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The Cochrane Database of Systematic... Dec 2020The use of insulin-sensitising agents, such as metformin, in women with polycystic ovary syndrome (PCOS) who are undergoing ovulation induction or in vitro fertilisation... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The use of insulin-sensitising agents, such as metformin, in women with polycystic ovary syndrome (PCOS) who are undergoing ovulation induction or in vitro fertilisation (IVF) cycles has been widely studied. Metformin reduces hyperinsulinaemia and suppresses the excessive ovarian production of androgens. It is suggested that as a consequence metformin could improve assisted reproductive techniques (ART) outcomes, such as ovarian hyperstimulation syndrome (OHSS), pregnancy, and live birth rates.
OBJECTIVES
To determine the effectiveness and safety of metformin as a co-treatment during IVF or intracytoplasmic sperm injection (ICSI) in achieving pregnancy or live birth in women with PCOS.
SEARCH METHODS
We searched the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL via the Cochrane Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO, LILACS, the trial registries for ongoing trials, and reference lists of articles (from inception to 13 February 2020).
SELECTION CRITERIA
Types of studies: randomised controlled trials (RCTs) comparing metformin treatment with placebo or no treatment in women with PCOS who underwent IVF or ICSI treatment.
TYPES OF PARTICIPANTS
women of reproductive age with anovulation due to PCOS with or without co-existing infertility factors. Types of interventions: metformin administered before and during IVF or ICSI treatment.
PRIMARY OUTCOME MEASURES
live birth rate, incidence of ovarian hyperstimulation syndrome.
DATA COLLECTION AND ANALYSIS
Two review authors independently selected the studies, extracted the data according to the protocol, and assessed study quality. We assessed the overall quality of the evidence using the GRADE approach.
MAIN RESULTS
This updated review includes 13 RCTs involving a total of 1132 women with PCOS undergoing IVF/ICSI treatments. We stratified the analysis by type of ovarian stimulation protocol used (long gonadotrophin-releasing hormone agonist (GnRH-agonist) or short gonadotrophin-releasing hormone antagonist (GnRH-antagonist)) to determine whether the type of stimulation used influenced the outcomes. We did not perform meta-analysis on the overall (both ovarian stimulation protocols combined) data for the outcomes of live birth and clinical pregnancy rates per woman because of substantial heterogeneity. In the long protocol GnRH-agonist subgroup, the pooled evidence showed that we are uncertain of the effect of metformin on live birth rate per woman when compared with placebo/no treatment (risk ratio (RR) 1.30, 95% confidence interval (CI) 0.94 to 1.79; 6 RCTs; 651 women; I = 47%; low-quality evidence). This suggests that if the chance for live birth following placebo/no treatment is 28%, the chance following metformin would be between 27% and 51%. Only one study used short protocol GnRH-antagonist and reported live birth rate. Metformin may reduce live birth rate compared with placebo/no treatment (RR 0.48, 95% CI 0.29 to 0.79; 1 RCT; 153 women; low-quality evidence). This suggests that if the chance for live birth following placebo/no treatment is 43%, the chance following metformin would be between 13% and 34% (short GnRH-antagonist protocol). We found that metformin may reduce the incidence of OHSS (RR 0.46, 95% CI 0.29 to 0.72; 11 RCTs; 1091 women; I = 38%; low-quality evidence). This suggests that for a woman with a 20% risk of OHSS without metformin, the corresponding risk using metformin would be between 6% and 14%. Using long protocol GnRH-agonist stimulation, metformin may increase clinical pregnancy rate per woman compared with placebo/no treatment (RR 1.32, 95% CI 1.08 to 1.63; 10 RCTs; 915 women; I = 13%; low-quality evidence). Using short protocol GnRH-antagonist, we are uncertain of the effect of metformin on clinical pregnancy rate per woman compared with placebo/no treatment (RR 1.38, 95% CI 0.21 to 9.14; 2 RCTs; 177 women; I = 87%; very low-quality evidence). We are uncertain of the effect of metformin on miscarriage rate per woman when compared with placebo/no treatment (RR 0.86, 95% CI 0.56 to 1.32; 8 RCTs; 821 women; I = 0%; low-quality evidence). Metformin may result in an increase in side effects compared with placebo/no treatment (RR 3.35, 95% CI 2.34 to 4.79; 8 RCTs; 748 women; I = 0%; low-quality evidence). The overall quality of evidence ranged from very low to low. The main limitations were inconsistency, risk of bias, and imprecision.
