Scientific Reports 6: Article number: 18764; published online: 08 January 2016; updated: 19 August 2016.

In the original version of this Article, there was an error in Affiliation 1 which was incorrectly given as ‘Department of Health Management, Southern Medical University, Guangzhou 510515, Guangdong, China’. The correct affiliation is listed below:

‘Department of Health Management, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China’.

This error has now been corrected in the PDF and HTML versions of the Article.