Short summary

The current method of monitoring the treatment of osteoporosis using bone mineral density (BMD), measured by Dual-energy X-ray absorptiometry (DXA), is associated with problems that reduce its viability as a monitoring tool. The expected change in BMD, even if the treatment is effective, is minute, and due to the slow nature of treatment induced changes in BMD, assessment of treatment response is only possible after 2 years.

The aim of our studies is to examine the value of baseline Bone Turnover Markers (BTMs) and changes in BTMs as indicators of treatment response. Using BTMs to monitor treatment response would potentially enable the clinician to identify non-responders within 3-6 months.

Rationale

Bone turnover markers (BTMs) have shown potential as a tool for assessing treatment response in osteoporotic treatment. Changes in BTMs-level occur within 3-6 months of anti-resorptive therapy, and studies have indicated that changes in BTMs have a higher predictive value than changes in BMD regarding changes in fracture risk.

Before BTMs are to be used clinically, it is important to know how to interpret and act on different levels of BTMs. Most osteoporotic patients have a high bone metabolism reflected in high levels of BTMs, but a small subgroup of the osteoporotic patients has low levels of BTMs. If the decrease in BTMs is an indicator of treatment response, the patients with low levels of BTMs would be expected to have no or low effect of anti-resorptive treatment. 

The BTMs that will be studied are the bone - resorption marker C-terminal telopeptide of type 1 collagen (CTx) and the bone - formation marker N-terminal propeptide of type I collagen (PINP), as these markers have been recommended by The International Osteoporosis Foundation and The International Federation of Clinical Chemistry and Laboratory Medicine for further research.

Description of the cohort

Our cohort exists of patients who have had CTx and/or PINP measured at one of the osteoporosis clinics in the Capital Region of Denmark or Region Zealand in the period 01.01.12 - 30.09.16. The BTMs where measured before the initiation of anti-osteoporotic treatment and after 3-6 months of therapy.

Data and biological material

National Patient Register:

• Fractures (primary outcome)
• Comorbidity

Register of Medicinal Product Statistics:

• Prescribed medication

CPR Register:

• Status (deceased/alive) and emigration

Cause of Death Register:

• Cause of death

The clinical physiological departments and the osteoporosis clinics in the Capital Region of Denmark and Region Zealand:

• BMD data
• Routine blood samples

The Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Glostrup

• BTM data

Collaborating researchers and departments

The projects will be done in collaboration with the Department of Clinical Biochemistry, Rigshospitalet, Glostrup.

OPEN Odense Patient data Explorative Network, Odense University Hospital & Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, Glostrup

• Professor Niklas Rye Jørgensen, PhD
• Associate Professor Katrine Hass Rubin, PhD

OPEN Odense Patient data Explorative Network, Odense University Hospital & Department of Medicine, Holbæk Hospital

• Professor and Consultant Endocrinologist Bo Abrahamsen, PhD

Department of Orthopeadic Surgery, Kolding Hospital

• Consultant Orthopaedic Surgeon, Nis Nissen, PhD

The following departments collaborate by providing BMD-data:

The Department of Clinical Physiology, Copenhagen University Hospital, Rigshospitalet, Glostrup

The Department of Clinical Physiology, Herlev/Gentofte Hospital

The Department of Clinical Physiology, Bispebjerg/Frederiksberg Hospital

The Department of Clinical Physiology, Hvidovre/Amager Hospital

The Department of Clinical Physiology, Nordsjællands Hospital

The Osteoporosis Clinic, Nordsjællands Hospital

The Osteoporosis Clinic, Copenhagen University Hospital, Rigshospitalet

The Osteoporosis Clinic, Hvidovre/Amager Hospital

The Osteoporosis Clinic, Køge University Hospital

The Osteoporosis Clinic, Holbæk Hospital