title: Bone hyperresorption is prevalent in chronically critically ill patients.
abstract: OBJECTIVE
  Chronically critically ill (CCI) patients are primarily elderly people who have survived a life-threatening episode of sepsis but remain profoundly debilitated and ventilator dependent. The objective of this study was to determine the prevalence of bone hyperresorption and parathyroid hormone (PTH)-vitamin D axis abnormalities in these patients.
  
  
  METHODS
  Prevalence survey.
  
  
  METHODS
  Respiratory care step-down unit (RCU) at a tertiary care teaching hospital.
  
  
  METHODS
  Forty-nine ventilator-dependent CCI patients transferred from ICUs within the same institution.
  
  
  METHODS
  None.
  
  
  RESULTS
  N-telopeptide (NTx) levels in 24-h urine collections and serum intact PTH, 25-vitamin D, and 1,25-vitamin D levels were measured within 48 h of RCU admission. Patients were hospitalized a median of 30 days before RCU admission. Four patients (9%) had normal NTx and PTH levels. Forty-five patients (92%) had elevated urine NTx levels consistent with bone hyperresorption. Nineteen patients (42% of total patients) had elevated PTH levels consistent with predominant vitamin D deficiency, 4 patients (9%) had suppressed PTH levels consistent with predominant hyperresorption from immobilization, and 22 patients (49%) had normal PTH levels consistent with an overlap of both vitamin D deficiency and immobilization. There were no differences in vitamin D metabolites among these groups.
  
  
  CONCLUSIONS
  CCI patients have a high prevalence of bone hyperresorption in which PTH levels may clarify the cause. Further studies will determine the efficacy and cost-effectiveness of routine NTx and PTH screening in these patients and the role of vitamin D and antiresorptive therapies.
authors.affiliation: Department of Medicine, The Mount Sinai Medical Center, New York, NY 10029-6574, USA. dnierma@smtplink.mssm.edu
authors.forename: D M
authors.initials: DM
authors.lastname: Nierman
authors.forename: J I
authors.initials: JI
authors.lastname: Mechanick
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood / Q000172:deficiency; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001510:Bed Rest / Q000009:adverse effects; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001862:Bone Resorption / Q000453:epidemiology* / Q000209:etiology / Q000378:metabolism; D002117:Calcitriol / Q000097:blood / Q000172:deficiency; D002908:Chronic Disease; D003094:Collagen / Q000652:urine; D024042:Collagen Type I; D016638:Critical Illness; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides / Q000652:urine; D015995:Prevalence; D011446:Prospective Studies; D012124:Respiratory Care Units; D014808:Vitamin D Deficiency / Q000150:complications / Q000378:metabolism
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015652:25-Hydroxyvitamin D 2; D003094:Collagen; D002117:Calcitriol