\documentclass{article}
\usepackage{prisma-flow-diagram}

\begin{document}

\begin{figure}[H]
\resizebox{\textwidth}{!}{
\prismaflowstart

% Nodes at the top
\prismaflownode{n1a}{left=of tc}{Records identified through database searching (n = 251)}{};
\prismaflownode{n1b}{right=of tc}{Additional records identified through other sources (n = 0)}{};
\prismaflownode{n2}{below=of tc |- n1a.south}{Records after duplicates removed (n = 41)}{n1a};
\prismaflowarrow{n1b}{n2};

% Screening Phase
\prismaflownode{n3}{below=of n2}{Records screened (n = 210)}{n2};
\prismaflownode{n3r}{right=of n3}{Records excluded (n = 175)}{};
\prismaflowarrow{n3}{n3r};

% Eligibility Phase
\prismaflownode{n4}{below=of n3}{Full-text articles assessed for eligibility (n = 35)}{n3};
\prismaflownode{n4r}{right=of n4}{Full-text articles excluded, with reasons (n = 4) \\ - Not Relevant (n = 3) \\ - Not Open/Available paper (n = 2)}{};
\prismaflowarrow{n4}{n4r};

% Inclusion Phase
\prismaflownode{n5}{below=of n4}{Studies included in qualitative synthesis (n = 30)}{n4};
\prismaflownode{n6}{below=of n5}{Studies included in quantitative synthesis (meta-analysis)}{n5};

% Labels
\prismalabel{1.3*\mh}{n1a.west}{Identification};
\prismalabel{1.3*\mh}{n1a.west |- {$(n2)!0.6!(n3)$}}{Screening};
\prismalabel{1.3*\mh}{n1a.west |- {$(n4)!0.2!(n5)$}}{Eligibility};
\prismalabel{1.3*\mh}{n1a.west |- n6}{Included};

\prismaflowend
}
\caption{PRISMA 2009 Flow Diagram}
\label{fig:prisma}
\end{figure}

\end{document}