Biomedical subjects
A Sorva
Publications and source records attributed to A Sorva.
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.
Association of calcaemic status with survival of elderly inpatients.
In 485 long-term geriatric inpatients (mean age 80 years), serum ionized calcium (CaI) concentrations were significantly associated with 2-year mortality. The cumulative 2-year survival was 37% in the hypocalcaemic group (CaI less than 1.17 mmol/l), 49% in the hypercalcaemic group (CaI greater than 1.29 mmol/l) and 57% in the normocalcaemic group. The association of calcaemia and survival remained significant even when patients with low serum albumin and high serum creatinine were excluded. However, serum total calcium concentrations, whether or not 'corrected' for albumin, were not significantly associated with survival. The use of diuretics may have had some influence on the calcaemic grouping of the patients, but the excess mortality in the hypercalcaemic group was not explained by heart failure or hypertension. The impaired survival in dyscalcaemic groups was not associated with sex, age, immobility, diabetes, hypertension, or renal failure.
Serum calcium and cardiovascular risks.
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Assessment of calcaemic status in geriatric hospital patients: serum ionized calcium versus albumin-adjusted total calcium.
To evaluate the accuracy of total serum calcium (CaT) and albumin-adjusted total calcium (CaA) determinations in the assessment of calcaemic status in the elderly, serum ionized calcium (CaI), CaT and serum albumin (Alb) concentrations were measured in 558 geriatric hospital patients. As expected, CaT was correlated with Alb (r = 0.316, p less than 0.001) and CaI with serum pH (r = -0.351, p less than 0.001) and they were closely interrelated (r = 0.746, p less than 0.001). Various albumin-adjustment formulas from the literature decreased the correlation of CaT and CaI. Using conventional reference limits for CaT only 12% and 72% of patients with CaI above or below the reference limits for CaI, respectively, were found. This study demonstrates the low sensitivity of total and albumin-adjusted calcium in the detection of slightly or moderately abnormal calcaemic states.
Survival and calcaemic status of geriatric inpatients.
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[Megacolon and pheochromocytoma].
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'Correction' of serum calcium values for albumin biased in geriatric patients.
Determination of serum ionized calcium concentration (Cal) is more tedious as a screening method than measuring serum total calcium concentration (CaT) and is not widely practicable. Thus, in clinical practice and even in research, it is customary to 'correct' the serum total calcium concentration (CaT) for that of albumin (Alb) to estimate the 'true' calcemic status,i.e. Cal. However, owing to confounding factors that are incompletely understood at present, the 'corrected' result is imprecise. The hypothesis of the present study was that in geriatric hypoalbuminemia, it could even be biased due to confounding factors associated with aging and related to the Alb level itself. To test this hypothesis, CaT, Alb and Cal were measured in 558 consecutive geriatric in-patients with varying degrees of hypoalbuminemia. The lower the Alb level, the more strikingly the sensitivity of CaT for detecting low Cal was impaired by the correction. In geriatric hypoalbuminemia, the correction is not merely imprecise but even biased (inaccurate). The bias increases with the degree of hypoalbuminemia (i.e. with the need for correction) and leads to underdiagnosis of 'true' (ionic) hypocalcemia.