Repeat bone mineral density screening and prediction of hip and major osteoporotic fracture.
OBJECTIVE
Screening for osteoporosis with bone mineral density (BMD) is recommended for older adults. It is unclear whether repeating a BMD screening test improves fracture risk assessment.


OBJECTIVE
To determine whether changes in BMD after 4 years provide additional information on fracture risk beyond baseline BMD and to quantify the change in fracture risk classification after a second BMD measure.


METHODS
Population-based cohort study involving 310 men and 492 women from the Framingham Osteoporosis Study with 2 measures of femoral neck BMD taken from 1987 through 1999.


METHODS
Risk of hip or major osteoporotic fracture through 2009 or 12 years following the second BMD measure.


RESULTS
Mean age was 74.8 years. The mean (SD) BMD change was -0.6% per year (1.8%). Throughout a median follow-up of 9.6 years, 76 participants experienced an incident hip fracture and 113 participants experienced a major osteoporotic fracture. Annual percent BMD change per SD decrease was associated with risk of hip fracture (hazard ratio [HR], 1.43 [95% CI, 1.16 to 1.78]) and major osteoporotic fracture (HR, 1.21 [95% CI, 1.01 to 1.45]) after adjusting for baseline BMD. At 10 years' follow-up, 1 SD decrease in annual percent BMD change compared with the mean BMD change was associated with 3.9 excess hip fractures per 100 persons. In receiver operating characteristic (ROC) curve analyses, the addition of BMD change to a model with baseline BMD did not meaningfully improve performance. The area under the curve (AUC) was 0.71 (95% CI, 0.65 to 0.78) for the baseline BMD model compared with 0.68 (95% CI, 0.62 to 0.75) for the BMD percent change model. Moreover, the addition of BMD change to a model with baseline BMD did not meaningfully improve performance (AUC, 0.72 [95% CI, 0.66 to 0.79]). Using the net reclassification index, a second BMD measure increased the proportion of participants reclassified as high risk of hip fracture by 3.9% (95% CI, -2.2% to 9.9%), whereas it decreased the proportion classified as low risk by -2.2% (95% CI, -4.5% to 0.1%).


CONCLUSIONS
In untreated men and women of mean age 75 years, a second BMD measure after 4 years did not meaningfully improve the prediction of hip or major osteoporotic fracture. Repeating a BMD measure within 4 years to improve fracture risk stratification may not be necessary in adults this age untreated for osteoporosis.
Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts 02131, USA. sarahberry@hsl.harvard.edu
Sarah D
SD
Berry
Elizabeth J
EJ
Samelson
Michael J
MJ
Pencina
Robert R
RR
McLean
L Adrienne
LA
Cupples
Kerry E
KE
Broe
Douglas P
DP
Kiel
D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D015331:Cohort Studies; D005260:Female; D005544:Forecasting; D006620:Hip Fractures / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000191:economics / Q000592:standards; D010024:Osteoporosis / Q000150:complications; D058866:Osteoporotic Fractures / Q000453:epidemiology* / Q000517:prevention & control; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors