PREVALENCE OF CENTRAL AUTONOMIC NEUROPATHY IN ELDERLY DIALYSIS PATIENTS

Background. Autonomic neuropathy is frequently present in dialysis pat ients. In addition, deterioration of autonomic function occurs with ag eing, This study examines the true prevalence of autonomic neuropathy in elderly dialysis patients and questions whether the combination of age and uraemia further increases the chance of dysautonomia being pre sent. Methods. We compared the results of live different tests (30:15 ratio; Valsalva ratio; heart rate response to deep breathing and the b lood pressure responses to sustained hand grip and standing) of parasy mpathetic and combined parasympathetic and sympathetic dysfunction in older haemodialysis patients (mean age 70.2 years), younger haemodialy sis patients (mean age 48.1 years) and two groups of subjects with nor mal renal function (mean age 73.0 years and 42.5 years respectively). Results. Parasympathetic dysfunction was most prevalent in older patie nts on dialysis (65.9% (95% confidence intervals 51.4-80.4%), compared with 33.3% (95% confidence intervals 19.0-47.5% in younger dialysis p atients), and 11.8 and 0% in the old and young control groups respecti vely). Combined parasympathetic and sympathetic dysfunction was seen i n 41.5% (95% confidence intervals 26.5-56.5%) and 11.9%(95% confidence intervals 2.1-56.5%) of the old and young dialysis patients respectiv ely but not in any of the control subjects, No interaction was seen be tween age and subject type. Conclusions. We conclude that although old er dialysis patients have severe impairment of cardiovascular autonomi c innervation, the prevalence of dysfunction is not higher than would be expected in an ageing population with uraemia.