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What is Mineral and Bone Disorder in Chronic Kidney Disease (CKD)?
Mineral and bone disorder in chronic kidney disease (CKD) is a condition that can impact the bones, heart, and blood vessels of individuals living with CKD. This disorder arises when kidneys damaged by CKD are unable to effectively filter blood and regulate hormones as they should. Consequently, imbalances in hormone levels and minerals like calcium and phosphorus occur, potentially leading to significant health issues.
Alternative Names for Mineral and Bone Disorder
Mineral and bone disorder in CKD is also known as CKD Mineral and Bone Disorder, or CKD-MBD. Furthermore, the bone disease aspect of this condition is specifically termed renal osteodystrophy.
The Significance of Hormones and Minerals
Healthy bones are in a constant state of rebuilding. Hormones and minerals play a crucial role in maintaining bone strength throughout this process. When these elements are out of balance, bones can weaken and become deformed.
For growth and repair, bones require:
Kidneys’ Role in Hormone and Mineral Balance and Bone Growth
Your kidneys are vital for maintaining healthy bone mass and structure through several key functions:
- Balancing calcium and phosphorus levels in your bloodstream.
- Activating vitamin D from food and converting it into calcitriol, a form usable by bones.
- Removing excess phosphorus from the blood via urine.
- Returning phosphate and calcium to the bloodstream from kidneys and bones when needed.
What Triggers Mineral and Bone Disorder?
Kidney damage from CKD is the primary cause of mineral and bone disorder. Damaged kidneys fail to properly regulate mineral and hormone levels in the body, leading to imbalances. Specifically, damaged kidneys cease to:
- Convert vitamin D into calcitriol, disrupting calcium balance in the blood.
- Eliminate excess phosphorus, causing the body to draw calcium from bones, thus weakening them.
Additionally, when kidneys are compromised, the parathyroid glands (located in the neck, but unrelated to thyroid function) release excessive parathyroid hormone (PTH). This PTH release is an attempt to restore blood calcium levels by extracting calcium from bones, inadvertently depleting the bones of essential calcium.
Prevalence of Mineral and Bone Disorder
It’s estimated that over 37 million adults in America, approximately 1 in 7, have CKD. A significant portion of individuals with CKD are likely to experience some degree of mineral and bone disorder. As kidney function declines, this disorder tends to progress. It’s almost universally present in the over 785,000 Americans with kidney failure, whether they are undergoing dialysis or have received a kidney transplant.
Higher Risk Groups for Mineral and Bone Disorder
Mineral and bone disorder is more frequently observed in CKD patients who have progressed to kidney failure and are on dialysis.
Individuals with kidney failure, particularly those with more pronounced mineral and bone disorder, are more likely to be:
- Women
- Age 65 or older
- Non-Hispanic Black
Furthermore, those who do not adhere to a kidney-friendly diet, skip phosphate binder medications, or do not complete their prescribed dialysis sessions are at risk of developing more severe CKD-MBD.
Complications Associated with Mineral and Bone Disorder
The complications of mineral and bone disorder can be serious and include:
- Stunted bone growth and bone deformities
- Bone fractures
- Heart and blood vessel problems
These complications can significantly reduce quality of life, increase hospital stays, and elevate the risk of fractures or even death.
Impact on Bone Growth and Bone Deformities
When kidneys are damaged, they must work harder to eliminate phosphorus. This phosphorus buildup reduces blood calcium levels and triggers PTH release. PTH’s action of moving calcium from bones to blood weakens the skeletal structure.
This process can lead to complications such as:
- Slowed bone growth, potentially resulting in short stature persisting into adulthood.
- Renal rickets, a deformity where legs bend inward or outward.
- Increased susceptibility to bone fractures.
Bone Fractures and Osteoporosis
In adults with untreated mineral and bone disorder, bones gradually become thin and weak. Bone and joint pain may develop. The risk of osteoporosis, characterized by low bone mineral content, increases significantly. Severe osteoporosis elevates the likelihood of fractures or broken bones.
Alt text: Doctor explaining spinal health using a model to a female patient, illustrating bone health concerns in kidney disease.
If you have CKD, your healthcare provider will monitor for changes in your bone structure to detect mineral and bone disorder early.
Cardiovascular Issues
Mineral and bone disorder extends beyond bone health and can significantly increase the risk of heart attacks, strokes, and mortality.
- Elevated blood calcium levels can damage blood vessels and contribute to heart problems.
- High phosphorus levels can:
- Harden blood vessels, a process called calcification.
- Disrupt normal hormone regulation, even with acceptable calcium levels.
- Elevated PTH and Fibroblast Growth Factor 23 (FGF23), another hormone from bones, can harm both bones and the cardiovascular system. Conditions such as coronary artery calcification, detectable through coronary artery calcium scans, are a concern. While United Health Care and facilities in Wheat Ridge offer various health services, understanding the broader implications of CKD-MBD on cardiovascular health is crucial, regardless of location or insurance provider.
