SOGC Osteoporosis Guidelines 2006

Notes for EBM Tutors – Michelle Howard

Review of Grades of Recommendations

A: consistent level 1 studies – systematic reviews with homogeneity

B: consistent level 2 or 3 studies – cohort, case-control, SR with heterogeneity

C: consistent level 4 studies – case series

D: level 5 (expert opinion, bench research) or other levels very inconsistent

Overall Guideline

-         no description of how it was done- except for sentence in abstract

Epidemiology/natural history

-         aged 50+ overall prevalence of 16% (definition includes BMD)

-         based on fracture 13-25%- 50-year old woman has lifetime risk of 40% for fragility fracture

-         BMD not entirely correlated with fracture- bone quality also a factor but no way currently to assess this- more than half fracture occur in women with –1.0 to –2.5

-         Increase in bone resorption markers are associated with increased vertebral and non-vertebral fractures independent of BMD

-         No optimal threshold of bone marker change known to minimize fracture

Screening

-         What are the criteria for screening?

o       good reliable non-invasive test available

o       effective therapy available

o       benefits outweigh risks (e.g. labeling, psychosocial)

o       consequences of missing cases are substantial

o       consequences of identifying false positives is not too substantial

o       how expensive/invasive is the definitive test?

Definition of OP

-         WHO based entirely on BMD- <2.5SD below young adult peak mass, based on data showing that 50% with fragility fracture are below 2.5 (somewhat arbitrary cutoff)

-         OSC incorporates age, sex, fracture history, glucocorticoid therapy to make 3 categories (no evidence that using this method to identify patients is efficacious but seems reasonable and not overly aggressive?)

Who to screen with BMD

-         age>65; fragility fracture after 40 (wrist, vertebral, hip), family history, glucocorticoid > 3 mos.

-         1 major OR 2 minor

-         decision tools- sensitivity>90%,  but wrongly identifies 30-60% with normal BMD

Monitoring

-         DXA on lumbar, hip, spine every 1-3 years- same instrument same procedure

-         Don’t use peripheral BMD with DXA, ultrasound, single x-ray absorptiometry

-         Use radiographs for women with height loss >6cm,  (prospective 2cm), kyphosis, back pain

Therapy

-         HRT- prevention of hip, vertebrae and others with E+P and E

-         Lower doses of estrogen shown to improve BMD and turnover but no fracture data

-         Etidronate – reduction of vertebral fracture only (RRR 37%)

-         Alendronate- 48%RRR for vertebral, 49% for non-vertebral- also reduces hip fracture in women with prevalent vert fracture or femoral neck <-2.5 and in women at high risk or with ostopenia (post-hoc)

-         Differences shown in 1 year (post-hoc)

-         Also reduction in women t-score –1.6 to –2.5 (post-hoc) after 3 years

-         Residronate – 38% RRR for vertebral fracture and 32% in non-vertebral, 65%RRR in previous fracture in first 3 years

o       74% RRR non-vertebral fracture in 1 year

o       80% RRR in 6 months for clinical vertebral fracture (post-hoc) and 66% non-vertebral

-         Raloxifene – vertebral fracture reduction in BMD<-2.5, 30% with prior fracture, 55% no prior fracture

o       Non-vert fracture not significant except in post-hoc pts with severe prevalent vertebral fracture

o       47-75% (post-hoc) in women with ostopenia at hip

o       meta-analysis RRR 40% for vertebral but not significant for non-vertebral

o       Tolerability and safety- emphasizes ARR (ie small) but all other efficacy data gives RRR (ie large)

o       No comparisons head-to-head to bisphosphonates?

-         Calcitonin – RRR 21% for vertebral fracture- not significant for non-vertebral

-         Parathyroid – RRR 65% vertebral,  53% non-vertebral

When to initiate therapy

-         high risk ie >20% (combination of age and BMD)

-         threshold for BMD lowers as age increases – other factors e.g. vitamin D deficiency

Conflicts of interest?  Sponsored by unrestricted educational grants from many drug companies