title: Angiotensin-converting-enzyme inhibition therapy in altitude polycythaemia: a prospective randomised trial.
abstract: BACKGROUND
  Angiotensin-converting-enzyme (ACE) inhibitors reduce packed cell volume and haemoglobin concentration in polycythaemia that follows renal transplantation, which, like altitude polycythaemia, is an erythropoietin-dependent form of polycythaemia. We aimed to establish the effect of ACE-inhibitor treatment in people with altitude polycythaemia.
  
  
  METHODS
  We did a prospective randomised study in 26 people with altitude polycythaemia (packed cell volume > or = 55%) and 24-h rate of urinary protein excretion greater than 150 mg, who had been referred to the Renal Disease Project in La Paz, Bolivia. 13 participants were assigned 5 mg/day enalapril for 2 years (study group), and 13 no treatment (controls). Blood pressure, packed cell volume and haemoglobin concentration, proteinuria, and renal function were compared by intention-to-treat analyses.
  
  
  RESULTS
  Baseline packed cell volume and haemoglobin concentration were positively correlated with bodyweight (p=0.02), systolic (p=0.01) and diastolic (p=0.04) blood pressure, serum creatinine (p=0.009), blood urea (p=0.008), and proteinuria (p=0.003). Systolic and diastolic blood pressure remained stable in the study group, but increased in controls. In study patients, mean (SD) packed cell volume, haemoglobin concentration, and proteinuria fell from 63.5% (4.9) to 56.8% (4.1), p<0.0001; 207 (18) to 164 g/L (13), p<0,0001; and from 358.6 (260.3) to 247.7 mg/24-h (208.2), p<0.002, respectively, but did not change significantly in controls. At 12 and 24 months of follow-up, packed cell volume, haemoglobin concentration, and proteinuria differed significantly between the groups (p<0.0001 for each comparison). In study patients, follow-up changes in packed cell volume (r=0.88, p<0.0001) or haemoglobin concentration (r=0.83, p<0.0001) and proteinuria were strongly correlated. Enalapril was well tolerated by all patients.
  
  
  CONCLUSIONS
  ACE-inhibition therapy effectively and safely ameliorates altitude polycythaemia and reduces proteinuria.
authors.affiliation: Biology Laboratories, Renal Disease Project, La Paz, Bolivia.
authors.forename: Raul
authors.initials: R
authors.lastname: Plata
authors.forename: Arturo
authors.initials: A
authors.lastname: Cornejo
authors.forename: Carla
authors.initials: C
authors.lastname: Arratia
authors.forename: Agustina
authors.initials: A
authors.lastname: Anabaya
authors.forename: Annalisa
authors.initials: A
authors.lastname: Perna
authors.forename: Borislav D
authors.initials: BD
authors.lastname: Dimitrov
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Remuzzi
authors.forename: Piero
authors.initials: P
authors.lastname: Ruggenenti
mesh_terms: D000328:Adult; D000531:Altitude; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D001794:Blood Pressure; D004656:Enalapril / Q000627:therapeutic use*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D011086:Polycythemia / Q000188:drug therapy*; D011446:Prospective Studies
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril