SEARCH · PubMed Health

Results for “summary statistics”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources

PubMed2006

Pharmacotherapy augmentation strategies in treatment-resistant anxiety disorders.

BACKGROUND: A large proportion of patients with anxiety disorders fail to respond to first-line medication interventions, despite evidence of the effectiveness of these agents. OBJECTIVES: To assess the effects of medication versus placebo augmentation in the treatment of patients with anxiety disorders who have failed to respond adequately to first-line drug therapies. SEARCH STRATEGY: The Cochrane Depression, Anxiety & Neurosis Group (CCDAN) specialised registers (CCDANCTR-Studies and CCDANCTR-References) were searched on 3/8/2005, MEDLINE (January 1966 to July 2005) and PsycINFO (1966 to 2005, Part A). Unpublished trials were identified through the Controlled Trials database and the National Institute of Health's Computer Retrieval of Information on Scientific Projects (CRISP) service (1972 to 2005). Additional studies in any language were sought in reference lists of retrieved articles. SELECTION CRITERIA: All randomised controlled trials (RCTs) of the medication augmentation of pharmacotherapy for treatment resistant anxiety disorders. DATA COLLECTION AND ANALYSIS: Two raters independently assessed RCTs for inclusion in the review, collated trial data, and assessed trial quality. Investigators were contacted to obtain missing data. Summary statistics were stratified by class of augmentation agent and anxiety disorder. Overall effect estimates were calculated using a random-effects model, heterogeneity was assessed and subgroup/sensitivity analyses were undertaken. MAIN RESULTS: Twenty eight short-term (average of seven weeks) randomised controlled trials (740 participants) were included in the review, 20 of which investigated augmentation of medication for treatment-resistant obsessive compulsive disorder (OCD). Summary statistics for responder status from nine trials demonstrate overall superiority of a variety of medication agents to placebo (relative risk of non-response (RR) 3.16, 95% CI 1.08 to 9.23). Similarly, symptom severity was significantly reduced in the medication groups, relative to placebo (number of trials (N) = 14, standardised mean difference (SMD) -0.87, 95% CI -1.37 to -0.36). There is no evidence of a difference between medication and placebo in total dropout rate, or in the number of dropouts due to adverse events. AUTHORS' CONCLUSIONS: Medication augmentation can be an effective and well-tolerated short-term treatment strategy for non-responders to first-line pharmacotherapy of anxiety disorders. However, any conclusions must be tentative in view of methodological and clinical heterogeneity, and the fact that much of the relevant database is based on antipsychotic augmentation trials in OCD patients resistant to serotonin reuptake inhibitors (SRIs). Additional data are needed to address several areas, including the efficacy of augmentation over the longer-term, and the value of medication augmentation in comparison to other strategies (e.g. switching medication, adding psychotherapy).

Anti-Anxiety Agents↗

PubMed2005

Temporal analysis of airborne particulate matter reveals a dose-rate effect on mortality in El Paso: indications of differential toxicity for different particle mixtures.

One of two topics explored is the limitations of the daily average in summarizing pollutant hourly profiles. The daily average of hourly measurements of air pollutant constituents provides continuity with previous studies using monitoring technology that only provided the daily average. However, other summary statistics are needed that make better use of all available information in 24-hr profiles. The daily average reflects the total daily dose, obscuring hourly resolution of the dose rate. Air pollutant exposures with comparable total daily doses may have very different effects when occurring at high levels over a few hours as opposed to low levels over a longer time. Alternative data-based choices for summary statistics are provided using principal component analysis to capture the exposure dose rate, while preserving ease of interpretation. This is demonstrated using the earliest hourly particle concentration data available for El Paso from archived records of particulate matter (PM)10. In this way, a significant association between evening PM10 exposures and nonaccidental daily mortality is found in El Paso from 1992 to 1995, otherwise missed using the daily average. Secondly, the nature and, hence, effects of particles in the ambient aerosol during El Paso sandstorms is believed different from that of particles present during still-air conditions resulting from atmospheric temperature inversions. To investigate this, wind speed (ws) is used as a surrogate variable to label PM10 exposures as Low-ws (primarily fine particles), High-ws (primarily coarse particles), or Mid-ws (a mixture of fine and coarse particles). A High-ws evening is significantly associated with a 10% lower risk of mortality on the succeeding third day, as compared with comparable exposures at Low- or Mid-ws. Although this analysis cannot be used to form firm conclusions because it uses a very small data set, it demonstrates the limitations of the daily average and suggests differential toxicity for different particle compositions.

