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1.
Efficacy and safety of adjuvant curcumin therapy in ulcerative colitis: A systematic review and meta-analysis.
Yin, J, Wei, L, Wang, N, Li, X, Miao, M
Journal of ethnopharmacology. 2022;:115041
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Curcumin, an active polyphenol extracted from Traditional Chinese medicine Curcuma longa (turmeric), has shown many health-related benefits and pharmacological effects. Adjuvant curcumin therapy for ulcerative colitis has become increasingly popular, but its efficacy and safety of which is still controversial. The purpose of this study is to evaluate the efficacy and safety of adjuvant curcumin therapy in ulcerative colitis. MATERIALS AND METHODS The Medline, EMBASE, the Cochrane Library, CNKI, VIP, WanFang, and SinoMed databases were searched from inception to June 2021, to identify all randomized controlled clinical trials with adjuvant curcumin therapy in ulcerative colitis. The primary outcomes were clinical and endoscopic remission, and subgroup analyses were also performed. RESULTS Six randomized trials with a total of 385 participants were included in this study. Qualified trials recommended that adjuvant curcumin therapy for ulcerative colitis was effective in inducing clinical remission (RR = 2.10, 95% CI 1.13 to 3.89), but not in clinical improvement (RR = 1.62, 95% CI 1.00 to 2.61), endoscopic remission (RR = 4.17, 95% CI 0.63 to 27.71) or endoscopic improvement (RR = 4.13, 95% CI 0.20 to 87.07). Included studies showed that appropriate dosage, formation, longer duration, and topical medication may have a greater potential advantage. No severe adverse effects had been reported. CONCLUSIONS Available evidence suggested that adjuvant curcumin therapy may be effective for clinical remission in ulcerative colitis patients without causing severe adverse effects. The appropriate methods of administration can achieve better curative effect, which requires further study to verify.
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2.
Interventions for treating iron deficiency anaemia in inflammatory bowel disease.
Gordon, M, Sinopoulou, V, Iheozor-Ejiofor, Z, Iqbal, T, Allen, P, Hoque, S, Engineer, J, Akobeng, AK
The Cochrane database of systematic reviews. 2021;(1):CD013529
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Abstract
BACKGROUND Inflammatory bowel disease affects approximately seven million people globally. Iron deficiency anaemia can occur as a common systemic manifestation, with a prevalence of up to 90%, which can significantly affect quality of life, both during periods of active disease or in remission. It is important that iron deficiency anaemia is treated effectively and not be assumed to be a normal finding of inflammatory bowel disease. The various routes of iron administration, doses and preparations present varying advantages and disadvantages, and a significant proportion of people experience adverse effects with current therapies. Currently, no consensus has been reached amongst physicians as to which treatment path is most beneficial. OBJECTIVES The primary objective was to evaluate the efficacy and safety of the interventions for the treatment of iron deficiency anaemia in people with inflammatory bowel disease. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, and two other databases on 21st November 2019. We also contacted experts in the field and searched references of trials for any additional trials. SELECTION CRITERIA Randomised controlled trials investigating the effectiveness and safety of iron administration interventions compared to other iron administration interventions or placebo in the treatment of iron deficiency anaemia in inflammatory bowel disease. We considered both adults and children, with studies reporting outcomes of clinical, endoscopic, histologic or surgical remission as defined by study authors. DATA COLLECTION AND ANALYSIS Two review authors independently conducted data extraction and 'Risk of bias' assessment of included studies. We expressed dichotomous and continuous outcomes as risk ratios and mean differences with 95% confidence intervals. We assessed the certainty of the evidence using the GRADE methodology. MAIN RESULTS We included 11 studies (1670 randomised participants) that met the inclusion criteria. The studies compared intravenous iron sucrose vs oral iron sulphate (2 studies); oral iron sulphate vs oral iron hydroxide polymaltose complex (1 study); oral iron fumarate vs intravenous