Table 4.
RCTs studying the effect of sodium reduction using sodium supplements among people with diabetes
| Study | Design | Comparison | N | Age (yrs) | Males (%) | Race | Population | Study Dur (wks) | BP Δ in lower sodium group | BP Δ in higher sodium group | Between-group Difference in BP Δ (lower sodium-higher sodium) | Contrast in 24-hour urine sodium |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lopes de Faria, 1997 (52) | Crossover study | Regular sodium diet (100mmol or 2300mg)* vs. high sodium supplement (300mmol or 6900mg)* | 10 | 30 | 70 | NR | Type 1 diabetes, normotensive, normoalbuminuria | 1 | NR | NR | MAP was similar in both diets, †between-group 2.0mmHg, p=0.25 | UNa excretion lower in regular vs. high sodium diet, 99±27mmol/day and 293±80mmol/day respectively; between-group diff NR, p<0.0001 |
| Muhlhauser, 1996 (53) | Parallel study | Sodium supplement (100 mmol or 2300mg sodium)* vs. placebo, while on 90mmol or 2070mg sodium diet | 14 | 31 | 75 | NR | Type 1 diabetes, increased proteinuria, high normal or mildly hypertensive BP | 4 | Clinic SBP change, 3.2 mmHg (−2.6 to 9) Clinic DBP change, 2.2 mmHg (−1.8 to 6.2) |
Clinic SBP change, −1.7 mmHg (−8.6 to 5.3) Clinic DBP change, −3.1 mmHg (−5.9 to −0.4) |
Clinic SBP: 4.9 mmHg (−3.3 to 13.1), p=0.22 Clinic DBP: 5.3 mmHg (1 to 9.7), p=0.02 |
UNa excretion greater in supplement vs placebo group, 199±52mmol/day and 92±33mmol/day respectively, between-group diff NR, p=0.0002 |
| Petrie, 1998 (54) | Crossover study | Sodium supplement (120 mmol or 3680mg sodium)* vs. placebo, while on 40 mmol or 920mg sodium diet* | 9 | 57 | 89 | White: 100% | Type 2 diabetes, diet controlled, without retinopathy or microalbuminuria | 5 days | NR | NR |
†Between-group diff in SBP 2.0mmHg, p=0.66 †Between-group diff in DBP 5.0mmHg, p=0.15 |
UNa excretion greater reduction in high vs. low sodium group, 197±76.0 mmol/day and 67±19.5 mmol/day respectively, between-group diff NR, p=0.03 |
| Suckling, 2016 (55) | Crossover study | Salt tablet (90mmol salt or 2053mg sodium)* vs. placebo, while on reduced salt diet (90mmol salt or 2053mg sodium)* | 26 | 56 | 54 | White: 65% Black: 23% Asian: 12% |
Type 2 diabetes, diet-controlled, untreated normal or high normal BP | 6 | NR | NR | BP lower in low vs. high sodium diet, between-group diff in SBP −4.2 mmHg (p<0.01) and DBP of −1.7 mmHg (p=0.055) | UNa excretion lower in low vs. high sodium group, between-group difference −48.6±9.3 mmol (p<0.001) |
Abbreviations: DBP, diastolic blood pressure; MAP, mean arterial pressure; NR, not reported; NS, non-significant; SBP, systolic blood pressure; UNa, urine sodium
*
Sodium content converted from mmol or mEq of sodium or sodium chloride to mg of sodium based on guidance from CDC: https://www.cdc.gov/salt/sodium_toolkit.htm
†
Calculated between-group difference