Air Pollutants↗

PubMed2025

FINEMAP-miss: fine-mapping genome-wide association studies with missing genotype information.

MOTIVATION: The most informative genome-wide association studies (GWAS) are meta-analyses that have combined multiple studies to increase the GWAS sample size. Statistical fine-mapping is a key downstream analysis of GWAS to jointly evaluate the probability of causality of all variants in a genomic region of interest. Current fine-mapping methods are miscalibrated in the meta-analysis setting due to variation in sample size across the variants. RESULTS: We introduce FINEMAP-miss, a new fine-mapping method that extends the FINEMAP model to account for variant-specific missingness. We show that FINEMAP-miss is well-calibrated in meta-analysis simulations where the standard fine-mapping fails. Compared to the summary statistics imputation approach, FINEMAP-miss provides clear improvement when the causal variants have low imputation information or when the sample size or complexity of the meta-analysis setting increase. We successfully apply FINEMAP-miss on a breast cancer GWAS meta-analysis where neither the standard fine-mapping nor the summary statistics imputation are applicable. AVAILABILITY: An open source implementation of FINEMAP-miss as an R package ("finemapmiss") is available at https://github.com/JoonasKartau/finemapmiss. The archived version of FINEMAP-miss used for this publication can be found on Zenodo at https://doi.org/10.5281/zenodo.17492622. SUPPLEMENTARY INFORMATION: is available at the journal's web site.

Genome-Wide Association Study↗

PubMed2000

The value of the number-needed-to-treat method in antiepileptic drug trials.

PURPOSE: There is controversy between clinicians and statisticians on the appropriateness of the number needed to treat (NNT) as a summary statistic to report the effectiveness of a treatment. We examine the two viewpoints and make proposals concerning the reporting of clinical trial results. METHODS: In the context of antiepileptic treatments, we explain the two different viewpoints and illustrate the use of the odds ratio, relative risk, absolute difference, and NNT on the results of randomized clinical trials with topiramate (TPM). Special attention is paid to the use of these summary statistics in meta-analyses. Here, the NNT is the expected number of patients one would need to treat to achieve a single occurrence of a specified good outcome (e.g., 50% reduction in seizure rate) in comparison to no (or placebo) treatment. RESULTS: Although the NNT is readily interpretable in some instances, it exhibits undesirable statistical behavior in other cases. In particular, confidence intervals for the NNT may split into two intervals and extend to positive and negative infinity when treatment efficacy is not clearly established by the data. Meta-analyses cannot be sensibly conducted directly on the NNT scale. CONCLUSIONS: Although other measures, such as the odds ratio, have been more commonly used in the context of meta-analyses, clinicians prefer the NNT because it gives them a clearer clinical interpretation of the effectiveness of a (new) treatment. On the other hand, statisticians do not recognize the value of the NNT, as it has undesirable statistical properties. Some reconciliation between the two views could be achieved when the clinicians acknowledge the weak aspects of the NNT and when statisticians realize that statistical appropriateness is not the same as clinical relevance. It is suggested that the NNT be used as a secondary reporting tool not on an equal footing with the classic scales.

Anticonvulsants↗

PubMed2006

Pharmacotherapy for post traumatic stress disorder (PTSD).