AUTHORS' CONCLUSIONS
This updated review on metformin versus placebo/no treatment before or during IVF/ICSI treatment in women with PCOS found no conclusive evidence that metformin improves live birth rates. In a long GnRH-agonist protocol, we are uncertain whether metformin improves live birth rates, but metformin may increase the clinical pregnancy rate. In a short GnRH-antagonist protocol, metformin may reduce live birth rates, although we are uncertain about the effect of metformin on clinical pregnancy rate. Metformin may reduce the incidence of OHSS but may result in a higher incidence of side effects. We are uncertain of the effect of metformin on miscarriage rate per woman.
Topics: Abortion, Spontaneous; Bias; Confidence Intervals; Female; Fertilization in Vitro; Humans; Hyperandrogenism; Hyperinsulinism; Hypoglycemic Agents; Live Birth; Metformin; Ovarian Hyperstimulation Syndrome; Ovulation Induction; Placebos; Polycystic Ovary Syndrome; Pregnancy; Pregnancy Rate; Randomized Controlled Trials as Topic; Sperm Injections, Intracytoplasmic
PubMed: 33347618
DOI: 10.1002/14651858.CD006105.pub4 -
EFORT Open Reviews Oct 2023The study of the placebo effect is key to elucidate the 'real effect' of conservative interventions for plantar fasciitis. The aim of this meta-analysis was to quantify...
PURPOSE
The study of the placebo effect is key to elucidate the 'real effect' of conservative interventions for plantar fasciitis. The aim of this meta-analysis was to quantify the impact of placebo in the different conservative treatments of plantar fasciitis.
METHODS
A systematic literature review was performed on double-blind placebo-controlled trials (RCTs) according to PRISMA guidelines on PubMed, Embase, and Web of Science. The meta-analysis primary outcome was the 0-10 pain variation after placebo treatments analyzed at 1 week, 1, 3, 6, and 12 months. The risk of bias was assessed using the RoB 2.0 tool, while the overall quality of evidence was graded according to the GRADE guidelines.
RESULTS
The placebo effect for conservative treatments was studied in 42 double-blind RCTs on 1724 patients. The meta-analysis of VAS pain showed a statistically significant improvement after placebo administration of 2.13/10 points (P < 0.001), being highest at 12 months with 2.79/10 points (P < 0.001). The improvement of the placebo groups was higher in the extracorporeal shock wave therapy studies compared to the injection studies (2.59 vs 1.78; P = 0.05). Eight studies had a low risk of bias, 23 studies had 'some concerns,' and 4 studies had a high risk of bias. The GRADE evaluation showed an overall high quality of evidence.
CONCLUSION
This systematic review and meta-analysis demonstrated that the placebo effect represents an important component of all conservative approaches to treat plantar fasciitis. This effect is statistically and clinically significant, increases over time, and depends on the type of conservative treatment applied to address plantar fasciitis.
PubMed: 37787480
DOI: 10.1530/EOR-23-0082 -
Molecular Psychiatry Mar 2022There is growing evidence that placebo effects can meaningfully modulate the brain. However, there has been little consideration of whether these changes may overlap... (Meta-Analysis)
Meta-Analysis
There is growing evidence that placebo effects can meaningfully modulate the brain. However, there has been little consideration of whether these changes may overlap with regions/circuits targeted by depression treatments and what the implications of this overlap would be on measuring efficacy in placebo-controlled clinical trials. In this systematic review and meta-analysis, we searched PubMed/Medline and Google Scholar for functional MRI and PET neuroimaging studies of placebo effects. Studies recruiting both healthy subjects and patient populations were included. Neuroimaging coordinates were extracted and included for Activation Likelihood Estimation (ALE) meta-analysis. We then searched for interventional studies of transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS) for depression and extracted target coordinates for comparative spatial analysis with the placebo effects maps. Of 1169 articles identified, 34 neuroimaging studies of placebo effects were included. There were three significant clusters of activation: left dorsolateral prefrontal cortex (DLPFC) (x = -41, y = 16, z = 34), left sub-genual anterior cingulate cortex (sgACC)/ventral striatum (x = -8, y = 18, z = -15) and the right rostral anterior cingulate cortex (rACC) (x = 4, y = 42, z = 10). There were two significant deactivation clusters: right basal ganglia (x = 20, y = 2, z = 7) and right dorsal anterior cingulate cortex (dACC) (x = 1, y = -5, z = 45). TMS and DBS targets for depression treatment overlapped with the left DLPFC cluster and sgACC cluster, respectively. Our findings identify a common set of brain regions implicated in placebo effects across healthy individuals and patient populations, and provide evidence that these regions overlap with depression treatment targets. We model the statistical impacts of this overlap and demonstrate critical implications on measurements of clinical trial efficacy for this field.
