Table 3 Summary of nonmodifiable factors

Biological sex

[23, 29, 39]

Female / M-A of 9 studies

2022_Yang_Zi

OR 1.34, 95% CI (1.06–1.71), p = 0.02; I² = 16%, p = 0.30

Female sex were significantly associated with ICUAW

Female / M-A of 4 studies, 19 individual studies

2017_Annoni

OR 1.6 95% CI (1.22–2.14);

I² = 0% p = 0.46

M-A of 4 studies shows a significant association. Low heterogeneity. Female gender was associated with ICUAW in 5 of 19 individual studies

Female / 1 study

2018_Yang_2

Not M-A

OR 4.66 95% CI (1.19–18.30)

p = 0.02

Associated with increased odds of developing ICUAW on multivariate analysis in each single studies

Age [23, 29, 39]

Age / M-A of 8 studies

2022_Yang_Zi

MD 6.33 95% CI (5.05–7.61); p < 0.00001; I² = 50%, p = 0.06

MD age was higher in individuals with ICU-AW, and it was statistically significant

Age, M-A of 5 studies

2018_Yang_2

OR 1.01; 95% CI (0.99–1.03); I² = 82.4%

There was no significant association found between age and ICUAW based on the overall effect size. High heterogeneity

M-A of 5 studies, 19 individual studies

2017_Annoni

MD 3.46 95% CI (0.94–5.98); I² = 18% p = 0.30

M-A shows a significant association (low heterogeneity). 4 of 19 studies reported a positive association between older age and ICUAW

Comorbidities [39]

Diabetes / M-A of 2 studies, 7 individual studies

2017_Annoni

OR 1.27; 95% CI (0.75–2.15); I² = 22%, p = 0.26

History of diabetes was not associated with ICUAW in any of seven studies or in M-A of 2 studies. Low heterogeneity

Severity of illness at ICU admission: APACHE [23, 29, 36, 39]

APACHE II / M-A of 9 studies

2022_Yang_Zi

MD 4.78 CI 95% (1.96–7,60), I² = 93%, p = 0.0009

M-A shows association with very high heterogeneity

APACHE II / M-A of 5 studies

2018_Yang_2

OR 1.05 CI 95% (1.01–1.10); I² = 79%

The overall effect size demonstrated a statistically significant association of APACHE II with ICUAW, with high heterogeneity

APACHE II / M-A of 3 studies, 20 individual studies

2017_Annoni

MD 3.52 CI 95% (1.47–5.57); I² = 64%, p = 0.06

M-A shows a significant association, with high heterogeneity. Severity of illness were positively associated with ICUAW in 12 of 20 studies

APACHEII > 15 / 1 study

2018_Yang_2

Not M-A

RR 11.6 CI 95% ( 4.9–27.2)

The result of an individual study indicates that an APACHEII > 15 is associated with ICUAW

APACHE III and SIRS / 1 study

2006_Hohl

Not M-A

Overall incidence of CIPNM was 33%

APACHE III score and the presence of SIRS were predictors for the development of CIPNM. The overall incidence of CIPNM in this sample of 98 patients was 33%

Systemic inflammatory response syndrome: SIRS [23, 36]

SIRS / M-A of 3 studies

2022_Yang_Zi

OR 2.24 CI 95% (0.57–9.56); I² = 81%

Not found consistent evidence that sepsis have any effect on ICUAW risk

SIRS

2018_Yang_2

Not M-A

OR 3.75 CI (1.59–8.86) p = 0.003

Result of an independent study, were significantly associated with ICUAW

SIRS 1 week (d) > 3

2018_Yang_2

Not M-A

RR 3.74 CI (1.37–10.2) p < 0.05

Were regarded as significant risk factors for ICUAW development based on multivariate analysis of one single study

SIRS and APACHE III

2006_Hohl

Not M-A

A study categorized patients based on the presence of SIRS to determine risk groups for developing CIPNM. The risk categories for assessing patients level of risk are as follows: high risk (72%): initial APACHE III score ≥ 85 and SIRS, medium risk (28%): APACHE III score 71–84, low risk (8%): APACHE III score ≤ 70 and absence of SIRS

Sepsis [22, 23, 29, 39]

Sepsis / M-A of 3 studies

2022_Yang_Zi

OR 1.27, IC 95% (0.41–3.96) p = 0.67;

