Alpha-synuclein pathology in isolated rapid eye movement sleep behaviour disorder: a meta-analysis.

Accumulating evidence indicates that patients with isolated rapid eye movement sleep behaviour disorder (iRBD), a prodromal stage of synucleinopathies, show abnormal deposition of misfolded alpha-synuclein (a-Syn) in peripheral tissues. The clinical utility of testing for a-Syn in iRBD is unclear. This meta-analysis focused on the utility of testing for the abnormal a-Syn phosphorylated at Ser129 (p-syn) and a-Syn seeding activity (a-Syn seed amplification assays [aSyn-SAA]). Following an electronic database search, 15 studies were included that provided at a minimum data on test positivity in participants with iRBD. Test positivity from cerebrospinal fluid (CSF) was 80% (95% confidence interval [CI] 68-88%, I2 = 71%) and for skin was 74.8% (95% CI 53.2-88.5%, I2 = 64%) for aSyn-SAA and 78.5% (95% CI 70.4-84.9%, I2 = 14%) for p-syn. The phenoconversion rate ratio of biopsy-positive versus biopsy-negative iRBD was 1.28 (95% CI 0.68-2.41, I2 = 0%). Skin as a source had a specificity of 99% (95% CI 95-100%, I2 = 0%; p = 0.01 compared to CSF). As a test, p-syn, had a specificity of 100% (95% CI 93-100%, I2 = 0%; p < 0.001) compared to aSyn-SAA. The odds ratio of a-Syn test positivity in iRBD versus other RBDs was 112 (95% CI 20-629, I2 = 0%). These results demonstrate clinically significant test positivity in iRBD and favour skin over CSF as the source of a-Syn pathological analysis, and p-syn over aSyn-SAA as the testing method. Overall, these findings indicate that testing for a-Syn could help in differentiating iRBD from RBD secondary to other conditions.

Accuracy of residual respiratory event detection by CPAPs: a meta-analysis.

PURPOSE: Most continuous positive airway pressure (CPAP) machines have built-in manufacturer-specific proprietary algorithms for automatic respiratory event detection (AED) based on very specific respiratory events scoring criteria. With regards to the accuracy of these data from CPAP machines, evidence from the literature seems conflicting, which formed the basis for this meta-analysis. METHODS: A meta-analysis was performed on studies that reported Bland-Altman analysis data on agreement (mean bias and limits of agreement [LoA]) of CPAP-determined apnea-hypopnea index (AHI) at therapeutic pressures (AHIFLOW) with that determined from simultaneously conducted polysomnograms (AHIPSG). RESULTS: In six studies, ResMed CPAPs were used, and in another six studies, Respironics CPAPs were used, while only one study used Fisher & Paykel (F&P) CPAPs. The pooled mean AHI bias from ResMed CPAP studies was - 1.01 with pooled LoAs from - 3.55 to 1.54 (I2 = 17.5%), and from Respironics CPAP studies, pooled mean AHI bias was - 0.59 with pooled LoAs from - 3.22 to 2.05 (I2 = 0%). Pooled percentage errors (corresponding to LoAs) from four ResMed CPAP studies, four Respironics CPAP studies, and the F&P CPAP study were 73%, 59%, and 112%, respectively. A review of the literature for this meta-analysis also revealed lack of uniformity not only in the CPAP manufacturers' respiratory events scoring criteria but also in that used for PSGs across the studies analyzed. CONCLUSIONS: Even though the pooled results of mean AHI bias suggest good clinical agreement between AHIPSG and AHIFLOW, percentage errors calculated in this meta-analysis indicate the possibility of a significant degree of imprecision in the estimation of AHIFLOW by CPAP machines.

Comparative efficacy of mandibular advancement devices in obstructive sleep apnea: a network meta-analysis.

