Serum levels of YKL-40 are increased in patients with psoriasis: a meta-analysis

Background: YKL-40, also named chitinase-3-like protein 1, has been confirmed as an inflammatory glycoprotein associated with cardiovascular disease, diabetes or metabolic syndrome which are common comorbidities in psoriasis. Growing evidence has demonstrated that serum levels of YKL-40 in psoriatic patients were increased, however the results were appearance contradictory among the current published studies. Methods: Research involved in serum levels of YKL-40 in psoriatic patients and healthy control individuals was searched in PUBMED, EMBASE, and The Cochrane Library databases (up to 31 December 2018). Weight mean difference (WMD) with 95% confidence interval (CI) was calculated by random-effect model analysis. Heterogeneity test was performed by the Q-statistic and quantified using I-2, and publication bias was evaluated using a funnel plot and Egger's linear regression test. Additionally, the subgroup and sensitivity analyses were also performed. Results: In total, 340 articles were obtained. Among these, 11 studies with 528 psoriatic patients and 460 control individuals were included. Our meta-analysis revealed that psoriatic patients had a higher serum YKL-40 levels compared to the control group, with the WMD of 53.6 ng/ml (95% CI: 31.3 to 75.9, P< 0.001). Furthermore, results of meta-regression analysis and subgroup analysis revealed that the disease duration and the value of psoriasis area and severity index (PASI) were related to the observed YKL-40 differences between two groups. Conclusions: Our meta-analysis indicates that psoriatic patients have higher serum YKL-40 levels when compared to healthy control individuals, and the levels are significantly affected by the disease duration and PASI.