I² = 77%, p = 0.04

Reviews found significant heterogeneity in the results. Sensitivity analyses had minimal impact on overall estimates and did not eliminate heterogeneity

Sepsis and corticosteroids / M-A of 4 studies

2018_Yang_1

OR 1.96 CI 95% (0.61–6.30) p = 0.6260;

I² = 80.8%

p = 0.001

Four trials with sepsis participants reported an association between the use of corticosteroids and ICUAW, and demonstrated an incidence of 34% in the corticosteroid group and 30% in the control group. The pooled effect revealed no significant association, with high heterogeneity

Sepsis (on admission) / M-A of 3 studies

2017_Annoni

OR 1.48; CI 95% (1.09–2.00); I² = 0%, p = 0.62

A M-A shows significative association, with low heterogeneity. Sepsis on admission were positively associated with ICUAW in two of 11 studies

Sepsis /

1 study

2018_Yang_2

Not M-A

OR, 2.20 CI 95% (1.30–3.71) p < 0.05

Result of an independent study, were significantly associated with ICUAW

Days with sepsis /

1 study

2018_Yang_2

Not M-A

HR, 1.48 CI 95% (1.22–1.81) p < 0.05

Result of an independent study, were significantly associated with ICUAW

Organ Failure: Sequential organ failure assessment: SOFA, Multiple organ failure: MOF [23, 29, 38, 39]

SOFA / M-A of 2 studies

2022_Yang_Zi

OR 1.07, 95% CI: 0.24–1.90; p = 0.01; I² = 0% p = 0.44

The combined effect was statistically significant with ICUAW

SOFA / M-A of 2 studies

2018_Yang_2

OR 0.99; CI 95% (0.92–1.08); I² = 6.6%

p = 0.301

M-A reveals no significant association

SOFA / M-A of 4 studies, 13 individual studies

2017_Annoni

MD 1.96; 95% CI (1.41–2.50); I² = 0% p = 0.77

M-A reveals significant association, with low heterogeneity. Also SOFA were positively associated with ICUAW in five of 13 studies

MOF SOFA > 7 score / 1 study

2018_Yang_2

Not M-A

RR, 2.03 CI 95% (1.02–4.12), p < 0.05

Individual studies indicated that a SOFA > 7 were independent risk factors for ICUAW

MOF SOFA > 45 score / 1 study

2018_Yang_2

Not M-A

RR 2.38; 95% CI (1.02–5.53) p < 0.05

Individual studies indicated that a total SOFA score during the first week > 45 were independent risk factors for ICUAW

Organ failure / 4 individual studies

1998_DeJonghe

Not M-A

Not data

Two studies reported abnormalities in 70% and 82% of patients, with axonal neuropathy being the most prevalent in CIP. In the other two studies, primary muscle disease was observed in 78% of patients, often accompanied by signs of denervation related to axonopathy

Shock [23]

2018_Yang_2

Not M-A

OR 2.58; CI 95% (1.02–6.51) p = 0.045

Result of an independent study, were significantly associated with ICUAW

Infectious disease [29]

M-A of 4 studies

2022_Yang_Zi

OR 1.67, 95% CI (1.20–2.33) p = 0.002; I² = 0% p = 0.002

M-A of 4 studies a reveals significant association, with low heterogeneity

Neurologic failure [23]

Neurologic failure (GSC < 10) / 1 study

2018_Yang_2

Not M-A

OR 24.02

CI 95% (3.68–156.7) p = 0.001

Result an individual study reveal an association between ICUAW and neurological failure (correlated with the GCS sub score of the SOFA)

Mechanical ventilation [22, 23, 28, 29, 31, 33, 36, 38, 39]

Duration of MV (days) / M-A of 5 studies

2022_Yang_Zi

OR 2.73 CI 95% 1.65 a 3.80 p < 0.00001; I² = 76% p = 0.005

The M-A result indicates an association between MV and ICU-AW, but significant heterogeneity was observed. Sensitivity studies excluding trials with a relatively small sample size showed no significant change in the overall estimate, but heterogeneity persisted

Duration of MV (days) / M-A of 11 studies

2020_Medrinal

Standard MD 0.69 CI 95%

(0.50–0.87); I² = 57.28%

Muscle weakness was often associated with a longer duration of MV and a longer ICU LOS