Topics: Depression; Gyrus Cinguli; Humans; Magnetic Resonance Imaging; Neuroimaging; Placebo Effect; Prefrontal Cortex; Transcranial Magnetic Stimulation
PubMed: 34903861
DOI: 10.1038/s41380-021-01397-3 -
Canadian Journal of Psychiatry. Revue... Jul 2023Obsessive-compulsive disorder (OCD) is a major mental health condition with a lifetime prevalence rate of 1.3% among adults. While placebo effects are well described for... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Obsessive-compulsive disorder (OCD) is a major mental health condition with a lifetime prevalence rate of 1.3% among adults. While placebo effects are well described for conditions such as depressive and anxiety disorders, they have not been systematically characterized in OCD.
OBJECTIVES
We aimed to determine the impact of placebos in improving different symptom domains in patients with OCD.
METHODS
We systematically searched PubMed, EMBASE, Scopus, Web of Science, Ovid, the Cochrane Library, and Google Scholar databases/search engine from inception to January 2021 for randomized controlled trials of treatments for OCD with a placebo arm. A modified Cohen's effect size (ES) was calculated using change in baseline to endpoint scores for different measurement scales within placebo arms to estimate placebo effects and to investigate their correlates by random-effects model meta-analyses.
RESULTS
Forty-nine clinical trials (placebo group = 1993), reporting 80 OCD specific (153 measures in general) were included in the analysis. Overall placebo ES (95% confidence interval [CI]) was 0.32 (0.22-0.41) on OCD symptoms, with substantial heterogeneity (I-square = 96.1%). Among secondary outcomes, general scales, ES: 0.27 (95%CI: 0.14-0.41), demonstrated higher ES than anxiety and depression scales, ES: 0.14 (95%CI: -0.4 to 0.32) and 0.05 (95%CI: -0.05 to 0.14), respectively. Clinician-rated scales, ES: 0.27(95%CI: 0.20-0.34), had a higher ES than self-reported scales, ES: 0.07 (95%CI: -0.08 to 0.22). More recent publication year, larger placebo group sample size, shorter follow-up duration, and younger age of participants were all associated with larger placebo ES. Egger's test reflected possible small-study effect publication bias ( = 0.029).
CONCLUSION
Placebo effects are modest in OCD trials and are larger in clinician ratings, for younger patients, and early in the treatment course. These findings underscore the need for clinicians and scientists to be mindful of placebo effects when formulating treatments or research trials for OCD.
SYSTEMATIC REVIEW REGISTRATION NUMBER
PROSPERO CRD42019125979.
Topics: Adult; Humans; Placebo Effect; Obsessive-Compulsive Disorder; Anxiety Disorders
PubMed: 35876317
DOI: 10.1177/07067437221115029 -
International Journal of Environmental... Oct 2022Background: Evaluate whether the design of placebo control groups could produce different interpretations of the efficacy of manual therapy techniques. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
Background: Evaluate whether the design of placebo control groups could produce different interpretations of the efficacy of manual therapy techniques.
METHODS
Nine databases were searched (EMBASE, CINAHL, PsycINFO, MEDLINE, PubMed, SCOPUS, WEB of SCIENCE, COCHRANE, and PEDro). Randomized placebo-controlled clinical trials that used manual therapy as a sham treatment on subjects suffering from pain were included. Data were summarized qualitatively, and meta-analyses were conducted with R.
