Moderators of the effect of therapeutic exercise for knee and hip osteoarthritis: a systematic review and individual participant data meta-analysis

Background Many international clinical guidelines recommend therapeutic exercise as a core treatment for knee and hip osteoarthritis. We aimed to identify individual patient-level moderators of the effect of therapeutic exercise for reducing pain and improving physical function in people with knee osteoarthritis, hip osteoarthritis, or both. Methods We did a systematic review and individual participant data (IPD) meta-analysis of randomised controlled trials comparing therapeutic exercise with non-exercise controls in people with knee osteoathritis, hip osteoarthritis, or both. We searched ten databases from March 1, 2012, to Feb 25, 2019, for randomised controlled trials comparing the effects of exercise with non-exercise or other exercise controls on pain and physical function outcomes among people with knee osteoarthritis, hip osteoarthritis, or both. IPD were requested from leads of all eligible randomised controlled trials. 12 potential moderators of interest were explored to ascertain whether they were associated with short-term (12 weeks), medium-term (6 months), and long-term (12 months) effects of exercise on self-reported pain and physical function, in comparison with non-exercise controls. Overall intervention effects were also summarised. This study is prospectively registered on PROSPERO (CRD42017054049). Findings Of 91 eligible randomised controlled trials that compared exercise with non-exercise controls, IPD from 31 randomised controlled trials (n=4241 participants) were included in the meta-analysis. Randomised controlled trials included participants with knee osteoarthritis (18 [58%] of 31 trials), hip osteoarthritis (six [19%]), or both (seven [23%]) and tested heterogeneous exercise interventions versus heterogeneous non-exercise controls, with variable risk of bias. Summary meta-analysis results showed that, on average, compared with non-exercise controls, therapeutic exercise reduced pain on a standardised 0–100 scale (with 100 corresponding to worst pain), with a difference of –6·36 points (95% CI –8·45 to –4·27, borrowing of strength [BoS] 10·3%, between-study variance [τ2] 21·6) in the short term, –3·77 points (–5·97 to –1·57, BoS 30·0%, τ2 14·4) in the medium term, and –3·43 points (–5·18 to –1·69, BoS 31·7%, τ2 4·5) in the long term. Therapeutic exercise also improved physical function on a standardised 0–100 scale (with 100 corresponding to worst physical function), with a difference of –4·46 points in the short term (95% CI –5·95 to –2·98, BoS 10·5%, τ2 10·1), –2·71 points in the medium term (–4·63 to –0·78, BoS 33·6%, τ2 11·9), and –3·39 points in the long term (–4·97 to –1·81, BoS 34·1%, τ2 6·4). Baseline pain and physical function moderated the effect of exercise on pain and physical function outcomes. Those with higher self-reported pain and physical function scores at baseline (ie, poorer physical function) generally benefited more than those with lower self-reported pain and physical function scores at baseline, with the evidence most certain in the short term (12 weeks). Interpretation There was evidence of a small, positive overall effect of therapeutic exercise on pain and physical function compared with non-exercise controls. However, this effect is of questionable clinical importance, particularly in the medium and long term. As individuals with higher pain severity and poorer physical function at baseline benefited more than those with lower pain severity and better physical function at baseline, targeting individuals with higher levels of osteoarthritis-related pain and disability for therapeutic exercise might be of merit

Predicting Greenhouse Gas Emissions and Soil Carbon from Changing Pasture to an Energy Crop

Bioenergy related land use change would likely alter biogeochemical cycles and global greenhouse gas budgets. Energy cane (Saccharum officinarum L.) is a sugarcane variety and an emerging biofuel feedstock for cellulosic bio-ethanol production. It has potential for high yields and can be grown on marginal land, which minimizes competition with grain and vegetable production. The DayCent biogeochemical model was parameterized to infer potential yields of energy cane and how changing land from grazed pasture to energy cane would affect greenhouse gas (CO2, CH4 and N2O) fluxes and soil C pools. The model was used to simulate energy cane production on two soil types in central Florida, nutrient poor Spodosols and organic Histosols. Energy cane was productive on both soil types (yielding 46–76 Mg dry mass?ha 21). Yields were maintained through three annual cropping cycles on Histosols but declined with each harvest on Spodosols. Overall, converting pasture to energy cane created a sink for GHGs on Spodosols and reduced the size of the GHG source on Histosols. This change was driven on both soil types by eliminating CH4 emissions from cattle and by the large increase in C uptake by greater biomass production in energy cane relative to pasture. However, the change from pasture to energy cane caused Histosols to lose 4493 g CO 2 eq?m 22 over 15 years of energy cane production. Cultivation of energy cane on forme

Site information for studies used in DAYCENT model validation.