BACKGROUND: Post traumatic stress disorder (PTSD) is a prevalent and disabling disorder. Evidence that PTSD is characterised by specific psychobiological dysfunctions has contributed to a growing interest in the use of medication in its treatment. OBJECTIVES: To assess the effects of medication for post traumatic stress disorder. SEARCH STRATEGY: We searched the Cochrane Depression, Anxiety and Neurosis Group specialised register (CCDANCTR-Studies) on 18 August 2005, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library issue 4, 2004), MEDLINE (January 1966 to December 2004), PsycINFO (1966 to 2004), and the National PTSD Center Pilots database. Reference lists of retrieved articles were searched for additional studies. SELECTION CRITERIA: All randomised controlled trials (RCTs) of pharmacotherapy for PTSD. DATA COLLECTION AND ANALYSIS: Two raters independently assessed RCTs for inclusion in the review, collated trial data, and assessed trial quality. Investigators were contacted to obtain missing data. Summary statistics were stratified by medication class, and by medication agent for the selective serotonin reuptake inhibitors (SSRIs). Dichotomous and continuous measures were calculated using a random effects model, heterogeneity was assessed, and subgroup/sensitivity analyses were undertaken. MAIN RESULTS: 35 short-term (14 weeks or less) RCTs were included in the analysis (4597 participants). Symptom severity for 17 trials was significantly reduced in the medication groups, relative to placebo (weighted mean difference -5.76, 95% confidence intervals (CI) -8.16 to -3.36, number of participants (N) = 2507). Similarly, summary statistics for responder status from 13 trials demonstrated overall superiority of a variety of medication agents to placebo (relative risk 1.49, 95% CI 1.28 to 1.73, number needed to treat = 4.85, 95% CI 3.85 to 6.25, N = 1272). Medication and placebo response occurred in 59.1% (N = 644) and 38.5% (628) of patients, respectively. Of the medication classes, evidence of treatment efficacy was most convincing for the SSRIs. Medication was superior to placebo in reducing the severity of PTSD symptom clusters, comorbid depression and disability. Medication was also less well tolerated than placebo. A narrative review of 3 maintenance trials suggested that long term medication may be required in treating PTSD. AUTHORS' CONCLUSIONS: Medication treatments can be effective in treating PTSD, acting to reduce its core symptoms, as well as associated depression and disability. The findings of this review support the status of SSRIs as first line agents in the pharmacotherapy of PTSD, as well as their value in long-term treatment. However, there remain important gaps in the evidence base, and a continued need for more effective agents in the management of PTSD.

Antidepressive Agents↗

PubMed2006

Pharmacotherapy for post-traumatic stress disorder - a systematic review and meta-analysis.

BACKGROUND: Post-traumatic stress disorder (PTSD) is a prevalent and disabling condition. Evidence that PTSD is characterized by specific psychobiological dysfunctions has contributed to a growing interest in use of medication in its treatment. OBJECTIVES: To assess the effects of medication in the treatment of PTSD. DESIGN: Systematic review of randomised controlled trials (RCTs) following the Cochrane Collaboration guidelines. A more detailed version of the review is published in the Cochrane Database of Systematic Reviews. METHODS: We searched the Cochrane Depression, Anxiety and Neurosis Group specialised register, the Cochrane Central Register of Controlled Trials (Cochrane Library issue 4, 2004), MEDLINE (January 1966 - December 2004), PsycINFO (1966 - 2004), the National PTSD Center Pilots database, and the meta register module of the Controlled Trials database. Reference lists of retrieved articles were searched for additional studies. Two raters independently assessed RCTs for inclusion in the review, collated trial data, and assessed trial quality. Investigators were contacted to obtain missing data. Summary statistics were stratified by medication class, and by medication agent for the selective serotonin re-uptake inhibitors (SSRIs). Dichotomous and continuous measures were calculated using a random effects model, heterogeneity was assessed, and subgroup/sensitivity analyses were done. MAIN RESULTS: Thirty-five short-term (14 weeks or less) RCTs were included in the analysis (4 597 participants). Symptom severity for 17 trials was significantly reduced in the medication groups, relative to placebo (weighted mean difference (WMD) = -5.76, 95% confidence interval (CI)-8.16 - -3.36, N = 2 507). Similarly, summary statistics for responder status from 13 trials demonstrated overall superiority of a variety of medication agents compared with placebo (relative risk (RR) = 1.49, 95% CI: 1.28, 1.73, number needed to treat (NNT) = 4.85, N = 1 272). Medication and placebo response occurred in 59.1% (N = 644) and 38.5% (N = 628) of patients, respectively. Of the medication classes, evidence of treatment efficacy was most convincing for the SSRIs. Medication was also effective in reducing the severity of the PTSD re-experiencing/intrusion, avoidance/numbing, and hyperarousal symptom clusters in 9 trials (N = 1 304). In addition, medication was superior to placebo in reducing comorbid depression and disability. Medication was also less well tolerated than placebo. A narrative review of the 3 maintenance trials suggested that long-term medication may be required in treating PTSD. CONCLUSION: Medication treatments can be effective in treating PTSD, acting to reduce its core symptoms, as well as associated depression and disability, and should be considered as part of the treatment of this disorder. The findings of this review support the status of SSRIs as first-line agents in the pharmacotherapy of PTSD, as well as their value in longterm treatment. However, there remain important gaps in the evidence base, and there is a continued need for more effective agents in the management of PTSD.

