Construction and validation of a simplified fracture risk assessment tool for Canadian women and men: results from the CaMos and Manitoba cohorts
William D Leslie, Claudie Berger, Lisa Langsetmo
Lisa M Lix, Jonathan D Adachi, G Ioannidis, Christopher S Kovacs, Tanveer Towheed, Jerilynn C Prior, David Goltzman, David A Hanley, Robert G Josse, S Jamal, S Kaiser, W P Olszynski, Canadian Multicentre Osteoporosis Study (CaMos) Research Group , Nancy Kreiger
A procedure for creating a simplified version of fracture risk assessment tool (FRAX®) is described. Calibration, fracture prediction, and concordance were compared with the full FRAX tool using two large, complementary Canadian datasets.
Introduction
The Canadian Association of Radiologists and Osteoporosis Canada (CAROC) system for fracture risk assessment is based upon sex, age, bone mineral density (BMD), prior fragility fracture, and glucocorticoid use. CAROC does not require computer or web access, and categorizes 10-year major osteoporotic fracture risk as low (<10%), moderate (10-20%), or high (>20%).
Methods
Basal CAROC fracture risk tables (by age, sex, and femoral neck BMD) were constructed from Canadian FRAX probabilities for major osteoporotic fractures (adjusted for prevalent clinical risk factors). We assessed categorization and fracture prediction with the updated CAROC system in the CaMos and Manitoba BMD cohorts.
Results
The new CAROC system demonstrated high concordance with the Canadian FRAX tool for risk category in both the CaMos and Manitoba cohorts (89% and 88%). Ten-year fracture outcomes in CaMos and Manitoba BMD cohorts showed good discrimination and calibration for both CAROC (6.1-6.5% in low-risk, 13.5-14.6% in moderate-risk, and 22.3-29.1% in high-risk individuals) and FRAX (6.1-6.6% in low-risk, 14.4-16.1% in moderate-risk, and 23.4-31.0% in high-risk individuals). Reclassification from the CAROC risk category to a different risk category under FRAX occurred in <5% for low-risk, 20-24% for moderate-risk, and 27-30% for high-risk individuals. Reclassified individuals had 10-year fracture outcomes that were still within or close to the original nominal-risk range..
Conclusion
The new CAROC system is well calibrated to the Canadian population and shows a high degree of concordance with the Canadian FRAX tool. The CAROC system provides s a simple alternative when it is not feasible to use the full Canadian FRAX tool.
simplified fracture risk tool Canada, fracture risk assessment validation, osteoporosis screening tool construction, clinical fracture prediction simplified, bone density risk calculator, major osteoporotic fracture tool, fracture prediction without DXA, population-based fracture assessment, osteoporosis case finding tool, fracture risk clinical variables
PMID 20967422 20967422 DOI 10.1007/s00198-010-1445-5 10.1007/s00198-010-1445-5
Cite this article
Leslie, W. D., Berger, C., Langsetmo, L., Lix, L. M., Adachi, J. D., Hanley, D. A., Ioannidis, G., Josse, R. G., Kovacs, C. S., Towheed, T., Kaiser, S., Olszynski, W. P., Prior, J. C., Jamal, S., Kreiger, N., Goltzman, D., & Canadian Multicentre Osteoporosis Study Research Group (2011). Construction and validation of a simplified fracture risk assessment tool for Canadian women and men: results from the CaMos and Manitoba cohorts. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 22(6), 1873-1883. https://doi.org/10.1007/s00198-010-1445-5
Leslie WD, Berger C, Langsetmo L, Lix LM, Adachi JD, Hanley DA, et al. Construction and validation of a simplified fracture risk assessment tool for Canadian women and men: results from the CaMos and Manitoba cohorts. Osteoporos Int. 2011;22(6):1873-1883. doi:10.1007/s00198-010-1445-5
Leslie, W. D., et al. "Construction and validation of a simplified fracture risk assessment tool for Canadian women and men: results from the CaMos and Manitoba cohorts." Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, vol. 22, no. 6, 2011, pp. 1873-1883.
A new Canadian WHO fracture risk assessment (FRAX®) tool to predict 10-year fracture probability was compared with observed 10-year fracture outcomes in a large Canadian population-based study (CaMos). The Canadian FRAX tool showed good calibration and discrimination for both hip and major osteoporotic fractures.
The purpose of this study was to validate a new Canadian WHO fracture risk assessment (FRAX®) tool in a prospective, population-based cohort, the Canadian Multicentre Osteoporosis Study (CaMos). A FRAX tool calibrated to the Canadian population was developed by the WHO Collaborating Centre for Metabolic Bone Diseases using national hip fracture and mortality data. Ten-year FRAX probabilities with and without bone mineral density (BMD) were derived for CaMos women (N = 4,778) and men (N = 1,919) and compared with observed fracture outcomes to 10 years (Kaplan-Meier method). Cox proportional hazard models were used to investigate the contribution of individual FRAX variables. Mean overall 10-year FRAX probability with BMD for major osteoporotic fractures was not significantly different from the observed value in men [predicted 5.4% vs. observed 6.4% (95%CI 5.2-7.5%)] and only slightly lower in women [predicted 10.8% vs. observed 12.0% (95%CI 11.0-12.9%)]. FRAX was well calibrated for hip fracture assessment in women [predicted 2.7% vs. observed 2.7% (95%CI 2.2-3.2%)] but underestimated risk in men [predicted 1.3% vs. observed 2.4% (95%CI 1.7-3.1%)]. FRAX with BMD showed better fracture discrimination than FRAX without BMD or BMD alone. Age, body mass index, prior fragility fracture and femoral neck BMD were significant independent predictors of major osteoporotic fractures; sex, age, prior fragility fracture and femoral neck BMD were significant independent predictors of hip fractures. The Canadian FRAX tool provides predictions consistent with observed fracture rates in Canadian women and men, thereby providing a valuable tool for Canadian clinicians assessing patients at risk of fracture.
