[The chronic renal failure epidemic: an underestimated public health problem]. / L'epidemia d'insufficienza renale cronica. Un sottovalutato problema sanitario di prima grandezza.

Renal failure is considered a rare disease. However, recent epidemiological surveys like the NHANES III survey in the USA have shown that mild and moderate renal insufficiency is much more common: 31% and 4% of Americans, respectively, are affected by a mild or moderate degree of renal insufficiency. Such an epidemic is of particular concern because of the high cardiovascular risk brought about by kidney failure. Renal insufficiency is now considered a public health priority. Together with diabetes and smoking, the metabolic syndrome is the principal factor responsible for this epidemic. The prevalence of chronic renal insufficiency is in fact strictly proportional to the number of components of the metabolic syndrome being present in individual patients. As renal function deteriorates, other risk factors come into play like those peculiar to renal insufficiency (anemia, hyperparathyroidism) and some so-called emerging risk factors (inflammation, hyperhomocysteinemia and high plasma levels of endogenous inhibitors of NO synthase such as asymmetric dimethylarginine).

Nocturnal hypoxemia, night-day arterial pressure changes and left ventricular geometry in dialysis patients.

It is well established that nocturnal hypoxemia in sleep apnea causes an inversion of the circadian arterial pressure rhythm and triggers nocturnal hypertension. Since sleep apnea is very frequent in dialysis patients, we hypothesized that nocturnal hypoxemia may be a factor that contributes to alter the 24-hour arterial pressure profile in these patients. To test the hypothesis 32 dialysis patients underwent 24-hour blood pressure (BP) monitoring and continuous monitoring of arterial O2 saturation during the night-time. Hemodialysis patients were studied during the non-dialysis day. All patients underwent an echocardiographic study. Thirteen patients had no episode of nocturnal hypoxemia (group I), 7 had at least one episode overnight but less than 2 episodes/hr (group II) and 12 had > or = 2 episodes/hr (group III). The average daytime systolic pressure was similar in the three groups. However, the average nocturnal systolic pressure fell in the first group (-2.5 +/- 4.2%) and rose in the second (+2.0 +/- 3.6%) and in the third (+3.9 +/- 2.2%) group (one way ANOVA, P < 0.005). The relative wall thickness of the left ventricle (RWT) was significantly (P < 0.05) higher in group III than in group I, and in the aggregate (N = 32) there was an inverse relationship between average nocturnal SaO2 and RWT (r = -0.43, P = 0.015). The proportion of patients with concentric remodeling or concentric hypertrophy was higher (P = 0.05) in the group with a more severe degree of nocturnal hypoxemia (group III, 8 of 12) than in the other two groups (group I, 3 of 13; group II, 2 of 7). Nocturnal hypoxemia is associated with the "non-dipping" arterial pressure profile in dialysis patients. Disturbed respiratory control during the night may represent an important cardiovascular risk factor in dialysis patients.