RESULTS
53 articles were included in the qualitative analysis and 48 were included in the quantitative analyses. Manipulation techniques did not show higher effectiveness when compared with all types of sham groups that were analyzed (SMD 0.28; 95%CI [-0.24; 0.80]) (SMD 0.28; 95%CI [-0.08; 0.64]) (SMD 0.42; 95%CI [0.16; 0.67]) (SMD 0.82; 95%CI [-0.57; 2.21]), raising doubts on their therapeutic effect. Factors such as expectations of treatment were not consistently evaluated, and analysis could help clarify the effect of different sham groups. As for soft tissue techniques, the results are stronger in favor of these techniques when compared to sham control groups (SMD 0.40; 95%CI [0.19, 0.61]). Regarding mobilization techniques and neural gliding techniques, not enough studies were found for conclusions to be made.
CONCLUSIONS
The literature presents a lack of a unified placebo control group design for each technique and an absence of assessment of expectations. These two issues might account for the unclear results obtained in the analysis.
Topics: Humans; Manipulation, Osteopathic; Musculoskeletal Manipulations; Randomized Controlled Trials as Topic
PubMed: 36360901
DOI: 10.3390/ijerph192114021 -
Critical Reviews in Food Science and... 2023Although creatine supplementation is well-known to increase exercise performance in acute high-intensity exercises, its role in aerobic performance based on VOmax is... (Meta-Analysis)
Meta-Analysis
Although creatine supplementation is well-known to increase exercise performance in acute high-intensity exercises, its role in aerobic performance based on VOmax is more controversial. Thus, we performed a systematic review and meta-analysis on the effects of creatine supplementation on VOmax. PubMed, Cochrane, Embase, and ScienceDirect were searched for randomized controlled trials (RCTs) reporting VOmax in creatine supplementation and placebo groups before and after supplementation. We computed a random-effects meta-analysis on VOmax at baseline, within groups following supplementation, on changes on VOmax between groups, and after supplementation between groups. Sensitivity analyses and meta-regression were conducted. We included 19 RCTs for a total of 424 individuals (mean age 30 years old, 82% men). VOmax did not differ at baseline between groups (creatine and placebo). Participants in both groups were engaged in exercise interventions in most studies (80%). Using changes in VOmax, VOmax increased in both groups but increased less after creatine supplementation than placebo (effect size [ES] = -0.32, 95%CI = -0.51 to -0.12, = 0.002). Comparisons after creatine supplementation confirmed a lower VOmax in the creatine group compared to the placebo group (ES= -0.20, 95%CI = -0.39 to -0.001, = 0.049). Meta-analysis after exclusion from meta-funnel resulted in similar outcomes in a subgroup of young and healthy participants. Meta-regressions on characteristics of supplementation, physical training, or sociodemographic were not statistically significant. Creatine supplementation has a negative effect on VOmax, regardless of the characteristics of training, supplementation, or population characteristics.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.2008864 .
Topics: Male; Humans; Adult; Female; Creatine; Exercise; Dietary Supplements
PubMed: 34859731
DOI: 10.1080/10408398.2021.2008864 -
European Journal of Clinical... Jul 2022Randomized controlled trials (RCT) in mental disorders research commonly use active control groups including psychotherapeutic shams or inactive medication. This... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Randomized controlled trials (RCT) in mental disorders research commonly use active control groups including psychotherapeutic shams or inactive medication. This meta-analysis assessed whether placebo conditions (active controls) had an effect compared to no treatment or usual care (passive controls).
METHODS
PubMed, Scopus, PsycINFO, PsycARTICLES, Ovid, the Cochrane Central Register of Controlled Trials and Web of Science were searched from inception to April 2021 and reference lists of relevant articles. Three-arm RCTs, including active and passive control groups, were selected. Where individual standardized mean difference (SMD) was calculable, random effects meta-analyses were performed to estimate an overall effect size with 95% confidence intervals (CI) comparing active vs passive controls. Heterogeneity was assessed using I² statistic and meta-regression. Funnel asymmetry was evaluated using Egger's test (Prospero registration: CRD42021242940).
RESULTS
24 articles with 25 relevant RCTs were included in the review, of which 11 studies were of high risk of bias. There was an improvement in outcomes favouring the placebo conditions, compared to passive controls, overall (25 studies, SMD 0.24, 95% CI 0.06-0.42, I² = 43%) and in subgroups with anxiety (SMD 0.45, 95% CI 0.07-0.84, I² = 59%) or depression (SMD 0.22, 95% CI 0.04-0.39, I² = 0%). Meta-regression did not show a significant explanation for heterogeneity. Egger's test showed no asymmetry (p = .200).
