Colleen Christmas, MD
Christmas C.; Hip Fracture. Ann Intern Med. 2011;155:ITC6-1. doi: 10.7326/0003-4819-155-11-201112060-01006
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Published: Ann Intern Med. 2011;155(11):ITC6-1.
Hip fracture is the most serious consequence of osteoporosis. About 1% of all falls in the elderly residing in the community result in hip fracture, often with life-changing consequences. Acute mortality from hip fracture is 3%–5%; the lifetime risk for death from hip fracture is similar to that from breast cancer. Far fewer than half of patients with hip fracture fully recover their ability to perform all of their basic activities of daily living. Outcomes are even more grim for those who have postoperative complications. Timely diagnosis and highly attentive perioperative care of the complex patient with a hip fracture aim to reduce the risk for such complications and to facilitate rapid transition to rehabilitation in the hopes of improving functional recovery.
Juan Carlos, Ayus, MD, FACP, FASN, Director of Clinical Research, Armando Luis Negri MD, FACP, Institute for Metabolic Research, del Salvador University, Buenos Aires, Argentina
Renal Consultants of Houston
December 16, 2011
Hyponatremia As A Novel Risk Factor For Hip Fracture
In the review of hip fracture by Christmas(1), the section about screening and prevention mentions that comorbid conditions can increase the risk for falls and hip fracture in the elderly. Among the conditions they list is gait instability.
One factor that is not frequently considered, but which can cause gait instability and increased risk of falls, is hyponatremia. In 1999, our group first described bone fractures secondary to falls as a consequence of hyponatremia in 25% of patients(2). This observation has been validated by a recent study(3). Among patients admitted with asymptomatic hyponatremia compared to normonatremic-matched controls, the incidence of falls was 21% in the hyponatremic group compared to 5% in the controls. The hyponatremic group demonstrated highly unstable gait and attention impairment, more severe than that observed in subjects with moderate alcohol consumption. The attention and gait abnormalities completely reversed following the correction of hyponatremia.
Furthermore, recent work in animals suggests that hyponatremia per se does in fact induce osteoporosis(4). The study found that rats that were made hyponatremic for 3 months had a 30% reduction in bone mineral density compared with control. Thus the data from human and animal studies indicates that hyponatremia can contribute to orthopedic injuries in the elderly by two separate mechanisms: (A) impaired cognitive function with unstable gait and falls, and (B) osteoporosis resulting from increased bone reabsorption to mobilize sodium from the bone(5).
In summary, chronic hyponatremia should be viewed as a risk factor for hip fracture in the elderly.
Juan Carlos Ayus, MD, FACP, FASN Director of Clinical Research Renal Consultants of Houston, Texas
Armando Luis Negri MD, FACP Institute for Metabolic Research, del Salvador University, Buenos Aires, Argentina email@example.com
1. Porto Carriero F and Christmas C. Hip fracture. Ann Intern Med 2011; 155:ITC6-1
2. Ayus JC, Arieff AI. Chronic hyponatremic encephalopathy in postmenopausal women: association of therapies with morbidity and mortality. JAMA 1999;281:2299-304.
3. Renneboog B, Musch W, Vandemergel X, Manto MU, Decaux G. Mild chronic hyponatremia is associated with falls, unsteadiness, and attention deficits. Am J Med 2006;119:71 e1-8.
4. Verbalis JG, Barsony J, Sugimura Y, Tian Y, Adams DJ, Carter EA, Resnick HE. Hyponatremia-induced osteoporosis. J Bone Miner Res 2010; 25(3):554-63.
5. Ayus JC, Moritz ML. Bone disease as a new complication of hyponatremia: moving beyond brain injury. Clin J Am Soc Nephrol 2010;5:167 -8.
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Endocrine and Metabolism, Metabolic Bone Disorders, Prevention/Screening.
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Print ISSN: 0003-4819 | Online ISSN: 1539-3704
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