Comorbidity burden assessed by the Charlson comorbidity index and its influence on prognosis of patients admitted due to heart failure

Background Heart failure (HF) affects approximately 1-2% of the adult population and is accompanied by high morbidity and mortality. Although HF risk stratification is primarily based on symptoms including the NYHA classification, laboratory markers such as natriuretic peptides and assessment of left ventricular ejection fraction, the ability to withstand underlying and important stressors and prevention of poor outcome depends also on patients’ individual comorbidity burden. Regarding risk stratification in HF, comorbidity burden is not yet taken sufficiently into account. This highlights a significant gap in healthcare, where the complexity of patients having multiple chronic conditions and comorbidities is often underestimated in treatment planning, research, and cost analysis. In this context the Charlson Comorbidity Index is one established approach to evaluate the comorbidity profile. Purpose The objective of the present study is to investigate the impact of the comorbid profile on prognosis of patients with HF in a large nationwide inpatient sample. Methods The German nationwide inpatient statistics (NIS) of the years 2005-2022 was used for statistical analysis (source: RDC of the Federal Statistical Office and the Statistical Offices of the federal states, DRG Statistics 2005-2022, and own calculations). Hospitalizations of patients, who were admitted due to HF in German hospitals, were stratified for Charlson comorbidity class. The patients were categorized in mild severity (Charlson Comorbidity Index 1-2 points), moderate severity (Charlson Comorbidity Index 3-4 points) and severe severity (Charlson Comorbidity Index >4 points) and severity classes were compared. Results Overall, 7,265,342 hospitalizations of patients admitted due to HF were recorded in Germany between 2005 and 2022. HF hospitalizations were stratified by the Charlson Comorbidity Index class. Among these, 206,165 (2.8%) were categorized as mild, 1,017,108 (14.0%) as moderate, and 6,042,069 (83.2%) as patients with a severe comorbidity burden. In-hospital case-fatality increased with the current Charlson Comorbidity Index class: 1.6% in mild, 3.2% in moderate and 10.4% in the severe Charlson Comorbidity Index class (P<0.001). The Charlson Comorbidity Index class was significantly associated with increased in-hospital case-fatality (OR 1.219 [95%CI 1.218-1.221], P<0.001). Conclusion The results of our study may help to better understand and measure the association between an aggravated comorbidity profile and increased in-hospital case-fatality in patients with HF.