Table 3.
Summary of findings describing the effect of phosphate-specific medical nutrition therapy provided by a dietitian on serum phosphate levels
| Outcomes | Anticipated Absolute Effectsa (95% CI) | No. of Participants (studies) | Certainty of the Evidence (GRADE) | Comments | ||
|---|---|---|---|---|---|---|
| Risk with Usual Care | Risk with Phosphate-Focused Diet Therapy | |||||
| QALY; follow-up: 6 mo | Reference | — | 545 (one RCT) | ⊕⊕◯◯ lowb,c | Phosphate-focused diet therapy from a dietitian may result in little or no difference in QALY. | |
| Serum phosphate levels; follow-up: range, 2.5–12 mo | Reference | MD 0.76 mg/dld lower (1.12 lower to 0.41 lower) | Total: 1168 (12 RCTs) In meta-analysis: 1144 (11 RCTs) |
⊕⊕◯◯ lowe,f | The evidence suggests phosphate-focused diet therapy from a dietitian reduces serum phosphate levels. | |
| Serum phosphate levels; follow-up: 10 wk | Reference | MD 0.87 mg/dld lower (1.57 lower to 0.17 lower) | 61 (one nonrandomized study)g | ⊕⊕◯◯ lowh,i | The evidence suggests phosphate-focused diet therapy from a dietitian results in a reduction in serum phosphate levels. | |
| Adverse events; follow-up: 3 mo | Not estimable | Not estimable | 279 (one RCT) | ⊕⊕◯◯ lowc,g | Phosphate-focused diet therapy from a dietitian may result in little or no difference in adverse events. | |
GRADE Working Group grades of evidence: high certainty, we are very confident the true effect lies close to that of the estimate of the effect; moderate certainty, we are moderately confident in the effect estimate, the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different; low certainty, our confidence in the effect estimate is limited, the true effect may be substantially different from the estimate of the effect; very low certainty, we have very little confidence in the effect estimate, the true effect is likely to be substantially different from the estimate of the effect. ⊕⊕◯◯ indicates “low” certainty of evidence. 95% CI, 95% confidence interval; GRADE, Grading of Recommendations Assessment, Development, and Evaluation; QALY, quality-adjusted life-years; RCT, randomized controlled trial; MD, mean difference.
The risk in the intervention group (and its 95% CI) is determined on the basis of the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
Risk of bias from randomization and missing outcomes data.
One study only.
Conversion factors for units: serum phosphate levels in mg/dl to mmol/L ×3.096.
Of the 11 included studies, three had high risk of bias and eight had some concerns in risk of bias using the ROB 2.0 tool.
Heterogeneity of results was moderate I2=63.2%; wide 95% CI.
Risk of bias from randomization and deviations of intended intervention.
Some concerns in ROB as assessed by the ROBINS-I tool.
Small sample size and/or wide 95% CI.