Abstract
BackgroundAlthough several previous studies have examined the association between the platelet to lymphocyte ratio (PLR) and acute appendicitis (AA), findings have been controversial. We aimed to systematically assess the available evidence to elucidate the overall relationship between the PLR and AA.MethodsPubmed and Embase databases were searched for all available published literature before August, 2019 by two independent investigators for observational studies reporting the association between the PLR and AA. Random effects models were applied for all meta-analyses. Pooled standardized mean difference (SMD) and 95% confidence interval (CI) were calculated as effect estimates.ResultsEleven articles met the inclusion criteria and included in this study. Meta-analysis showed that the level of PLR in the AA group was significantly higher than that in the control group (SMD: 1.19, 95% CI: 0.75 to 1.62, P<0.001). A series of subgroup analyses were conducted to investigate the heterogeneity, showing a significant increase in PLV levels in adults with age ≥30 years (SMD: 1.46, 95% CI: 0.89 to 2.02),compared to those in adult <30 years(SMD: 0.58, 95% CI: 0.12 to 1.04) or in children (SMD: 1.03, 95% CI: 0.51 to 1.56). Compared to non-AA controls, a significant increased PLR level was also observed in non-perforated AA (SMD: 1.23, 95% CI: 0.88 to 1.59) and in AA patients during pregnancy (SMD: 0.70, 95% CI: 0.36 to 1.04), while not in perforated AA (SMD: 2.28, 95% CI: -1.72 to 6.28).ConclusionsA significant increase in PLR level is found in patients with AA, indicating that PLR is a promising biomarker for AA. PLR provides a convenient option for emergency department to quickly screen for clinically or radiologically confirmed AA awaiting appendectomy, especially for pregnant women suspected of having AA. More high-quality evidence is needed to further confirm the diagnostic accuracy of PLR for AA.
Highlights
Acute appendicitis (AA) affects approximately 50000 and 300000 individuals annually who receive appendectomies in the UK and in the US, respectively [1]
Meta-analysis showed that the level of platelet to lymphocyte ratio (PLR) in the AA group was significantly higher than that in the control group (SMD: 1.19, 95% confidence limit (CI): 0.75 to 1.62, P
Compared to non-AA controls, a significant increased PLR level was observed in non-perforated AA (SMD: 1.23, 95% CI: 0.88 to 1.59) and in AA patients during pregnancy (SMD: 0.70, 95% CI: 0.36 to 1.04), while not in perforated AA (SMD: 2.28, 95% CI: -1.72 to 6.28)
Summary
Acute appendicitis (AA) affects approximately 50000 and 300000 individuals annually who receive appendectomies in the UK and in the US, respectively [1]. It has been proposed that AA is characterized by a series of pathophysiological events including obstruction of the appendix lumen, reduced blood flow to the appendix, destruction of mucosal barrier function, bacterial invasion, inflammatory cell infiltration, tissue hypoxia, necrosis and even perforation [2, 3]. It is reported that perforation may occur in 13–20% of AA patients [4, 5]. Though several diagnostic approaches have been widely applied in clinical practice [6,7,8,9,10], the optimum strategy with non-invasiveness or radiationfree imaging modalities or other laboratory examinations has still not reached consensus, representing a long march for both the patients and surgeons to go. Several previous studies have examined the association between the platelet to lymphocyte ratio (PLR) and acute appendicitis (AA), findings have been controversial. We aimed to systematically assess the available evidence to elucidate the overall relationship between the PLR and AA.
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