iron sucrose (1 study); intravenous ferric carboxymaltose vs intravenous iron sucrose (1 study); erythropoietin injection + intravenous iron sucrose vs intravenous iron sucrose + injection placebo (1 study); oral ferric maltol vs oral placebo (1 study); oral ferric maltol vs intravenous ferric carboxymaltose (1 study); intravenous ferric carboxymaltose vs oral iron sulphate (1 study); intravenous iron isomaltoside vs oral iron sulphate (1 study); erythropoietin injection vs oral placebo (1 study). All studies compared participants with CD and UC together, as well as considering a range of disease activity states. The primary outcome of number of responders, when defined, was stated to be an increase in haemoglobin of 20 g/L in all but two studies in which an increase in 10g/L was used. In one study comparing intravenous ferric carboxymaltose and intravenous iron sucrose, moderate-certainty evidence was found that intravenous ferric carboxymaltose was probably superior to intravenous iron sucrose, although there were responders in both groups (150/244 versus 118/239, RR 1.25, 95% CI 1.06 to 1.46, number needed to treat for an additional beneficial outcome (NNTB) = 9). In one study comparing oral ferric maltol to placebo, there was low-certainty evidence of superiority of the iron (36/64 versus 0/64, RR 73.00, 95% CI 4.58 to 1164.36). There were no other direct comparisons that found any difference in the primary outcomes, although certainty was low and very low for all outcomes, due to imprecision from sparse data and risk of bias varying between moderate and high risk. The reporting of secondary outcomes was inconsistent. The most common was the occurrence of serious adverse events or those requiring withdrawal of therapy. In no comparisons was there a difference seen between any of the intervention agents being studied, although the certainty was very low for all comparisons made, due to risk of bias and significant imprecision due to the low numbers of events. Time to remission, histological and biochemical outcomes were sparsely reported in the studies. None of the other secondary outcomes were reported in any of the studies. An analysis of all intravenous iron preparations to all oral iron preparations showed that intravenous administration may lead to more responders (368/554 versus 205/373, RR 1.17, 95% CI 1.05 to 1.31, NNTB = 11, low-certainty due to risk of bias and inconsistency). Withdrawals due to adverse events may be greater in oral iron preparations vs intravenous (15/554 versus 31/373, RR 0.39, 95% CI 0.20 to 0.74, low-certainty due to risk of bias, inconsistency and imprecision). AUTHORS' CONCLUSIONS Intravenous ferric carboxymaltose probably leads to more people having resolution of IDA (iron deficiency anaemia) than intravenous iron sucrose. Oral ferric maltol may lead to more people having resolution of IDA than placebo. We are unable to draw conclusions on which of the other treatments is most effective in IDA with IBD (inflammatory bowel disease) due to low numbers of studies in each comparison area and clinical heterogeneity within the studies. Therefore, there are no other conclusions regarding the treatments that can be made and certainty of all findings are low or very low. Overall, intravenous iron delivery probably leads to greater response in patients compared with oral iron, with a NNTB (number needed to treat) of 11. Whilst no serious adverse events were specifically elicited with any of the treatments studied, the numbers of reported events were low and the certainty of these findings very low for all comparisons, so no conclusions can be drawn. There may be more withdrawals due to such events when oral is compared with intravenous iron delivery. Other outcomes were poorly reported and once again no conclusions can be made as to the impact of IDA on any of these outcomes. Given the widespread use of many of these treatments in practice and the only guideline that exists recommending the use of intravenous iron in favour of oral iron, research to investigate this key issue is clearly needed. Considering the current ongoing trials identified in this review, these are more focussed on the impact in specific patient groups (young people) or on other symptoms (such as fatigue). Therefore, there is a need for studies to be performed to fill this evidence gap.
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A Systematic Review and Meta-analysis of Paediatric Inflammatory Bowel Disease Incidence and Prevalence Across Europe.
