Abstract

Previous studies have shown that renal and cardiac insufficiency cause an elevation of ionic plasma fluoride (IPF) concentration in patients suffering from these diseases. The relationship between serum or plasma fluoride concentration and the degree of renal impairment has been tested only twice; with somewhat contrasting results, although some previous results strongly suggest such a relationship. The first aim of the present study was therefore to test the possible correlation, between IPF and serum creatinine concentrations in patients with renal insufficiency (= elevated serum creatinine level). Secondly, the reason why cardiac insufficiency causes elevated IPF levels has not been studied at all. The second aim of the present study was therefore to test the correlation between individual IPF levels and serum creatinine concentrations. By comparing the results obtained from patients suffering from both renal and cardiac failure with those obtained from individuals with either of the two diseases, an attempt was also made to study the mechanism of fluoride retention during cardiac insufficiency. The results from the patients with renal impairment showed a strong positive correlation between individual IPF and serum creatinine concentrations, whereas the correlation between IPF level and age was insignificant. Based on the present findings it is concluded that the main factor determining the IPF level of a patient with renal failure seems to be the degree of the renal impairment. Age may have only a slightly modifying effect.

In individuals with cardiac failure the relationship between individual IPF levels and serum, creatinine concentrations was statistically almost significant. During cardiac insufficiency the circulatory system makes a special effort to maintain the blood flow to the brain and heart. As a result the concentrations of fluoride and creatinine in the blood may be higher than expected on the basis of the kidneys’ ability to excrete. It is possibly for this haemodynamic reason that IPF levels and serum creatinine concentrations are unexpectedly well correlated. In any case, it is obvious that fluoride retention because of cardiac insufficiency is the result of a different mechanism than that caused by renal failure, because the individuals suffering from both diseases had highly, significantly greater mean IPF levels than the patients with only renal failure, although the mean creatinine levels were similar in both· groups.

In individuals with cardiac failure the relationship between individual IPF levels and serum, creatinine concentrations was statistically almost significant. During cardiac insufficiency the circulatory system makes a special effort to maintain the blood flow to the brain and heart. As a result the concentrations of fluoride and creatinine in the blood may be higher than expected on the basis of the kidneys’ ability to excrete. It is possibly for this haemodynamic reason that IPF levels’ and serum creatinine concentrations are unexpectedly well correlated. In any case, it is obvious’ that fluoride’ retention because of cardiac insufficiency is the result of a different mechanism than that caused by renal failure, because the individuals suffering from both diseases had highly, significantly greater mean .IPF levels than the patients with only renal failure, although the mean creatinine levels were similar in both· groups.