Bart L. Clarke, M.D.

The research program of Bart L. Clarke, M.D., focuses on clinical studies of steroid-induced osteoporosis, transplant-related osteoporosis, age-related osteoporosis, primary hyperparathyroidism, hypoparathyroidism and metabolic bone disease. He has developed collaborative clinical research protocols in these and other areas.

Focus areas

• Steroid-induced osteoporosis. Previous research projects in the area of steroid-induced osteoporosis include an industry-funded study to prevent bone loss in patients with primary biliary cirrhosis with once-weekly bisphosphonate, which was done in collaboration with Keith D. Lindor, M.D., and colleagues from the Division of Gastroenterology and Hepatology.
• Transplant-associated osteoporosis. Several research projects have been completed in the area of transplant-associated osteoporosis. These include an analysis of bone histomorphometric changes before and after liver transplantation, which was done in collaboration with J. Eileen Hay, M.B., Ch.B., of the Division of Gastroenterology and Hepatology, as well as an analysis of fracture risk in Olmsted County patients undergoing renal transplantation between 1965-1995 done in collaboration with L. Joseph Melton III, M.D., of the Department of Health Sciences Research and Line Vautour, M.D., of McGill University in Montreal, Canada.
• Non-hip femoral fractures. A research project evaluating the risk of non-hip femoral fractures across the lifespan in Olmsted County from 1984-2008 has been completed in collaboration with Dr. Melton and others. It showed an increasing risk of this type of less common femur fracture over time.
• Hypoparathyroidism. Phase III and phase I clinical trials of the new drug parathyroid hormone 1-84 in patients with hypoparathyroidism have recently been completed, along with a low-dose parathyroid hormone 1-84 clinical trial, with an extension study from the phase III clinical trial still ongoing. Epidemiological studies in Olmsted County of comorbidities associated with hypoparathyroidism before and after diagnosis, and the costs of caring for patients with hypoparathyroidism, are ongoing.
• CT colonography to predict bone strength. A research project assessing the ability of CT colonography to predict bone strength using finite element analysis is under way in an effort to demonstrate that CT data can be used to predict osteoporosis risk. This is being done in collaboration with Jeff L. Fidler, M.D., in the Department of Radiology and Tony M. Keaveny, Ph.D., at the University of California, Berkeley.
• Other projects in metabolic bone disease. Other projects in metabolic bone disease with fellows in the Mayo Clinic endocrine training program include retrospective chart reviews of patients with Erdheim-Chester disease, Hajdu-Cheney syndrome, fibrous dysplasia and primary hyperparathyroidism, and Camurati-Engelmann syndrome.

Significance to patient care

These research projects have advanced the understanding of postmenopausal osteoporosis and other forms of osteoporosis, and given new insights into treatment options for bone and calcium disorders.

Alendronate is now commonly used to treat patients with low bone density who have inflammatory bowel disease. Evaluation of bone disease associated with liver transplantation has increased the understanding of effects of transplantation and immunosuppressive therapy on the skeleton, and clarified means by which bone loss may be prevented after organ transplantation.

Better definition of the frequency of non-hip femur fractures in the population of Olmsted County has helped treat patients with osteoporosis more effectively.

Evaluation of the prevalence of hypoparathyroidism, as well as complications and costs of this disorder, in the community has given perspective on new treatments for this condition. Treatment of patients with hypoparathyroidism has been significantly advanced with the new drug Natpara (PTH 1-84), which is the first-in-class treatment for this rare disorder.

The combination of these collaborative efforts will improve the care of patients with osteoporosis and other metabolic bone diseases.