Clinical Trials as Topic↗

PubMed1998

Evaluation of the effect on heart rate variability of some agents acting at the beta-adrenoceptor using nonlinear scatterplot and sequence methods.

There is evidence that the processes regulating heart rate variability (HRV) reflect nonlinear complexity and show "chaotic" determinism. Data analyses using nonlinear methods may therefore reveal patterns not apparent with the standard methods for HRV analysis. We have consequently used two nonlinear methods, the Poincaré plot (scatterplot) and cardiac sequence (quadrant) analysis, in addition to the standard time-domain summary statistics, during a normal volunteer investigation of the effects on HRV of some agents acting at the cardiac beta-adrenoceptor. Under double-blind and randomized conditions (Latin square design), 25 normal volunteers received placebo, salbutamol 8 mg (beta 2-adrenoceptor partial agonist), pindolol 10 mg (beta 2-adrenoceptor partial agonist), or atenolol 50 mg (beta 1-adrenoceptor antagonist). Single oral doses of medication (at weekly intervals) were administered at 22:30 hours, with sleeping heart rates recorded overnight. The long-term (SDNN, SDANN) and short-term (rMSSD) time-domain summary statistics were reduced by salbutamol 8 mg and increased by atenolol 50 mg compared with placebo. The reductions in both SDNN and SDANN were greater after salbutamol 8 mg compared with pindolol 10 mg. The reduced HRV after pindolol 10 mg differed from the increased HRV following atenolol 50 mg. The Poincaré plot, constructed by plotting each RR interval against the preceding RR interval, was measured using a reproducible computerized method. Scatterplot length and area were reduced by salbutamol 8 mg and increased by atenolol 50 mg compared with placebo; scatterplot length and area were lower after pindolol 10 mg compared with atenolol 50 mg. Geometric analysis of the scatterplots allowed width assessment (i.e., dispersion) at fixed RR intervals. At the higher percentiles (i.e., 90% of scatterplot length: low HR), salbutamol 8 mg reduced and atenolol 50 mg increased dispersion; at lower percentiles (i.e., 10%, 25%, and 50% length), atenolol 50 mg and pindolol 10 mg increased dispersion compared with placebo and salbutamol 8 mg. Cardiac sequence analysis (differences between three adjacent beats; delta RR vs. delta RRn + 1) was used to assess the short-term patterns of cardiac acceleration and deceleration. Four patterns were identified: +/+ (a lengthening sequencing), +/- or -/+ (balanced sequences), and finally -/- (a shortening sequence). Cardiac acceleration episodes (i.e., number of times delta RR and delta RRn + 1 were both changed) were increased in quadrants -/- and +/+ following pindolol 10 mg and salbutamol 8 mg; the beat-to-beat difference (delta RRn + 1) was reduced after salbutamol 8 mg compared with the three other groups. These results demonstrated a shift towards sympathetic dominance (beta-adrenoceptor partial agonist salbutamol 8 mg) or parasympathetic dominance (beta 1-adrenoceptor antagonist atenolol 50 mg); pindolol 10 mg exhibited HR-dependent effects, reducing HRV at low but increasing variability at high prevailing heart rates. These nonlinear methods appear to be valuable tools to investigate HRV in health and to study the implications of perturbation of HRV with drug therapy in disease states.

Adrenergic beta-Agonists↗

PubMed2002

Distribution analysis of airborne nicotine concentrations in hospitality facilities.

