Table 1. Characteristics of the included studies.

Study author	Publication year	Study period	Design	Location	Age (years)	MVP (n)	MVR (n)	Follow-up (years)	NOS score
Ailawadi et al. (11)	2008	1998–2006	Retrospective OS	USA	≥75	70	47	4.2	7
Chikwe et al. (12)	2011	1998–2008	Retrospective OS	USA and Germany	≥80	227	95	2.4	9
DiGregorio et al. (13)	2004	1990–2000	Retrospective OS	USA	≥80	46	13	5.7	7
Gaur et al. (14)	2014	2002–2011	Retrospective OS	USA	≥70	556	102	4.1	8
Gogbashian et al. (15)	2006	1992–2002	Prospective OS	USA	≥70	147	36	6.3	9
Nloga et al. (16)	2011	1987–2007	Retrospective OS	France	≥80	75	54	3.4	7
Silaschi et al. (17)	2016	1994–2015	Retrospective OS	UK	≥75	221	120	5.3	8

MR, mitral regurgitation; MVP, mitral valve repair; MVR, mitral valve replacement; NA, not applicable; NOS, Newcastle-Ottawa Scale; OS, observational study.