Roberts, SE, Thorne, K, Thapar, N, Broekaert, I, Benninga, MA, Dolinsek, J, Mas, E, Miele, E, Orel, R, Pienar, C, et al
Journal of Crohn's & colitis. 2020;(8):1119-1148
Abstract
BACKGROUND AND AIMS Inflammatory bowel disease [IBD] is often one of the most devastating and debilitating chronic gastrointestinal disorders in children and adolescents. The main objectives here were to systematically review the incidence and prevalence of paediatric IBD across all 51 European states. METHODS We undertook a systematic review and meta-analysis based on PubMed, CINAHL, the Cochrane Library, searches of reference lists, grey literature and websites, covering the period from 1970 to 2018. RESULTS Incidence rates for both paediatric Crohn's disease [CD] and ulcerative colitis [UC] were higher in northern Europe than in other European regions. There have been large increases in the incidence of both paediatric CD and UC over the last 50 years, which appear widespread across Europe. The largest increases for CD have been reported from Sweden, Wales, England, the Czech Republic, Denmark and Hungary, and for UC from the Czech Republic, Ireland, Sweden and Hungary. Incidence rates for paediatric CD have increased up to 9 or 10 per 100 000 population in parts of Europe, including Scandinavia, while rates for paediatric UC are often slightly lower than for CD. Prevalence reported for CD ranged from 8.2 per 100 000 to approximately 60 and, for UC, from 8.3 to approximately 30. CONCLUSIONS The incidence of paediatric IBD continues to increase throughout Europe. There is stronger evidence of a north-south than an east-west gradient in incidence across Europe. Further prospective studies are needed, preferably multinational and based on IBD registries, using standardized definitions, methodology and timescales.
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4.
Efficacy of adjuvant curcumin therapy in ulcerative colitis: A meta-analysis of randomized controlled trials.
Zheng, T, Wang, X, Chen, Z, He, A, Zheng, Z, Liu, G
Journal of gastroenterology and hepatology. 2020;(5):722-729
Abstract
BACKGROUND AND AIM Aminosalicylic acids are recognized to be the first-line treatment options for ulcerative colitis. Currently, the effectiveness of curcumin as an adjuvant treatment in ulcerative colitis has been investigated, which was still controversial. This study aimed to systematically review and meta-analyze the efficacy and safety of curcumin as an adjuvant treatment in ulcerative colitis. METHODS The PubMed, EMBASE, and Cochrane Library databases were searched from original to July 2019, and relevant randomized controlled clinical trials were enrolled and analyzed. The primary outcomes were clinical and endoscopic remission; meanwhile, the secondary outcomes were clinical and endoscopic improvement. Subgroup analyses of doses, delivery way, form, and intervention time of curcumin were also conducted. RESULTS Six randomized controlled clinical trials with a total of 349 patients were included. Eligible trials suggested that adjuvant curcumin treatment in ulcerative colitis was effective in inducing clinical remission (odds ratio [OR] = 5.18, 95% confidence interval [CI]: 1.84-14.56, P = 0.002), endoscopic remission (OR = 5.69, 95% CI: 1.28-25.27, P = 0.02), and endoscopic improvement (OR = 17.05, 95% CI: 1.30-233.00, P = 0.03), but not in clinical improvement (OR = 4.79, 95% CI: 1.02-22.43, P = 0.05). We can see the potential advantages in large dosage, topical enema, special drug form, and longer duration from the enrolled studies. There were no severe side effects reported. CONCLUSIONS Curcumin, as an adjuvant treatment of mesalamine, was proved to be effective and safe in ulcerative colitis. Better efficacy can be achieved with suitable dose, delivery way, formation, and intervention time, which needs further study to verify.
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5.
Curcumin therapy for ulcerative colitis remission: systematic review and meta-analysis.
Goulart, RA, Barbalho, SM, Rubira, CJ, Araújo, AC, Lima, VM, Rogerio Leoni, B, Guiguer, EL
Expert review of gastroenterology & hepatology. 2020;(12):1171-1179
Abstract
INTRODUCTION Despite significant advances in the study of Ulcerative colitis (UC) management, up to a third of patients may be refractory to conventional therapy, and specialists have considered natural compounds such as curcumin. AREA COVERED The meta-analyzes found in the literature compare the effects of curcumin used in different administration routes or compare patients in remission with patients with active disease. Due to the biases in these studies, we performed a systematic review and meta-analysis of randomized clinical trials (RCTs) that investigated the efficacy of orally administrated curcumin in mild-to-moderate active UC. EXPERT OPINION Curcumin produces relevant anti-inflammatory and antioxidant effects that are crucial in inducing remission in UC patients. Unfortunately, in the treatment of UC, we have not observed studies with standardization of dose and routes of administration. Existing meta-analyses are biased because they compare studies using different administration routes and patients in different stages of the disease. Our meta-analysis is the only one that tried to make a comparison with a few of biases as possible and show that curcumin can help in the induction of remission in UC subjects.
