Multiple BMD Screens Show Little Value

Sep 30, 2013

Results from the Framingham Ostoporosis Study show that change in bone mineral density over baseline offers little predictive value. Also last week: More support for diet and exercise to reduce the pain of knee OA.

Last week's articles on rheumatology topics in the major non-rheumatology journals.

Repeat Bone Mineral Density Screening and Prediction of Hip and Major Osteoporotic FractureJAMA, September 25, 2013

After one bone mineral density (BMD) measurement, a second BMD measurement four years did not improve the prediction of hip or major osteoporotic fracture. In the Framingham Osteoporosis Slater tudy, 310 men and 492 women, mean age 75 years at baseline, had two femoral neck BMD measurements four years apart. In a 10-year followup, the mean BMD change was -0.6% per year, delivering a standard deviation (SD) of 1.8%. One SD decrease was associated with a 1.43 hazard ratio (HR) for hip fracture and 1.21 HR for major osteoporotic fracture. At 10 years, 1 SD decrease in BMD was associated with 3.9 excess hip fractures per 100 persons. However, in the receiver operating characteristic curve analysis, baseline BMD predicted fracture better than BMD change, and combining baseline and change did not significantly improve prediction. BMD change provided little clinical value beyond baseline, although a small number of people who went on to experience fracture would have been reclassified.

Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults With Knee Osteoarthritis: The IDEA Randomized Clinical TrialJAMA, September 25, 2013

A randomized trial compared diet alone, exercise alone, and diet plus exercise in overweight and obese patients with pain and radiographic knee osteoarthritis over 18 months. The diet intervention, which included comprehensive counseling and specified meal plans and meal-replacement shakes, aiming for at least a 10% weight loss. Primary outcomes were knee joint compressive force and plasma interleukin-6 levels. Secondary outcomes were pain, function, mobility, and quality of life. Diet patients had a ≥10% reduction in body weight. On the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index baseline function score was 24.2; for the diet and exercise group at 18 months, it was 14.1. Baseline pain score was 6.5; in the diet and exercise group it dropped to 3.6.

Also of interest:Genetic Variants Regulating Immune Cell Levels in Health and DiseaseCell, Sept. 26, 2013

A genome-wide association study found that 89 independent gene variants overlap with known autoimmune disease associations, including rheumatoid arthritis, systemic sclerosis, primary sclerosing cholangitis, juvenile rheumatoid arthritis, and vitiligo. The variants were on 53 sites in 95 leukocyte subtypes and included HLA, IL2RA, and SH2B3/ATXN2. The research involved more than 1,600 Sardinians.