Statistical control versus classification of study quality in meta-analysis

2012 ◽  
Vol 4 (1) ◽  
pp. 43-72 ◽  
Author(s):  
Philip C. Abrami ◽  
Robert M. Bernard
2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Angeline Jeyakumar ◽  
Vidhya Shinde ◽  
Reshma Ravindran

Abstract Background Vitamin D deficiency among pregnant women is a public health concern globally. In India, individual studies report high prevalence. However, lack of national data masks the true burden. This work determined the pooled prevalence of vitamin D deficiency among pregnant women in India through a systematic review of literature and meta-analysis. Methods Three different search engines yielded 15 eligible articles. Study quality was assessed by 10 different criteria and summary of study quality was categorized as per Cochrane standards. Meta-analysis was performed to estimate pooled prevalence of vitamin D deficiency among healthy pregnant women and heterogeneity among selected studies. A sample of n = 4088 was used to study the pooled prevalence among pregnant women. Results The random effects combined estimate was 32.35% (95% CI, (12.58–117.48). High heterogeneity (tau2 = 0.39, I2 = 100%) and high risk of bias was observed among the selected studies. The test for overall effect was observed to be z = 2.54(P = 0.01). Conclusion Pooled estimate > 30% emphasizes the need for screening through antenatal care services and initiate preventive measures to address the deficiency.


Author(s):  
Beatrice Heim ◽  
Florian Krismer ◽  
Klaus Seppi

AbstractDifferential diagnosis of parkinsonian syndromes is considered one of the most challenging in neurology. Quantitative MR planimetric measurements were reported to discriminate between progressive supranuclear palsy (PSP) and non-PSP-parkinsonism. Several studies have used midbrain to pons ratio (M/P) and the Magnetic Resonance Parkinsonism Index (MRPI) in distinguishing PSP patients from those with Parkinson's disease. The current meta-analysis aimed to compare the performance of these measures in discriminating PSP from multiple system atrophy (MSA). A systematic MEDLINE review identified 59 out of 2984 studies allowing a calculation of sensitivity and specificity using the MRPI or M/P. Meta-analyses of results were carried out using random effects modelling. To assess study quality and risk of bias, the QUADAS-2 tool was used. Eight studies were suitable for analysis. The meta‐analysis showed a pooled sensitivity and specificity for the MRPI of PSP versus MSA of 79.2% (95% CI 72.7–84.4%) and 91.2% (95% CI 79.5–96.5%), and 84.1% (95% CI 77.2–89.2%) and 89.2% (95% CI 81.8–93.8%), respectively, for the M/P. The QUADAS-2 toolbox revealed a high risk of bias regarding the methodological quality of patient selection and index test, as all patients were seen in a specialized outpatient department without avoiding case control design and no predefined threshold was given regarding MRPI or M/P cut-offs. Planimetric brainstem measurements, in special the MRPI and M/P, yield high diagnostic accuracy for the discrimination of PSP from MSA. However, there is an urgent need for well-designed, prospective validation studies to ameliorate the concerns regarding the risk of bias.


Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 821
Author(s):  
Marek Petráš ◽  
Ivana Králová Lesná ◽  
Jana Dáňová ◽  
Alexander M. Čelko

Vaccination as an important tool in the fight against infections has been suggested as a possible trigger of autoimmunity over the last decades. To confirm or refute this assumption, a Meta-analysis of Autoimmune Disorders Association With Immunization (MADAWI) was conducted. Included in the meta-analysis were a total of 144 studies published in 1968–2019 that were available in six databases and identified by an extensive literature search conducted on 30 November 2019. The risk of bias classification of the studies was performed using the Newcastle–Ottawa Quality Assessment Scale. The strength of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation. While our primary analysis was conducted in terms of measures of association employed in studies with a low risk of bias, the robustness of the MADAWI outcome was tested using measures independent of each study risk of bias. Additionally, subgroup analyses were performed to determine the stability of the outcome. The pooled association of 0.99 (95% confidence interval, 0.97–1.02), based on a total of 364 published estimates, confirmed an equivalent occurrence of autoimmune disorders in vaccinated and unvaccinated persons. The same level of association reported by studies independently of the risk of bias was supported by a sufficient number of studies, and no serious limitation, inconsistency, indirectness, imprecision, and publication bias. A sensitivity analysis did not reveal any discrepancy in the primary result. Current common vaccination is not the cause of any of the examined autoimmune disorders in the medium and long terms.


1993 ◽  
Vol 23 (4) ◽  
pp. 843-858 ◽  
Author(s):  
A. Jablensky ◽  
H. Hugler ◽  
M. Von Cranach ◽  
K. Kalinov

SynopsisA meta-analysis was carried out on 53 cases of dementia praecox (DP) and 134 cases of manic-depressive insanity (MDI) originally diagnosed by Kraepelin or his collaborators in Munich in 1908. The original case material was coded in terms of Present State Examination syndromes and analysed statistically for internal consistency and discrimination between the two diagnostic entities. Kraepelin's DP and MDI were found to define homogeneous groups of disorders which could be clearly distinguished from one another. A CATEGO re-classification of the cases revealed an 80·2% concordance rate between Kraepelin's diagnoses and ICD-9. Cluster analysis of the original data reproduced closely Kraepelin's dichotomous classification of the psychoses but suggested that DP was a narrower concept than schizophrenia today, while MDI was a composite group including both ‘typical’ manic-depressive illnesses and schizoaffective disorders.


