Mean platelet volume in acute pancreatitis: a systematic review and meta-analysis

Background Several studies have suggested there may be statistically significant differences in mean platelet volume (MPV) between the onset and remission of acute pancreatitis (AP). This systematic review and meta-analysis aimed to better characterize the correlation between MPV and AP by identifying all relevant studies and summarizing their results. Methods A comprehensive literature review was conducted using EMBASE, PubMed/MEDLINE, Cochrane Library, ClinicalTrials.gov, and Google Scholar from January 2000 to December 2019 to identify all studies that reported MPV at the onset or remission of AP, or both. Effect estimates from each study were extracted and combined using the random-effect, generic inverse variance method of DerSimonian and Laird. The Newcastle-Ottawa quality assessment scale was used to appraise the quality of the included studies. Results Ten observational studies, including 1019 patients and 363 controls, were included in the meta-analysis. MPV was smaller at the onset of AP than on remission (standardized mean difference= -0.33 fL, 95% confidence interval -0.54 to -0.12 fL; P=0.002); however, a moderate degree of heterogeneity (I-2=72%, P <= 0.001) was observed. Subgroup analysis indicated comparable MPV in relation to the severity of AP. Similarly, no statistically significant difference was detected between AP patients and controls at either onset (P=0.760) or remission (P=0.700) of the disease. No statistically significant publication bias was detected (Eggers' regression P=0.938). Subgroup analysis suggested age (P<0.001) and sex (P=0.01) adjustment as potential sources of heterogeneity. Conclusion MPV is smaller at the onset of AP. Further clinical evaluation is needed to assess its potential prognostic value.