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Table 2 Certainty of evidence of each outcome

From: Efficacy and safety of carnitine supplementation on NAFLD: a systematic review and meta-analysis

Outcome

Study results and measurements

Absolute effect estimates

Certainty of the evidence

Plain language summary

Placebo

L-carnitine

AEs

Relative risk: 0.72

(CI 95% 0.47–1.08)

Based on data from 192 participants in 3 studies

Follow-up 12 weeks

323 per 1000

233 per 1000

Moderatea

L-carnitine probably has little or no difference on AEs

Difference: 90 fewer per 1000 (CI 95% 171 fewer to 26 more)

Changes in the AST level

Measured by:

Scale: high better

Based on data from 406 participants in 6 studies

Follow-up 12/24 weeks

6.85

 

Lowb

L-carnitine may increase changes in the AST level

Mean

Mean

Difference: MD 15.89 lower (CI 95% 29.87 lower to 1.91 lower)

Changes in the ALT level

Measured by:

Scale: high better

Based on data from 406 participants in 6 studies

Follow-up 12/24 weeks

11.15

 

Lowb

L-carnitine may increase changes in the ALT level

Mean

Mean

Difference: MD 26.38 lower (CI 95% 45.46 lower to 7.30 lower)

Changes in the γ-GT level

Measured by:

Scale: high better

Based on data from 204 participants in 3 studies

Follow-up 12/24 weeks

12.9

 

Lowb

L-carnitine may have little or no difference in changes in the γ-GT level

Mean

Mean

Difference: MD 8.88 lower (CI 95% 25.43 lower to 7.67 lower)

Changes in the HDL cholesterol level

Measured by:

Scale: high better

Based on data from 204 participants in 3 studies

Follow-up 12/24 weeks

0.5

 

Moderatea

L-carnitine probably increases changes in the HDL cholesterol level

Mean

Mean

Difference: MD 1.14 higher (CI 95% 0.21 higher to 2.07 higher)

Changes in the LDL cholesterol level

Measured by:

Scale: high better

Based on data from 204 participants in 3 studies

Follow-up 12/24 weeks

5.4

 

Lowb

L-carnitine may have little or no difference in changes in the LDL cholesterol level

Mean

Mean

Difference: MD 6.8 lower (CI 95% 23.27 lower to 9.68 higher)

Changes in the total cholesterol level

Measured by:

Scale: high better

Based on data from 186 participants in 3 studies

Follow-up 12/24 weeks

6

 

Lowb

L-carnitine may have little or no difference in changes in the Total cholesterol level

Mean

Mean

Difference: MD 11.8 lower (CI 95% 27.13 lower to 3.53 higher)

Changes in the triglyceride level

Measured by:

Scale: high better

Based on data from 264 participants in 4 studies

Follow-up 12/24 weeks

6.24

 

Moderatea

L-carnitine probably increases changes in the triglyceride level

Mean

Mean

Difference: MD 6.92 lower (CI 95% 13.82 lower to 0.07 lower)

Changes in the BMI

Measured by:

Scale: high better

Based on data from 417 participants in 6 studies

Follow-up 12/24 weeks

0.45

 

Moderatea

L-carnitine probably has little or no difference in changes in the BMI

Mean

Mean

Difference: MD 0 lower (CI 95% 0.23 lower to 0.24 higher)

Changes in the waist circumference

Measured by:

Scale: high better

Based on data from 211 participants in 3 studies

Follow-up 12 weeks

1.5

 

Lowb

L-carnitine may have little or no difference in changes in the waist circumference

Mean

Mean

Difference: MD 0.57 lower (CI 95% 1.82 lower to 0.67 higher)

Changes in the weight

Measured by:

Scale: high better

Based on data from 291 participants in 4 studies

Follow-up 12/24 weeks

0.6

 

Moderatea

L-carnitine probably has little or no difference in changes in the weight

Mean

Mean

Difference: MD 0.2 lower (CI 95% 0.5 lower to 0.09 higher)

Changes in the hs-CRP

Measured by:

Scale: high better

Based on data from 123 participants in 2 studies

Follow-up 12 weeks

0.27

 

Very lowc

We are uncertain whether L-carnitine increases or decreases changes in the hs-CRP

Mean

Mean

Difference: MD 1.03 lower (CI 95% 3.23 lower to 1.16 higher)

  1. aRated down 1 level for risk of bias due to incomplete data
  2. bRated down 2 levels for risk of bias due to incomplete data and for serious inconsistency due to statistical heterogeneity
  3. cRated down 2 levels for risk of bias due to incomplete data, for serious inconsistency due to statistical heterogeneity, and for serious imprecision due to few patients