PURPOSE: To analyze relative efficacies of mandibular advancement devices (MAD) in sleep apnea treatment. METHODS: From eligible randomized controlled trials (RCT), MADs were classified based on their mechanistic designs. Data on apnea-hypopnea index (AHI), Epworth sleepiness scale (ESS), nadir oxygen saturation (minSaO2), and sleep efficiency (SE%) from RCTs were then analyzed in network meta-analyses, and relative ranking of different MADs was computed based on P scores (a method of ranking similar to SUCRA). Similar analyses were conducted based on the different brands of MADs. RESULTS: There were no statistically significant differences between MADs in any of the outcomes analyzed. However, the P-scores, based on the point estimates and standard errors of the network estimates, ranked some MADs higher than others in some of the outcomes. Of the different mechanistic designs, the highest P scores were achieved for attached midline traction (P score = 0.84) and unattached bilateral interlocking (P score = 0.78) devices for AHI reduction, attached bilateral traction (P score = 0.78) and unattached bilateral interlocking (P score = 0.76) for ESS, monobloc (P score = 0.91) and unattached bilateral interlocking (P score = 0.64) for minSaO2, and unattached bilateral interlocking (P score = 0.82) and attached bilateral traction (P score = 0.77) for SE%. Notable findings in the network meta-analyses based on MAD brands, of the limited number of studies that specified them were the effects of SomnoDent Flex™, TAP™, and IST® in their effects on AHI reduction, with P scores of 0.94, 0.83, and 0.82, respectively. Monobloc decreased supine-AHI the most (- 44.46 [- 62.55; - 26.36], P score = 0.99), and unattached bilateral interlocking had the greatest effect on REM-AHI (- 11.10 [- 17.10; - 5.10], P score = 0.87). CONCLUSIONS: Findings from this study show clinically (but not statistically) significant differences between MADs in terms of their relative efficacy when analyzed for different sleep apnea treatment outcomes and sleep apnea phenotypes.

Central sleep apnea treatment in patients with heart failure with reduced ejection fraction: a network meta-analysis.

PURPOSE: Adaptive servo-ventilation (ASV) is contraindicated for the treatment of central sleep apnea (CSA) in patients with heart failure with reduced ejection fraction (HFrEF), limiting treatment options. Though continuous positive airway pressure (CPAP), bi-level PAP with back-up rate (BPAP-BUR), and transvenous phrenic nerve stimulation (TPNS) are alternatives, not much is known about their comparative efficacies, which formed the basis of conducting this network meta-analysis. We sought to analyze their comparative effectiveness in reducing apnea hypopnea index (AHI). Additionally, we also studied their comparative effectiveness on subjective daytime sleepiness as assessed by Epworth sleepiness score (ESS). METHODS: Randomized controlled trials (RCTs) from PubMed were analyzed in a network meta-analysis and relative superiority was computed based on P-score ranking and Hasse diagrams. RESULTS: Network meta-analysis based on 8 RCTs showed that when compared to guideline-directed medical therapy (GDMT-used as a common comparator across trials), reduction in AHI by ASV (- 26.05 [- 38.80; - 13.31]), TPNS (- 24.90 [- 42.88; - 6.92]), BPAP-BUR (- 20.36 [- 36.47; - 4.25]), and CPAP (- 16.01 [- 25.42; - 6.60]) were statistically significant but not between the interventions. Based on 6 RCTs of all the interventions, only TPNS showed a statistically significant decrease in ESS (- 3.70 (- 5.58; - 1.82)) when compared to GDMT, while also showing significant differences when compared with ASV (- 3.20 (- 5.86; - 0.54)), BPAP-BUR (- 4.00 (- 7.33; - 0.68)), and CPAP (- 4.45 (- 7.75; - 1.14)). Ranking of treatments based on Hasse diagram, accounting for both AHI and ESS as outcomes for relative hierarchy showed relative superiority of both ASV and TPNS over BPAP-BUR and CPAP. CONCLUSIONS: Results indicated relative superiority of TPNS and ASV to BPAP-BUR and CPAP in their effects on AHI and ESS.

