Patients Who Stick to the Plan Reduce Fractures in Osteoporosis

Newswise — Monitoring treatment and increasing adherence (willingness to follow prescribed treatment routine) may reduce fractures in patients with osteoporosis, according to research presented at the American College of Rheumatology Annual Scientific Meeting in Boston, Mass.Osteoporosis is a silent disease of the bones that makes them weaken and prone to fracture. Bone is living tissue that is in a constant state of regeneration, as old bone is removed (bone resorption) and replaced by new bone (bone formation). By their mid-30s, most people begin to gradually lose bone strength as the balance between bone resorption and bone formation shifts, so that more bone is lost than can be replaced. As a result, bones become thinner and structurally weaker.

The disease is "silent" because there are no symptoms when a person has osteoporosis, and the condition may come to attention only after they break a bone. With osteoporosis, this can occur even after a minor injury, such as a fall.

Once a patient suffers a fracture, the risk of additional fractures is increased. The next fracture, particularly in the elderly, might lead to additional health problems and even death. The most common fractures occur at the spine, wrist and hip. Spine and hip fractures in particular may lead to chronic pain, long-term disability and even death. The goal of treating osteoporosis is to prevent such fractures in the first place.

Canadian researchers conducted a population study of 74,085 men and women age 67 or older to determine if adherence to treatment routines would impact fractures. The main predictor of fractures was refill compliance, which was defined as the number days supplied from first to last prescription divided by 730 days (or two years, the duration of the study period). For example, if someone filled six prescriptions in the two-year period to represent 180 days of prescription use, the refill compliance would be 180 divided by 730, or a 25 percent refill compliance rate. Researchers studied results against the following adherence rates: 67 percent, 80 percent, 82 percent, 85 percent and 90 percent. The outcome was a fracture in the period after the initiation of medication.

There were 1751 (2.4 percent) fractures across the entire study population. By monitoring the frequency of prescription refills, researchers found that patients who follow their osteoporosis treatment routine and fill at least 67 percent of their prescription are much less likely to have to have fractures over a two-year period. Other factors were found to reduce fractures were younger age, being female and regular bone density testing.

"A year after hip fracture, a significant proportion of patients (about 20 percent) are dead, and another group can no longer live independently and require long term nursing care, so we really want to avoid these fractures," said Gillian Hawker, MD, MSc FRCPC; professor of medicine, Women's College Hospital, University of Toronto; and an investigator in the study. "These drugs need to be taken as prescribed in order to work to reduce fracture risk; since people with OP cannot "see" the benefit as they can say with a pain medication given to a person in pain, it helps to show them they are getting benefit through monitoring BMD."

The ACR is an organization of and for physicians, health professionals, and scientists that advances rheumatology through programs of education, research, advocacy and practice support that foster excellence in the care of people with or at risk for arthritis and rheumatic and musculoskeletal diseases. For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.

Editor's Notes: Dr. Hawker will present this research during the ACR Annual Scientific Meeting at the Boston Convention and Exhibition Center from 4:30 " 6:00 pm ET on Saturday, November 10, 2007, in Room 156. Presentation Number: 2117

Impact of Adherence to Osteoporosis Medications on Fracture Rates: A Population-Based Study

Purpose: The purpose of this study was to examine if current efforts at managing osteoporosis led to a reduction in fracture in elderly men and women in Ontario, Canada. Specifically we determined the impact of differing levels of adherence to osteoporosis medications on subsequent fracture in a population-based study.

Methods: Ontario residents over the age of 65 have universal access to Medicare and to certain osteoporosis medications. We identified all persons aged 67 and older who initiated an osteoporosis medication between April 1, 2002 - March 31, 2004 and who did not have a drug claim for an osteoporosis medication (bisphosphonate or SERM) during the 2 years prior to initiation date (N=90,723). We excluded patients with erroneous records (prescribed 1 pill for 1 day, n=866 or adherence > 120%, n = 4,605), prescription for salmon calcitonin (n=687), history of Paget's, epilepsy, cancer, pathological fracture (n=163), discharged to nursing home (n=2,458) or died before the end of the 2 year follow-up period from medication initiation (n=7,859) for a final cohort of 74,085 patients. The main predictor was refill compliance calculated using the Medication Possession Ratio (MPR) defined as the number days supplied from first to last prescription / length of follow-up (730 days). This was defined at 4 cut-offs, 30%, 50%, 67% and 80%. The outcome was fracture in the period after the initiation of medication. There were 1751 (2.4%) fractures. Logistic regression analyses were conducted for each refill compliance cut-off adjusted for age, sex, BMD test, number of non-osteoporosis medications, and number of physician visits in 2 year period prior to initiation of treatment, BMD test after initiation of treatment, and Charlson co-morbidity index.

Results: Only 80% and 67% refill compliance were statistically significantly associated with fracture reduction: Odds ratio (80%) = 0.85, p = 0.046; Odds ratio (67%) = 0.85, p = 0.013. Age <75 (OR = 0.63), being female (OR = 0.54), having had a BMD test prior to treatment (OR = 0.85) and one after (OR = 0.89) were also statistically significantly associated with fracture reduction.

Conclusions: Patients who are at least 67% adherent with their osteoporosis medications over a two-year period are less likely to fracture. Other factors associated with fracture reduction are younger age, female sex, and BMD testing. These are important findings, which confirm at a population level previous reports based on selected clinical trials patients. We now have evidence to show decision-makers that if we continue our efforts to monitor treatment and increase adherence even bigger gains in fracture reduction might be possible.

Disclosure Block: S.B. Jaglal, None; D. Thiruchelvam, None; G.A. Hawker, None.