Low serum ionized to total calcium ratio: association with geriatric diabetes mellitus and with other cardiovascular risk factors?

Serum total calcium concentrations (CaT) were increased, ionized calcium concentrations (CaI) normal, and the CaI/CaT ratios decreased in 125 geriatric diabetics as compared with 379 non-diabetic controls. In the whole population of 558 consecutive geriatric inpatients, the CaI/CaT ratios were inversely correlated with body weight, diastolic blood pressure and plasma glucose. The findings and calculations help to explain some inconsistencies and discrepancies in previous studies concerning calcaemia in diabetes, hypertension and the 'metabolic syndrome' of clustered risk factors for cardiovascular diseases. They also demonstrate that CaT and the 'correction' of CaT for serum albumin concentration can be biased in diabetes and other conditions closely associated with cardiovascular risks. Increased serum free fatty acids could at least in part explain low ratios.