A number of publications report statistical summaries for environmental tobacco smoke (ETS) concentrations. Despite compelling evidence for the data not being normally distributed, these publications typically report the arithmetic mean and standard deviation of the data, thereby losing important information related to the distribution of values contained in the original data. We were interested in the frequency distributions of reported nicotine concentrations in hospitality environments and subjected available data to distribution analyses. The distribution of experimental indoor airborne nicotine concentration data taken from hospitality facilities worldwide was fit to lognormal, Weibull, exponential, Pearson (Type V), logistic, and loglogistic distribution models. Comparison of goodness of fit (GOF) parameters and indications from the literature verified the selection of a lognormal distribution as the overall best model. When individual data were not reported in the literature, statistical summaries of results were used to model sets of lognormally distributed data that are intended to mimic the original data distribution. Grouping the data into various categories led to 31 frequency distributions that were further interpreted. The median values in nonsmoking environments are about half of the median values in smoking sections. When different continents are compared, Asian, European, and North American median values in restaurants are about a factor of three below levels encountered in other hospitality facilities. On a comparison of nicotine concentrations in North American smoking sections and nonsmoking sections, median values are about one-third of the European levels. The results obtained may be used to address issues related to exposure to ETS in the hospitality sector.

Air Pollution, Indoor↗

PubMed1999

Analysing repeated measurements data: a practical comparison of methods.

A variety of methods are available for analysing repeated measurements data where the outcome is continuous. However, there is little information on how established methods, such as summary statistics and repeated measures analysis of variance (RMAOV), compare in practice with methods that have become available to applied statisticians more recently, such as marginal models (based on generalized estimating equation methodology) and multilevel models (that is, hierarchical random effects models). The aim of this paper is to exemplify the use of these methods, and directly compare their results by application to a clinical trial data set. The focus is on practical aspects rather than technical issues. The data considered were taken from a clinical trial of treatments for asthma in 240 children, in which a baseline and four post-randomization measurements of outcomes were taken. The simplicity of the method of summary statistics using the post-randomization mean of observations provided a useful initial analysis. However, fixed time effects or treatment-time interactions cannot be included in such an analysis, and choice of appropriate weighting when there is substantial missing data is problematic. RMAOV, marginal models and multilevel models generally provided similar estimates and standard errors for the treatment effects, although in one example with a relatively complex variance structure the marginal model produced less efficient estimates. Two advantages of multilevel models are that they provide direct estimates of variance components which are often of interest in their own right, and that they can be naturally extended to handle multivariate outcomes.

Adolescent↗

PubMed2002

How to estimate moments and quantiles of environmental data sets with non-detected observations? A case study on volatile organic compounds in marine water samples.

Concentrations of 27 priority volatile organic compounds were measured in water samples of the North Sea and Scheldt estuary during a 3-year monitoring study. Despite the use of a sensitive analytical method, a number of data were censored. That is, some concentrations were below the decision limit or critical level defined by IUPAC. To characterize the observed measurement results, an attempt was made to identify an appropriate procedure to compute summary statistics for the censored data sets. Several parametric and robust parametric approaches based on the maximum likelihood principle and probability-plot regression method were evaluated for the estimation of the mean, standard deviation, median and interquartile range using three uncensored analytes (1,1,2-trichloroethane, tetrachloroethene and o-xylene) from the monitoring survey. Performance was assessed by artificially censoring the observed concentrations and estimating moments and quantiles at each censoring level. Results showed that methods with the least distributional assumptions, such as the robust bias-corrected restricted maximum likelihood method, perform best for estimating the mean and standard deviation, while both parametric and robust parametric techniques can be used for quantiles. Hence, summary statistics could be estimated with little bias (5-10%) up to 80% of censoring for the data sets employed in this study.

Likelihood Functions↗

PubMed2026

Reassessing Instrument Strength in Two-Sample Mendelian Randomization Analysis.

