Serum calcium levels and in-hospital death in patients affected by acute heart failure

Background: Intracellular calcium is essential for muscle cells contrac- tion. Several drugs such as amines and levosimendan increase inotropism by acting directly or indirectly on intracellular calcium levels or sensitiv- ity. Serum calcium levels (SCL) are not directly correlated to intracellular calcium concentration, but a reduced gradient could influence intracellular concentrations. For this reason, we aimed to evaluate whether SCL could be related to in-hospital survival among patients affected by acute heart failure. Materials and Methods: 216 consecutive patients admitted to our Internal Medicine Department (IMD) for acute heart failure were retrospectively enrolled. In-hospital mortality and comorbidities (hypertension, diabetes, atrial fibrillation, chronic heart failure, acute coronary syndrome, COPD, sepsis, chronic kidney disease and cancer) were collected as binary vari- ables. Days of hospitalization were treated as continuous data. SCL were synthesized as an ordinal variable (25% low percentile, 50% middle percen- tile and 25% high percentile).Cox regression model was set up to evaluate the role of serum calcium levels on in-hospital mortality inserting in the model all the comorbidities, days of hospitalization, age and sex as covari- ates. Statistic was performed with SPSS 13.0 for Windows Systems. Results: Mean age was 80 years (±12,55 years), with M:F ratio of 1:1 (males 52.7%). Diabetes was present in 23,1%, hypertension in 34,3%, ac- tive cancer in 8,8%, atrial fibrillation in 30,1%, chronic ischemic cardiopa- thy in 28,2%, acute coronary syndrome in 12,5%, congestive heart failure in 42,6%, COPD in 18,1%, sepsis in 1,4%, chronic kidney disease in 18,5% of the sample. 13,4% of the sample died during the admission. Mean of the days of hospitalization was of 12,65 days (±8,28 days). In the Cox model, correcting for all the above-mentioned covariates, serum calcium levels taken at the admission behaved as an independent risk factor for in-hospital death (Figure 1). Lower or normal serum calcium levels were associated to a higher risk of in-hospital mortality (OR: 8,308; 95%CI:1,075-64,21; p<0,05). Conclusions: Higher SCL are associated to higher risk of in-hospital mor- tality. Larger, perspective studies are required in order to confirm this observation.