CONCLUSIONS
A small placebo effect was observed in mental disorders research overall, and in patients with anxiety or depression. These findings should be interpreted with caution in the light of heterogeneity and risk of bias.
Topics: Anxiety; Humans; Mental Disorders; Placebo Effect
PubMed: 35224726
DOI: 10.1111/eci.13762 -
Otology & Neurotology : Official... Apr 2024To quantify the placebo effect in randomized clinical trials treating tinnitus with oral or intratympanic placebo treatment. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To quantify the placebo effect in randomized clinical trials treating tinnitus with oral or intratympanic placebo treatment.
DATA SOURCES
CINAHL, PubMed, and Scopus were searched for articles from conception to October 2022. MESH and key terms such as "tinnitus," "placebo," and "medication" were used to find randomized, placebo-controlled trials. The search was limited to articles in English.
METHODS
Randomized controlled trials with adult subjects evaluating tinnitus pretreatment and posttreatment with an oral or intratympanic medication versus a placebo arm were included. Crossover studies, studies involving middle/inner ear operations or devices, and studies that exclusively included nonidiopathic etiologies of tinnitus were excluded. Mean tinnitus symptom survey scores for the Tinnitus Handicap Inventory (THI), Tinnitus Severity Index, Tinnitus Functional Index, Tinnitus Handicap Questionnaire, and Visual Analog Scales for tinnitus Intensity/Loudness (VAS-L), Annoyance (VAS-An), and Awareness (VAS-Aw) were extracted for both placebo and experimental groups.
RESULTS
953 studies were screened with 23 studies being included in the final analysis. Meta-analysis of mean difference (MD) was calculated using RevMan 5.4. MD between pretreatment and posttreatment THI scores of the placebo arms was 5.6 (95% confidence interval, 3.3-8.0; p < 0.001). MD between pretreatment and posttreatment VAS scores of the placebo groups for Loudness, Annoyance, and Awareness were 0.8 (0.0 to 1.6, p = 0.05), 0.2 (-0.2 to 0.5, p = 0.34), and 0.3 (-0.0 to 0.7, p = 0.08), respectively.
CONCLUSIONS
Placebo treatment has shown effectiveness in improving patient-reported evaluations of tinnitus when using some standardized metrics such as THI and VAS-L; however, the improvement is not as substantial as nonplacebo treatment.
Topics: Adult; Humans; Tinnitus; Placebo Effect; Randomized Controlled Trials as Topic; Surveys and Questionnaires
PubMed: 38361332
DOI: 10.1097/MAO.0000000000004139 -
The Cochrane Database of Systematic... Oct 2022Motion sickness is a syndrome that occurs as a result of passive body movement in response to actual motion, or the illusion of motion when exposed to virtual and moving... (Review)
Review
BACKGROUND
Motion sickness is a syndrome that occurs as a result of passive body movement in response to actual motion, or the illusion of motion when exposed to virtual and moving visual environments. The most common symptoms are nausea and vomiting. Antihistamines have been used in the management of motion sickness for decades, however studies have shown conflicting results regarding their efficacy.
OBJECTIVES
To assess the effectiveness of antihistamines in the prevention and treatment of motion sickness in adults and children.
SEARCH METHODS
The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials; Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 7 December 2021.
SELECTION CRITERIA
Randomised controlled trials (RCTs) in susceptible adults and children in whom motion sickness was induced under natural conditions such as air, sea and land transportation. We also included studies in which motion sickness was induced under experimental conditions (analysed separately). Antihistamines were included regardless of class, route or dosage and compared to no treatment, placebo or any other pharmacological or non-pharmacological interventions.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methods. Our primary outcomes were 1) the proportion of susceptible participants who did not experience any motion sickness symptoms; 2) the proportion of susceptible participants who experienced a reduction or resolution of existing symptoms. Secondary outcomes were 1) physiological measures (heart rate, core temperature and gastric tachyarrhythmia (electrogastrography)) and 2) adverse effects (sedation, impaired cognition, blurred vision). We used GRADE to assess the certainty of the evidence for each outcome.
