Fifteen studies (766 paired liver biopsies) were included in the review. Eight studies (401 paired liver biopsies) were prospective studies and seven (365 paired liver biopsies) were retrospective studies.
The percentage reduction in BMI ranged from 19.1 to 41.76 kg/m2 (where stated).
The pooled proportion of patients with improvement or resolution of steatosis was 91.6% (95% CI: 82.4, 97.6, 15 studies), steatohepatitis was 81.3% (95% CI: 61.9, 94.9, nine studies) and fibrosis was 65.5% (95% CI: 38.2, 88.1, five studies). The pooled proportion of patients with complete resolution of steatohepatitis was 69.5% (95% CI: 42.4, 90.8; 9 studies). All meta-analyses were subject to significant heterogeneity (I2 >88%).
Subgroup analyses or sensitivity analyses did not significantly affect the results. Publication bias was observed.