Fig. 1.
PRISMA flow diagram of search strategy and selection of studies.
Fig. 2.
Risk of bias summary: review authors’ judgements about each risk of bias item for each included study
Table 1.
Quality assessment of selected studies using Newcastle-Ottawa Scale (NoS)
| Study | Selection | Comparability | Outcome of interest | Overall Quality of study | |||||
|---|---|---|---|---|---|---|---|---|---|
| Representativeness of the exposed cohort | Selection of non-exposed cohort | Ascertainment of exposure | Outcome present at start of study | Comparability of cohorts | Assessment of outcome | Length of follow-up | Adequacy of follow-up | ||
| Vicic [2013] | * | * | * | * | * | * | * | Poor | |
| Song [2017] | * | * | * | * | * | * | * | * | Good |
| Bendavid [2019] | * | * | * | * | ** | * | * | * | Good |
| Koekkoek [2019] | * | * | * | * | ** | * | * | * | Good |
| Sim [2021] | * | * | * | * | ** | * | * | * | Good |
Table 2.
Basic characteristics of the selected studies
| Study/Year/Country | Study Type | Patient | Early Protein (EP) | Late Protein (LP) | Outcome measures | Reference No. |
|---|---|---|---|---|---|---|
| Casaer/ 2011/Belgium | Prospective randomized, control, parallel group, multicenter trial. |
| Within 48 hours of ICU | ≥8 days of ICU admission | Mortality, length of ICU stay, length of hospital stay, any new infection, metabolic complications, organ failure. | |
| Doig/2013/Australia | Randomized, single blind, multicenter clinical trial |
| Within 24 hours of admission | Standard care | Mortality (>60 days), ICU length of stay, hospital length of stay, infection, organ failure | |
| Vicic/2013/Croatia | Prospective multicenter cohort study |
| Within 4 hours of admission in ICU | After first wound dressing | Mortality, pneumonia, sepsis, renal failure, wound infection, multi-organ failure, bacterial and fungal infections. | |
| Sun/2013/China | Randomized controlled single center trial |
| Within 48 hours after admission | From the 8th day after admission | Mortality, length of ICU stay, pancreatic infection, multiple organ dysfunction, systemic inflammatory response syndrome (SIPS), surgery | |
| Bakkar/2014/Netherlands | Randomized controlled multicenter trial |
| Within 24 hours after randomization | Standard care 72 hours after presentation | Mortality, infected pancreatic necrosis, pneumonia, bacteremia, mechanical ventilation, organ failure, ICU length of stay. | |
| Li/2014/China | Randomized controlled single center trial |
| Post-operative day 2 | Standard care | Wound infection, urinary tract infection, post-operative fever, vomiting, nausea, bloating | |
| Mehmoodzadeh/2014/Iran | Randomized controlled single center trial |
| First post-operative day (oral) | No oral nutrition until the first bowel sounds returned and there was resolution of ileus. | Pneumonia, ICU length of stay, hospital length of stay, Rehospitalization, peritonitis, esophageal fistula, paralysis of the recurrent laryngeal nerve. | |
| Song/2017/Korea | Prospective single center cohort study |
| Within the first 24 hours of ICU admission | Standard care | ICU Mortality, 28 day mortality, hospital mortality, hospital length of stay. | |
| Bendavid/2019/Israel | Retrospective single center cohort study |
| Within first 3 days of ICU admission | After first 3 days of ICU admission | Mortality (60 days) | |
| Koekkoek/2019/Netherlands | Retrospective multicenter cohort study |
| <3 days of ICU admission | After 3 days of ICU admission | ICU mortality, hospital mortality, mortality (6 months), days on mechanical ventilation, ICU length of stay, hospital length of stay. | |
| Sim/2021/Korea | Retrospective cohort study |
| Within 48 hours of ICU admission | After 48 hours | Mortality (30 days), in-hospital mortality, infectious complications, pneumonia, ICU length of stay, hospital length of stay. | |
| Ortiz-Reyes/2022/USA | Randomized controlled multi-national trial |
| <48 hours from ICU admission | >48 hours from ICU admission | Mortality (60 days), multiple organ dysfunction syndrome (MODS), sepsis, days on mechanical ventilation, gut ischemia. | |
| Gao/2022/China | Randomized controlled multicenter trial |
| From day 3 after surgery | From day 8 after surgery | Nasocomial infections, infectious complications, non-infectious complications, adverse events, days on mechanical ventilation, ICU length of stay, hospital length of stay. |
Fig. 3.
Forest plot for mortality
Fig. 4.
Forest plot for infectious complications
Fig. 5.
Forest plot for overall complications
Fig. 6.
Forest plot for pneumonia
Fig. 7.
Forest plot for ICU length of stay
Fig. 8.
Forest plot for hospital length of stay
Fig. 9.
Forest plot for number of days on mechanical ventilation