Table 2.

Included studies and the extracted results used in the syntheses.

Study	Country/region	Number of participants (female/male ratio)	Study qualitya	Extracted results regarding risk factors (X: yes)
				Age	Male sex	Obesity	DM	CV	Pulm	HTN	Smoking	PMS	EDSS	DD	CS	DMTc
[5]	North America	1626	Good	X	X	X	X	X	X	X	X	X	X	X	X	X
[6]	Italy	844	Good	X	X	X	X	X		X	X	X	X	X	X	X
[7]	International	715	Fair	X	X	X	X	X	X	X		X
[8]	France	347	Good	X	X	X	X	X	X		X	X	X
[9]	International	344	Fair	X	X	X	X	X	X	X
[10]	Turkey	309	Fair	X	X						X	X	X		X
[11]	Latin America	129	Fair	X	X	X					X	X		X
[12]	Spain	93	Fair	X	X	X	X		X	X	X	X	X	X	X	X
[13]	The Netherlands	86	Fair		X							X				X
[14]	United States	76	Fair		X	X	X	X		X		X	X			X
[15]	Iran	68	Fair		X							X				X
[16]	Spain	51	Fair	X	X		X		X	X	X	X	X	X		X
[17]	United States	40	Fair		X		X		X	X	X	X	Xb		X	X

DM: diabetes mellitus; CV: cardiovascular comorbidities; Pulm: pulmonary comorbidities; HTN: hypertension; PMS: progressive multiple sclerosis; EDSS: expanded disability status scale; DD: disease duration; CS: corticosteroid within 2 months; DMT: disease-modifying therapy.

^aBased on a consensus reached by two independent reviewers (AAS and HN), using NIH quality assessment tools.

^bOnly extracted data for EDSS > 6.

^cData pertaining to some DMTs could not be extracted from some mentioned studies.