Table 3.

Certainty assessment (Factors)

Nº of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Effect	Certainty
Age: [38] Harrold, [39] Adams 2001, [35] Williams, [37] Stark
4	observational studies	seriousa	seriousb	not serious	seriousc	all plausible residual confounding would reduce the demonstrated effect	Most studies showed increased workload with patient´s age	⨁⨁◯◯ Low
Gender: [38] Harrold, [39] Adams 2001
2	observational studies	not seriousa	not serious	not serious	seriousd	all plausible residual confounding would reduce the demonstrated effect	Higher workload in man	⨁⨁⨁⨁ High
Functional status: [32] Bonifassi, [38] Harrold
2	observational studies	seriousa	not serious	Very seriouse,f	seriousa,c	all plausible residual confounding would reduce the demonstrated effect dose response gradient	Increased workload in patients with poorer functional status	⨁⨁◯◯ Low
Clinical diagnoses: [38] Harrold J, [28] Adams 2000, [29] Lee, [44] Trisolini, [35] Williams, [34] Cox,
6	observational studies	seriousa	not serious	seriousf	seriousa,c	all plausible residual confounding would reduce the demonstrated effect	There is an association between workload and the number or type of clinical diagnoses of patients	⨁⨁◯◯ Low
Visit type: [44] Trisolini, [30] Payne
2	observational studies	seriousa	Not serious	Seriousf	Seriousc	all plausible residual confounding would reduce the demonstrated large effect	New admissions increased workload	⨁⨁⨁◯ Moderate
Rural environment: [39] Adams 2001
1	observational studies	not serious	not serious	not serious	not serious	strong association all plausible residual confounding would reduce the demonstrated effect dose response gradient	Living in a rural locale increased workload comparison to living in an urban locale	⨁⨁⨁⨁ High

^a Convience sample overall the studies

^b Different results on effect size, direction of association and significance

^c Precision of results not reported in most of the studies

^d The standard error of some of the studies is large

^e Very specific population. Generalization problems

^f Different ways of measuring outcome (workload) and factor