BackgroundStudying physical activity (PA) trends in older populations and potential interventions for increasing PA is important, as PA is a factor in many age-related health outcomes such as chronic disease, premature mortality, physical function and injuries from falls. Objective measures of PA provide valuable information regarding the functional impact that ageing and chronic disease states may have on a patient’s life.AimsThe purpose of this study was to test the validity of the AX3 PA monitor in an older population and to investigate whether the AX3 is a valid measure of distinct types or levels of activity in older people with a spectrum of mobility.MethodsValidity of the AX3 PA monitor was tested using the RT3 as a means of cross-validating the AX3. Study participants wore both the AX3 and the RT3 accelerometers, positioned on their non-dominant side, whilst completing a series of standardised everyday activities.ResultsAlthough overall correlation was high (r > 0.8) between the RT3 and lower-limb-mounted AX3 counts, the correlation between the two devices was much stronger for walking activity than for any of the non-walking activities.DiscussionActivity counts at all lower limb positions for the AX3 and RT3 were highly correlated. Correlation between wrist-mounted AX3 counts and lower limb AX3 counts was only moderate, and worsened when walking aids were in use.ConclusionsThe results of this study indicate that the AX3 monitor is a valid tool, which might be used to objectively measure walking activity in older functionally impaired adults, a welcome finding for this under-researched area.

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4Background 5Bisphosphonate therapy may have actions beyond bone, including effects on cardiovascular, 6 immune and muscle function. We tested whether bisphosphonate treatment is associated with 7 improved outcomes in older people undergoing inpatient rehabilitation 8 9 Methods 10Analysis of prospectively collected, linked routine clinical datasets. Participants were divided 11 into never users of bisphosphonates, use prior to rehabilitation only, use after rehabilitation 12 only, and current users (use before and after rehabilitation). We calculated change in 20-point 13Barthel scores during rehabilitation, adjusting for comorbid disease and laboratory data using 14 multivariable regression analysis. Cox regression analyses were performed to analyse the 15 association between bisphosphonate use and time to death or hospitalisation. 16 17Results 18 2797 patients were included in the analysis. Current bisphosphonate users showed greater 19 improvement in Barthel score during rehabilitation than non-users (5.0 points [95%CI 4.3 to 20 5.7] vs 3.8 [95%CI 3.6 to 3.9]), but no difference compared to those receiving bisphosphonates 21 only after discharge (5.1 [95%CI 4.6 to 5.5]). Previous bisphosphonate use was significantly 22 associated with time to death (adjusted hazard ratio 1.41 [95%CI 1.15 to 1.73]) but less strongly 23 with time to combined endpoint of hospitalisation or death (adjusted hazard ratio 1.18 [95%CI 24 0.98 to 1.48]). Use after discharge from rehabilitation was associated with reduced risk of death 25 (adjusted hazard ratio 0.64 [95%CI 0.55 to 0.73]; hazard ratio per year of bisphosphonate 26 prescription 0.98 [95%CI 0.97 to 0.99]) 27 28 Conclusion 29Bisphosphonate use is unlikely to be causally associated with improved physical function in 30 older people, but continuing use may be associated with lower risk of death. 31 32