Intracranial haemorrhage following treatment for pulmonary embolism: analysis of the german nationwide inpatient sample

Abstract Background Intracranial haemorrhage (ICH) can be a life-threatening complication of pulmonary embolism (PE) and its treatment during the acute phase. Purpose To characterize patients hospitalized with PE and ICH by identifying risk factors across different treatment groups, and to detect temporal trends in a large nationwide sample. Methods The German nationwide inpatient sample was screened for patients admitted with PE during the period 2005-2020. All hospitalizations were stratified based on the occurrence of ICH and accordingly, risk factors for ICH were investigated (source: Research data center [RDC] of the Federal Statistical Office and the Statistical Offices of the federal states, DRG Statistics 2005-2020, own calculations). Results Overall, 816,653 hospitalizations were included in the present study; among them, 2516 (0.3%) experienced an ICH event and 84,810 (10.4%) died in-hospital. The annual number of hospitalizations of patients admitted due to PE increased steadily from 38,749 in 2005 to 54,966 in 2020, whereas the incidence of ICH remained, despite annual fluctuations, largely stable over time, both in the entire study population and in the subgroup of patients with severe PE as defined by clinical and haemodynamic parameters (n=270,980 [33.2%]). ICH was overall more frequent after the seventh decade of life but, interestingly, no correlation with age was found amongst patients with severe PE (Figure 1). ICH in hospitalized PE patients was associated with an aggravated comorbidity burden mirrored by a higher Charlson Comorbidity Index (5.0 [interquartile range 4.0-7.0] vs. 4.0 [2.0-5.0], P<0.001). This was mainly driven by the higher prevalence of heart failure (27.3% vs. 19.4%, P<0.001) and acute or chronic kidney disease (27.6% vs. 18.1%, P<0.001) in patients with ICH. In addition, severe PE (OR 3.09 [95% CI 2.84-3.35], P<0.001), acute kidney injury (OR 3.60 [3.09-4.18], P<0.001), and particularly ischaemic stroke (OR 14.64 [12.61-17.00], P<0.001) were identified as independent predictors of ICH by multivariable logistic regressions. Overall, 27% of the ICH cases were related to systemic thrombolysis. In PE patients treated with systemic thrombolysis, age ≥70 years as well as female sex were independent predictors of ICH. Finally, ICH was independently associated with a substantial increase in case-fatality in patients hospitalized with PE (univariate OR: 5.38 [4.97-5.84], P<0.001; multivariable OR: 6.16 [5.64-6.72], P<0.001). Conclusions In this healthcare dataset of the German nationwide inpatient sample, the overall incidence of ICH remained low at 0.3% over the 15-year study period. Severe PE, age, comorbidity burden, kidney disease, heart failure and ischaemic stroke were independent risk factors for ICH.