Mendelian randomization (MR) analysis is widely used to estimate causal relationships between risk factors and outcomes of interest. Two-sample MR approaches have gained increasing attention in genetic epidemiology due to the growing availability of Genome-Wide Association Study (GWAS) summary statistics from public databases. A critical step in two-sample MR is the selection of genetic variants as instrumental variables (IVs). Although genome-wide significant variants are typically preferred, the inclusion of variants with weaker association p-values is considered, as they may potentially improve power through an increased instrument number of instruments, while they may introduce weak instrument bias and attenuate effect estimates towards the null. Our simulation results show that even modest levels of pleiotropy substantially increase the variability of causal effect estimates, while the inclusion of weak IVs does not substantially affect the direction and variability of causal effect estimates in most cases. In real data analyses, we used two released versions of FinnGen GWAS summary statistics with different sample sizes as exposure GWASs to assess the influence of weak IVs. Here, the inclusion of IVs with higher exposure-association p-values resulted in weakened estimated effect sizes, particularly when the exposure GWAS sample size was small. These findings suggest that incorporating weak IVs is reasonable when the exposure GWAS sample size is large, but it poses a risk of falsely concluding null associations when the exposure GWAS sample size is small.

Journal Article↗

PubMed2004

Selection versus demography: a multilocus investigation of the domestication process in maize.

The domestication of maize (Zea mays ssp. mays) from its wild ancestor (Zea mays ssp. parviglumis) led to a loss of genetic diversity both through a population bottleneck and through directional selection at agronomically important genes. In order to discriminate between those effects and to investigate the nature of the domestication bottleneck, we analyzed nucleotide diversity data from 12 chromosome 1 loci in parviglumis. We found an average loss of nucleotide diversity of 38% across genes, but this average was skewed downward by four putatively selected loci (tb1, d8, ts2, and zagl1). To better understand the domestication process, we used the coalescent with recombination to simulate bottlenecks under various lengths and population sizes. For each locus, we determine the likelihood of the observed data using three summary statistics: the number of segregating sites, an estimate of the population recombination parameter, and Tajima's D. Based on the eight neutrally evolving loci, a model with a bottleneck had a significantly higher likelihood than a model without one. The four putatively selected loci had significantly different likelihood optimums than the neutral loci, and this approach confirmed that ts2 and d8 were selected either during domestication or breeding. Overall, the best-fitting models had a bottleneck in which the population size and the bottleneck duration had a ratio of approximately 4- to approximately 5; for example, if the initial domestication event occurred over a 500-year period, the population size was roughly 2,000 to 2,500 individuals. However, this range did vary with the summary statistic used to assess the fit of simulations to data. In this context, Tajima's D performed poorly as a goodness-of-fit statistic, probably because Z. mays ssp. parviglumis has a frequency spectrum that is significantly skewed toward low-frequency variants. Finally, we found that demography is unlikely to account for the previously observed positive correlation between nucleotide diversity and the population-recombination parameter in maize, leaving this observation difficult to interpret.

Amino Acid Sequence↗

PubMed2005

Early hominid dental remains from Members 4 and 5 of the Sterkfontein Formation (1966-1996 excavations): catalogue, individual associations, morphological descriptions and initial metrical analysis.

The fossils recovered from the Sterkfontein Formation represent, without doubt, the largest collection of early hominid specimens from a single locality. Among the over 600 entries in the catalogue of fossil hominid specimens recovered since 1966, there are 242 dental remains (isolated teeth, jaws with two or more teeth, isolated teeth in association) for a total number of 495 teeth. The aim of this paper is to provide morphological descriptions of all hominid dental specimens recovered between 1968 and 1996 from areas presently known as Members 4 and 5 of the Sterkfontein site. Together with the descriptions, explanatory catalogue information is provided, along with basic measurements and summary statistics. This paper consists of six sections, with descriptive tables: (1) Catalogue of dental remains, arranged numerically. This includes isolated teeth, specimens with teeth still in position within their jaws, and specimens comprised of isolated teeth in association. (2) List of specimens with more complete dentition and the numbers of available teeth per tooth class. (3) List of specimens subdivided in tooth class, with an indication of their preservation, of the wear, if any, and with measurements (mesiodistal and buccolingual diameters) of the individual teeth. (4) List of associations of isolated teeth as individuals i.e. dental remains that can be associated with one another. Some remarks on the relative abundance of maxillary versus mandibular teeth, and on the numbers of available teeth are presented. (5) Morphological descriptions. (6) Summary statistics for the entire Sterkfontein sample (thus including specimens recovered both before and after 1966) and updated descriptive statistics for South African early hominids (A. africanus, A. robustus, South African early Homo). We have compared the coefficients of variation for the MD and BL diameters of the permanent teeth of the Sterkfontein Member 4 hypodigm of A. africanus with the hypodigms of the early hominid taxa. The results show that the Sterkfontein Member 4 sample is not consistently more variable than the other fossil hominid samples analysed; it turned out to be generally less variable than H. habilis sensu lato and A. boisei; it shows overall similar levels of variability to A. afarensis and higher levels than A. robustus. These results, per se, do not provide evidence of the existence of multiple species in the Sterkfontein Member 4 sample.

