LAUSR

Declining mortality rates of heart failure (HF) patients over the last decades is a testament to the progress and efforts made by the HF community to change medicine through randomized trials and clinical vigilance. This progress is evident in the HF guidelines that are updated and published every few years. However, one aspect of HF management has not experienced a similar progress in scientific findings—the management of co-morbidities in HF patients. It is thoroughly documented through registries and trial data that patients with HF more often than not are burdened with cardiac (e.g. atrial fibrillation) and non-cardiac (e.g. diabetes) co-morbidities. Despite this fact, substantial gaps in our knowledge of how co-morbid burden affects HF patients exist. The European Society of Cardiology HF guidelines acknowledge the importance of co-morbidity and HF, but the evidence to suggest differences in treatment regimens between patients with a co-morbid condition ± HF is generally poor.1 Guidelines generally describe how modifications to the standard HF treatment may be warranted in case of a select few concurring co-morbid conditions (e.g. caution with angiotensin-converting enzyme inhibitors in HF patients with renal disease). But should co-morbidity and HF merely be viewed as separate entities, or is the picture more nuanced? Importantly, many HF patients have more than one co-morbid condition—in fact HF patients have on average three–four co-morbid conditions in excess of their HF.2 This makes inferences on the impact of each individual co-morbid condition and HF over-simplified, considering the vast number of possible combinations of co-morbid diseases and HF and their possible interactions. This analytical issue is not easily resolved, and most studies have chosen to view each co-morbidity separately or assign all co-morbid conditions a similar weight in their analyses, with the obvious advantage of being able to make general inferences on total co-morbid burden and outcomes. Using this methodology, Iorio and co-workers provide a welcome addition to our understanding of the prognostic impact of