Introduction:
Kidney transplant recipients are prone to metabolic bone diseases and
have a high risk of fractures. A high prevalence of osteoporosis (ranged
13.9% to 53% [1-5]) and osteopenia (ranged 7 % to 52.5% [3,
5-9]), leading to fractures, has been reported after kidney
transplantation (KT). Although hip fractures often present with clinical
signs, most vertebral fractures occur atypically [10]. Patients may
benefit from radiographic screening for vertebral fractures. Vertebral
fractures are often overlooked, but even undiagnosed vertebral fractures
negatively affect physical function [11], quality of life [12],
and mortality [13].
It has been well demonstrated that rapid bone loss occurs primarily in
the first six months after KT. Following this initial period, the
decrease proceeds at a slower rate or stabilizes. Approximately 2.9% to
6.8% bone loss at the spine over the first six months after kidney
transplantation was detected [9, 14-16]. After the 18th month, the
annual bone loss rate decreases to 1.7% [17]. Bone loss after
kidney transplantation is mainly associated with glucocorticoids and
other immunosuppressive drugs and previous renal osteodystrophy. Other
risk factors for bone loss include hyperparathyroidism, decreased
vitamin D, diabetes mellitus, post-transplant metabolic acidosis,
kidney/pancreas transplantation, and the predictors of osteoporosis in
the general population such as age, smoking, female gender, low body
mass index (BMI). As a consequence of these factors, renal transplant
recipients have shown three times increased bone fracture risk compared
to age-matched controls [18, 19].
The incidence of fractures in the first five years after kidney
transplantation has been reported between 8% and 45% in previous
studies [4, 5, 18, 20, 21]. Bone fractures mainly occur within two
years after transplantation [5]. Peripheral fractures (involving
hands, ankles, feet, and femur) are detected more commonly than spinal
fractures [22].
In clinical studies, there is a wide range of distribution of vertebral
fracture (VF) ratios, ranged between 1.8 to 38.5 % [4, 18, 23-25],
and there are conflicting results about predictors of fracture.
This descriptive clinical study aimed to determine vertebral fracture
prevalence using lateral spinal radiographs and the factors associated
with vertebral fractures and to evaluate bone mineral density
measurements in kidney transplant recipients on a multicenter basis.