Gao, Wei
Gulliford, Martin
Morgan, Myfanwy
Higginson, Irene J.
Funding for this research was provided by:
National Institute for Health Research (CLAHRC-2013-10022, NIHR Applied Research Collaboration South London)
Article History
Received: 5 September 2019
Accepted: 11 March 2020
First Online: 29 April 2020
Ethics approval and consent to participate
: The CPRD has broad National Research Ethics Service Committee (NRES) ethics approval for purely observational research. No further ethical approval was required for the analysis of the data as this study was purely observational research using anonymised CPRD data.
: Not applicable.
: The authors declare that they have no competing interests.