Emma McMahon|Katrina L. Campbell|Judith Bauer|David W. Mudge
Altered dietary salt intake for people with chronic kidney disease
University of Queensland
background salt intake shows great promise modifiable risk factor reducing heart disease incidence delaying kidney function decline people chronic kidney disease ckd however clear consensus benefits reducing salt people ckd lacking objectives review evaluated benefits harms altering dietary salt intake people ckd search methods searched cochrane renal groups specialised register 13 january 2015 contact trials search coordinator using search terms relevant review selection criteria included randomised controlled trials rcts compared two levels salt intake people stage ckd data collection analysis two authors independently assessed studies eligibility conducted risk bias evaluation results expressed risk ratios rr 95 confidence intervals ci dichotomous outcomes mean difference md 95 ci continuous outcomes mean effect sizes calculated using randomeffects models main results included eight studies 24 reports 258 participants duration included studies short 1 26 weeks test effect salt restriction endpoints mortality cardiovascular events ckd progression changes salt intake blood pressure secondary risk factors applied three studies parallel rcts five crossover studies selection bias low five studies unclear three performance detection biases low two studies unclear six attrition reporting biases low four studies unclear four one study potential high carryover effect three high risk bias baseline characteristics change medication diet two studies industry funded significant reduction 24 hour sodium excretion associated low salt interventions range 52 141 mmol 8 studies 258 participants md 10586 mmold 95 ci 11920 9251 i2 51 reducing salt intake significantly reduced systolic blood pressure 8 studies 258 participants md 875 mm hg 95 ci 1133 616 i2 0 diastolic blood pressure 8 studies 258 participants md 370 mm hg 95 ci 509 230 i2 0 one study reported restricting salt intake reduced risk oedema 56 salt restriction significantly increased plasma renin activity 2 studies 71 participants md 108 ngmlh 95 ci 051 165 i2 0 serum aldosterone 2 studies 71 participants 620 ngdl 95 ci 382 858 i2 0 antihypertensive medication dosage significantly reduced low salt diet 2 studies 52 participants rr 548 95 ci 127 2366 i2 0 significant difference egfr 2 studies 68 participants md 114 mlmin173 m2 95 ci 438 211 i2 0 creatinine clearance 3 studies 85 participants md 460 mlmin 95 ci 1178 257 i2 0 serum creatinine 5 studies 151 participants md 514 moll 95 ci 898 1926 i2 59 body weight 5 studies 139 participants md 146 kg 95 ci 455 164 i2 0 significant change total cholesterol relation salt restriction 3 studies 105 participants md 023 mmoll 95 ci 057 010 i2 0 symptomatic hypotension 2 studies 72 participants rr 660 95 ci 077 5655 i2 0 salt restriction significantly reduced urinary protein excretion studies reported proteinuria outcome however data could metaanalysed authors conclusions found critical evidence gap longterm effects salt restriction people ckd meant unable determine direct effects sodium restriction primary endpoints mortality progression endstage kidney disease eskd found salt reduction people ckd reduced blood pressure considerably consistently reduced proteinuria reductions could maintained longterm effect may translate clinically significant reductions eskd incidence cardiovascular events research longterm effects sodiumrestricted diet people ckd warranted investigation adherence low salt diet