2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Marie E Westwood ◽  
Penny F Whiting ◽  
Jos Kleijnen
Keyword(s):  

2014 ◽  
Vol 45 (2) ◽  
pp. 231-246 ◽  
Author(s):  
A. van Straten ◽  
J. Hill ◽  
D. A. Richards ◽  
P. Cuijpers

BackgroundIn stepped care models patients typically start with a low-intensity evidence-based treatment. Progress is monitored systematically and those patients who do not respond adequately step up to a subsequent treatment of higher intensity. Despite the fact that many guidelines have endorsed this stepped care principle it is not clear if stepped care really delivers similar or better patient outcomes against lower costs compared with other systems. We performed a systematic review and meta-analysis of all randomized trials on stepped care for depression.MethodWe carried out a comprehensive literature search. Selection of studies, evaluation of study quality and extraction of data were performed independently by two authors.ResultsA total of 14 studies were included and 10 were used in the meta-analyses (4580 patients). All studies used screening to identify possible patients and care as usual as a comparator. Study quality was relatively high. Stepped care had a moderate effect on depression (pooled 6-month between-group effect size Cohen'sdwas 0.34; 95% confidence interval 0.20–0.48). The stepped care interventions varied greatly in number and duration of treatment steps, treatments offered, professionals involved, and criteria to step up.ConclusionsThere is currently only limited evidence to suggest that stepped care should be the dominant model of treatment organization. Evidence on (cost-) effectiveness compared with high-intensity psychological therapy alone, as well as with matched care, is required.


Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000012919
Author(s):  
Yanjun Guo ◽  
Iyas Daghlas ◽  
Padhraig Gormley ◽  
Franco Giulianini ◽  
Paul M Ridker ◽  
...  

Background and Objective:To evaluate phenotypic and genetic relationships between migraine and lipoprotein subfractions.Methods:We evaluated phenotypic associations between migraine and 19 lipoprotein subfractions measures in the Women’s Genome Health Study (WGHS, N=22,788). We then investigated genetic relationships between these traits using summary statistics from the International Headache Genetics Consortium (IHGC) for migraine (Ncase=54,552, Ncontrol=297,970) and combined summary data for lipoprotein subfractions (N up to 47,713).Results:There was a significant phenotypic association (odds ratio=1.27 [95% confidence interval:1.12-1.44]) and a significant genetic correlation at 0.18 (P=0.001) between migraine and triglyceride-rich lipoproteins (TRLP) concentration but not for LDL or HDL subfractions. Mendelian randomization (MR) estimates were largely null implying that pleiotropy rather than causality underlies the genetic correlation between migraine and lipoprotein subfractions. Pleiotropy was further supported in cross-trait meta-analysis revealing significant shared signals at four loci (chr2p21 harboring THADA, chr5q13.3 harboring HMGCR, chr6q22.31 harboring HEY2, and chr7q11.23 harboring MLXIPL) between migraine and lipoprotein subfractions. Three of these loci were replicated for migraine (P<0.05) in a smaller sample from the UK Biobank. The shared signal at chr5q13.3 colocalized with expression of HMGCR, ANKDD1B, and COL4A3BP in multiple tissues.Conclusions:The current study supports the association between certain lipoprotein subfractions, especially for TRLP, and migraine in populations of European ancestry. The corresponding shared genetic components may be help identify potential targets for future migraine therapeutics.Classification of Evidence:This study provides Class I evidence that migraine is significantly associated with some lipoprotein subfractions.


2021 ◽  
Author(s):  
Frida Björkman ◽  
Örjan Ekblom

ABSTRACT Introduction Post-traumatic stress disorder (PTSD) is a cluster of physical and psychiatric symptoms following military or civilian trauma. The effect of exercise on PTSD symptoms has previously been investigated in several studies. However, it has not been fully determined what type of exercise most impacts PTSD symptoms. The aim of the present study was to systematically review the effects of different types of exercise on PTSD symptom severity and symptoms of coexisting conditions in adults. Materials and Methods Electronic searches were conducted in the databases PubMed, APA PsycInfo, and SportDiscus, from database inception up until February 1, 2021. Inclusion criteria were randomized controlled trials published in English, participants having a PTSD diagnosis or clinically relevant symptoms, and participants randomly allocated to either a non-exercising control group or an exercise group. Data concerning the number of participants, age, exercise type and duration, PTSD symptom severity (primary outcome), and symptoms of coexisting conditions (secondary outcomes) were extracted. The subgroup analysis included high or low training dose, military trauma versus non-military trauma, the type of intervention (yoga versus other exercise), active or passive control condition, group training versus individual exercise, and study quality. The study quality and risk of bias were assessed using grading of recommendation assessment, development and evaluation (GRADE) guidelines. A meta-analysis was performed with a mixed-effects model and restricted maximum likelihood as model estimator, and effect size was calculated as the standardized difference in mean and 95% CI. Results Eleven studies were included in the present review. Results showed a main random effect of exercise intervention (0.46; 95% CI: 0.18 to 0.74) and a borderline significant interaction between more voluminous (&gt;20 hours in total) and less voluminous (≤20 hours in total) exercise interventions (P = .07). No significant findings from the subgroup analysis were reported. The secondary outcome analysis showed a small but significant effect of exercise on depressive symptoms (0.20, 95% CI: 0.01 to 0.38), and a larger effect on sleep (0.51, 95% CI: 0.29 to 0.73). For substance use (alcohol and drugs combined) and quality of life, we found significant effects of 0.52 (95% CI: 0.06 to 0.98) and 0.51 (95% CI: 0.34 to 0.69), respectively. No significant effect was found for anxiety (0.18, 95% CI: −0.15 to 0.51), and no sign of publication bias was found. Conclusions Exercise can be an effective addition to PTSD treatment, and greater amounts of exercise may provide more benefits. However, as there were no differences found between exercise type, possibly due to the inclusion of a low number of studies using different methodologies, further research should aim to investigate the optimal type, dose, and duration of activity that are most beneficial to persons with PTSD.


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