Bisphosphonate Users Radiographic Characteristics of the Hip (BURCH) Study

Objective:

Bisphosphonates are a class of medications that treat osteoporosis and prevent fractures, and have been available for more than a decade. However, there have been recent studies that have shown that, on rare occasions, they may be associated with an atypical hip fracture after long-term use. Radiographic features such as beaking and thickening along the side of the hip bone have been frequently observed with these atypical femur fractures, but most of the studies to date have only been focused on finding the fractures, not the x-ray features. It is not known how common these x-ray features and pain symptoms are amongst bisphosphonate users that have not yet experienced a fracture. If there is a difference between users and non-users, these features may be a valuable finding to help catch fractures before they happen. A recent hypothesis has emerged that a genetic condition, hypophosphatasia, may play a role.

Study population:

This study will evaluate the presence of these features in users of bisphosphonates and the general population. Individuals from the community who have taken bisphosphonates for five or more years (and still taking or have since stopped) will be compared with individuals recently starting bisphosphonate treatment and individuals without osteoporosis and not taking bisphosphonates but similar in age. Another cohort of patients who have sustained atypical femur fractures will also be recruited.

Design:

This study will be look at the frequency of subtrochanteric beaking and cortical thickening between three groups of people: long-term users, short-term users, and non-users. Thorough medication usage history, physical examination of the hip and radiographs (x-rays) will be taken three times over the course of three years, and a one time bone density scan will be performed upon enrolling. We will also perform genetic testing for hypophosphatasia in long term asymptomatic users and patients who have sustained the atypical femur fracture.

Outcome measures:

We will be looking for the presence of these "beaks" and measuring the thickness of the hip bone at a certain spot. We are interested in seeing if there is a difference between our three groups of people at first and also if these two features change over three years. We will also monitor for thigh pain, a feature of impending fracture, and if any fractures are found on x-rays. We will compare the prevalence of hypophosphatasia mutations in asymptomatic bisphosphonate users and subjects who have sustained the atypical femur fracture.

• INCLUSION CRITERIA - LONGITUDINAL STUDY GROUP:
• For the respective groups, individuals need to be either:

• Diagnosis of Osteoporosis or Osteopenia AND have received bisphosphonate therapy for at least 5 years
• Diagnosis of Osteoporosis or Osteopenia AND have received bisphosphonate therapy for less than 1 year
• Diagnosis of Osteoporosis or Osteopenia AND have received bisphosphonate therapy for 1 to 5 years
• No Diagnosis of Osteoporosis or Osteopenia AND have never received bisphosphonate therapy
• Inclusion Criteria In Common Will Be:

• Age 50 or older
• Ambulatory
• Living independently

Exclusion criteria

- LONGITUDINAL STUDY GROUP:

• Exclusion Criteria Will Be:

• Inability to provide informed consent
• Cognitive Impairment (MCI/dementia)
• Current diagnosis of cancer including: breast, prostate, lung, colon, stomach, bladder, uterus, rectum, thyroid, and kidney
• Previous bilateral hip fractures
• Pregnancy
• Small bowel resections
• Malabsorption
• Paget s Disease of the Bone
• Preexisting osteomalacia, active malignancy, prior bone metastasis, osteogenesis imperfecta, fibrous dysplasia, history of kidney failure.

Inclusion criteria

- GENETICS STUDY GROUP:

For the respective groups, individuals need to be either:

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• Diagnosis of atypical femur fracture within the past 10 years, regardless of bisphosphonate use.

OR

• Diagnosis of Osteoporosis or Osteopenia AND have received bisphosphonate therapy for at least 5 years without atypical femur fracture.
• Inclusion Criteria In Common Will Be:

• Age 45 or older
• Ambulatory
• Living independently

Exclusion criteria

- GENETICS STUDY GROUP:

• Exclusion Criteria will be:

• Inability to provide informed consent
• Cognitive Impairment (MCI/dementia)
• Current diagnosis of cancer including: breast, prostate, lung, colon, stomach, bladder, uterus, rectum, thyroid, and kidney
• Pregnancy
• Small bowel resections
• Malabsorption
• Paget s Disease of the Bone

The following information pertains to individuals in the Longitudinal Group.

Individuals who currently have thigh pain will not be excluded from this study. As the goal of this study is to correlate medication usage with a radiographic feature, individuals concurrently with thigh pain will still be considered, but we will take note of the duration of medication usage and the start of thigh pain per participant history. Duration of thigh pain prior to fracture will likewise be considered. If a current fracture is found on radiographs or suspicion is high for a fracture, selected participants will be sent for MRI of bilateral femurs and participant will be referred back to their primary provider for additional evaluation and treatment.

Individuals who have previously had a unilateral hip fracture or arthroplasty will also not be excluded. As several previous studies have shown, bilateral fractures are not uncommon. We will continue to monitor the progress on the contralateral hip. We will query for details regarding history of first fracture and medication usage. These participants will be subanalyzed for medication usage and time between fractures. Individuals with bilateral (but not unilateral) fractures and bilateral arthroplasty initially will be excluded. However, individuals who are found to have unilateral or bilateral fractures during radiographic studies or undergo unilateral or bilateral arthroplasty during their three years of participation will be allowed to remain in the protocol, and we will assess for change in their anatomy.

Individuals who are being treated with corticosteroids or other types of medications will not be excluded from this study. These variables will be considered confounders and will be analyzed by univariate analysis.

Individuals with anatomical variations such as coxa vara or coxa valga will not be excluded. We will assume that they will be equally distributed into control and treatment groups. These individuals may be at higher risk for atypical fractures, and will be subanalyzed with appropriate femoral-angle matched controls.

Controls that choose to begin bisphosphonate during the study will not be excluded from the study, but will be included in a subanalysis of individuals with less than 3 years of bisphosphonate exposure. Likewise, participants who choose to discontinue bisphosphonate usage will also not be dropped from the study. Analysis will be carried through with groups designated by intent to treat. Users who have taken the drug for 5 years and more who are currently on a drug holiday are eligible (because the drug stays in the bone for so long).