Animals↗

PubMed2001

Multifocal versus monofocal intraocular lenses after cataract extraction.

BACKGROUND: Good unaided distance visual acuity is now a realistic expectation following cataract surgery and intraocular lens implantation. Near vision however still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal) intraocular lenses are available that are claimed to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal intraocular lenses. OBJECTIVES: The objective of this review is to assess the effects of multifocal intraocular lenses, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register - CENTRAL (which includes the Cochrane Eyes and Vision Group specialised register), MEDLINE and EMBASE. The reference lists of relevant articles were searched. Investigators of included studies and manufacturers of multifocal intraocular lenses were contacted for information about additional published and unpublished studies. SELECTION CRITERIA: All randomised controlled trials comparing a multifocal intraocular lens of any type with a monofocal intraocular lens as control were included. Both unilateral and bilateral implantation trials were included. DATA COLLECTION AND ANALYSIS: Data were collected and trial quality assessed. Where possible, statistical summary measures were calculated, otherwise data were tabulated. MAIN RESULTS: One ongoing and six completed trials were identified. There was significant variability between the trials in the outcomes reported. Unaided distance acuity was similar in multifocal and monofocal intraocular lenses (Peto odds ratio 1.27 (95% Confidence Interval (CI) 0.76 to 2.11)), with a small increase in the proportion of multifocal intraocular lens participants achieving less than 6/6 best corrected visual acuity (Peto odds ratio 1.64 (95% CI 1.10 to 2.42)). Unaided near vision tended to improve with the multifocal intraocular lenses. This resulted in decreased spectacle dependence with use of the multifocal intraocular lenses (Peto odds ratio 0.16 (95% CI 0.11 to 0.23)). Adverse effects included reduced contrast sensitivity and the subjective experience of haloes around lights. REVIEWER'S CONCLUSIONS: Multifocal intraocular lenses are effective at improving near vision relative to monofocal intraocular lenses. Whether that improvement outweighs the adverse effects of multifocal intraocular lenses will vary between patients, with motivation to achieve spectacle independence likely to be the deciding factor.

Cataract Extraction↗

PubMed2026

PYRAMA: an open-source tool for advanced meta-analysis of genome wide association studies.

MOTIVATION: Genome-wide association study (GWAS) meta-analysis tools are essential for integrating summary statistics across multiple cohorts, thereby increasing statistical power and validating genetic associations. Widely cited tools, such as METAL, PLINK, and GWAMA, have facilitated numerous significant discoveries in the field of GWAS. Nevertheless, these tools offer a limited set of meta-analysis methods and typically require users to have prior experience with command-line tools to be executed. RESULTS: We present here PYRAMA, an open-source tool which is designed for meta-analysis of genome wide association studies. This work introduces an easy-to-use software package that includes several meta-analysis methods that are absent in similar software packages. PYRAMA is faster compared to other tools, supports robust methods for analysis and meta-analysis, fixed-effects, random-effects and Bayesian meta-analysis and it is currently the only tool that supports meta-analysis with imputation of summary statistics. It is available both as a standalone tool and as a freely available web server. AVAILABILITY AND IMPLEMENTATION: https://github.com/pbagos/PYRAMA, https://doi.org/10.5281/zenodo.17830449.

Genome-Wide Association Study↗

PubMed2002

Estimation of the Doppler ultrasound umbilical maximal waveform envelope: II. Prediction of fetal distress.

