title: Associations of coefficient of variation of serum GH with previous radiotherapy, hypopituitarism and cardiac disease in patients with treated acromegaly.
abstract: BACKGROUND
  Cardiovascular complications represent the biggest cause of mortality in acromegaly. It is therefore important to optimally stratify acromegalic patients according to disease activity and complication risk. GH is secreted in a pulsatile manner from the pituitary gland, but GH pulsatility is not routinely assessed clinically. The coefficient of variation of serum GH (GHCV) during oral glucose tolerance test (OGTT) quantifies the variation of GH secretion in patients with acromegaly, but has not been reported previously.
  
  
  OBJECTIVE
  To investigate whether GHCV during OGTT is associated with clinical parameters predicted to relate with hypothalamo-pituitary dysfunction during acromegaly, such as radiotherapy treatment, pituitary deficiency and cardiac disease.
  
  
  METHODS
  GHCV was calculated during 584 OGTTs and compared with nadir serum GH and IGF-1 in 111 acromegalic patients treated at a single centre.
  
  
  RESULTS
  Acromegalic patients treated with radiotherapy had a 37% lower level of GHCV when compared to the nonradiotherapy group (mean GHCV: 0·298 ± 0·015, no radiotherapy; 0·189 ± 0·007, radiotherapy; P < 0·001). Neither serum IGF-1 nor nadir GH was significantly altered in the radiotherapy group. Mean GHCV was 50% lower in the acromegalic patients with cardiac failure when compared to acromegalic patients with normal echocardiogram (0·161 ± 0·034 vs 0·297 ± 0·055; P < 0·05). Neither serum IGF-1 nor nadir GH was significantly altered during cardiac failure.
  
  
  CONCLUSIONS
  Our preliminary data suggest that GHCV during OGTT may be reduced during acromegaly in patients with previous radiotherapy, pituitary deficiencies and cardiac disease. Larger studies are required to determine whether GHCV could provide help to assess the morbidity status of patients with treated acromegaly.
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Channa N
authors.initials: CN
authors.lastname: Jayasena
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Chioma
authors.initials: C
authors.lastname: Izzi-Engbeaya
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Shakunthala
authors.initials: S
authors.lastname: Narayanaswamy
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Manish
authors.initials: M
authors.lastname: Modi
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Holly
authors.initials: H
authors.lastname: Clarke
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Gurjinder M K
authors.initials: GM
authors.lastname: Nijher
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Karim
authors.initials: K
authors.lastname: Meeran
authors.affiliation: Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
authors.forename: Waljit S
authors.initials: WS
authors.lastname: Dhillo
mesh_terms: D000172:Acromegaly / Q000097:blood / Q000150:complications / Q000532:radiotherapy; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods; D006331:Heart Diseases / Q000097:blood / Q000209:etiology; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007018:Hypopituitarism / Q000097:blood / Q000209:etiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011878:Radiotherapy / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D006113:United Kingdom
chemical_list: D019382:Human Growth Hormone