Journal of Rehabilitation Medicine 51-4inkOmslag | Page 35

Impact of PiD on outcome after TBI and aSAH
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Thyroid axis Adrenal and somatotrophic axis
GOSE scores were significantly lower (p = 0.011) in
the subgroup with high thyroid levels in comparison
with those with normal thyroid levels. Patients with
high thyroid levels were significantly (p = 0.011)
older (mean 59.9 years (SD 9.3) than patients with
normal thyroid levels (mean 50.0 years (SD 14.7).
Comparisons of the other baseline variables showed
no significant differences in any subgroup.
Multiple linear regression analysis demonstrated
a significant relationship between GOSE score at 12
months after the event with age (b = –0.04, p = 0.004,
CI: –0.07––0.01), but not with sex (b = 0.30, p = 0.420),
or with GCS (b=0.08, p = 0.086), or with high T4
(b = –0.90, p = 0.051), or with low T4 (b = –0.16,
p = 0.696). Thyroid level, age, GCS and sex explain
21.2% of the variance in the GOSE scores (adjusted
R 2  = 0.212). GOSE scores did not differ significantly between
subgroups of patients with different cortisol levels
(p = 0.305) and IGF-I levels (p = 0.158).
Gonadal axis
GOSE scores were significantly lower (p = 0.011) in
the subgroups with low gonadotrophin levels in com-
parison with those with normal levels. Patients with
low gonadotrophin levels were significantly (p = 0.013)
older (mean 57.4 years (SD 12.2) than patients with
normal gonadotrophin levels (mean 49.6 years (SD
14.6). Comparisons of the other baseline variables
showed no significant differences in any subgroup.
Multiple linear regression analysis demonstrated sig-
nificant relationships between GOSE score at 12 months
after the event with age (b = –0.046, p = 0.001, CI: –0.07–
–0.02), GCS (b = 0.11, p = 0.025, CI: 0.01–0.21) and low
gonadotrophins (b = –0.80, p = 0.033, CI: –1.54––0.07),
but not with sex (b = 0.16, p = 0.675). Gonadotrophin
level, age, GCS and sex explained 24.5% of the variance
on the GOSE scores (adjusted R 2  = 0.245).
Prolactin
GOSE scores were significantly lower (p = 0.022) in
the subgroup with high prolactin levels in comparison
with those with normal prolactin levels. Comparisons
of the other baseline variables showed no significant
differences in any subgroup.
Multiple linear regression analysis demonstrated
significant relationship between GOSE score at 12
months after the event with age (b = –0.05, p < 0.001,
CI: –0.08––0.03) and high prolactin (b = –1.49,
p = 0.006, CI: –2.55––0.43), but not with sex (b = 0.03,
p = 0.926), GCS (b = 0.07, p = 0.132) or low prolactin
(b = –0.84, p = 0.354). Prolactin level, age, GCS and
sex explain 25.5% of the variance on the GOSE scores
(adjusted R 2 =0.255).
Multiple axes
Multiple linear regression analysis demonstrated no
significant relationship between GOSE score at 12
months after the event and low (b =–0.44, p = 0.213)
or high hormone levels (b =0.42, p = 0.215).
DISCUSSION
The main finding of this study of patients with TBI
or aSAH, is that low levels of gonadal hormones and
high levels of somatotrophic hormones (IGF-I) and
prolactin, occurring at any of the 4 test-points during
the first year after the event, were independently as-
sociated with poorer clinical outcome at 12 months.
The magnitude of some of the observed effects of PiDs
seem clinically relevant, with, for example, regression
coefficients indicating that presence of hypogonadism
during the first year after the event will lower the
GOSE score at 12 months by 1 point. Taken together,
the identified independent variables explained 16–25%
(R 2 ) of the variation in outcome variables. Thus, there
are, other factors explaining a large part of the varia-
tion in outcome.
It is notable that signs of pituitary hypofunction or
hyperfunction were frequent during the first year after
the event, and most of these were transient, as reported
previously (18). The most common hypofunction in the
current study group was for gonadal hormones, obser-
ved in 38%, and most common hyperfunction for high
cortisol levels in 52% (Table II). As recently reported
(19), although both cognitive and global function
improves significantly until 12 months after both TBI
and aSAH, impairments remain at 12 months. In the
current study group, cognitive impairment according
to BNIS was present in 54% of cases and impaired
global outcome according to GOSE in 37%. Higher
age and lower GCS score had an independent effect
on cognitive and global outcome, while no association
was observed with sex or the other injury severity
variables, which agrees with the results of previous
studies (26–29).
Associations between abnormal hormone levels and
outcome
This study investigated whether signs of pituitary
dysfunction (hypo- or hyper-function) at any time-
point were associated with outcome. In our study we
J Rehabil Med 51, 2019