Prevalence and Causes of Low Bone Density and Fractures in Kidney Transplant Patients

Abstract

Osteoporosis is known to occur in patients with kidney transplants, but limited information is available about the prevalence and causes of this complication. We asked all 330 patients with kidney transplants in our unit to participate in this study of whom 165 (50%) agreed to do so. The characteristics of the participating patients were similar to the remaining 165 nonparticipants. Seventy of 165 (42%) of the participants were women of whom 40 were postmenopausal in contrast to the men of whom only one was hypogonadal. Bone mineral density (BMD) was significantly reduced at the radius (Z score, ؊1.5) and femoral neck (Z score, ؊0.7), but the lumbar spine was normal. BMD was lower in women than men at all skeletal sites. Osteoporosis was found in 10 -44% and osteopenia was found in 35-50% of women depending on the site. BMD was related inversely to time since transplantation and cumulative prednisolone dose. Twenty-seven of the 165 (16%) patients had either vertebral deformities or a history of a low trauma fracture after transplantation. This fracture group consisted of 10/27 (37%) men and 17/27 (63%) women, of whom 14 were postmenopausal. Fracture patients tended to be older and have a longer duration of renal failure, dialysis, transplantation, greater cumulative steroid dose, and higher bone resorption markers than the nonfracture group. No differences were found for cumulative doses of cyclosporin or tacrolimus. Logistic regression showed that only duration of dialysis and time since transplantation significantly increased fracture risk, with odds ratio (OR) for each year of dialysis or transplantation being 1.21 (CI, 1.00 -1.48) and 1.14 (CI, 1.05-1.23), respectively. These data show that low bone density and fractures are common in patients with kidney transplant and are determined by both pre-and posttransplant variables. Fracture risk was greatest in women, particularly if they were postmenopausal and we recommend that this subgroup is targeted for assessment and treatment.

Bone Disease after Renal Transplantation

“…Ball et al (8) found that after 3 yr after kidney transplantation, the risk for hip fracture increased by 34% when compared with dialysis patients. Patel et al (9) evaluated 165 transplant patients and found evidence of osteoporosis, depending on gender or measured site, in 10 to 44% of the patients. Similarly, 27 (16%) patients had either vertebral deformities or a history of a low trauma fracture after transplantation.…”

Osteoporose após transplante de órgãos sólidos

“…que os mais idosos, os pacientes com maior tempo de evolução da doença renal, aqueles submetidos a maior tempo de diálise, os transplantados há mais tempo, os pacientes que utilizaram a maior dose cumulativa de glicocorticóide e aqueles com elevados níveis séricos de marcadores de reabsorção óssea sofrem mais fraturas após o transplante renal. Nenhuma diferença foi encontrada a respeito da dose cumulativa de tacrolimus e ciclosporina (31). Em um estudo de coorte retrospectivo, Vantour e cols.…”

KOSTNYY METABOLIZM I POTERYa KOSTNOY TKANI V OTDALENNYE SROKI POSLE ALLOTRANSPLANTATsII TRUPNOY POChKI (ATP) (ODNOMOMENTNOE ISSLEDOVANIE)

“…Остеопения, остеопоpоз и пеpеломы pазличной ло-кализации -частое осложнение после пересадки почки [9,16,17,18,21]. По данным одномомент-ных исследований, до 40-45% реципиентов как в ранние, так и отдаленные сроки после аллотpанс-плантации тpупной почки (АТП) имеют остеопе-нию, а от 10% до 50% пациентов -остеопороз [7,10,13,14].…”

“…Снижение же МПК в области бедра может прогрессировать [12,19]. Потери костной ткани после АТП являются результатом нарушений процессов костного ремоделирования, большую роль в возникновении которых играют предшествующие пересадке почки почечная недостаточность и лечение ге-модиализом [14,17], иммуносупрессивная терапия (глюко-кортикоиды и циклоспорин) и вторичный гиперпаратиреоз [5,12,21]. Действительно, костная резорбция, по данным исследований биохимических маркеров костного обмена, усилена у большинства реципиентов АТП, в то время как костное формирование может быть повышенным, не нару-шенным либо сниженным [1,2,5,7,8,10,15].…”

“…В отдельных работах удалось выявить особенности нарушений костного обмена после АТП. Показано, что у женщин-реципиентов значительнее подавлен синтез остеобластами кальцийсвя-зывающего белка остеокальцина [1,2], и риск развития ос-теопороза и переломов костей у них повышен [17]. Однако данные о непосредственной связи между потерями костной ткани и биохимическими маркерами костного обмена [3,14,15], а также между снижением МПК и иммуносупрес-сивной терапией [3,6,8,9,12,14,15,16] в отдаленные сроки после АТП противоречивы.…”