Table 1 Items included in the methodological quality assessment.

Study participation

1

Setting of recruitment is described

2

Moment of identification is described and equal for all included children (inception cohort)

3

Percentage participation of eligible children is described

4

Inclusion and exclusion criteria are described and age, fever and relevant co-morbidity are reported

5

Baseline study sample is described for key characteristics age and sex

Study attrition

6

Number of loss to follow-up in cohort study/RCT is <20%, or the number missing for analysis (the difference between number included and number analyzed) in cross-sectional studies is <20%

7

Reasons for loss to follow-up/missing for analysis are provided

8

Key characteristics (at least age and sex) of participants lost to follow-up/missing for analysis do not differ significantly from the study sample

Prognostic factor measurement

9

Prognostic factor duration of fever: method of measurement is described and valid (thermometer)

10

Prognostic factor duration of fever: duration prior to presentation is described

11

Prognostic factor SBI: definition of diagnosis is described and valid

12

If continuous variables are used, they are reported as continuous variables or appropriate cut-off points (not data dependent) are used

Outcome measurement

13

A clear definition of the outcome (duration of fever, SBI or hospitalization) is provided

14

Method and setting of outcome measurement are the same for all study participants

15

SBI was assessed independently from the assessment of fever

Confounding measurement and account

16

Antipyretics use before and/or during the study is assessed and reported

17

Antibiotics use before and/or during the study is assessed and reported

18

Level of illness is measured and measurement method is appropriate (e.g. Yale score) and the same for all children

19

The potential confounders antipyretics use, antibiotics use and illness level are accounted for in the study design or analysis

Analysis

20

There is data presentation of the prognostic factors duration of fever and/or SBI

21

The association of prognostic factor and outcome is given in percentages or means/medians, or in OR/RRs with confidence interval/SD, or calculation of these measures is possible

22

A multivariate model is used in the analysis