Blood flow variables obtained via Doppler ultrasound (US) waveform estimation have been investigated for prediction of fetal distress. The umbilical flow was assessed using a number of waveform summary statistics in addition to the currently used resistance indices. We examined the relationship between umbilical artery waveform patterns and intrauterine growth restriction, preterm delivery and hypertensive disorders. To enhance prediction, we defined waveform skewness profiles based on pivotal points of the umbilical waveform that appeared to be related to the incidence of preterm delivery and that facilitated construction of IUGR prediction models. The data comprised 204 unselected pregnancies with the umbilical artery images recorded at 18 pregnancy weeks. The sample was divided into 114 pregnancies used to estimate model parameters and 90 pregnancies to validate the model. Logistic prediction models for detection of abnormal velocity waveforms associated with intrauterine growth restriction were derived, based on the waveform information. The estimated model sensitivity and specificity on the training data were 74% and 84%, respectively. Validation of the model on independent data yielded a sensitivity of 57% and specificity of 84%. The logistic IUGR prediction model appears to have significant predictive ability and potential for clinical use, even at this early gestational age. Our data suggest that prediction of IUGR at 18 pregnancy weeks can be much improved when the waveform shape is captured with a number of summary statistics in addition to resistance indices.

Algorithms↗

PubMed2004

Comparative evaluation of a new effective population size estimator based on approximate bayesian computation.

We describe and evaluate a new estimator of the effective population size (N(e)), a critical parameter in evolutionary and conservation biology. This new "SummStat" N(e) estimator is based upon the use of summary statistics in an approximate Bayesian computation framework to infer N(e). Simulations of a Wright-Fisher population with known N(e) show that the SummStat estimator is useful across a realistic range of individuals and loci sampled, generations between samples, and N(e) values. We also address the paucity of information about the relative performance of N(e) estimators by comparing the SummStat estimator to two recently developed likelihood-based estimators and a traditional moment-based estimator. The SummStat estimator is the least biased of the four estimators compared. In 32 of 36 parameter combinations investigated using initial allele frequencies drawn from a Dirichlet distribution, it has the lowest bias. The relative mean square error (RMSE) of the SummStat estimator was generally intermediate to the others. All of the estimators had RMSE > 1 when small samples (n = 20, five loci) were collected a generation apart. In contrast, when samples were separated by three or more generations and N(e) < or = 50, the SummStat and likelihood-based estimators all had greatly reduced RMSE. Under the conditions simulated, SummStat confidence intervals were more conservative than the likelihood-based estimators and more likely to include true N(e). The greatest strength of the SummStat estimator is its flexible structure. This flexibility allows it to incorporate any potentially informative summary statistic from population genetic data.

Bayes Theorem↗

PubMed2000

Interventions for treating tuberculous pericarditis.

BACKGROUND: Tuberculous (TB) pericarditis is becoming more common. The infection can result in fluid around the heart, which can be fatal. OBJECTIVES: To evaluate evidence from trials about the effects of medical and surgical treatments for TB pericarditis on death and life-threatening conditions. SEARCH STRATEGY: The Cochrane Infectious Diseases Group trials register, the Cochrane controlled trials register, Medline, Embase and reference lists of articles; contact with experts in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials of treatments for TB pericarditis. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Meta-analysis using fixed effects models calculated summary statistics, provided there was no significant heterogeneity, and expressed results as relative risk. MAIN RESULTS: Three trials met the inclusion criteria, with a total of 411 participants. Treatments were adjuvant steroids and surgical drainage. Two small trials tested steroids. There were fewer deaths (all causes) in the intervention group, but the numbers were small and the result could have occurred by chance (relative risk [RR] 0.65, 95% confidence interval [CI] 0.36 to 1.16, n = 350). In one trial studying patients with effusion, "cure" was higher in the steroid group (alive and free of disability at 2 years (RR 0.69, 95% CI 0.29 to 0.80, n = 221). One trial examined open surgical drainage compared with conservative management, and showed no impact of surgery on death, but a protective effective against cadiac tamponade (RR 0.04, 95% CI 0.00 to 0.64). REVIEWER'S CONCLUSIONS: Steroids have potentially large impacts on survival, but trials are too small to test this. We believe further placebo controlled trials of steroids are warranted, exploring whether the presence of effusion or fibrosis modifies effects. Surgical options also require further evaluation.

Adrenal Cortex Hormones↗