A network meta-analysis of different positive airway pressure interventions in obesity hypoventilation syndrome.

Continuous positive airway pressure (CPAP) and different types of non-invasive ventilation (NIV) have been studied in obesity hypoventilation syndrome such as bi-level PAP with back-up rate (BPAP-BUR), BPAP without BUR, and the new hybrid devices that target a pre-set volume by adjustment of pressure support (VT-PS). Although several studies have compared one PAP intervention with the other, none has compared all four in a head-to-head design, which formed the basis of this network meta-analysis. PubMed and Web of Science were searched for potentially includable randomised active comparator trials. Changes in partial pressure of carbon dioxide (PaCO2 ) and Epworth Sleepiness Score (ESS) were the primary outcomes of interest. Network meta-analysis was done in R program using the 'frequentist' framework. A total of seven trials were included. Only VT-PS and BPAP-BUR showed statistically significant reductions in PaCO2 compared to control, with no significant inter-PAP differences except for the comparison between VT-PS and CPAP. Only VT-PS showed a statistically significant improvement in ESS as compared to control, with no other significant inter-PAP differences. P-score ranking (based on effect size and standard errors) and Hasse diagram ranked VT-PS and BPAP as superior to other PAPs for both primary outcomes. There were no significant differences between the different PAP interventions for hospital or emergency department admissions. The results of this network meta-analysis suggest superiority of VT-PS and BPAP over other PAP interventions at least for daytime hypercapnia and subjective daytime somnolence.

Effect of Anti-IL5, Anti-IL5R, Anti-IL13 Therapy on Asthma Exacerbations: A Network Meta-analysis.

BACKGROUND: Several new treatments for severe asthma have become available in the last decade; yet, little data exist to guide their use in specific patient populations. OBJECTIVE: A network meta-analysis was conducted comparing the efficacy of FDA-approved monoclonal antibody therapies in preventing exacerbations in patients with severe eosinophilic asthma. METHODS: PubMed and Ovid were searched from inception until July 2019 for randomized controlled trials that studied the efficacy of benralizumab, dupilumab, mepolizumab, and reslizumab, in preventing acute exacerbations of asthma. Studies were included if they reported data for patients with severe eosinophilic asthma (defined in this meta-analysis as absolute eosinophil count ≥ 250 cells/µL). Annualized rate ratios for asthma exacerbations (during treatment) were calculated and converted to log rate ratios. Direct and indirect treatment estimates (for inter-drug differences) were analyzed using frequentist network meta-analysis methodology in R and treatments were ranked based on P-scores. RESULTS: In total, nine studies were included in the final analysis. Network meta-analysis revealed that all drugs were superior to placebo in preventing rates of asthma exacerbation in the study population and no inter-drug differences existed. Dupilumab was found to have the greatest magnitudes of effect on decreasing log rate ratio of asthma exacerbation based on P-score (0.83). CONCLUSION: Benralizumab, dupilumab, mepolizumab, and reslizumab are all associated with decreased asthma exacerbations in patients with eosinophilic asthma, with no significant inter-drug differences.

A Meta-analysis of Diagnostic Test Agreement Between Eucapnic Voluntary Hyperventilation and Cardiopulmonary Exercise Tests for Exercise-Induced Bronchoconstriction.

