Table 3.
Meta-Regression of Weight Gain and Metabolic Parameters
| Outcome | Duration ≤13 wk | Duration >13 wka | ||||
|---|---|---|---|---|---|---|
| No. of studies | Coefficient (95% CI) | P value | No. of studies | Coefficient (95% CI) | P value | |
| Weight gain, kg | ||||||
| Duration, wk | 12 | 0.30 (0.11 to 0.50) | .002 | NA | – | – |
| Mean dose, mg | 12 | −0.17 (−0.40 to 0.05) | .13 | 7 | 0.59 (−0.30 to 1.48) | .19 |
| Completion rate, % | 10 | −0.002 (−0.060 to 0.055) | .93 | 7 | 0.03 (−0.02 to 0.09) | .25 |
| Mean age, y | 10 | −0.16 (−0.59 to 0.28) | .47 | 6 | −0.35 (−0.75 to 0.05) | .08 |
| Male, % | 11 | 0.06 (−0.02 to 0.14) | .15 | 7 | −0.01 (−0.15 to 0.14) | .93 |
| BMI, kg/m2 | ||||||
| Duration, wk | 9 | 0.06 (−0.10 to 0.22) | .48 | NA | – | – |
| Mean dose, mg | 9 | −0.04 (−0.18 to 0.10) | .58 | 3 | 0.11 (−0.50 to 0.73) | .71 |
| Completion rate, % | 8 | −0.01 (−0.03 to 0.01) | .44 | 3 | 0.01 (−0.01 to 0.03) | .33 |
| Mean age, y | 8 | −0.10 (−0.17 to −0.03) | .008 | 0 | – | – |
| Male, % | 9 | 0.031 (−0.01 to 0.07) | .12 | 3 | −0.02 (−0.06 to 0.01) | .19 |
| Blood glucose, mg/dL | ||||||
| Duration, wk | 9 | −0.39 (−1.58 to 0.81) | .52 | NA | – | – |
| Mean dose, mg | 9 | 0.72 (−0.02 to 1.46) | .057 | 5 | 1.01 (−0.01 to 2.04) | .053 |
| Completion rate, % | 7 | 0.00 (−0.23 to 0.23) | 1 | 5 | 0.01 (−0.13 to 0.14) | .94 |
| Mean age, y | 7 | 0.17 (−0.45 to 0.79) | .59 | 4 | −1.44 (−3.79 to 0.91) | .23 |
| Male, % | 8 | −0.01 (−0.43 to 0.41) | .97 | 5 | −0.01 (−0.25 to 0.24) | .95 |
| Insulin (µU/mL) | ||||||
| Duration, wk | 5 | −1.20 (−3.51 to 1.11) | .31 | NA | – | – |
| Mean dose, mg | 5 | −1.25 (−3.87 to 1.37) | .35 | 3 | −0.14 (−1.08 to 0.80) | .77 |
| Completion rate, % | 5 | −0.13 (−0.56 to 0.30) | .55 | 3 | −0.01 (−0.06 to 0.05) | .87 |
| Mean age, y | 4 | 1.03 (−0.18 to 2.24) | .10 | 0 | – | – |
| Male, % | 5 | 0.20 (−1.02–1.42) | .74 | 3 | 0.004 (−0.11 to 0.12) | .95 |
| HOMA-IR | ||||||
| Duration, wk | 4 | −0.05 (−0.25 to 0.15) | .64 | NA | – | – |
| Mean dose, mg | 4 | −0.01 (−0.23 to 0.20) | .90 | 1 | – | – |
| Completion rate, % | 4 | −0.02 (−0.04 to 0.003) | .08 | 1 | – | – |
| Mean age, y | 3 | −0.19 (−0.47 to 0.10) | .21 | 1 | – | – |
| Male, % | 4 | 0.05 (−0.03 to 0.13) | .19 | 1 | – | – |
| Total cholesterol, mg/dL | ||||||
| Duration, wk | 8 | 0.12 (−2.56 to 2.79) | .93 | NA | – | – |
| Mean dose, mg | 8 | −0.21 (−2.04 to 1.62) | .82 | 4 | 5.75 (−3.17 to 14.67) | .21 |
| Completion rate, % | 7 | 0.03 (−0.39 to 0.46) | .88 | 4 | 0.34 (0.17 to 0.51) | <.001 |
| Mean age, y | 7 | −0.49 (−1.19 to 0.22) | .18 | 3 | 3.27 (−5.21 to 11.74) | .45 |
| Male, % | 8 | −0.22 (−1.03 to 0.60) | .60 | 4 | −0.84 (−1.46 to −0.22) | .008 |
| Triglycerides, mg/dL | ||||||
| Duration, wk | 8 | −1.63 (−5.90 to 2.65) | .46 | NA | – | – |
| Mean dose, mg | 8 | 2.87 (−1.38 to 7.13) | .19 | 4 | 6.00 (−18.82 to 30.82) | .64 |
| Completion rate, % | 6 | 0.34 (−0.41 to 1.10) | .38 | 4 | −0.426 (−1.17 to 0.32) | .26 |
| Mean age, y | 6 | 1.74 (0.29 to 3.20) | .019 | 3 | −13.56 (−29.34 to 2.21) | .09 |
| Male, % | 7 | −0.26 (−1.82–1.30) | .74 | 4 | 0.16 (−1.60 to 1.92) | .86 |
| LDL cholesterol, mg/dL | ||||||
| Duration, wk | 5 | 0.83 (−1.37 to 3.03) | .46 | NA | – | – |
| Mean dose, mg | 5 | −1.02 (−2.92 to 0.87) | .29 | 3 | 4.89 (1.45 to 8.33) | .005 |
| Completion rate, % | 5 | −0.13 (−0.42 to 0.16) | .39 | 3 | 0.35 (−0.08 to 0.77) | .11 |
| Mean age, y | 4 | −0.52 (−0.65 to −0.38) | <.001 | 0 | – | – |
| Male, % | 5 | 0.29 (−0.77 to 1.34) | .59 | 3 | −0.35 (−1.28 to 0.57) | .45 |
| HDL cholesterol, mg/dL | ||||||
| Duration, wk | 7 | −0.07 (−1.05 to 0.91) | .89 | NA | – | – |
| Mean dose, mg | 7 | 0.39 (−0.37 to 1.15) | .31 | 4 | −0.36 (−2.18 to 1.46) | .70 |
| Completion rate, % | 5 | −0.05 (−0.32 to 0.22) | .72 | 4 | 0.04 (−0.03 to 0.11) | .22 |
| Mean age, y | 5 | −0.71 (−1.56 to 0.150) | .11 | 3 | 1.51 (0.69 to 2.34) | <.001 |
| Male, % | 6 | −0.11 (−0.57 to 0.35) | .63 | 4 | −0.05 (−0.22 to 0.11) | .51 |
Abbreviations: BMI, body mass index; HDL, high-density lipoprotein; HOMA-IR, Homeostatic Model Assessment for Insulin Resistance; LDL, low-density lipoprotein; NA, not applicable.
aAll studies with duration >13 weeks reporting on secondary outcomes have similar duration (52 weeks); thus, duration in weeks is not a feasible moderator variable.