<p>Yield values from the literature and modeled yields for energy cane and sugarcane represent total aboveground biomass expressed as Mg ha⁻¹ on a dry mass basis. Climate variables include mean annual maximum and minimum temperature (°C) and mean annual precipitation (mm).</p

Changes in total greenhouse gas (GHG) from pasture and land converted to energy cane in Highlands County, Florida.

<p>Positive values indicate GHG efflux and negative values indicate GHG uptake. A) Total annual GHG flux, reported as CO₂ equivalents converted to account for differences in warming potential (g CO₂e⋅m⁻²). The solid vertical line represents year of land use conversion from pasture to energy cane. B) Mean greenhouse gas flux in CO₂ equivalents converted to account for differences in warming potential (g CO₂e⋅m⁻²⋅yr⁻¹, ± SD) for 15 years in pasture, and for 5, 3-year ratoon cycles in energy cane (each bar represents the average of 5 values, one for each year for each stage in the planting cycle).</p

Modeled CH₄ flux from pasture and land converted to energy cane in Highlands County, Florida.

<p>A) Total annual CH₄ flux (g C⋅m⁻²). The solid vertical line represents year of land use conversion from pasture to energy cane, positive values indicate CH₄ efflux and negative values indicate CH₄ uptake. B) Mean CH₄ flux (g C⋅m⁻²⋅yr⁻¹, ± SD) for 15 years in pasture, and for 5, 3-year ratoon cycles in energy cane (each bar represents the average of 5 values, one for each year for each stage in the planting cycle).</p

Changes in total soil organic C from pasture and land converted to energy cane in Highlands County, Florida.

<p>A) Total annual SOC flux (g C⋅m⁻²). The solid vertical line represents year of land use conversion from pasture to energy cane. B) Mean SOC flux (g C⋅m⁻²⋅yr⁻¹, ± SEM) for 15 years in pasture, and for 5, 3-year ratoon cycles in energy cane (each bar represents the average of 5 values, one for each year for each stage in the planting cycle).</p

Modeled heterotrophic respiration (R_H) from pasture and land converted to energy cane in Highlands County, Florida.

<p>A) Total annual heterotrophic respiration (g C⋅m⁻²). Dashed line represents year of land use conversion from pasture to energy cane. B) Mean heterotrophic respiration (g C⋅m⁻²⋅yr⁻¹, ± SD) for 15 years in pasture, and for 5, 3-year ratoon cycles in energy cane (each bar represents the average of 5 values, one for each year for each stage in the planting cycle).</p

Modeled total soil CO₂ flux from pasture and land converted to energy cane in Highlands County, Florida.

<p>A) Total annual soil CO₂ flux (expressed as g C⋅m⁻²). Dashed line represents year of land use conversion from pasture to energy cane. B) Mean total soil CO₂ flux (g C⋅m⁻²⋅yr⁻¹, ± SD) for 15 years in pasture, and for 5, 3-year ratoon cycles in energy cane (each bar represents the average of 5 values, one for each year for each stage in the planting cycle).</p

Modeled N₂O flux from pasture and land converted to energy cane in Highlands County, Florida.

<p>A) Total annual N₂O flux (g N⋅m⁻²). The solid vertical line represents year of land use conversion from pasture to energy cane, positive values indicate N₂O efflux and negative values indicate N₂O uptake. B) Mean N₂O flux (g N⋅m⁻²⋅yr⁻¹, ± SD) for 15 years in pasture, and for 5, 3-year ratoon cycles in energy cane (each bar represents the average of 5 values, one for each year for each stage in the planting cycle).</p