According to the report in the Annals of Internal Medicine for May 19, each standard deviation increase in kyphosis increased the risk of death over the next dozen years by 58% (p = 0.024). This was independent of the severity and extent of vertebral fractures or any underlying spinal osteoporosis.
It is well known that vertebral fractures in the elderly are associated with an increased risk of death, Dr. Deborah M. Kado, from the University of California, Los Angeles, and colleagues note. There has also been some evidence linking hyperkyphosis with mortality. However, because the two often co-exist it has been difficult to determine if hyperkyphosis, in and of itself, is a risk factor.
To answer this question, Dr. Kado’s team analyzed data from 610 women, age 67 to 93 years, who were recruited from four areas in the US from 1986 to 1988. At baseline, vertebral fractures were determined with standard radiography and a few years later, kyphosis was assessed using a flexicurve. The subjects were then followed for 13.5 years, on average.
As noted, as the degree of kyphosis increased, so did the risk of death. On the overall analysis, hyperkyphosis was significant linked to mortality with a relative hazard of 1.15 per standard deviation increase (p = 0.029).
Further analysis, however, showed that a statistically significant association was found only in women with vertebral fractures at baseline (relative hazard = 1.58). Still, the number and severity of the fractures did not affect the risk.
Along with prior reports, the current results suggest that hyperkyphosis is a “clinically important finding,” the authors state. “Because it is readily observed and is associated with ill health in older persons, hyperkyphosis should be recognized as a geriatric syndrome — a ‘multifactorial health condition that occurs when the accumulated effect of impairments in multiple systems renders a person vulnerable to situational challenges’.”
Ann Intern Med 2009;150:681-687.