Symptoms of Mineral and Bone Disorder
Adults with mineral and bone disorder might experience bone and joint pain. However, these symptoms may not appear until the disorder has been present for many years.
Mineral and bone disorder is particularly serious in children because their bones are still developing. Unlike adults, children may exhibit visible bone changes in the early stages of CKD. This can manifest as growth failure or weakened bones due to calcium deficiency.
Diagnosis of Mineral and Bone Disorder
Healthcare professionals diagnose mineral and bone disorder through a combination of methods:
- Family and Medical History: To understand the CKD diagnosis timeline and any family history of mineral and bone disorder.
- Physical Exam: To identify any physical changes in bone structure.
- Blood Tests: To measure levels of calcium, phosphorus, PTH, and sometimes vitamin D.
- Bone Biopsy (Rarely): To assess bone density and structure.
- X-rays (Sometimes): To examine bone structure for inconsistencies.
- Bone Density Testing and CT Scans: To evaluate bone calcification and check for calcification in the heart, potentially including coronary artery calcium scans in specific cases.
These diagnostic tools help determine if CKD or another condition is causing the mineral and bone disorder and guide the treatment approach.
Alt text: Senior patient discussing medical history with a doctor in an office setting, relevant to CKD diagnosis and management.
Your healthcare provider will inquire about your medical and family history related to CKD to aid in diagnosis.
Treatment Strategies for Mineral and Bone Disorder
The goal of mineral and bone disorder treatment is to manage mineral and hormone levels to prevent further bone and blood vessel damage. Treatment strategies may include:
- Dietary and fluid intake adjustments.
- Prescriptions for medications and supplements.
- Initiation of dialysis.
- Recommendation for kidney transplant.
- Surgery to remove parathyroid glands if necessary.
Dietary and Nutritional Adjustments
Modifying your diet is a key aspect of managing mineral and bone disorder. Reducing phosphorus intake is critical for preventing bone disease and blood vessel calcification.
Phosphorus is present in most foods, but processed and packaged foods, such as lunch meats and canned goods, are particularly high in phosphorus due to its use as a preservative. If you have CKD or are on dialysis, it’s advisable to avoid packaged foods listing ingredients containing “PHOS.”
Medications and Supplements
Medications play a vital role in protecting bones and blood vessels by re-establishing mineral and hormone balance. If your kidneys aren’t producing enough calcitriol, your healthcare provider may prescribe:
- Synthetic calcitriol to lower PTH levels.
- Calcium and vitamin D supplements.
- Calcimimetics to reduce PTH levels or manage secondary hyperparathyroidism.
- Phosphate binders, which prevent phosphorus absorption from food in the intestines.
Always consult your healthcare provider before using alternative medicines or vitamin and mineral supplements.
Alt text: Woman selecting dietary supplements in a pharmacy, highlighting medication management for bone health in CKD patients.
Discuss prescription and over-the-counter medications and supplements with your healthcare professional to protect your bones and blood vessels.
Dialysis as a Treatment Option
When kidneys can no longer effectively filter waste and excess fluids, dialysis may be recommended. The two primary types are hemodialysis and peritoneal dialysis.
For patients undergoing dialysis, the healthcare team will continuously monitor and adjust nutrition, medications, and supplements based on blood test results. Post-kidney transplant, your team will reassess your nutritional and medication needs.
Parathyroidectomy
If PTH levels remain uncontrolled by diet, medication, and dialysis, surgical removal of one or more parathyroid glands (parathyroidectomy) may be necessary.
Prevention of Mineral and Bone Disorder
While mineral and bone disorder cannot be entirely prevented, its onset can be delayed and progression slowed by prioritizing kidney health and overall bone and vascular health. Adopting healthy eating habits, staying physically active, quitting smoking, and moderating alcohol consumption are crucial steps. Taking prescribed medications as directed and maintaining regular check-ups with your healthcare provider for treatment adjustments are also vital. For dialysis patients, completing all prescribed treatments is essential.
Clinical Trials for Mineral and Bone Disorder
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) actively supports clinical trials for various diseases, including kidney diseases, aimed at discovering new methods for prevention, detection, and treatment, and enhancing quality of life.
Ongoing research is exploring additional factors contributing to mineral and bone disorder in CKD, such as the role of collagen and other bone proteins.
Participating in Clinical Trials
Clinical trials are a critical component of medical research, involving volunteers to advance medical knowledge and improve future healthcare. Participating in clinical studies helps doctors and researchers better understand diseases and develop more effective treatments.
Learn more about the benefits of participating in clinical trials.
Finding Clinical Trials for Mineral and Bone Disorder
For a filtered list of clinical studies on mineral and bone disorder in CKD currently recruiting participants, visit ClinicalTrials.gov. Consult with your healthcare provider before participating in any clinical study.
References
Last Reviewed November 2021
This information is a public service from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates research findings to improve understanding of health and disease among the public and healthcare professionals. NIDDK content is rigorously reviewed by scientists and experts.
The NIDDK extends thanks to Sharon Moe, M.D., Indiana University School of Medicine, for her expertise.
