The causes behind a startling increase in mortality following an osteoporotic fracture require urgent attention, an expert has told the ANZBMS conference here in Tasmania.
Dr Weiwen Chen, from the Garvan Institute of Medical Research in Sydney, and her colleagues used the New South Wales ’45 and Up’ study to examine mortality in patients who presented to emergency departments with a fracture.
They found mortality was almost trebled in men and doubled in women who have an osteoporotic fracture, even after accounting for comorbidities.
The massive database includes 267,000 people aged at least 45 who signed up to the study between 2006 and 2009.
A total of 9,384 women and 5,588 men had a hospital-treated fracture by the end of 2013.
Overall, any fracture was associated with a relative risk of mortality of 2.8 in men and 2.3 in women compared to participants without a fracture.
“Increased mortality emerged soon after the fracture event, emphasising the need for early intervention given that we know osteoporosis treatment can improve survival,” Dr Chen told delegates.
The calculations were adjusted for age, BMI, smoking, prior fracture and, importantly, comorbidities, to help distinguish whether fractures were in themselves a risk factor for death or just a marker of older age and poor health.
“Increased mortality was demonstrated after all proximal fractures, with the hazard ratio ranging from 2.00 for elbow and humeral fractures to 3.02-3.71 for hip fractures, as well as wrist fractures in both sexes and ankle fractures in men,” Dr Chen said.
“In general, the relative risk of mortality was higher in younger participants.
“Only fractures of the hand, finger, foot and toe were not associated with increased mortality.”
Bisphosphonates reduce risk
Associate Professor Jackie Center, also from the Garvan Institute, presented data from the Canadian Multicentre Osteoporosis Study (CaMOS) showing that treatment with bisphosphonates appears to reduce all-cause and post-fracture mortality risk.
The study collected fracture and mortality data prospectively between 1996 and 2011 from 5,321 women and 2,119 men with osteoporosis, including annual assessments of BMD, comorbidities, medication use and lifestyle factors.
After adjusting for potential confounders, current or past use of bisphosphonates in women was associated with a 52-54% reduction in mortality, but hormone therapy had no significant effect.
Mortality risk in men was also reduced by 30% in current bisphosphonate users and by 50% in past users. The benefit was greater with the more potent agents alendronate and risedronate compared to etidronate.
“A longer period on a bisphosphonate after a fracture was also positively associated with better survival, with a 20% reduction for each additional year on treatment,” Professor Center said.