METHODS: The study comprised a systematic review with meta-analysis and trial sequential analysis (TSA) of randomized controlled trials (RCTs). We searched for RCTs published up until September 2016. Retrieved trials were evaluated using risk of bias. Primary outcome measures were the incidences of any recurrent adenomas and of advanced adenomas. Meta-analytic estimates were calculated with the random-effects model and random errors were evaluated with trial sequential analyses (TSAs).
RESULTS: Five randomized trials (2234 patients with a history of adenomas) were included. Two of the 5 trials showed either unclear or high risks of bias in most criteria. Meta-analysis of good quality RCTs suggest a moderate protective effect of calcium supplementation on recurrence of adenomas (relative risk [RR], 0.88 [95% CI 0.79-0.99]); however, its effects on advanced adenomas did not show statistical significance (RR, 1.02 [95% CI 0.67-1.55]). Subgroup analyses demonstrated a greater protective effect on recurrence of adenomas with elemental calcium dose ≥1600 mg/day (RR, 0.74 [95% CI 0.56-0.97]) compared to ≤1200 mg/day (RR, 0.84 [95% CI 0.73-0.97]). No major serious adverse events were associated with the use of calcium, but there was an increase in the incidence of hypercalcemia (P = .0095). TSA indicated a lack of firm evidence for a beneficial effect. Concerns with directness and imprecision rated down the quality of the evidence to "low."
CONCLUSION: The available good quality RCTs suggests a possible beneficial effect of calcium supplementation on the recurrence of adenomas; however, TSA indicated that the accumulated evidence is still inconclusive. Using GRADE-methodology, we conclude that the quality of evidence is low. Large well-designed randomized trials with low risk of bias are needed.
METHODS: We will acquire eligible studies through a systematic search of MEDLINE, EMBASE, the Cochrane Central Registry of Controlled Trials, CINAHL plus, IPA and clinicaltrials.gov website. The Cochrane Risk of Bias Tool will be used to assess the quality of included studies. The primary outcomes are the incidence of CRC, the incidence/recurrence of any adenoma or change in polyp burden (number or size). Quantitative synthesis or meta-analysis will be considered. We will also construct a network meta-analysis (NMA) to improve precision of the comparisons among chemo-preventive interventions by combining direct and indirect evidence. The probability of each treatment being the best and/or safest, the number-needed-to-treat [NNT; 95% credible interval (CrIs)], and the number-needed-to-harm (NNH; 95% CrIs) will be calculated to provide measures of treatment efficacy. The GRADE approach will be used to rate the quality of evidence of estimates derived from NMA.
RESULTS: This protocol has been registered (registration number: CRD42015025849) with the PROSPERO (International Prospective Register of Systematic Reviews). The procedures of this systematic review and NMA will be conducted in accordance with the PRISMA-compliant guideline. The results of this systematic review and NMA will be submitted to a peer-reviewed journal for publication.
CONCLUSIONS: To the best of our knowledge, this study will be the first NMA to identify the comparative effectiveness of interventions for the prevention of CRC. The results of our study will update evidence for chemoprevention of CRC, identify key areas for future research, and provide a framework for conducting large systematic reviews involving indirect comparisons.
METHODS: We searched for RCTs published up until September 2016. Retrieved trials were evaluated using risk of bias. We performed both pairwise analysis and network meta-analysis (NMA) of RCTs to compare the effects of CPAs on the recurrence of colorectal adenomas (primary outcome). Using NMA, we ranked CPAs based on efficacy.