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6.
Probiotics for maintenance of remission in ulcerative colitis.
Iheozor-Ejiofor, Z, Kaur, L, Gordon, M, Baines, PA, Sinopoulou, V, Akobeng, AK
The Cochrane database of systematic reviews. 2020;(3):CD007443
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BACKGROUND Ulcerative colitis is an inflammatory condition affecting the colon, with an annual incidence of approximately 10 to 20 per 100,000 people. The majority of people with ulcerative colitis can be put into remission, leaving a group who do not respond to first- or second-line therapies. There is a significant proportion of people who experience adverse effects with current therapies. Consequently, new alternatives for the treatment of ulcerative colitis are constantly being sought. Probiotics are live microbial feed supplements that may beneficially affect the host by improving intestinal microbial balance, enhancing gut barrier function and improving local immune response. OBJECTIVES The primary objective was to determine the efficacy of probiotics compared to placebo, no treatment, or any other intervention for the maintenance of remission in people with ulcerative colitis. The secondary objective was to assess the occurrence of adverse events associated with the use of probiotics. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, and two other databases on 31 October 2019. We contacted authors of relevant studies and manufacturers of probiotics regarding ongoing or unpublished trials that may be relevant to the review, and we searched ClinicalTrials.gov. We also searched references of trials for any additional trials. SELECTION CRITERIA Randomised controlled trials (RCTs) that compared probiotics against placebo or any other intervention, in both adults and children, for the maintenance of remission in ulcerative colitis were eligible for inclusion. Maintenance therapy had to be for a minimum of three months when remission has been established by any clinical, endoscopic,histological or radiological relapse as defined by study authors. DATA COLLECTION AND ANALYSIS Two review authors independently conducted data extraction and 'Risk of bias' assessment of included studies. We analysed data using Review Manager 5. We expressed dichotomous and continuous outcomes as risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE methodology. MAIN RESULTS In this review, we included 12 studies (1473 randomised participants) that met the inclusion criteria. Participants were mostly adults. The studies compared probiotics to placebo, probiotics to 5-aminosalicylic acid (5-ASA) and a combination of probiotics and 5-ASA to 5-ASA. The studies ranged in length from 12 to 52 weeks. The average age of participants was between 32 and 51, with a range between 18 and 88 years. Seven studies investigated a single bacterial strain, and five studies considered mixed preparations of multiple strains. The risk of bias was high in all except three studies due to selective reporting, incomplete outcome data and lack of blinding. This resulted in low- to very low-certainty of evidence. It is uncertain if there is any difference in occurrence of clinical relapse when probiotics are compared with placebo (RR 0.87, 95% CI 0.63 to 1.18; 4 studies, 361 participants; very low-certainty evidence (downgraded for risk of bias, imbalance in baseline characteristics and imprecision)). It is also uncertain whether probiotics lead to a difference in the number of people who maintain clinical remission compared with placebo (RR 1.16, 95% CI 0.98 to 1.37; 2 studies, 141 participants; very low-certainty evidence (downgraded for risk of bias, imbalance in baseline characteristics and imprecision)). When probiotics are compared with 5-ASA, there may be little or no difference in clinical relapse (RR 1.01, 95% CI 0.84 to 1.22; 2 studies, 452 participants; low-certainty evidence) and maintenance of clinical remission (RR 1.06, 95% CI 0.90 to 1.25; 1 study, 125 participants; low-certainty evidence). It is uncertain if there is any difference in clinical relapse when probiotics, combined with 5-ASA are compared with 5-ASA alone (RR 1.11, 95% CI 0.66 to 1.87; 2 studies, 242 participants; very low-certainty evidence (downgraded due to risk of bias and imprecision)). There may be little or no difference in maintenance of remission when probiotics, combined with 5-ASA, are compared with 5-ASA alone (RR 1.05, 95% CI 0.89 to 1.24; 1 study, 122 participants; low-certainty evidence). Where reported, most of the studies which compared probiotics with placebo recorded no serious adverse events or withdrawals due to adverse events. For the comparison of probiotics and 5-ASA, one trial reported 11/110 withdrawals due to adverse events with probiotics and 11/112 with 5-ASA (RR 1.02, 95% CI 0.46 to 2.25; 222 participants; very low-certainty evidence). Discontinuation of therapy was due to gastrointestinal symptoms. One study (24 participants) comparing probiotics combined with 5-ASA with 5-ASA alone, reported no withdrawals due to adverse events; and two studies reported two withdrawals in the probiotic arm, due to avascular necrosis of bilateral femoral head and pulmonary thromboembolism (RR 5.29, 95% CI 0.26 to 107.63; 127 participants; very low-certainty evidence). Health-related quality of life and need for additional therapy were reported infrequently. AUTHORS' CONCLUSIONS The effectiveness of probiotics for the maintenance of remission in ulcerative colitis remains unclear. This is due to low- to very low-certainty evidence from poorly conducted studies, which contribute limited amounts of data from a small number of participants. Future trials comparing probiotics with 5-ASA rather than placebo will better reflect conventional care given to people with ulcerative colitis. Appropriately powered studies with a minimum length of 12 months are needed.