MAIN RESULTS
We included nine RCTs (658 participants). Studies were conducted across seven countries, with an overall age range of 16 to 55 years. Motion sickness was induced naturally in six studies and experimentally in four studies (rotating chair). All the naturally induced studies only evaluated first-generation antihistamines (cinnarizine and dimenhydrinate). Risk of bias across the studies varied, with mostly low risk for random sequence generation and allocation concealment, and mostly high risk for selective reporting. Only the experimentally induced studies measured physiological parameters and only the naturally induced studies evaluated adverse effects. There were no studies that clearly assessed the paediatric population. Antihistamines versus placebo or no treatment Antihistamines are probably more effective than placebo at preventing motion sickness symptoms under natural conditions (symptoms prevented: 25% placebo; 40% antihistamines) (risk ratio (RR) 1.81, 95% confidence interval (CI) 1.23 to 2.66; 3 studies; 240 participants) (moderate-certainty). The evidence is very uncertain about the effect of antihistamines on preventing motion sickness under experimental conditions (standardised mean difference (SMD) 0.32, 95% CI -0.18 to 0.83; 2 studies; 62 participants) (very low-certainty). No studies reported results on the resolution of existing motion sickness symptoms. Antihistamines may result in little or no difference in gastric tachyarrhythmia under experimental conditions (mean difference (MD) -2.2, 95% CI -11.71 to 7.31; 1 study; 42 participants) (low-certainty). No studies reported results for any other physiological measures. When compared to placebo, antihistamines may be more likely to cause sedation (sedation: 44% placebo; 66% antihistamines) (RR 1.51, 95% CI 1.12 to 2.02; 2 studies; 190 participants) (low-certainty); they may result in little or no difference in blurred vision (blurred vision: 12.5% placebo; 14% antihistamines) (RR 1.14, 95% CI 0.53 to 2.48; 2 studies; 190 participants) (low-certainty); and they may result in little or no difference in terms of impaired cognition (impaired cognition: 33% placebo; 29% antihistamines) (RR 0.89, 95% CI 0.58 to 1.38; 2 studies; 190 participants) (low-certainty). Antihistamines versus scopolamine The evidence is very uncertain about the effect of antihistamines on preventing motion sickness under natural conditions when compared to scopolamine (symptoms prevented: 81% scopolamine; 71% antihistamines) (RR 0.89, 95% CI 0.68 to 1.16; 2 studies; 71 participants) (very low-certainty). No studies were performed under experimental conditions. No studies reported results on the resolution of existing motion sickness symptoms. The evidence is very uncertain about the effect of antihistamines on heart rate under natural conditions (narrative report, 1 study; 20 participants; "No difference in pulse frequency"; very low-certainty). No studies reported results for any other physiological measures. When compared to scopolamine, the evidence is very uncertain about the effect of antihistamines on sedation (sedation: 21% scopolamine; 30% antihistamines) (RR 0.82, 95% CI 0.07 to 9.25; 2 studies; 90 participants) (very low-certainty) and on blurred vision (narrative report: not a significant difference; 1 study; 51 participants; very low-certainty). No studies evaluated impaired cognition. Antihistamines versus antiemetics Antihistamines may result in little or no difference in the prevention of motion sickness under experimental conditions (MD -0.20, 95% CI -10.91 to 10.51; 1 study; 42 participants) (low-certainty). The evidence is of low certainty due to imprecision as the sample size is small and the confidence interval crosses the line of no effect. No studies assessed the effects of antihistamines versus antiemetics under natural conditions. No studies reported results on the resolution of existing motion sickness symptoms. Antihistamines may result in little or no difference in gastric tachyarrhythmia (MD 4.56, 95% CI -3.49 to 12.61; 1 study; 42 participants) (low-certainty). No studies reported results for any other physiological measures. No studies evaluated sedation, impaired cognition or blurred vision. One study reported physiological data for this outcome, evaluating gastric tachyarrhythmia specifically. Antihistamines may result in little or no difference in gastric tachyarrhythmia (MD 4.56, 95% CI -3.49 to 12.61; 1 study; 42 participants; low-certainty evidence). This evidence is of low certainty due to imprecision as the sample size is small and the confidence interval crosses the line of no effect. Antihistamines versus acupuncture The evidence is very uncertain about the effects of antihistamines on the prevention of motion sickness under experimental conditions when compared to acupuncture (RR 1.32, 95% CI 1.12 to 1.57; 1 study; 100 participants) (very low-certainty). This study did not assess the prevention of motion sickness under natural conditions, nor the resolution of existing motion sickness symptoms. There was no study performed under natural conditions. Physiological measures and adverse effects were not reported.
