Question

on the study of osteoporotic fracture 1-what is the disease measure? 2-what is the exposure? 3-who is the population? 4-how was the study implemented? is it prospective or retrospective? 5-how is it measured? what is the conclusion or the final result? Please write the solution without handwriting and the answer will not be part of the website's solutions

Answer 1

The study of osteoporotic fracture (OSF) is a cohort of 10,366 women who were greater than or equal to 65 years old at enrollment in 1986-7. During 18 years and 8 examinations, SOF has developed a comprehensive array of phenotypic data, along with archives of 53,000 biological specimens and 67,500 radiographs.

1-The Study of Osteoporotic Fractures (SOF) was initially established to identify the risk factors associated with osteoporotic fractures in postmenopausal women aged 65 and older. Over time, the scope of the study expanded to include assessment of sleep, cognitive function, osteoarthritis, breast cancer, cognitive function and healthy aging.

Women aged 65 or older are most at risk for developing osteoporosis, a condition that causes the bones to become fragile. The increase in bone frailty makes this group more susceptible to osteoporotic fractures, which commonly occur at the hip, spine and wrist. Although there has been some research pertaining to fracture risk, most studies have not been able to thoroughly investigate this issue due to various limitations. There was a need for longitudinal research of a specific cohort of women, to determine what factors were most strongly related to fracture risk.

A bone mineral density (BMD) test is the best way to determine  your bone health. This test  can identify osteoporosis  determine your risk for fractures  ( broken bones), and measure your response to osteop  treatment. The most widely recognized BMD test  is called a dual-energy x-ray absorptiometry, or DXA test.

2-Cumulative use of tenofovir or lopinavir/ritonavir independently raised the risk of osteoporotic fracture, but only in the combination antiretroviral therapy according to results of a 27,000-person analysis of the Veterans Affairs' (VA) Clinical Case Registry HCV coinfection, low body mass index, tobacco use, older age, and white race also independently boosted osteoporotic fracture risk.

Two earlier cohort studies found a higher fracture prevalence in people with HIV than in the general US population But the Women's Interagency HIV Study found equivalent fracture risk in HIV-positive US women and women at risk of HIV .

Whereas tenofovir (TDF) exposure has been associated with decreased bone density, it remains unclear whether it is associated with increased risk of osteoporotic fractures. Patients with any osteoporotic fracture (defined as wrist, vertebral or hip fracture) occurring after HIV diagnosis were identified by International Classification of Diseases -

Osteoporotic fracture risk associated with cumulative exposure to TDF and other antiretrovirals was examined in univariate analysis and multivariate model 1 (MV1 - controlling for race, age, tobacco use, diabetes, body mass index, and hepatitis C status) .

3-The burden of osteoporotic fractures is significant, including functional decline, loss of independence, substantial economic impact, and increased morbidity and mortality . Hip fractures tend to be the most costly and debilitating of fractures, with approximately 10 to 20% mortality in the year following a hip fracture and more than half of patients unable to return to independent living post-fracture. Fractures at other skeletal sites, including the spine and wrist, are also associated with substantial disability and functional decline . Specifically, Medicare patients over 65 years of age with a spine fracture have been shown to have approximately two times the overall mortality of matched controls, with survival rates consistently significantly lower at 3, 5, and 7 years post-fracture . Mortality rates were significantly greater for men than women and relative differences in mortality in patients with a spine fracture versus controls was greatest in younger patients (aged 65–69 years) and declined as age at time of fracture increased .

Several studies have examined hip fracture trends in the USA. A study by Brauer et al. showed a steady decline in hip fracture incidence from 1995 to 2005 in men and women after a previous rise in rates from 1986 to 1995 in a Medicare population . A recent study by Lewiecki et al. found that US hip fracture rates in the Medicare population declined between 1995 and 2012 but then plateaued in 2013, with a higher than projected incidence in 2013

4-Implementation of case findings according to guidelines for osteoporosis in fracture patients presenting at a Fracture Liaison Service (FLS) was evaluated. Despite one guideline, all FLSs differed in the performance of patient selection and prevalence of clinical risk factors (CRFs) indicating the need for more concrete and standardised guidelines.

Patients older than 50 years with a recent clinical fracture who were able and were willing to participate in fracture risk evaluation were included. Performance was evaluated by criteria for patient recruitment, patient characteristics, nurse time, evaluated clinical risk factors (CRFs), bone mineral density (BMD) and laboratory testing and results of CRFs and BMD are presented. Differences between FLSs were analysed for performance (by chi-square and Student’s t test) and for prevalence of CRFs (by relative risks (RR)).

All five participating FLSs with a dedicated fracture nurse differed in the performance of patient selection, CRFs and in the prevalence of CRFs, indicating the need for more concrete and standardised guidelines to organise evaluation of patients at the time of fracture in daily practice.

A fracture liaison service (FLS) is one of the initiatives in the field of post-fracture care to integrate osteoporosis assessment [13–16]. An evaluation of FLSs allowed to identify similarities and differences in the performance of evidence-based medicine and prevalence of CRFs and can be helpful to detect strengths and weaknesses of guideline advices and their implementation.

1. In prospective individuals are followed over time and data about them is collected as their characteristics or circumstances change. Birth cohort studies are a good example of prospective studies .
2. In retrospective studiesindividuals are sampled and information is collected about their past.

Both retrospectively and prospectively designed studies consistently show low bone mass and/or bone mineral content (BMC) to be risk factor for low-trauma fractures in postmenopausal women. Along with the reports of such studies there has been concern expressed that BMC measurements overlap between fracture groups, i.e., some women with high BMC develop fractures and some women with low BMC do not. In these commonly used epidemiologic study designs, BMC does not discriminate between those who have and have not experienced the untoward event at some level of the exposure factor. The ability to discriminate is more properly determined by the sensitivity and specificity of the measured value. To contrast the concepts of risk and sensitivity, a nested case-control study was conducted within a 24-year cohort study of women at risk for osteoporosis.

5-main out come measure

Each subject's longitudinal health service record was assessed for the presence of nontrauma fracture codes (hip, spine, wrist, and humerus) after bone density testing. Age-adjusted hazard ratios for fracture were derived from Cox proportional hazards models.

Results

Site-specific and overall fracture rates were significantly associated with each site of bone density measurement (all P < 0.00001). The 95% confidence intervals overlapped those from a widely cited metaanalysis of fracture prediction from different sites. Although fracture prediction was not significantly different between the three hip measurement sites, each hip site was better than the lumbar spine for predicting overall fractures (nonoverlapping 95% confidence intervals). The manufacturer sd (equivalent to a unit change in T-score) resulted in a significantly smaller gradient of risk for the spine than when the population sd was used.

Conclusion

Bone density measurements are effective for predicting fractures in clinical practice. However, hip measurements were superior to the spine in overall osteoporotic fracture prediction.