A randomized placebo-controlled study of enalapril in the treatment of erythrocytosis after renal transplantation

BACKGROUND: Erythrocytosis is a common complication of renal transplantationwith an incidence of up to 17%. It is associated with an increasedrisk of complications due to thromboembolic events and has traditionallybeen treated by intermittent venesection. More recently, angiotensin-convertingenzyme inhibitors have been shown to cause a fall in haematocritin a number of groups of subjects and some uncontrolled studieshave shown these drugs to be of possible therapeutic benefitin post renal transplant erythrocytosis. METHODS: We performed a randomized double-blind placebo-controlled studyin 25 patients with post-transplant erythrocytosis. Subjectsreceived either 2.5 mg of enalapril daily or a placebo for 4months and all patients completed the study period without anyserious adverse effects. RESULTS: Haematocrit fell from 52.7 (±SEM 0.7) to 47.1 (±1.8) at 1 month and 46.1 (± 1.2) after 4 months in patientsreceiving enalapril, with no change in the placebo group (P=0.004).We did not demonstrate any change in serum erythropoietin ineither group. CONCLUSION: Angiotensin-converting enzyme inhibitors are a safe and effectiveform of treatment for erythrocytosis developing after renaltransplantation. The mechanism of action, however, is not mediatedby changes in erythropoietin production and remains uncertain.     

Does the Prepubertal Duration of Diabetes Influence the Onset of Microvascular Complications?

This study investigated the relationship between the development of diabetic retinopathy and pubertal status at onset of diabetes in 521 Type 1 diabetic patients diagnosed between 1950 and 1985. Pubertal status was based on age at onset (girls ≧ 11 years and boys ≧ 12 years). Retinopathy (all forms) developed in 112 patients (21.5%; 65 background and 47 proliferative retinopathy). For subjects diagnosed in either the prepubertal or postpuberal period, a similar proportion survived without developing retinopathy for any given duration of diabetes (X² = 0.3822, p = 0.54). However, if only the postpubertal duration of diabetes is considered, then the proportion of patients surviving without retinopathy was significantly less for those diagnosed in the prepubertal period (X² = 14.2, p = 0.002). This study suggests that the prepubertal duration of diabetes is an important phase and that the years prior to puberty do contribute to the risk of developing microvascular injury.