Rate of bone density change does not enhance fracture prediction in routine clinical practice

CONTEXT

There is contradictory information on whether the rate of bone mineral density (BMD) loss is an independent risk factor for osteoporotic fractures and whether this should be included in fracture prediction systems.

OBJECTIVE

This study was undertaken to better define rate of BMD loss as a contributor to fracture risk in routine clinical practice.

DESIGN AND SETTING

We performed a retrospective cohort study using a database of all clinical BMD results for the province of Manitoba, Canada.

PATIENTS

We included 4498 untreated women age 40 yr and older at the time of a second BMD test performed between April 1996 and March 2009.

MAIN OUTCOME MEASURES

A total of 146 women with major osteoporotic fracture outcomes after the second BMD test (mean observation, 2.7 yr) and relevant covariates were identified in population-based computerized health databases.

RESULTS

Annualized percentage change in total hip BMD was no greater in fracture compared to nonfracture women (-0.4 ± 1.7 vs. -0.5 ± 1.4; P = 0.166). After adjustment for final total hip BMD, other covariates, and medication use, rate of total hip BMD change did not predict major osteoporotic fractures (hazard ratio, 0.95 per sd decrease; 95% confidence interval, 0.81-1.10). Similar results were also seen in analyses based upon change in lumbar spine and femoral neck BMD.

CONCLUSIONS

We found no evidence that BMD loss, as detected during routine clinical monitoring, was a significant independent risk factor for major osteoporotic fractures.

Population-based trends in osteoporosis management after new initiations of long-term systemic glucocorticoids (1998-2008)

OBJECTIVES

Our objective was to describe changes in glucocorticoid-induced osteoporosis (GIOP) preventive care from 1998-2008 including rates and correlates of bone mineral density (BMD) testing and osteoporosis treatment in new long-term glucocorticoid initiations.

METHODS

A population-based study of adults aged 20 yr or older in Manitoba, Canada, was conducted using linked healthcare databases. Subjects with new long-term (≥90 d) systemic glucocorticoid initiations were identified within each fiscal year. High-quality GIOP preventive care was defined by the composite of BMD testing or osteoporosis treatment within 6 months of starting glucocorticoids. For each initiation, we identified sociodemographic and clinical characteristics, prednisone dose equivalents, and prescriber specialty. Multivariable Poisson regression models were used to calculate adjusted incidence rate ratios (aIRR).

RESULTS

We studied 17,736 new long-term glucocorticoid initiations; one third were at least 10 mg prednisone daily, and most (64%) were prescribed by general practitioners. Overall, 6-month rates of BMD testing were 6%, osteoporosis treatment 22%, and the composite of testing or treatment 25%. From 1998-2008, there were modest increases in BMD testing (from 4 to 6%), osteoporosis treatment (from 15 to 24%), and testing or treatment [from 17 to 27%; aIRR = 1.51; 95% confidence interval (CI) = 1.40-1.63]. High-quality GIOP preventive care varied significantly by age (16% for those <50 yr vs. 27% for those ≥70 yr; aIRR = 0.57; 95% CI = 0.52-0.63), sex (13% for men vs. 34% for women; aIRR = 0.40; 95% CI = 0.37-0.43), and prescriber (23% general practice vs. 44% rheumatology; aIRR = 0.56; 95% CI = 0.52-0.60).

CONCLUSIONS

Quality of GIOP preventive care has improved but remains suboptimal with only one quarter of those starting long-term glucocorticoids receiving BMD testing or osteoporosis treatment. Interventions to improve GIOP prevention, especially targeting younger patients, men, and nonspecialists, are needed.

Direct costs of fractures in Canada and trends 1996-2006: a population-based cost-of-illness analysis

Cost-of-illness (COI) analysis is used to evaluate the economic burden of illness in terms of health care resource (HCR) consumption. We used the Population Health Research Data Repository for Manitoba, Canada, to identify HCR costs associated with 33,887 fracture cases (22,953 women and 10,934 men) aged 50 years and older that occurred over a 10-year period (1996-2006) and 101,661 matched control individuals (68,859 women and 32,802 men). Costs (in 2006 Canadian dollars) were estimated for the year before and after fracture, and the change (incremental cost) was modeled using quantile regression analysis to adjust for baseline covariates and to study temporal trends. The greatest total incremental costs were associated with hip fractures (median $16,171 in women and $13,111 for men), followed by spine fractures ($8,345 in women and $6,267 in men). The lowest costs were associated with wrist fractures ($663 in women and $764 in men). Costs for all fracture types were greater in older individuals (p < 0.001). Similar results were obtained with regression-based adjustment for baseline factors. Some costs showed a slight increase over the 10 years. The largest temporal increase in women was for hip fracture ($13 per year, 95% CI $6-$21, p < 0.001) and in men was for humerus fracture ($11 per year, 95% CI $3-$19, p = 0.007). At the population level, hip fractures were responsible for the largest proportion of the costs after age 80, but the other fractures were more important prior to age 80. We found that there are large incremental health care costs associated with incident fractures in Canada. Identifying COI from HCR use offers a cost baseline for measuring the effects of evidence-based guidelines implementation.