How large are the nonspecific effects of acupuncture? A meta-analysis of randomized controlled trials.

BACKGROUND: While several recent large randomized trials found clinically relevant effects of acupuncture over no treatment or routine care, blinded trials comparing acupuncture to sham interventions often reported only minor or no differences. This raises the question whether (sham) acupuncture is associated with particularly potent nonspecific effects. We aimed to investigate the size of nonspecific effects associated with acupuncture interventions. METHODS: MEDLINE, Embase, Cochrane Central Register of Controlled Clinical Trials and reference lists were searched up to April 2010 to identify randomized trials of acupuncture for any condition, including both sham and no acupuncture control groups. Data were extracted by one reviewer and verified by a second. Pooled standardized mean differences were calculated using a random effects model with the inverse variance method. RESULTS: Thirty-seven trials with a total of 5754 patients met the inclusion criteria. The included studies varied strongly regarding patients, interventions, outcome measures, methodological quality and effect sizes reported. Among the 32 trials reporting a continuous outcome measure, the random effects standardized mean difference between sham acupuncture and no acupuncture groups was -0.45 (95% confidence interval, -0.57, -0.34; I2 = 54%; Egger's test for funnel plot asymmetry, P = 0.25). Trials with larger effects of sham over no acupuncture reported smaller effects of acupuncture over sham intervention than trials with smaller nonspecific effects (ß = -0.39, P = 0.029). CONCLUSIONS: Sham acupuncture interventions are often associated with moderately large nonspecific effects which could make it difficult to detect small additional specific effects. Compared to inert placebo interventions, effects associated with sham acupuncture might be larger, which would have considerable implications for the design and interpretation of clinical trials.

"Climatic fluctuations in the hyperarid core of the Atacama Desert during the past 215 ka".

Paleoclimate records from the Atacama Desert are rare and mostly discontinuous, mainly recording runoff from the Precordillera to the east, rather than local precipitation. Until now, paleoclimate records have not been reported from the hyperarid core of the Atacama Desert (<2 mm/yr). Here we report the results from multi-disciplinary investigation of a 6.2 m drill core retrieved from an endorheic basin within the Coastal Cordillera. The record spans the last 215 ka and indicates that the long-term hyperarid climate in the Central Atacama witnessed small but significant changes in precipitation since the penultimate interglacial. Somewhat 'wetter' climate with enhanced erosion and transport of material into the investigated basin, commenced during interglacial times (MIS 7, MIS 5), whereas during glacial times (MIS 6, MIS 4-1) sediment transport into the catchment was reduced or even absent. Pelagic diatom assemblages even suggest the existence of ephemeral lakes in the basin. The reconstructed wetter phases are asynchronous with wet phases in the Altiplano but synchronous with increased sea-surface temperatures off the coasts of Chile and Peru, i.e. resembling modern El Niño-like conditions.

Are sham acupuncture interventions more effective than (other) placebos? A re-analysis of data from the Cochrane review on placebo effects.

BACKGROUND AND OBJECTIVE: A recent Cochrane review on placebo interventions for all kinds of conditions found that 'physical placebos' (which included sham acupuncture) were associated with larger effects over no-treatment control groups than 'pharmacological placebos'. We re-analyzed the data from this review to investigate whether effects associated with sham acupuncture differed from those of other 'physical placebos'. METHODS: All trials included in the Cochrane review as investigating 'physical placebos' were classified as investigating either (sham) acupuncture or other physical placebos. The latter group was further subclassified into groups of similar interventions. Data from the Cochrane review were re-entered into the RevMan 5 software for meta-analysis. The primary analysis was a random-effects analysis of trials reporting continuous outcomes of trials that used either sham acupuncture or other physical placebos. RESULTS: Out of a total of 61 trials which reported a continuous outcome measure, 19 compared sham acupuncture and 42 compared other physical placebos with a no-treatment control group. The trials re-analyzed were highly heterogeneous regarding patients, interventions and outcomes measured. The pooled standardized mean difference was -0.41 (95% confidence interval -0.56, -0.24) between sham acupuncture and no treatment and -0.26 (95% CI -0.37, -0.15) between other physical placebos and no treatment (p value for subgroup differences = 0.007). Significant differences were also observed between subgroups of other physical placebos. CONCLUSION: Due to the heterogeneity of the trials included and the indirect comparison our results must be interpreted with caution. Still, they suggest that sham acupuncture interventions might, on average, be associated with larger effects than pharmacological and other physical placebos.