Our objective was to describe patterns and predictors of sedentary behavior (sitting time) over 10 years among a large Canadian cohort. Data are from the Canadian Multicentre Osteoporosis Study, a prospective study of women and men randomly selected from the general population. Respondents reported socio-demographics, lifestyle behaviors and health outcomes in interviewer-administered questionnaires; weight and height were measured. Baseline data were collected between 1995 and 1997 (n = 9418; participation rate = 42%), and at 5- (n = 7648) and 10-year follow-ups (n = 5567). Total sitting time was summed across domain-specific questions at three time points and dichotomized into "low" (≤ 7 h/day) and "high" (> 7 h/day), based on recent meta-analytic evidence on time sitting and all-cause mortality. Ten-year sitting patterns were classified as "consistently high", "consistently low", "increased", "decreased", and "mixed". Predictors of sedentary behavior patterns were explored using chi-square tests, ANOVA and logistic regression. At baseline (mean age = 62.1 years ± 13.4) average sitting was 6.9 h/day; it was 7.0 at 5and 10-year follow-ups (p for trend = 0.12). Overall 23% reported consistently high sitting time, 22% consistently low sitting, 14% decreased sitting, 17% increased sitting with 24% mixed patterns. Consistently high sitters were more likely to be men, university educated, full-time employed, obese, and to report consistently low physical activity levels. This is one of the first population-based studies to explore patterns of sedentary behavior (multi-domain sitting) within men and women over years. Risk classification of sitting among many adults changed during follow-up. Thus, studies of sitting and health would benefit from multiple measures of sitting over time.
Self-reported health status measures, like the Short Form 36-item Health Survey (SF-36), can provide rich information about the overall health of a population and its components, such as physical, mental, and social health. However, differential item functioning (DIF), which arises when population sub-groups with the same underlying (i.e., latent) level of health have different measured item response probabilities, may compromise the comparability of these measures. The purpose of this study was to test for DIF on the SF-36 physical functioning (PF) and mental health (MH) sub-scale items in a Canadian population-based sample. Study data were from the prospective Canadian Multicentre Osteoporosis Study (CaMos), which collected baseline data in 1996-1997. DIF was tested using a multiple indicators multiple causes (MIMIC) method. Confirmatory factor analysis defined the latent variable measurement model for the item responses and latent variable regression with demographic and health status covariates (i.e., sex, age group, body weight, self-perceived general health) produced estimates of the magnitude of DIF effects. The CaMos cohort consisted of 9423 respondents; 69.4% were female and 51.7% were less than 65 years. Eight of 10 items on the PF sub-scale and four of five items on the MH sub-scale exhibited DIF. Large DIF effects were observed on PF sub-scale items about vigorous and moderate activities, lifting and carrying groceries, walking one block, and bathing or dressing. On the MH sub-scale items, all DIF effects were small or moderate in size. SF-36 PF and MH sub-scale scores were not comparable across population sub-groups defined by demographic and health status variables due to the effects of DIF, although the magnitude of this bias was not large for most items. We recommend testing and adjusting for DIF to ensure comparability of the SF-36 in population-based investigations.
To prospectively assess changes in health-related quality of life (HRQOL) over 10 years, by age and sex, and to compare measured within-person change to estimates of change based on cross-sectional data. Participants in the Canadian Multicentre Osteoporosis Study completed the 36-item short form (SF-36) in 1995/1997 and 2005/2007. Mean within-person changes for domain and summary components were calculated for men and women separately, stratified by 10-year age groups. Projected changes based on published ageand sex-stratified cross-sectional data were also calculated. Mean differences between the two methods were then estimated, along with the 95 % credible intervals of the differences. Data were available for 5,569/9,423 (59.1 %) of the original cohort. Prospectively collected 10-year changes suggested that the four physically oriented domains declined in all but the youngest group of men and women, with declines in the elderly men exceeding 25 points. The four mentally oriented domains tended to improve over time, only showing substantial declines in vitality and role emotional in older women, and all four domains in older men. Cross-sectional estimates identified a similar pattern of change but with a smaller magnitude, particularly in men. Correspondence between the two methods was generally high. Changes in HRQOL may be minimal over much of the life span, but physically oriented HRQOL can decline substantially after middle age. Although clinically relevant declines were more evident in prospectively collected data, differences in 10-year age increments of cross-sectional data may be a reasonable proxy for longitudinal changes, at least in those under 65 years of age. Results provide additional insight into the natural progression of HRQOL in the general population.