Placebo response in pharmacological and dietary supplement trials of autism spectrum disorder (ASD): systematic review and meta-regression analysis.

BACKGROUND: Placebo response in autism spectrum disorder (ASD) might dilute drug-placebo differences and hinder drug development. Therefore, this meta-analysis investigated placebo response in core symptoms. METHODS: We searched ClinicalTrials.gov , CENTRAL, EMBASE, MEDLINE, PsycINFO, WHO-ICTRP (up to July 8, 2018), and PubMed (up to July 4, 2019) for randomized pharmacological and dietary supplement placebo-controlled trials (RCTs) with a minimum of seven days of treatment. Single-group meta-analyses were conducted using a random-effects model. Standardized mean changes (SMC) of core symptoms in placebo arms were the primary outcomes and placebo positive response rates were a secondary outcome. Predictors of placebo response were investigated with meta-regression analyses. The protocol was registered with PROSPERO ID CRD42019125317 . RESULTS: Eighty-six RCTs with 2360 participants on placebo were included in our analysis (87% in children/adolescents). The majority of trials were small, single-center with a duration of 8-12 weeks and published after 2009. Placebo response in social-communication difficulties was SMC = - 0.32, 95% CI [- 0.39, - 0.25], in repetitive behaviors - 0.23[- 0.32, - 0.15] and in scales measuring overall core symptoms - 0.36 [- 0.46, - 0.26]. Overall, 19%, 95% CI [16-22%] of participants were at least much improved with placebo. Caregiver (vs. clinician) ratings, lower risk of bias, flexible-dosing, larger sample sizes and number of sites, less recent publication year, baseline levels of irritability, and the use of a threshold of core symptoms at inclusion were associated with larger placebo response in at least a core symptom domain. LIMITATIONS: About 40% of the trials had an apparent focus on core symptoms. Investigation of the differential impact of predictors on placebo and drug response was impeded by the use of diverse experimental interventions with essentially different mechanisms of action. An individual-participant-data meta-analysis could allow for a more fine-grained analysis and provide more informative answers. CONCLUSIONS: Placebo response in ASD was substantial and predicted by design- and participant-related factors, which could inform the design of future trials in order to improve the detection of efficacy in core symptoms. Potential solutions could be the minimization and careful selection of study sites as well as rigorous participant enrollment and the use of measurements of change not solely dependent on caregivers.

Endovascular thrombectomy with or without systemic thrombolysis?

OBJECTIVES: Current recommendations advocate that pretreatment with intravenous thrombolysis (IVT) should first be offered to all eligible patients with emergent large vessel occlusion (ELVO) before an endovascular thrombectomy (ET) procedure. However, there are observational data that question the safety and efficacy of IVT pretreatment in patients with ELVO. METHODS: We performed a meta-analysis of the included subgroups from ET randomized controlled trials (RCTs) to evaluate the comparative efficacy between direct ET without IVT pretreatment and bridging therapy (IVT and ET) in patients with ELVO. RESULTS: We included a total of seven RCTs, including 1764 patients with ELVO (52.8% men). Patients receiving bridging therapy (IVT followed by ET) had lower rates (p = 0.041) of 90-day death/severe dependency (modified Rankin Scale-score of 5-6; 19.0%, 95% CI: 14.1-25.1%) compared with patients receiving only ET (31.0%, 95% CI: 21.2-42.9%). Moreover, patients receiving IVT and ET had a nonsignificant (p = 0.389) trend towards higher 90-day functional independence rates (51.4%, 95% CI: 42.5-60.1%) compared with patients undergoing only ET (41.7%, 95% CI: 24.1-61.7%). Finally, shift-analysis uncovered a nonsignificant trend towards functional improvement at 90 days for bridging therapy over ET (cOR = 1.28, 95% CI: 0.91-1.89; p = 0.155). It should be noted that patients included in the present meta-analysis were not randomized to receive IVT, and thus the two groups (bridging therapy versus ET monotherapy) may differ in terms of baseline characteristics and, in particular, in terms of onset to groin puncture time and thus the risk of confounding bias cannot be ruled out. CONCLUSION: Despite the limitations and the risk of confounding bias, our findings contradict the recent notion regarding potential equality between ET and bridging therapy in ELVO patients and suggest that IVT and ET are complementary therapies that should be pursued in a parallel and noncompeting fashion.