BMJ Open. 2021; 11(5): e041219. Published online 2021 May 5. doi: 10.1136/bmjopen-2020-041219 PMCID: PMC8103380 PMID: 33952533 Systematic review on the instruments used for measuring the association of the level of multimorbidity and clinically important outcomes Eng Sing Lee, Moira Stewart Moira S…