RESULTS: We identified 20 eligible RCTs enrolling 12,625 participants with a history of colorectal cancer or adenomas who were randomly assigned to receive either a placebo or one of 12 interventions. NMA using all trials demonstrated that celecoxib 800 mg/day (relative risk [RR] 0.61, 95% confidence interval [CI] 0.45-0.83), celecoxib 400 mg/day (RR 0.70, 95% CI 0.55-0.87), low-dose aspirin (RR 0.75, 95% CI 0.59-0.96) and calcium (RR 0.81, 95% CI 0.69-0.96) were significantly associated with a reduction in the recurrence of any adenomas. NMA results were consistent with those from pairwise meta-analysis. The evidence indicated a high (celecoxib), moderate (low-dose aspirin) and low (calcium) Grading of Recommendations, Assessment, Development and Evaluation (GRADE) quality. NMA ranking showed that celecoxib 800 mg/day and celecoxib 400 mg/day were the best CPAs, followed by low-dose aspirin and calcium. Considering advanced adenoma recurrence, only celecoxib 800 mg/day and celecoxib 400 mg/day were demonstrated to have a protective effect (RR 0.37, 95% CI 0.27-0.52 vs RR 0.48, 95% CI 0.38-0.60, respectively).
CONCLUSION: The available evidence from NMA suggests that celecoxib is more effective in reducing the risk of recurrence of colorectal adenomas, followed by low-dose aspirin and calcium. Since cyclooxygenase-2 (COX-2) inhibitors (eg, celecoxib) are associated with important cardiovascular events and gastrointestinal harms, more attention is warranted toward CPAs with a favorable benefit-to-risk ratio, such as low-dose aspirin and calcium.
Methods: We did a network meta-analysis based on a systematic review of randomized controlled trials (RCTs) that compared at least one CPA (aspirin, antioxidants, folic acid, vitamin B6, vitamin B12, calcium, vitamin D, alone or in combination) to placebo or other CPA in persons without history of CRC. Several databases were searched from inception up to March 2017. Primary outcomes were early and long-term CRC incidence and mortality.
Results: Twenty-one RCTs comprising 281,063 participants, 9 RCTS comprising 160,101 participants, and 7 RCTs comprising 24,001 participants were included in the network meta-analysis for early risk of CRC incidence, long-term risk of CRC incidence and mortality, respectively. For early CRC incidence, no CPAs were found to be effective. For long-term CRC incidence and mortality, aspirin was the only intervention that showed protective effects with potential dose-dependent effects (risk ratio [RR], 0.74 [95% CI, 0.57-0.97] for high-dose [≥325 mg/day] and RR, 0.81 [95% CI, 0.67-0.98] for very-low-dose [≤100 mg/day]). Similar trend was found for mortality (RR, 0.43 [95% CI, 0.23-0.81] for low-dose [>100-325 mg/day] and RR, 0.65 [95% CI, 0.45-0.94] for very-low-dose). However, in net clinical benefit analysis, when combining risk estimates on mortality from CRC, cardiovascular disease, and pooled risk estimates of major gastrointestinal bleeding, low-dose aspirin provided the highest net survival gain (%) of 1.736 [95% CI, 1.010-2.434].
Conclusion: Aspirin at the dose range of 75-325 mg/day is a safe and effective primary prevention for long-term CRC among people at average risk. None of the other CPAs were found to be effective. There may potentially be differential effects among various doses of aspirin that needs further investigation.
METHODS: Our objective was to update and systematically evaluate the evidence for aspirin and other NSAIDs on the incidence of recurrent colorectal adenomas taking into consideration the risks of random error and to appraise the quality of evidence using GRADE (The Grading of Recommendations, Assessment, Development and Evaluation) approach. Retrieved trials were evaluated using Cochrane risk of bias instrument. Meta-analytic estimates were calculated with random-effects model and random errors were evaluated with trial sequential analysis (TSA).