INTRODUCTION: Exercise-induced bronchoconstriction (EIB) is very common in athletes. Cardiopulmonary exercise tests (CPET) have traditionally been used for the diagnosis of EIB. However, alternative indirect bronchoprovocation tests have recently been used as surrogate tests. One of these is the eucapnic voluntary hyperventilation (EVH). This meta-analysis studied the agreement between the two tests. METHODS: An extensive search in PubMed and Medline was conducted for studies where participants underwent both CPET and EVH with measurement of forced expiratory volume in 1-second (FEV1). After extracting data using two-by-two contingency tables, pooled positive and negative agreements were first calculated between the two tests, with EVH benchmarked against CPET, and then, pooled positive and negative agreements were calculated with CPET benchmarked against EVH. RESULTS: The pooled positive and negative agreements between EVH and CPET (with CPET as the reference) were 0.62 [(95% confidence interval 0.54-0.70), I2 77%] and 0.61 [(0.56-0.65)), I2 81%]. The pooled positive and negative agreements between CPET and EVH (with EVH as the reference) were 0.36 [(0.30-0.42), I2 93%] and 0.82 [(0.77-0.86), I2 78%]. The average of positive test results with EVH across all studies was greater than that of CPETs (58.84% vs. 39.51%). CONCLUSIONS: Results of this meta-analysis show poor positive agreement between the two tests but high negative agreement (specifically using EVH as reference), suggesting that either test can be used for correctly identifying those without EIB. Results also suggest that the chances of a test resulting positive are higher with EVH than with CPET.

A Network Comparative Meta-analysis of Percutaneous Dilatational Tracheostomies Using Anatomic Landmarks, Bronchoscopic, and Ultrasound Guidance Versus Open Surgical Tracheostomy.

BACKGROUND: Several different tracheostomy techniques (percutaneous and surgical) have been studied extensively in previous direct pairwise meta-analyses. However, a network comparative meta-analysis comparing all has not been conducted before. OBJECTIVE: We sought to compare three percutaneous dilatational tracheostomy techniques with open surgical tracheostomy technique (performed in the operating room or in the intensive care unit by bedside) in terms of their association with procedure-related major complications and procedure time. DATA SOURCES: We searched PubMed and Cochrane register of randomized active comparator trials. DATA EXTRACTION AND SYNTHESIS: A network comparative meta-analysis was performed in Stata using frequentist methodology. Major complications were defined as a composite of a priori-selected procedure-related complications. Tracheostomy techniques that did not require any direct bronchoscopic or ultrasonographic visualization of the entire procedure were grouped under the heading-anatomic landmark-based dilatational tracheostomy (ALDT). This along with bronchoscopic-guided dilatational tracheostomy (BDT), ultrasound-guided (UDT), and surgical tracheostomy (SGT) were compared with each other using network meta-analysis in Stata after all major assumptions (similarity, transitivity, and consistency) for performing a network were met. Log odds ratio (and standard errors) of the comparison of major complications between any two tracheostomy techniques (using indirect estimates) was statistically insignificant. Pairwise meta-analysis showed significant differences in procedure times between SGT and ALDT [mean difference: 9.96 min (SE 3.18)] and between SGT and BDT [15.67 min (SE 3.85)]. The indirect network meta-analysis comparing one versus the other also showed a statistically significant time difference between surgical tracheostomy when compared with every other technique. CONCLUSIONS: The results of our network meta-analysis show that all tracheostomy techniques are comparable with respect to associated procedure-related complications, but all three percutaneous techniques take far less procedure time compared to the surgical tracheostomy.

Comparative Efficacy of Anti IL-4, IL-5 and IL-13 Drugs for Treatment of Eosinophilic Asthma: A Network Meta-analysis.

