Analysis of administrative claims data, provided by the German health insurance, from all hospitals for all individual patients who were mechanically ventilated between 2019 and 2022. The data included age, sex, diagnoses, length of stay, procedures (e.g., form and duration of mechanical ventilation), outcome (dead vs. alive) and costs. We included all patients who were at least 18 years old at the time of discharge from January 1st, 2019 to December 31st, 2022. Patients were grouped according to year, age group and the form of mechanical ventilation. We further analyzed subgroups of patients being resuscitated and those being COVID-19 positive (vs. negative). Findings: During the four years, 1,003,882 patients were mechanically ventilated in 1395 hospitals. Rates per 100,000 inhabitants varied across age groups from 110 to 123 (18-59 years) to 1101-1275 (>80 years). The top main diagnoses were other forms of heart diseases, pneumonia, chronic obstructive pulmonary disease (COPD), ischemic heart diseases and cerebrovascular diseases. 43.3% (437,031/1,003,882) of all mechanically ventilated patients died in hospital with a remarkable increase in mortality with age and from 2019 to 2022 by almost 5%-points. The in-hospital mortality of ventilated COVID-19 patients was 53.7% (46,553/86,729), while it was 42.6% (390,478/917,153) in non-COVID patients. In-hospital mortality varied from 27.0% in non-invasive mechanical ventilation (NIV) only to 53.4% in invasive mechanical ventilation only cases, 59.4% with early NIV failure, 68.6% with late NIV failure, to 74.0% in patients receiving VV-ECMO and 80.0% in VA-ECMO. 17.5% of mechanically ventilated patients had been resuscitated before, of whom 78.2% (153,762/196,750) died. Total expenditure was around 6 billion Euros per year, i.e. 0.17% of the German GDP. Interpretation: Mechanical ventilation was widely used, before, during and after the COVID-19 pandemic in Germany, reaching more than 1000 patients per 100,000 inhabitants per year in the age over 80 years. In-hospital mortality rates in this nationwide and complete cohort exceeded most of the data known by far. Funding: This research did not receive any dedicated funding.