Osteoporosis in patients with diabetes after kidney transplantation

Secondary hyperparathyroidism and adverse health outcomes in adults with chronic kidney disease

Background

Secondary hyperparathyroidism (sHPT) develops frequently in patients with chronic kidney disease (CKD). However, the burden and long-term impact of sHPT on the risk of adverse health outcomes are not well studied.

Methods

We evaluated all adults receiving nephrologist care in Stockholm during 2006–11 who were not undergoing kidney replacement therapy and had not developed sHPT. Incident sHPT was identified by using clinical diagnoses, initiated medications or two consecutive parathyroid hormone (PTH) measurements ≥130 pg/mL. We characterized sHPT incidence by estimated glomerular filtration rate (eGFR) strata, evaluated clinical predictors and quantified the association between incident sHPT (time-varying exposure) and the risk of fractures, CKD progression, major adverse cardiovascular events (MACEs) and death.

Results

We identified 2556 adults with CKD Stages 1–5 (mean age 66 years, 38% women), of whom 784 developed sHPT during follow-up. The incidence of sHPT increased with advancing CKD: from 57 cases/1000 person-years in CKD Stage G3 to 230 cases/1000 person-years in Stage G5. In multivariable analyses, low eGFR was the strongest sHPT predictor, followed by young age, male sex and diabetes. Incident sHPT was associated with a 1.3-fold (95% confidence interval 1.1–1.8) increased risk of death, a 2.2-fold (1.42–3.28) higher risk of MACEs, a 5.0-fold (3.5–7.2) higher risk of CKD progression and a 1.3-fold (1.5–2.2) higher risk of fractures. Results were consistent in stratified analyses and after excluding early events.

Conclusions

Our findings illustrate the burden of sHPT in advanced CKD and highlight the susceptibility for adverse outcomes of patients developing sHPT. This may inform clinical decisions regarding pre-sHPT risk stratification, PTH monitoring and risk-prevention strategies post-sHPT development.

Calcium citrate: from biochemistry and physiology to clinical applications

Adequate daily calcium intake should normally be achieved by dietary sources. Since low calcium diets are quite common in subjects that do not reach the recommended intake and particularly those at risk of fractures, calcium supplements may become necessary. Different forms of calcium salts are available, but products containing calcium citrate and calcium carbonate complexes are the most frequently used. Although only limited evidence on the efficacy and long-term safety of calcium citrate is available, these supplements may represent a valuable product for the management of different chronic pathological conditions. The aim of this review was to evaluate the current and potential clinical applications of calcium citrate. In particular, we focused on the use of calcium citrate supplementation in subjects with osteoporosis or in bariatric patients. Other pathological conditions that could benefit calcium citrate supplementation may include achloridria, chronic hypoparathyroidism and hypocitraturic subjects with moderate/high risk of nephrolithiasis. Indeed, citrate salts are widely used in the treatment of nephrolithiasis, since they have shown an inhibitory effect on kidney stone formation and recurrence.

Changes in Bone Mineral Density After Kidney Transplantation

BACKGROUND

Numerous studies have shown that osteoporosis is common in kidney transplant recipients. However, the change in bone mineral density after kidney transplantation (KT) is not fully understood.

METHODS

Thirty-nine kidney transplant recipients with bone densitometry at pretransplant and 24 months after KT were reviewed.

RESULTS

The recipients' median age (44.5 ± 10.7 years) and dialysis duration before KT (4.2 ± 3.4 years) were recorded. The T-scores of the lumbar spine and femur neck at 24 months after KT were positively associated with the respective pretransplant T-score (P < .001 in the lumbar spine and P < .001 in the femur neck). However, the T-score after KT did not show significant change (P = .680 in lumbar spine, P = .093 in femur neck). Changes in the T-scores of the lumbar spine and femur neck over 24 months (delta T-score) were negatively associated with the respective pretransplant T-scores (P = .001 in lumbar spine, P = .026 in femur neck). Changes in the T-scores of the lumbar spine and femur neck over 24 months (delta T-score) were also associated with the pretransplant T-scores after the adjustment of other variables.

CONCLUSION

The change of bone mineral density was related with pretransplant bone mineral density. Careful follow-up of bone densitometry for KT recipients was needed.

Lumbar Spine Fusion Surgery in Solid Organ Transplant Recipients Is Associated With Increased Medical Complications and Mortality

STUDY DESIGN

Retrospective database review.

OBJECTIVE

To characterize the outcomes of solid organ transplant (SOT) patients after one- or two-level lumbar fusion surgery.

SUMMARY OF BACKGROUND DATA

Over the past decade advances in SOT patients have improved graft survival. As such, this patient population is increasingly eligible for elective surgery such as lumbar fusion procedures to improve mobility and quality of life. However, the outcomes of spine surgery in this population are not well defined.

METHODS

Data from the full 100% Medicare sample between 2005 and 2014 were used for the study. Patients were included if they had an elective one- or two-level lumbar spine fusion and previous history of renal, heart, liver, or lung SOT patients during this period. SOT patients were compared to non-SOT patients with respect to baseline characteristics, 90-day medical complications, 1-year rate of revision surgery, and 1-year mortality.

RESULTS

There were 961 patients in the transplant cohort and 258,342 in the non-SOT cohort. Seventy-seven percent of the SOT patients had prior renal transplant. SOT patients had a longer length of stay (P < 0.001), and a higher 30-day readmission rate compared to non-SOT patients (P =  < 0.001). In addition, SOT patients experienced a 23.8% rate of 90-day postoperative major medical complications and 3.0%, 1-year mortality, significantly larger than respective rates in the control population (P < 0.001). One-year infection, revision surgery rates, and wound dehiscence were not significantly different between the two cohorts.

CONCLUSION

Spine surgery is associated with significant medical complications and 1-year mortality in the SOT population. Although there may be a substantial benefit from lumbar fusion in the SOT population, judicious patient selection is of paramount importance.

LEVEL OF EVIDENCE

3.