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Diet Therapy for Inflammatory Bowel Diseases: A Call to the Dining Table.
Limketkai, BN, Gordon, M, Mutlu, EA, De Silva, PS, Lewis, JD
Inflammatory bowel diseases. 2020;(4):510-514
Abstract
There is vigorous interest among patients, caregivers, clinicians, and scientists to identify useful dietary interventions for inflammatory bowel diseases (IBD). Through the Cochrane Collaboration, we recently performed a systematic review and meta-analysis of dietary interventions for the induction or maintenance of remission in Crohn's disease (CD) and ulcerative colitis (UC) to assess the latest state of research. The current quality of evidence was formally graded to be low or very low for various methodological reasons, such as small sample sizes, heterogeneity among studies, and incomplete reporting. There are nonetheless emerging observational studies that progressively advance our knowledge and provide hope for a role of diet among traditional therapies to improve inflammation and symptoms. Further investments and concerted efforts in research are needed to significantly move the needle in identifying effective dietary therapies for IBD.
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8.
Use of Fecal Occult Blood Testing as a Diagnostic Tool for Clinical Indications: A Systematic Review and Meta-Analysis.
Lee, MW, Pourmorady, JS, Laine, L
The American journal of gastroenterology. 2020;(5):662-670
Abstract
INTRODUCTION Fecal occult blood tests (FOBTs) are validated only for colorectal cancer (CRC) screening, but are commonly used as a diagnostic test in other clinical settings. We performed a systematic review to assess performance characteristics of FOBT as a diagnostic test for clinical indications. METHODS Bibliographic databases were searched to identify studies in adult patients with a specific gastrointestinal symptom or condition who underwent FOBT and a reference test and provided data on diagnoses. Our primary end point was sensitivity. Risk of bias was assessed with the QUADAS-2 tool. RESULTS Twenty-two studies met the inclusion criteria: 12 in iron deficiency anemia (IDA) (5 fecal immunochemical (FIT) and 7 guaiac based), 8 in ulcerative colitis (FIT), and 2 in acute diarrhea (guaiac based). Only 2 studies had low risk of bias on all domains of the QUADAS-2. On meta-analysis, FOBT had a sensitivity of 0.58 (95% confidence interval [CI] 0.53-0.63) and a specificity of 0.84 (95% CI 0.75-0.89) in predicting presumptive causes of IDA at endoscopy, with comparable results for guaiac-based tests and FIT. Sensitivity was higher for CRC (0.83) than non-CRC lesions (0.54). FIT had a sensitivity of 0.72 (95% CI 0.57-0.84) and a specificity of 0.80 (95% CI 0.67-0.89) in predicting endoscopic activity in UC. Sensitivities of FOBT for positive stool culture in acute diarrhea were 0.38 and 0.87. DISCUSSION Sensitivity of FOBT is poor for IDA: 42% of patients with identifiable causes of IDA had false-negative FOBT. Our results did not show acceptable performance characteristics for FOBT to guide decisions regarding endoscopic evaluation and do not support its use in IDA.
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9.
Assessing the efficacy and safety of fecal microbiota transplantation and probiotic VSL#3 for active ulcerative colitis: A systematic review and meta-analysis.
