Table 3.

Methodological index for nonrandomized studies criteria for each paper.

Criteria	Studies
	Aiken et al [5]		Nguhuni et al [3]		Pathak et al [4]
	Score	Description	Score	Description	Score	Description
1a	2	—b	2	—	2	—
2c	2	—	1	Did not state reason some patients were excluded	1	No inclusion criteria stated
3d	1	References a pilot study	0	Doesn't report a pilot or protocol	0	No pilot or protocol mentioned
4e	2	SSIsf diagnosed in reference to the standardized CDC-NHNSg risk criteria	2	SSIs diagnosed in reference to the standardized CDC-NHNS risk criteria	0	No criteria for SSI diagnosis explained
5h	1	Not stated whether those in clinic were blinded to the telephone outcomes	1	Not stated whether those in clinic were blinded to the telephone outcomes	1	Not stated whether those in clinic were blinded to the telephone outcomes
6i	2	30 days	2	30 days	2	30 days
7j	0	The loss to follow up was not commented on	1	Loss to follow up was 13%, but 26% of those who had been contacted by phone did not return to clinic	2	No loss to follow up
8k	2	Specificity, sensitivity	2	Specificity, sensitivity, positive predictive values, negative predictive values	1	Not recorded
9l	2	Compared against clinical diagnosis	2	Compared against clinical diagnosis	2	Compared against clinical diagnosis
10m	2	Patients were their own control	2	Patients were their own control	2	Patients were their own control
11n	0	No Table 1 referenced	2	—	0	No data on group equivalence mentioned
12o	2	—	2	—	1	No statistics mentioned for SSI detection via mobile phone
Total scorep	18	—	19	—	14	—

^aHas a clearly stated aim.

^bNot applicable/no description given.

^cIncludes all eligible patients.

^dCollected data according to a preestablished protocol.

^eThere was an appropriate endpoint to the aim of the study.

^fSSI: surgical site infection.

^gCDC-NHNS: Centers for Disease Control and Prevention-National Healthcare Safety Network.

^hThere was an unbiased assessment of the study endpoint.

ⁱHad an appropriate follow-up period.

^jHad a loss to follow up less than 5%.

^kProspectively calculated the study size.

^lUtilized an adequate control group.

^mStudy group was managed during the same time period as the control.

ⁿBaseline equivalence of the study group and control group.

^oAdequate statistical analysis.

^pOut of 24.