METHODS
Search Strategy
We followed the recommendation of the Preferred Reporting Items for
Systematic Reviews and Meta-Analyses (PRISMA)
statement.13 We queried the electronic databases
Medline, Cochrane databases, CINAHL using the following search keywords:
‘Echocardiography’, ‘Speckle tracking’, and ‘Sarcoidosis’. We only
compiled articles published in English language.
Study Selection and Data Extraction
We included all studies reporting LVGLS and/or GCS, comparing patients
with confirmed extra-cardiac sarcoidosis versus a control group of
healthy patients. Studies that exclusively included patients with
probable or definite CS were excluded. We also collected studies that
reported LVGLS in sarcoidosis patient’s experiencing major cardiac
events (MCEs) which was defined as composite outcomes of all cause
death, arrhythmia, heart failure hospitalization, cardiac device
implantation, or appropriate firing of defibrillator. We excluded case
reports, review articles, editorials, and correspondences to the editor.
Data was extracted by two independent investigators (K.B., M.C). into a
predefined collection sheet. All disagreements were resolved in
consensus with a third reviewer (D.R.). Extracted data included baseline
characteristics, echocardiographic parameters, LVGLS and LVGCS.
Statistical Analysis
Continuous data (e.g., LVGLS and GCS) were pooled as a standard mean
difference (SMD) between the sarcoidosis group and the control group.
Random effect model was adopted in all analyses. We used inverse
variance method with Restricted Maximum-Likelihood estimator of Tau2,
for random effect analysis. We assessed between-study heterogeneity
using Q and I2 statistics. AI2 statistic <25% indicates a low
amount of heterogeneity and >50% indicates a high
heterogeneity. Analyses were conducted using STATA 16 (State Corp LLC,
College Station, Texas). P-value <0.05 was considered
statistically significant.
Quality Assessment
Quality of included studies was assessed using the Newcastle-Ottawa
Scale (NOS).14 This included a checklist for
representativeness of included cohort, ascertainment of exposure,
comparability and adequacy of follow-up as per the NOS. A maximum of 9
stars were awarded to each study. Studies awarded ≥6 stars were
considered moderate-to-high quality studies.14