BACKGROUND: Several new biologics have been studied in patients with eosinophilic asthma with varying degrees of response on clinical outcomes. No head-to-head trial has directly compared the efficacy of these drugs. OBJECTIVE: To synthesize data on the relative efficacy of benralizumab, dupilumab, lebrikizumab, mepolizumab, reslizumab, and tralokinumab using network meta-analysis. DATA SOURCES: We searched PubMed from inception to December 15th, 2017. DATA EXTRACTION AND SYNTHESIS: We used the 'frequentist' methodology with random effect models using primarily 'netmeta' function in R to generate network meta-analysis results. Outcomes assessed included changes in forced expiratory volume-in 1 s (FEV1), asthma control questionnaire (ACQ), and asthma quality of life questionnaire (AQLQ). We also separately analyzed the annualized rate ratios for asthma exacerbations for each drug and compared to placebo. For all outcomes assessed, all drugs were superior to placebo except tralokinumab. In terms of magnitude of effect, dupilumab, followed by reslizumab and benralizumab showed the greatest increase in FEV1, 0.16L (95% CIs: 0.08-0.24), 0.13L (0.10-0.17), and 0.12L (0.08-0.17), compared to placebo. While mepolizumab, followed by dupliumab, benralizumab, and reslizumab showed reductions in ACQ scores, in order of magnitude of effect, dupilumab, followed by mepolizumab, benralizumab, and reslizumab showed the greatest increase in AQLQ scores. All drugs decreased asthma exacerbations but the results were only significant for reslizumab and dupilumab. CONCLUSIONS: All drugs except for tralokinumab showed improvements in FEV1, ACQ, and AQLQ. Only reslizumab and dupilumab were associated with statistically significant reductions in asthma exacerbation rates.

Effects of exercise training on sleep apnea: a meta-analysis.

BACKGROUND: Several studies have shown a favorable effect of supervised exercise training on obstructive sleep apnea (OSA). This meta-analysis was conducted to analyze the data from these studies on the severity of OSA (primary outcome) in adults. Secondary outcomes of interest included body mass index (BMI), sleep efficiency, daytime sleepiness and cardiorespiratory fitness. METHODS: Two independent reviewers searched PubMed and Embase (from inception to March 6, 2013) to identify studies on the effects of supervised exercise training in adults with OSA. Pre- and postexercise training data on our primary and secondary outcomes were extracted. RESULTS: A total of 5 studies with 6 cohorts that enrolled a total of 129 study participants met the inclusion criteria. The pooled estimate of mean pre- to postintervention (exercise) reduction in AHI was −6.27 events/h (95 % confidence interval [CI] -8.54 to -3.99; p < 0.001). The pooled estimates of mean changes in BMI, sleep efficiency, Epworth sleepiness scale and VO2 peak were -1.37 (95 % CI −2.81 to 0.07; p = 0.06), 5.75 % (95 % CI 2.47-9.03; p = 0.001), -3.3 (95 % CI -5.57 to -1.02; p = 0.004), and 3.93 mL/kg/min (95 % CI 2.44-5.42; p < 0.001), respectively. CONCLUSIONS: This meta-analysis shows a statistically significant effect of exercise in reducing the severity of sleep apnea in patients with OSA with minimal changes in body weight. Additionally, the significant effects of exercise on cardiorespiratory fitness, daytime sleepiness, and sleep efficiency indicate the potential value of exercise in the management of OSA.

Cardiovascular safety of long acting beta agonist-inhaled corticosteroid combination products in adult patients with asthma: a systematic review.

INTRODUCTION: Long-acting beta agonists and inhaled corticosteroids combination products (LABA-ICS) are widely used in the treatment of asthma. However, there appears to be little data on their cardiovascular safety. The purpose of this study was to conduct a systematic review of the available studies and trials on the cardiovascular safety of LABA-ICS in adults with asthma. METHODS: Two independent reviewers screened citations from PubMed and National Clinical Trials registry to identify studies and trials on the cardiovascular effects of LABA-ICS in patients with asthma. RESULTS: A total of 15 studies (with 17 cohorts on LABA-ICS to compare with a comparator or placebo) with 5,440 total study participants met the inclusion criteria. Two studies on budesonide-formoterol and one on fluticasone-salmeterol reported treatment emergent cardiovascular adverse events, all of which were dysrhythmias. For comparison, the pooled estimate of the Peto odds ratio (0.72; 95 % confidence interval [CI] 0.17-3; p = 0.65) and the summary risk ratio (0.77; 95 % CI 0.26-2.3; p = 0.64) indicated a nonsignificant difference between LABA-ICS and comparator/placebo groups. CONCLUSIONS: Our systematic review found that few studies and trials reported treatment emergent cardiovascular adverse events with LABA-ICS. However, the Peto odds ratio and risk ratio for these outcomes was statistically nonsignificant. This suggests that LABA-ICS products may have a safe cardiovascular profile in asthma patients.