Dang, X, Xu, M, Liu, D, Zhou, D, Yang, W
PloS one. 2020;(3):e0228846
Abstract
BACKGROUND Fecal microbiota transplantation is an effective treatment for many gastrointestinal diseases, such as Clostridium difficile infection and inflammatory bowel disease, especially ulcerative colitis. Changes in colonic microflora may play an important role in the pathogenesis of ulcerative colitis, and improvements in the intestinal microflora may relieve the disease. Fecal bacterial transplants and oral probiotics are becoming important ways to relieve active ulcerative colitis. PURPOSE This systematic review with meta-analysis compared the efficacy and safety of basic treatment combined with fecal microbiota transplantation or mixed probiotics therapy in relieving mild to moderate ulcerative colitis. METHODS The PubMed, Embase, and Cochrane libraries (updated September 2019) were searched to identify randomized, placebo-controlled, or head-to-head trials assessing fecal microbiota transplantation or probiotic VSL#3 as induction therapy in active ulcerative colitis. We analyze data using the R program to obtain evidence of direct comparison and to generate intermediate variables for indirect treatment comparisons. RESULTS Seven randomized, double-blind, placebo-controlled trials were used as the sources of the induction data. All treatments were superior to placebo. In terms of clinical remission and clinical response to active ulcerative colitis, direct comparisons showed fecal microbiota transplantation (OR = 3.47, 95% CI = 1.93-6.25) (OR = 2.48, 95% CI = 1.18-5.21) and mixed probiotics VSL#3 (OR = 2.40, 95% CI = 1.49-3.88) (OR = 3.09, 95% CI = 1.53-6.25) to have better effects than the placebo. Indirect comparison showed fecal microbiota transplantation and probiotic VSL#3 did not reach statistical significance either in clinical remission (RR = 1.20, 95% CI = 0.70-2.06) or clinical response (RR = 0.95, 95% CI = 0.62-1.45). In terms of safety, fecal microbiota transplantation (OR = 1.15, 95% CI = 0.51-2.61) and VSL #3 (OR = 0.90, 95% CI = 0.33-2.49) showed no statistically significant increase in adverse events compared with the control group. In terms of serious adverse events, there was no statistical difference between the fecal microbiota transplantation group and the control group (OR = 1.29, 95% CI = 0.46-3.57). The probiotics VSL#3 seems more safer than fecal microbiota transplantation, because serious adverse events were not reported in the VSL#3 articles. CONCLUSIONS Fecal microbiota transplantation or mixed probiotics VSL#3 achieved good results in clinical remission and clinical response in active ulcerative colitis, and there was no increased risk of adverse reactions. There was no statistical difference between the therapeutic effect of fecal microbiota transplantation and that of mixed probiotics VSL#3. However, the use of fecal microbiota transplantation and probiotics still has many unresolved problems in clinical applications, and more randomized controlled trials are required to confirm its efficacy.
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10.
Probiotics for induction of remission in ulcerative colitis.
Kaur, L, Gordon, M, Baines, PA, Iheozor-Ejiofor, Z, Sinopoulou, V, Akobeng, AK
The Cochrane database of systematic reviews. 2020;(3):CD005573
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Abstract
BACKGROUND Ulcerative colitis is an inflammatory condition affecting the colon, with an annual incidence of approximately 10 to 20 per 100,000 people. The majority of people with ulcerative colitis can be put into remission, leaving a group who do not respond to first- or second-line therapies. There is a significant proportion of people who experience adverse effects with current therapies. Consequently, new alternatives for the treatment of ulcerative colitis are constantly being sought. Probiotics are live microbial feed supplements that may beneficially affect the host by improving intestinal microbial balance, enhancing gut barrier function and improving local immune response. OBJECTIVES To assess the efficacy of probiotics compared with placebo or standard medical treatment (5-aminosalicylates, sulphasalazine or corticosteroids) for the induction of remission in people with active ulcerative colitis. