TABLE 2.
Description of prospective cohort studies
| Author (Country) | Study design | Sample (%completed) | Patients included | Intervention | Clinical outcomes | Weight loss outcomes | Liver disease outcomes | Safety |
|---|---|---|---|---|---|---|---|---|
| Schwenger 2018 (Canada) | Prospective cohort study | 139 (N/A) | Bariatric surgery candidates, NAFLD | Meal replacement 900 kcal/day for a median of 2.6 weeks | Liver biopsy histological assessment, weight loss, waist circumference, lipids, LFTs, HOMA‐IR | Weight loss per week was 3.7 kg (9.6 kg total) | NAFLD diagnosed in 76.3% of patients (18.9% NASH), ALT and AST increased on VLCD | No adverse events reported |
| Hohenester 2018 (Germany) | Prospective cohort study | 121 (79.6%) | Obesity, NAFLD | 12 weeks of 800 kcal/day followed by normal diet to 52 weeks | Therapy response is 5% weight loss in BMI <35 and 10% in BMI of ≥35, LFTs, abdominal ultrasound, fatty liver index | With ITT analysis, 67.8% had a treatment response and 85.1% had per protocol response | FLI declined from 98.1% to 54.3% of patients; abnormal ALT declined from 81% to 50.5% of patients | No adverse events reported |
| D’Abbondanza 2020 (Italy) | Prospective cohort study | 70 (96%) | Obesity, NAFLD | 25 days of low carbohydrate diet (<50 g) 800 kcal or less per day | Body weight, waist circumference, body composition via bioimpedance, abdominal ultrasound, LFTs, hemoglobin A1c, HOMA‐IR | Average weight loss of 13 kg for males and 10 kg for females | Grade 3 steatosis decreased from 58.3% of male participants to 18.8% and from 41.7% of females to 18.2% | No adverse events reported |
| Watanabe 2020 (Italy) | Prospective cohort study | 45 (69%) | Obesity, NAFLD | 45 days of 800 kcal/day with meal replacements then 45 days of 1150 kcal/day | HSI, body weight changes, waist circumference, body composition, lipids, hemoglobin A1c, LFTs | Average weight loss of 8.6% ± 2.5% after the first phase and 12.5% ± 3.7% at the end | HSI decreased from 47.5 ± 7.5 to 33.5 ± 4.6. ALT decreased from 22 to 16. | No adverse events reported |
| Colles 2006 (Australia) | Prospective cohort study | 32 (86%) | Obesity, LAGB candidates, NAFLD | 12 weeks of 450–680 kcal/day meal replacement with non‐starchy vegetables | Body weight changes, BMI, waist circumference, liver volume, VAT, LFTs, hemoglobin A1c, lipids | Average weight loss of 14.8 ± 7.2 kg | Liver volume decreased 18.7%, VAT decreased 16.9%, and LFTs did not change | Four patients had taste intolerance, nausea and vomiting |
| Scragg 2020 (UK) | Prospective cohort study | 27 (90%) | Obesity, NAFLD | 8–12 weeks of 800 kcal/day with 4 weeks of food reintroduction and 20‐week weight maintenance phase | Feasibility and 10% weight loss at follow up, body weight, LFTs, glucose, lipids, hemoglobin A1c, elastography | 34% of patients had ≥10% weight loss at 9 months. At the end of VLCD 53% achieved ≥10% weight loss. Mean weight loss was 9.7% ± 5.8%. LSM improved between baseline and post‐VLCD (13.0 ± 6.7 to 7.9 ± 2.9 kPa) that was maintained at 9‐month (7.0 ± 2.0 kPa) | AST reduced from 35 ± 18 to 24 ± 14, ALT reduced from 47 ± 30 to 23 ± 10, and GGT reduced from 82 ± 74 to 35 ± 20 by 9 months | No adverse events reported |
| Lewis 2006 (Australia) | Prospective cohort study | 18 (85.7%) | LAGB candidates, NAFLD | 6 weeks of 450–800 kcal/day meal replacement | Liver size/fat content, weight loss, and ease of operative access | Average weight loss of 9.1 kg | Relative reduction in liver fat and volume were 43% and 14.7%, respectively | 3 patients did not tolerate VLCD |
| Haas 2020 (Sweden) | Prospective cohort sub‐study | 10 (90%) | Obesity, diabetes, NAFLD | 7 weeks of 800 kcal/day followed by 2‐week reintroduction and weight maintenance for a year | Body weight change, body composition, elastography to estimate hepatic steatosis, ALT, hemoglobin A1c | Average weight loss of 15 kg over 7 weeks | ALT reduced from 0.57 to 0.40 mmol/L | 1 participant had gastro‐intestinal adverse effects and dropped out after 3 weeks |
| Yu 2014 (China) | Prospective cohort study | 8 (N/A) | Obesity, NAFLD | 8 weeks of 800 kcal/day | Weight loss, body composition, liver fat, hepatic glucose production | Average weight loss of 7% (6.8 kg) | Relative liver fat percentage decreased 67% and HGP decreased 22% | No adverse events reported |
Abbreviations: ALT, alanine transaminase; AST, aspartate transaminase; BMI, body mass index; FLI, fatty liver index; GGT, gamma‐glutamyl transferase; HGP, hepatic glucose production; HOMA‐IR, homeostatic model assessment of insulin resistance; HSI, hepatic steatosis index; ITT, intention to treat analysis; LAGB, laparoscopic adjustable gastric banding; LFT, liver function test; NAFLD, nonalcoholic fatty liver disease; NASH, nonalcoholic steatohepatitis; VAT, visceral adipose tissue; VLCD, very‐low‐calorie diet.