Predictors of efficacy for endobronchial valves in bronchoscopic lung volume reduction: A meta-analysis.

Over the last several years, numerous trials have been carried out to check the efficacy of one-way valves in the management of advanced emphysema. While the design of the valves has not altered much, by selectively studying these valves in a select group of participants, such as those with and without intact fissures (FI+ and FI-), and by using different procedural techniques, our understanding of the valves has evolved. In this meta-analysis, we sought to study the effect of these factors on the efficacy of one-way valves. From PubMed and Embase, we included only those studies that provided separate data on fissure integrity or collateral ventilation. Our study outcomes included the mean change in forced expiratory volume in first second (FEV1), 6-minute walk distance (6MWD) and the St George's Respiratory Questionnaire (SGRQ). In the FI+ subgroup of participants, the pooled standardized mean difference in FEV1, 6MWD, and SGRQ were 0.50 (95% confidence interval (CI): 0.34 to 0.67), p ≤ 0.001, 0.29 (95% CI: 0.13 to 0.45), p ≤ 0.001 and -6.02 (95% CI: -12.12 to 0.06), p = 0.05, respectively. In comparison, these results were superior to the FI- subgroup of participants. A separate analysis of the FI+ subgroup based on lobar occlusion versus nonlobar occlusion favored the former for superior efficacy. The preliminary findings of our meta-analysis confirm that one-way valves perform better in a select group of patients who show intact fissures on lung imaging pretreatment and in those who achieve lobar occlusion.

SPECT Ventilation/Perfusion Imaging for Acute Pulmonary Embolism: Meta-analysis of Diagnostic Test Accuracy.

RATIONALE AND OBJECTIVES: This study aimed to evaluate the diagnostic accuracies of ventilation/perfusion-single photon emission computed tomography (V/Q-SPECT) imaging modalities for acute pulmonary embolism (PE). These included, in addition to V/Q-SPECT, V/Q-SPECT with low-dose computed tomography (CT; V/Q-SPECT-CT), Q-SPECT with low-dose CT (Q-SPECT-CT), and Q-SPECT. MATERIALS AND METHODS: PubMed, Embase, CINAHL, and Web of Science databases were searched, and studies included if they studied ≥10 adult participants with acute PE and reported data on the imaging tests' diagnostic performance. Data were meta-analyzed using bivariate random effects regression model. RESULTS: Data from participants totaling 4146 from 11 V/Q-SPECT studies, 785 from 7 V/Q-SPECT-CT studies, 1196 from 7 Q-SPECT-CT studies, and 728 from five Q-SPECT studies were separately meta-analyzed. The bivariate weighted mean sensitivity and specificity were 0.94 (95% confidence interval [CI]: 0.88-0.97) and 0.95 (95% CI: 0.87-0.98) for V/Q-SPECT, 0.95 (95% CI: 0.88-0.98) and 0.99 (95% CI: 0.92-1.00) for V/Q-SPECT-CT, 0.92 (95% CI: 0.79-0.97) and 0.92 (95% CI: 0.83-0.96) for Q-SPECT-CT, and 0.89 (95% CI: 0.76-0.95) and 0.86 (95% CI: 0.67-0.95) for Q-SPECT studies. The positive and negative likelihood ratios (+LRs and -LRs) were 17.4 (6.9-44.0) and 0.06 (0.03-0.13), 76.7 (11.8-498.0) and 0.06 (0.02-0.13), 11.0 (5.3-22.9) and 0.09 (0.04-0.23), and 6.4 (2.6-15.8) and 0.13 (0.07-0.27) for V/Q-SPECT, V/Q-SPECT-CT, Q-SPECT-CT, and Q-SPECTs, respectively. CONCLUSION: In the diagnosis of acute PE, this meta-analysis showed that V/Q-SPECT-CT had the highest specificity and +LR. Conversely, Q-SPECT showed the lowest specificity and an unfavorably high -LR.