RESULTS: In patients with a previous history of colorectal cancer or adenomas, low-dose aspirin (80-160 mg/day) compared to placebo taken for 2 to 4 years reduces the risk of recurrent colorectal adenomas (relative risk (RR), 0.80 [95% CI (confidence interval), 0.70-0.92]). TSA indicated a firm evidence for this beneficial effect. The evidence indicated moderate GRADE quality. Low-dose aspirin also reduces the recurrence of advanced adenomas (RR, 0.66 [95% CI, 0.44-0.99]); however, TSA indicated lack of firm evidence for a beneficial effect. High-dose aspirin (300-325 mg/day) did not statistically reduce the recurrent adenomas (RR, 0.90 [95% CI, 0.68-1.18]). Cyclooxygenase-2 (COX-2) inhibitors (e.g. celecoxib 400 mg/day) were associated with a significant decrease in the recurrence of both adenomas (RR, 0.66 [95% CI, 0.59-0.72]) and advanced adenomas (RR, 0.45 [95% CI, 0.33-0.57]); however, this association did not persist and there was a trend of an increased risk of recurrent adenomas observed 2 years after the withdrawal.
CONCLUSION: Our findings confirm the beneficial effect of low-dose aspirin on recurrence of any adenomas; however, effect on advanced adenomas was inconclusive. COX-2 inhibitors seem to be more effective in preventing recurrence of adenomas; however, there was a trend of an increased risk of recurrence of adenomas observed after discontinuing regular use.
METHODS: We searched PubMed, Embase and the Cochrane Central systematically for the randomised control trials (RCTs) of interventions for preventing OM. Network meta-analysis (NMA) was performed to estimate risk ratios (RR) and 95% confidence intervals (CI) from both direct and indirect evidence. The primary outcome was any grade of OM. Secondary outcomes were mild-moderate OM, severe OM and adverse events, such as taste disturbance and gastrointestinal adverse events. This study was registered with PROSPERO, number CRD42016052489.
RESULTS: A total of 29 RCTs with 2348 patients (median age, 56.1 years; 57.5% male) were included. Cryotherapy was associated with a significantly lower risk of OM than control (RR 0.51, 95% CI 0.38 to 0.68), and zinc sulphate (RR 0.47, 95% CI 0.23 to 0.97), but not significantly lower than sucralfate and palifermin. No significant differences were observed between cryotherapy and control for taste disturbance and gastrointestinal adverse events. Palifermin was associated with the highest risk of taste disturbance.
CONCLUSIONS: This NMA suggests that cryotherapy was the most effective intervention for preventing chemotherapy-induced OM with a safety profile similar to control, but not significantly lower than sucralfate and palifermin. Large RCTs are needed to confirm these findings.
METHODS: A retrospective cohort study was conducted in a tertiary-care medical center in Thailand. Data were collected from an electronic medical database. Patients were categorized into OMT or non-OMT groups based on their discharge medications. OMT was defined as a combination of aspirin and P2Y12 inhibitors, statins, beta-blockers, and angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers. The primary outcome was 1-year all-cause mortality. The secondary outcome was major adverse cardiac events (MACE) which was defined as a composite of non-fatal myocardial infarction, non-fatal stroke, and all-cause mortality. The prescription trends were also estimated. A multivariate Cox's proportional hazard model was used to assess the association of OMT prescriptions at discharge with all-cause mortality and MACE.
RESULTS: A total of 3531 patients discharged with ACS [mean age, 69.5 (SD 12.4) years; 58.3% male] were identified. Only 42.6% were discharged with OMT. The rates of OMT prescriptions did not change over time. However, the prescription of OMT with high-intensity statin was significantly increased from 5.0% in 2013 to 38.3% in 2018 (p for trend <0.001). Multivariable analyses indicated that OMT significantly reduced all-cause mortality (adjusted HR: 0.77; 95%CI: 0.63-0.95; p=0.012) and MACE (adjusted HR 0.84; 95%CI: 0.71-0.99; p = 0.044). Subgroup analysis indicated that patients receiving OMT with high-intensity statins exhibited survival benefits (adjusted HR: 0.72; 95%CI: 0.56-0.92; p=0.008).
CONCLUSIONS: The five-drugs comprising OMT were associated with a reduction in all-cause mortality and MACE in patients with ACS. Nevertheless, OMT prescribing remains underused and could be enhanced in the real-world setting.