TABLE 3.

Characteristics of the negative studies regarding the relationship of Klotho with adverse outcomes (Low versus high sKlotho level) in MHD patients.

Author	Year	Country	Study design	N	Sample	Follow-up	Age	Outcomes	Conclusion	NOS
Erkus	2021	Turkey	Observational	136	Serum	—	48.2 ± 17.4	Uremic cardiomyopathy	sKlotho was not associated with uremic	5 stars
							58.9 ± 16.7		cardiomyopathy
Valenzuela	2019	Spain	Prospective	30	Plasma	18 months	71 ± 9	All-cause mortality	sKlotho levels were not associated	6 stars
									with mortality
Zheng	2018	China	Prospective	128	Serum	36 months	61.91 ± 15.3	CAC score	sKlotho levels were not associated	8 stars
			Observational					All-cause mortality	with mortality.
Buiten	2014	United Kingdom	Observational	127	Plasma	—	67 ± 7	AAC + CAC score	sKlotho levels were not associated	8 stars
								LV-dysfunction	with CV events or mortality
								CAD
Nowak	2014	Germany	Sectional	239	Plasma	2.53 years	68 ± 14	All-cause mortality	sKlotho levels were not associated	8 stars
			Prospective						with mortality.

MHD, maintenance hemodialysis; CAC, coronary artery calcification; LV, left ventricular; AF, atrial fibrillation; AAC, abdominal aorta calcification; CAD, coronary artery disease