Ji. Mechanick et al., PARATHYROID-HORMONE SUPPRESSION IN SPINAL-CORD INJURY PATIENTS IS ASSOCIATED WITH THE DEGREE OF NEUROLOGIC IMPAIRMENT AND NOT THE LEVEL OF INJURY, Archives of physical medicine and rehabilitation, 78(7), 1997, pp. 692-696
Objective: To demonstrate that after spinal cord injury (SCI) suppress
ion of the parathyroid-vitamin D axis is associated with the degree of
neurologic impairment and not the level of injury, Design: A retrospe
ctive analysis of clinical and biochemical data obtained from hospital
records of patients with SCI compared to a control group of patients
with traumatic brain injury (TBI). Setting: The inpatient rehabilitati
on unit of a tertiary care hospital. Subjects: The medical records of
82 consecutive admissions to the rehabilitation unit with a diagnosis
of SCI or TBI were reviewed. Patients with SCI were classified by the
American Spinal injury Association (ASIA) impairment scale and then gr
ouped based on the completeness and level of injury. Main Outcome Meas
ure: Comparisons of serum parathyroid hormone (PTH), 25-hydroxyvitamin
D, and 1,25-dihydroxyvitamin D (1,25-D) were planned. Multiple compar
isons were performed for total and ionized serum calcium levels, serum
phosphorus levels, and 24-hour urinary calcium excretion rates to ref
lect changes in mineral homeostasis. Multiple comparisons were also pe
rformed for serum albumin, prolactin, thyroid function tests, and AM c
ortisol levels, as well as 24-hour urinary urea nitrogen and cortisol
excretion rates to reflect metabolic responses to stress. Results: Pat
ients with SCI had significant suppression in PTH (p < .000009) and 1,
25-D (p < .02) levels with elevated phosphorus (p < 0.03) and prolacti
n (p < .03) levels compared to patients with TBI. Also, more patients
with SCI were hypoalbuminemic (p < .003) than patients with TBI. Patie
nts with complete SCI (ASIA A) had more suppressed PTH (p < .03) and h
igher urinary urea nitrogen (p < .05) levels than SCI patients with in
complete injuries (ASIA B-D). Patients with complete, but not incomple
te, SCI had lower albumin levels than patients with TBI (p < .05). The
se differences were not found between patients with tetraplegic and pa
raplegic SCI. ASIA motor scores did not correlate with any of the meas
ured parameters but when used as a covariate did abolish differences i
n PTH and 1,25-D among the study groups by ANOVA. Conclusion: In patie
nts with SCI, the degree of neurologic impairment. and not the level o
f injury, is associated with PTH suppression and markers of metabolic
stress. (C) 1997 by the American Congress of Rehabilitation Medicine a
nd the American Academy of Physical Medicine and Rehabilitation.