MV and corticosteroids / M-A of 12 studies

2018_Yang_1

OR 2.00 CI 95% (1.23–3.27) p = 0.006; I² = 66.0%

Twelve studies using MV and use of corticosteroids showed an event rate of 50% in the corticosteroid group and 40% in the control group. The overall effect size: Significant association, random effects model, considering heterogeneity

Duration of MV (days) / M-A of 5 studies

2017_Annoni

MD 4.50 95% CI (2.00–7.01); I² = 85% p < 0.0001

11 out of 15 studies showed a positive association with ICUAW, Duration of MV in ICUAW patients: 2–33 days v/s 1–18 days, with high heterogeneity

Duration of MV / 1 study

2018_Yang_2

Not M-A

OR 1.10 CI 95% (1.00–1.22) p = 0.049

Results of a multivariate analysis of a single independent study indicate an association with increased odds of developing ICUAW

Duration of MV and LOS / 2 individual studies

2012_Ydemann

Not M-A

In the analysis of 2 studies, CIPNM significantly increases the length of MV and the lengths of ICU and hospital stays. In patients with CIPNM and MV for more than seven to ten days, the mortality increases from 19–56.5% to 48–84%

Duration of MV (days) and ICU LOS / 3 individual studies

2010_Prentice

Not M-A

No significant differences in the duration of MV, ICU LOS, and weaning time were found among patients with CIP based on various measures in the analysis of three independent studies

Duration of MV (days) / 1 study

2006_Hohl

Not M-A

The results of an independent study indicate that the probability of developing CIPNM within 30 days of artificial ventilation varied from 8% in the low-risk group to 72% in the high-risk group

Duration of MV (days) / 3 individual studies

1998_DeJonghe

Not M-A

In a report of three independent studies on a population of patients ventilated for over 5 days, 76% showed electrophysiologic abnormalities. Two of the studies demonstrated a significant increase in MV duration (5 and 9 days) and double the mortality rate in patients with critical illness neuromuscular abnormalities compared to those without

ICU Length of stay

(ICU-LOS) [29, 32, 39]

M-A of 5 studies

2022_Yang_Zi

MD 3.78 CI 95% (2.06–5.51); I² = 88%, p < 0.0001

Sensitivity analysis revealed a significant association between the explored factors, accompanied by notable heterogeneity

6 individual studies

2017_Annoni

Not M-A

MD 8.60 CI 95% (4.72–12.48), I² = 85% p = 0.00001

ICU LOS of ICUAW patients ranged from 6 to 41 days and from 4 to 28 days in patients without ICUAW. 17 studies reported that patients with ICUAW stayed in ICU longer than patients without ICUAW

5 individual studies

2017_Sanchéz-Solana

Not M-A

Mean ICU LOS was generally higher for patients with CIPNM than those without, as seen in 5 primary studies. However, one study showed a slightly longer ICU stay for patients without neuromuscular changes, but the association was not statistically significant

Others: Highest lactate level [23]

1 study

2018_Yang_2

Not M-A

OR 2.18 CI 95% (1.3–3.43) p < 0.05

Results of a multivariate analysis of a single independent study indicate an association with increased odds of developing ICUAW

Others: Hyperosmolality [23]

1 study

2018_Yang_2

Not M-A

OR 4.8, 95% CI (1.05, 24.38) p = 0.046

Results of a multivariate analysis of a single independent study indicate an association with increased odds of developing ICUAW

Others: Electrolyte disturbances [23]

1 study

2018_Yang_2

Not M-A

OR 2.48; 95% CI (1.02, 6.01) p = 0.044

Result of an independent study, were significantly associated with ICUAW

Others: Severe Burns Injury [34]

7 individual studies

2017_Mc Kittrick

Not M-A

Incidence %: 4.4% gender: 71% males, age mean: 39,7 years

Analysis of 7 PCS with 2755 burned subjects revealed a 4.4% incidence of critical polyneuropathy. Severe burn injury increases ICU stay and risk of polyneuropathy

Others: Dysfunctions in respiratory muscles [33]

11 individual studies

2010_Prentice

Not M-A

The 11 analyzed studies showed milder respiratory muscle dysfunction compared to peripheral muscles in critically ill patients. One study found that low MIP, low MEP (< 30 cm H2O), and a low MRC sum score (< 41) independently predict delayed successful extubation for 7 or more days (8.02, 4.14, and 3.03 times higher risk, respectively)