Platelet indices and erectile dysfunction: A systematic review and meta-analysis.

Elevated platelet levels have been postulated to be associated with cardiovascular diseases, conditions closely linked to erectile dysfunction (ED). The current systematic review and meta-analysis was performed to assess the platelet indices, which including platelet count (PLT), mean platelet volume (MPV) and platelet distribution width (PDW) in subjects with ED compared to controls in an attempt to clarify the possible role of platelet indices in the pathogenesis of ED. We initially screened the candidate studies observing the possible association between platelet indices and ED following literature search of database Cochrane Library, PubMed, EMBASE and MEDLINE and therefore included the studies based on the pre-defined inclusion and exclusion criteria. Two independent investigators extracted the related information on article data and outcome measures from the qualified studies, and a meta-analysis was therefore performed using Stata 12.0 software. Subgroup analyses were conducted by the different ED aetiology obtained from the eligible studies. The standard mean difference (SMD) and the corresponding 95% confidence intervals (95% CIs) were applied to estimate the outcome measures. A total of 14 articles were qualified in our meta-analysis with a total of 1595 cases and 987 controls included. Pooled estimate was in favour of increased MPV levels in subjects with ED with a SMD of 0.651 fl, 95% CI 0.567-0.735, p = 0.000. Subgroup analysis showed that vasculogenic ED had a higher MPV levels than controls as well (SMD [95% CI] = 1.026 [0.823-1.228], p = 0.000). However, pooled analysis based on PLT and PDW levels has produced inconsistent results and not strong evidence on platelet level and ED correlation. In conclusion, vasculogenic ED patients had a higher MPV level in our study. However, the results need further interpretation with caution and more high-quality studies are warranted.