For Immediate Release
Contact: Steve Welch, ACCP, (847) 498-8305, [email protected]

Bone Loss In Critically Ill Patients

Researchers have found widespread bone loss and increased risk of osteoporosis in an emerging patient population described as the chronically critically ill (CCI), according to a new study reported today in CHEST, the journal of the American College of Chest Physicians (ACCP).

CCI patients are generally elderly individuals with multiple illnesses and conditions who have survived a life-threatening episode of sepsis (destruction of tissue by bacterial toxins) and are left profoundly debilitated and ventilator dependent. They often face months if not years of ventilator support following their acute critical illness.

Drs. David Nierman and Jeffrey Mechanick at the Mount Sinai Medical Center in New York City conducted a study to determine how much bone loss and parathyroid-vitamin D abnormalities existed in these patients. The study was one of the first to specifically focus on an acquired metabolic disorder in CCI patients that may adversely impact on their overall recovery.

The investigators pointed out that in the short run, vitamin D deficiency can lead to proximal muscle weakness and muscle pain and can hamper the patient's ability to wean from mechanical ventilation. In the longer run, they noted, osteoporosis will predispose these fragile survivors to the morbidity associated with vertebral compression and hip fractures.

Of forty-nine patients studied, 92% had elevated urine levels consistent with abnormally increased bone loss. Forty-two percent of the patients had elevated parathyroidism levels consistent with predominant vitamin D deficiency.

The authors of the study pointed out that as the overall care of these types of patients and their survival improves; morbidity associated with metabolic bone diseases becomes more significant. Further studies, they added, will determine the efficacy and cost-effectiveness of routine screening in CCI patients as well as the role of routine vitamin D and anti-bone loss therapies.

In an accompanying editorial in CHEST, Dr. Robert Aris and colleagues from the University of North Carolina Medical School said the findings of the study are important for several reasons. First, they said, they add to a growing body of literature that suggests patients with lung disorders suffer from either low bone mineral density, and its sequelae--fractures and kyphosis (abnormal curvature of the thoracic spine)--or the physiology that predisposes to bone loss. Dr. Aris added that Drs. Nierman and Mechanick deserve credit for implicating several causative factors (i.e., vitamin D deficiency and immobilization) for bone loss that are not often considered in lung disease or critical illness patients. These, he said, need to be added to the list of well-described risk factors for osteoporosis in lung disease patients. Other risk factors for osteoporosis include corticosteroid treatment, smoking, heavy alcohol intake, being of Caucasian or Asian heritage, and being thin or small boned.

Bone loss due to immobilization should not be assumed to be inconsequential, he said. Noting that earlier studies showed that 10 percent of bone loss was linked with immobilization, he said this degree of bone loss may double the risk of fractures.

Aris and colleagues also noted the evidence for the role of cykotines in promoting bone loss, with the strongest evidence implicating the tumor necrosis factor alpha (TNF-a). He said that TNF-a may be involved in bone resorption by facilitating the recruitment and maturation of osteoclast precursors. He added that data on cykotines "may supplement our understanding of the pathogenesis of osteoporosis and further encourage the screening and treatment (e.g., with bisphosphonates) of osteoporosis in lung disease patients, including those with critical illnesses."

CHEST is published by the American College of Chest Physicians (ACCP) which represents 15,000 members who provide clinical respiratory and cardiothoracic patient care in the U.S. and throughout the world.

Reporters may wish to contact Steve Welch, Managing Editor of CHEST, for a full copy of the article at (847) 498-8305. Dr. David Nierman can be contacted at the Mt. Sinai Medical Center at (212) 241-1386, and Dr. Aris can be contacted at the University of North Carolina at (919) 966-2531. The table of contents and abstracts of all articles appearing in the October issue of CHEST are available on the ACCP web site at http://www.chestnet.org

###

MEDIA CONTACT
Register for reporter access to contact details