Effect of continuous positive airway pressure on hemoglobin A(1c) in patients with obstructive sleep apnea: a systematic review and meta-analysis.

BACKGROUND: There is little conclusive data regarding the effect of continuous positive airway pressure (CPAP) on glycated hemoglobin (HbA(1c)). An earlier meta-analysis included two randomized controlled trials (RCTs) and found no significant effect of CPAP on HbA(1c). The meta-analysis presented here was conducted to include all relevant observational studies and RCTs on the effect of CPAP on HbA(1c). METHODS: We searched the PubMed database for all studies published prior to March 2012 for trials of the effect of CPAP on HbA(1c). Data from observational studies and RCTs that met the inclusion criteria were extracted for pre- and post-treatment HbA(1c). RESULTS: A total of nine studies that included 151 subjects met the inclusion criteria. The duration of the studies ranged from 41 days to 6 months. The mean net change in the HbA(1c) was -0.06 % [95 % CI: -0.24, 0.12] (p = 0.5). Five of the nine studies, with a total of 112 subjects, comprised patients with diabetes mellitus (DM) type 2. The mean net change in HbA(1c) for the subjects with DM type 2 was 0.08 % [95 % CI: -0.26, 0.42] (p = 0.65). The mean net change in HbA(1c) for subjects with DM type 2 in studies that were at least 3 months in duration was 0.16 % [95 % CI: -0.26, 0.58] (p = 0.45). CONCLUSIONS: This meta-analysis found that CPAP does not reduce HbA(1c) levels when used in the short term.

A meta-analysis of diagnostic test performance of peripheral arterial tonometry studies.

STUDY OBJECTIVES: The objective of this meta-analysis was to analyze agreement in apnea-hypopnea index (AHI) determination between peripheral arterial tonometry (PAT) and polysomnography (PSG) studies. METHODS: Mean AHI bias and standard deviation extracted from Bland-Altman plots reported in studies were pooled in a meta-analysis, which was then used to calculate percentage errors of limit agreement in AHI determination by PAT using PSG AHI as the reference. Individual participant data (where reported in studies) were used to compute Cohen's kappa to assess agreement between PSG and PAT on sleep apnea severity and for computing the sensitivity and specificity of PAT at different AHI thresholds using PSG AHI as the reference. RESULTS: From 17 studies and 1,318 participants (all underwent simultaneous PSG and use of the WatchPAT device), a pooled mean AHI bias of 0.30 (standard error [SE], 0.74) and a WatchPAT AHI percentage error of 230% was calculated. The meta-analysis of Cohen's kappa for agreement between PSG and WatchPAT studies for classifying patients with no sleep apnea, mild, moderate, or severe sleep apnea severity was 0.45 (SE, 0.06), 0.29 (SE, 0.05), 0.25 (SE, 0.07), and 0.64 (SE, 0.05), respectively. At AHI thresholds of 5, 15 and 30 events/h, WatchPAT studies showed pooled sensitivities and specificities of 94.11% and 43.47%, 92.21% and 72.39%, and 74.11% and 87.10%, respectively. Likelihood ratios were not significant at any AHI threshold. CONCLUSIONS: The results of this meta-analysis suggest clinically significant discordance between WatchPAT and PSG measurements of AHI, significant sleep apnea severity misclassification by PAT studies, and poor diagnostic test performance. CITATION: Iftikhar IH, Finch CE, Shah AS, Augunstein CA, Ioachimescu OC. A meta-analysis of diagnostic test performance of peripheral arterial tonometry studies. J Clin Sleep Med. 2022;18(4):1093-1102.