AUTHORS' CONCLUSIONS
There is probably a reduction in the risk of developing motion sickness symptoms under naturally occurring conditions of motion when using first-generation antihistamines, in motion sickness-susceptible adults, compared to placebo. Antihistamines may be more likely to cause sedation when compared to placebo. No studies evaluated the treatment of existing motion sickness, and there are few data on the effect of antihistamines in children. The evidence for all other outcomes and comparisons (versus scopolamine, antiemetics and acupuncture) was of low or very low certainty and we are therefore uncertain about these effects of antihistamines.
Topics: Adolescent; Adult; Antiemetics; Child; Cinnarizine; Dimenhydrinate; Histamine Antagonists; Humans; Middle Aged; Motion Sickness; Scopolamine Derivatives; Young Adult
PubMed: 36250781
DOI: 10.1002/14651858.CD012715.pub2 -
CNS Drugs Jan 2024Studies have suggested that levetiracetam may help improve cognitive function in patients with epilepsy. Recently, its efficacy in improving cognitive function was... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Studies have suggested that levetiracetam may help improve cognitive function in patients with epilepsy. Recently, its efficacy in improving cognitive function was reported in patients with amnestic mild cognitive impairment, schizophrenia, and Alzheimer's disease. However, the specific cognitive domains affected and the degree of evidence supporting these effects remain unclear. This systematic review and meta-analysis aimed to explore the effects of levetiracetam on different cognitive domains.
METHODS
This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. We defined our inclusion criteria for the systematic review as: (1) randomized placebo-controlled trials (RCTs) involving human subjects, (2) double-blinded RCTs, and (3) RCTs evaluating the quantitative differences in cognitive function between levetiracetam and placebo. We excluded: (1) non-RCT studies, (2) open-label studies, and (3) RCTs lacking cognitive assessments for either intervention. Two authors independently searched electronic databases, including PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov, from inception until 2 July 2023. The methodological quality of the included studies was assessed using the Cochrane risk of bias tool. Meta-analytic techniques were applied to examine the impact of levetiracetam on cognitive domain tests, with Hedges' g facilitating the comparison with placebo. The domains analyzed comprised multi-domain, executive function, processing speed, working memory, verbal memory/learning (verbal ML), visuospatial memory/learning (visuospatial ML), and language. We used odds ratios to compare the incidence of treatment-emergent adverse events between the groups, including somnolence, fatigue, dizziness, headache, irritability, and cognitive adverse events.
RESULTS
A random-effects model was utilized to perform a meta-analysis of 16 RCTs including 545 participants. Compared with a placebo, levetiracetam was associated with improved executive function [Hedges'g = - 0.390, 95% confidence interval (CI) = - 0.609 to - 0.172, p < 0.001, I = 24.0%]. Subgroup analysis showed that levetiracetam outperformed placebo in patients without epilepsy (Hedges' g = - 0.419, 95% CI = - 0.647 to - 0.191, p < 0.001, I = 26.2%). Meanwhile, low-dose levetiracetam showed a moderate favorable effect over placebo (Hedges' g = -0.544, 95% CI = - 1.085 to - 0.003, p = 0.049, I = 65.3%). In patients without epilepsy, low-dose levetiracetam was associated with improved executive function (Hedges'g = - 0.544, 95% CI = - 1.085 to - 0.003, p = 0.049, I = 65.3%). Concurrently, levetiracetam was associated with more frequent somnolence than a placebo (odds ratio = 4.654, 95% CI = 1.533 to 14.124, p = 0.007, I = 32.9%). Potential publication bias was observed in the executive function domain.
CONCLUSIONS
This exploratory study suggests that levetiracetam might improve executive function in specific populations. However, the diversity in study populations and potential publication bias warrant caution.
Topics: Humans; Cognition; Cognitive Dysfunction; Epilepsy; Levetiracetam; Randomized Controlled Trials as Topic; Sleepiness
PubMed: 38102532
DOI: 10.1007/s40263-023-01058-9