<p><strong>Background: </strong>The public health significance is not well described and PSW could have been abbreviated when used for the first time.</p><p><strong>Methods:</strong> the outcome variable is not defined, how was PSW assessed? how do we determine whether PSW there was positively affected or negatively affected? How do we define "PSW well"? &nbsp;</p><p><strong>Result and conclusion:</strong> The conclusion on the low prevalence of PSW is not supported by the results, and low prevalence compared with what? &nbsp;</p>