Older persons with hip fractures remain at increased risk of subsequent hip fractures. However, little is known about the frequency and characteristics of persons who sustain a second hip fracture.
Participants included 481 members of the Framingham Heart Study who sustained an initial hip fracture between April 1952 and December 31, 2003. Participants were followed up until a second hip fracture, death, dropout, or study completion. Age, sex, falls, stroke, dementia, residence, recent weight change, body mass index, and functional status were considered potential predictors of a second hip fracture.
During a median of 4.2 years of follow-up, 71 subjects (14.8%) experienced a second hip fracture. Following a first hip fracture, 2.5% of subjects experienced a second hip fracture within 1 year, and 8.2% of subjects (9.7% of women) experienced a second hip fracture within 5 years. One-year mortality following an initial hip fracture was 15.9% compared with 1-year mortality following a second hip fracture of 24.1%. The risk of a second hip fracture increased with age (hazard ratio [HR] per 5-year increase in age, 1.5; 95% confidence interval [CI], 1.1-1.8) and with high functional status (HR compared with moderate functional status, 2.7; 95% CI, 1.1-6.9). There was a statistically nonsignificant association between low functional status and the risk of second hip fracture (HR compared with moderate functional status, 3.7; 95% CI, 0.9-14.8).
Among survivors of an initial hip fracture, the incidence of a second hip fracture is substantial. Older age and functional status may be important predictors of a second hip fracture. There seems to be adequate time between the first and second hip fractures for interventions that may reduce second hip fractures.