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, and two other databases on 31 October 2019. We contacted authors of relevant studies and manufacturers of probiotics regarding ongoing or unpublished trials that may be relevant to the review, and we searched ClinicalTrials.gov. We also searched references of trials for any additional trials. SELECTION CRITERIA Randomised controlled trials (RCTs) investigating the effectiveness of probiotics compared to standard treatments or placebo in the induction of remission of active ulcerative colitis. We considered both adults and children, with studies reporting outcomes of clinical, endoscopic, histologic or surgical remission as defined by study authors DATA COLLECTION AND ANALYSIS Two review authors independently conducted data extraction and 'Risk of bias' assessment of included studies. We analysed data using Review Manager 5. We expressed dichotomous and continuous outcomes as risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE methodology. MAIN RESULTS In this review, we included 14 studies (865 randomised participants) that met the inclusion criteria. Twelve of the studies looked at adult participants and two studies looked at paediatric participants with mild to moderate ulcerative colitis, the average age was between 12.5 and 47.7 years. The studies compared probiotics to placebo, probiotics to 5-ASA and a combination of probiotics plus 5-ASA compared to 5-ASA alone. Seven studies used a single probiotic strain and seven used a mixture of strains. The studies ranged from two weeks to 52 weeks. The risk of bias was high for all except two studies due to allocation concealment, blinding of participants, incomplete reports of outcome data and selective reporting. This led to GRADE ratings of the evidence ranging from moderate to very low. Probiotics versus placebo Probiotics may induce clinical remission when compared to placebo (RR 1.73, 95% CI 1.19 to 2.54; 9 studies, 594 participants; low-certainty evidence; downgraded due to imprecision and risk of bias, number needed to treat for an additional beneficial outcome (NNTB) 5). Probiotics may lead to an improvement in clinical disease scores (RR 2.29, 95% CI 1.13 to 4.63; 2 studies, 54 participants; downgraded due to risk of bias and imprecision). There may be little or no difference in minor adverse events, but the evidence is of very low certainty (RR 1.04, 95% CI 0.42 to 2.59; 7 studies, 520 participants). Reported adverse events included abdominal bloating and discomfort. Probiotics did not lead to any serious adverse events in any of the seven studies that reported on it, however five adverse events were reported in the placebo arm of one study (RR 0.09, CI 0.01 to 1.66; 1 study, 526 participants; very low-certainty evidence; downgraded due to high risk of bias and imprecision). Probiotics may make little or no difference to withdrawals due to adverse events (RR 0.85, 95% CI 0.42 to 1.72; 4 studies, 401 participants; low-certainty evidence). Probiotics versus 5-ASA There may be little or no difference in the induction of remission with probiotics when compared to 5-ASA (RR 0.92, 95% CI 0.73 to 1.16; 1 study, 116 participants; low-certainty evidence; downgraded due to risk of bias and imprecision). There may be little or no difference in minor adverse events, but the evidence is of very low certainty (RR 1.33, 95% CI 0.53 to 3.33; 1 study, 116 participants). Reported adverse events included abdominal pain, nausea, headache and mouth ulcers. There were no serious adverse events with probiotics, however perforated sigmoid diverticulum and respiratory failure in a patient with severe emphysema were reported in the 5-ASA arm (RR 0.21, 95% CI 0.01 to 4.22; 1 study, 116 participants; very low-certainty evidence). Probiotics combined with 5-ASA versus 5-ASA alone Low-certainty evidence from a single study shows that when combined with 5-ASA, probiotics may slightly improve the induction of remission (based on the Sunderland disease activity index) compared to 5-ASA alone (RR 1.22 CI 1.01 to 1.47; 1 study, 84 participants; low-certainty evidence; downgraded due to unclear risk of bias and imprecision). No information about adverse events was reported. Time to remission, histological and biochemical outcomes were sparsely reported in the studies. None of the other secondary outcomes (progression to surgery, need for additional therapy, quality of life scores, or steroid withdrawal) were reported in any of the studies. AUTHORS' CONCLUSIONS Low-certainty evidence suggests that probiotics may induce clinical remission in active ulcerative colitis when compared to placebo. There may be little or no difference in clinical remission with probiotics alone compared to 5-ASA. There is limited evidence from a single study which failed to provide a definition of remission, that probiotics may slightly improve the induction of remission when used in combination with 5-ASA. There was no evidence to assess whether probiotics are effective in people with severe and more extensive disease, or if specific preparations are superior to others. Further targeted and appropriately designed RCTs are needed to address the gaps in the evidence base. In particular, appropriate powering of studies and the use of standardised participant groups and outcome measures in line with the wider field are needed, as well as reporting to minimise risk of bias.