Table 1.

Comparison of literature reviews.

Study	Research question	Sample size	Time range	Method
Archer et al [17]	PHRsa design, functionality, implementation, application, outcomes, and benefits	130	Unlimited-2010	Systematic review
Fernández-Alemán et al [16]	Security and privacy in EHRsb	49	2006-2011	Systematic review
Van Panhuis et al [19]	Barriers to data sharing	65	Unlimited-2013	Systematic review
Kruse et al [18]	Adoption factors of EHRs	31	2012-2015	Systematic review
Roehrs et al [6]	Data types, standards, profiles, goals, methods, functions, and architecture with PHRs	97	2008-2017	Systematic review
Yin et al [11]	Machine learning in online personal health data	103	2010-2018	Systematic review
Maher et al [20]	Ethical issues in passive data collection	48	Unlimited-2018	Systematic review
Abd-alrazaq et al [21]	Factors affecting the use of PHRs	97	2000-2018	Systematic review
Mehta and Pandit [22]	Big data analytics in PHDc	58	2013-2018	Systematic review
Wang et al [28]	Evolution of publication hotspots in EHRs	17,678	1957-2016	Bibliometric method
Wen et al [27]	Production trends of EHR	1803	1991-2005	Bibliometric method
Guo et al [23]	Status, hotspots of EHR	5095	2005-2010	Bibliometric method
Liang et al [24]	Status, directions of EHR	1262	1990-2013	Bibliometric method
Ruixian et al [25]	Status of EMRd in China	262	1999-2004	Bibliometric method
Zhenni and Yuxing [30]	Hot spots in EHR	13,438	1900-2019	Bibliometric method
Qian et al [29]	Landscape, hot topics, trends of EHRs	13,438	1900-2019	Bibliometric method
Lin et al [26]	Status of EMR research in China	1752	1999-2012	Bibliometric method
Karampela et al [2]	Publication source, publication year, research topic	246	Unlimited-2018	Systematic mapping study
This study	Knowledge evolution trajectory of PHD, including EHR, PHR, and EMR	8281	2009-2018	Bibliometric method

^aPHR: personal health record.

^bEHR: electronic health record.

^cPHD: personal health data.

^dEMR: electronic medical record.