The role of vitamin D in outcomes of critical care in COVID-19 patients: Evidence from an umbrella meta-analysis of interventional and observational studies

OBJECTIVES

Several meta-analyses have suggested the beneficial effect of vitamin D on patients infected with SARS-CoV-2. This umbrella meta-analysis aims to evaluate influence of vitamin D supplementation on clinical outcomes and the mortality rate of COVID-19 patients.

DESIGN

Present study was designed as an umbrella meta-analysis. The following international databases were systematically searched till March 2023: Web of Science, PubMed, Scopus, and Embase.

SETTINGS

Random-effects model was employed to perform meta-analysis. Using AMSTAR critical evaluation tools, the methodological quality of the included meta-analyses was evaluated.

PARTICIPANTS

Adult patients suffering from COVID-19 were studied.

RESULTS

Overall, 13 meta-analyses summarizing data from 4 RCTs and 9 observational studies were identified in this umbrella review. Our findings revealed that vitamin D supplementation and status significantly reduced mortality of COVID-19 [Interventional studies: (ES= 0.42; 95% CI: 0.10, 0.75, p <0.001; I2 = 20.4%, p=0.285) and observational studies (ES= 1.99; 95% CI: 1.37, 2.62, p <0.001; I2 = 00.0%, p=0.944). Also, vitamin D deficiency increased risk of infection and disease severity among patients.

CONCLUSION

Overall, vitamin D status is a critical factor influencing the mortality rate, disease severity, admission to ICU and being detached from mechanical ventilation. It is vital to monitor the vitamin D status in all patients with critical conditions including COVID patients.

Inositol supplementation and body mass index: A systematic review and meta‐analysis of randomized clinical trials

Background

Inositol is a sugar‐alcohol and recognized as a key component of cell membrane phospholipids. It has crucial role in the cell signaling pathways and contribute to improving glycemic responses. Although some earlier studies have revealed the effect of inositol mediating glucose uptake by improving insulin sensitivity, the benefit of inositol supplementation in patients with overweight and obesity is not completely understood. This study aimed to assess the impact of inositol supplementation on body mass index (BMI) through a systematic review and meta‐analysis of controlled clinical trials.

Methods

A systematic search was performed to August 2021 in the following databases: PubMed‐Medline, Embase, Web of Science and Scopus. Fifteen controlled clinical trials investigating the effect of inositol on adult's BMI were finally included in the study. A random‐effects model was employed to estimate the effect size. Subgroup analysis was performed by dose, duration, age, type of inositol. Meta‐regression was used to investigate presence of any linear relationship. Begg's and Egger's tests were carried out to detect small study effect.

Results

The results of pooled analysis showed that inositol supplementation significantly decreased BMI scores (WMD = −0.41 kg/m²; 95% CI: −0.78, −0.04; p = 0.028). Subgroup analysis was performed to identify the source of heterogeneity among studies (I² = 73.9%, p < 0.001), demonstrating supplementation duration, baseline BMI, mean age of participants, type of inositol and dosage were potential sources of heterogeneity. The effect of intervention was more clinically significant in participants with polycystic ovary syndrome (PCOS) and overweight/obesity. Inositol in the form of myo‐inositol (MI) had stronger effect on BMI reduction.

Conclusion

The meta‐analysis suggests that oral inositol supplementation has positive effect on BMI reduction. Inositol supplementation could be considered as an adjunct treatment to improve body mass index.