Table 3.

Criteria for methodological quality used to select studies for detailed critical appraisal

Study design	Study quality criteria for inclusion
Randomized controlled trials	Included at least one group of participants with reduced sodium intake and one group with higher sodium intake (control group) Category III and IV outcomes ≥4 wk in duration; Category I, II, and V ≥1 y in duration ≥2.3 g/day difference of salt intake (920 mg sodium, 40 mmol) between intervention and control group Measured sodium intake using 24‐h urine collection The intervention group did not have concomitant interventions (ie, antihypertensive drugs or other dietary interventions) so that the only difference between the intervention and control groups must have been sodium intake
Cohort studies	Prospective Dietary sodium or sodium excretion alone as the primary exposure variable Included ≥400 patients (continuous outcomes) or events (dichotomous outcomes) Category III outcomes ≥4 wk in duration; category I, II, and V ≥1 y in duration Measured sodium intake for at least 24 h using 24‐h urine collection, food record, 24‐h food recall, or a semiquantitative food frequency questionnaire