Table 2.
Summary of systematic reviews analysing the role of probiotics on clinical outcomes
| Outcome | Reference | No of studies/participants | Evidence of benefit? | Results/conclusions |
|---|---|---|---|---|
| Clostridium difficile associated diarrhoea in adults and children | Goldenberg et al (2017)111 | 39/9955 | Yes | Moderate quality evidence that probiotics are safe and effective for preventing C difficile associated diarrhoea. (RR 0.30, 95% CI 0.21 to 0.42) |
| Necrotising enterocolitis | Al Faleh et al (2014)112Rees et al (2017)113 | 17/5338 | Yes | Enteral supplementation of probiotics prevents severe necrotising enterocolitis (RR 0.43, 95%CI 0.33 to 0.56) and all cause mortality in preterm infants (RR 0.65, 95% CI 0.25 to 0.81) |
| Antibiotic associated diarrhoea in children | Goldenberg et al (2015)114 | 26/3898 | Yes | Moderate evidence of a fall in the incidence of antibiotic associated diarrhoea in the probiotic v control group (RR 0.46, 95% CI 0.35 to 0.61; I2=55%, 3898 participants) |
| Probiotics for preventing acute upper respiratory tract infections | Hao et al (2015)115 | 12/3720 | Yes | Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute upper respiratory tract infections, the mean duration of an episode , antibiotic use, and related school absence (12 trials, 3720 participants including children, adults, and older people) |
| Urinary tract infections | Schwenger et al (2015)116 | 9/735 | No | No significant benefit for probiotics compared with placebo or no treatment |
| Prevention of asthma and wheeze in infants | Azad et al (2013)117 | 6/1364 | No | No evidence to support a protective association between perinatal use of probiotics and doctor diagnosed asthma or childhood wheeze |
| Prevention of eczema in infants and children | Mansfield et al (2014) | 16/2797 | Yes | Probiotic supplementation in the first several years of life did have a significant impact on development of eczema (RR 0.74, 95% CI 0.67 to 0.82) |
| Prevention of invasive fungal infections in preterm neonates | Agrawal et al (2015) 119 | 19/4912 | Unclear | Probiotic supplementation reduced the risk of invasive fungal infections (RR 0.50, 95% CI 0.34 to 0.73, I2=39%) but there was high heterogeneity between studies. Analysis after excluding the study with a high baseline incidence (75%) showed that probiotic supplementation had no significant benefits (RR 0.89, 95% CI 0.44 to 1.78) |
| Prevention of nosocomial infections | Manzanares et al (2015)120 | 30/2972 | Yes | Probiotics were associated with a significant reduction in infections (RR 0.80, 95%CI 0.68 to 0.95, P=0.009; I2=36%, P=0.09). A significant reduction in the incidence of ventilator associated pneumonia was found (RR 0.74, 95% CI 0.61 to 0. 90, P=0.002; I2=19%) |
| Treatment of rotavirus diarrhoea in infants and children | Ahmadi et al (2015)121 | 14/1149 | Yes | Probiotic supplementation resulted in a mean difference of −0.41 (CI 95% −0.56 to −0.25; P<0.001) in the duration of diarrhoea. Probiotics exert positive effect on reducing the duration of acute rotavirus diarrhoea compared with control |
| Prevention and treatment of Crohn’s disease and ulcerative colitis | Saez Lara et al (2015)122 | 14/821 ulcerative colitis 8/374 Crohn’s disease |
Yes | The use of probiotics and/or synbiotics has positive effects in the treatment and maintenance of ulcerative colitis, whereas in Crohn’s disease clear effectiveness has only been shown for synbiotics (no meta- analysis was performed) |
| Pulmonary exacerbations in children with cystic fibrosis | Ananathan et al (2016)123 | 9/275 | Yes | Significant reduction in the rate of pulmonary exacerbation (two parallel group randomised controlled trials and one crossover trial: RR 0.25, 95% CI 0.15 to 0.41; P< 0.00001) |
| Type 2 diabetes (fasting glucose, glycated haemoglobin test) | Akbari et al (2016)124 | 13/805 | Yes | Probiotics significantly reduced fasting blood glucose compared with placebo (8 studies; standardised mean difference −1.583; 95% CI −4.18 to 4.18; P = 0.000). Significant reduction in HbA1c was also seen (6 studies; SMD −1.779; 95% CI, −2.657 to −0.901; P = 0.000) |
| Type 2 diabetes (insulin resistance, insulin levels) | Zhang et al (2016)125 | 7/425 | Yes | Probiotic therapy significantly decreased homeostasis model assessment of insulin resistance (HOMA-IR) and insulin concentration (WMD: −1.08, 95% CI −1.88 to −0.28; and weighted mean difference −1.35mIU/L, 95% CI -−2.38 to −0.31, respectively |
| Necrotising enterocolitis in pre-term neonates with focus on Lactobacillus reuteri | Athalye-Jape et al (2016)126 | 6/1778 | Yes | Probiotic reduced duration of hospitalisation (mean difference = −10.77 days, 95% CI −13.67 to −7.86; in 3 randomised controlled trials), and late onset sepsis (RR 0.66; 95% CI, 0.52 to 0.83; 4 RCTs) were reduced in the |
| Reduction of serum concentration of C reactive protein | Mazidi et al (2017)127 | 19/935 | Yes | Significant reduction in serum C reactive protein after probiotic administration with a WMD −1.35 mg/L, (95% CI −2.15 to −0.55, I2 65.1%) |
| Cardiovascular risk factors in patients with type 2 diabetes | Hendijani et al (2017)128 | 11/641 | Yes | Probiotic consumption significantly decreased systolic blood pressure (−3.28 mm Hg; 95% CI −5.38 to −1.18), diastolic (WMD −2.13 mm Hg; 95% CI −4.5 to 0.24), low density lipoprotein cholesterol (WMD 8.32 mg/dL; 95% CI −15.24 to −1.4), total cholesterol (WMD −12.19 mg/dL; 95% CI −17.62 to −6.75) and triglycerides(WMD −24.48 mg/dL; 95% CI −33.77 to −11.18) compared with placebo |
| Reduction of total cholesterol and low density lipoprotein cholesterol | Wu et al (2017)129 | 15/976 | Yes | Lactobacillus consumption significantly reduced total cholesterol by 0.26 mmol/L (95% CI −0.40 to −0.12) and LDL-C by 0.23 mmol/L (95% CI, −0.36 to −0.10) |
| Depressive symptoms | Wallace, and Milev (2017)79,130 | 6/1080 | Yes | No quantitative analysis was performed. Most studies found positive results, and the authors conclude that compelling evidence shows that probiotics alleviate depressive symptoms |
| Vulvovaginal candidiasis in non-pregnant women | Xie et al (2018)131 | 10/1656 | Yes | Probiotics increased the rate of short term clinical cure (RR 1.14, 95% CI 1.05 to 1.24, low quality evidence) and mycological cure (RR 1.06, 95% CI 1.02 to 1.10, low quality evidence) and decreased relapse rate at one month (RR 0.34, 95% CI 0.17 to 0.68, low quality evidence) |
| Chronic periodontitis | Ikram et al (2018) 132 | 7/220 | Yes | The overall mean difference for gaining clinical attachment level gain between probiotics and placebo was significant (weighted mean difference 1.41, 95% CI 0.15 to 2.67, P=0.028) |
RR=risk ratio, SBP systolic blood pressure, DBP= diastolic blood pressure, TC= total cholesterol, TG=serum triglycerides, SMD=standardised mean difference, WMD=weighted mean difference’ CI=confidence interval