“…Regarding data sources, a significant number of studies were conducted based on data primarily collected for other studies, such as the WHO's SAGE data, 25,26,55,67,68,95,96 World Health Survey data [77][78][79][80]97 or national health survey data 31,35,49,52,54,56,57,62,70,82,83,98 or other types of data such as electronic medical records. 50,58,59,73,75,76,82 Four pairs of studies used common data to answer different objectives: Chang et al 25,26 , Pati et al 69,72 , Alimohammadian et al 75,76 and Stubbs et al 78,79 Only 29 (38%) studies used data primarily collected for multimorbidity studies (Table 1).…”