ABSTRACT: BACKGROUND:Various nerve blocks with local anaesthetic agents have been used to reduce pain after hip fracture and subsequent surgery. This review was published originally in 1999 and was updated in 2001, 2002, 2009 and 2017. OBJECTIVES:This review focuses on the use of peripheral nerves blocks as preoperative analgesia, as postoperative analgesia or as a supplement to general anaesthesia for hip fracture surgery. We undertook the update to look for new studies and to update the methods to reflect Cochrane standards. SEARCH METHODS:For the updated review, we searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), MEDLINE (Ovid SP, 1966 to August week 1 2016), Embase (Ovid SP, 1988 to 2016 August week 1) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO, 1982 to August week 1 2016), as well as trial registers and reference lists of relevant articles. SELECTION CRITERIA:We included randomized controlled trials (RCTs) involving use of nerve blocks as part of the care provided for adults aged 16 years and older with hip fracture. DATA COLLECTION AND ANALYSIS:Two review authors independently assessed new trials for inclusion, determined trial quality using the Cochrane tool and extracted data. When appropriate, we pooled results of outcome measures. We rated the quality of evidence according to the GRADE Working Group approach. MAIN RESULTS:We included 31 trials (1760 participants; 897 randomized to peripheral nerve blocks and 863 to no regional blockade). Results of eight trials with 373 participants show that peripheral nerve blocks reduced pain on movement within 30 minutes of block placement (standardized mean difference (SMD) -1.41, 95% confidence interval (CI) -2.14 to -0.67; equivalent to -3.4 on a scale from 0 to 10; I2 = 90%; high quality of evidence). Effect size was proportionate to the concentration of local anaesthetic used (P < 0.00001). Based on seven trials with 676 participants, we did not find a difference in the risk of acute confusional state (risk ratio (RR) 0.69, 95% CI 0.38 to 1.27; I2 = 48%; very low quality of evidence). Three trials with 131 participants reported decreased risk for pneumonia (RR 0.41, 95% CI 0.19 to 0.89; I2 = 3%; number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 5 to 72; moderate quality of evidence). We did not find a difference in risk of myocardial ischaemia or death within six months, but the number of participants included was well below the optimal information size for these two outcomes. Two trials with 155 participants reported that peripheral nerve blocks also reduced time to first mobilization after surgery (mean difference -11.25 hours, 95% CI -14.34 to -8.15 hours; I2 = 52%; moderate quality of evidence). One trial with 75 participants indicated that the cost of analgesic drugs was lower when they were given as a single shot block (SMD -3.48, 95% CI -4.23 to -2.74; moderate quality of evidence). AUTHORS' CONCLUSIONS:High-quality evidence shows that regional blockade reduces pain on movement within 30 minutes after block placement. Moderate-quality evidence shows reduced risk for pneumonia, decreased time to first mobilization and cost reduction of the analgesic regimen (single shot blocks).
Project description:BACKGROUND:Nicotinic acid (niacin) is known to decrease LDL-cholesterol, and triglycerides, and increase HDL-cholesterol levels. The evidence of benefits with niacin monotherapy or add-on to statin-based therapy is controversial. OBJECTIVES:To assess the effectiveness of niacin therapy versus placebo, administered as monotherapy or add-on to statin-based therapy in people with or at risk of cardiovascular disease (CVD) in terms of mortality, CVD events, and side effects. SEARCH METHODS:Two reviewers independently and in duplicate screened records and potentially eligible full texts identified through electronic searches of CENTRAL, MEDLINE, Embase, Web of Science, two trial registries, and reference lists of relevant articles (latest search in August 2016). SELECTION CRITERIA:We included all randomised controlled trials (RCTs) that either compared niacin monotherapy to placebo/usual care or niacin in combination with other component versus other component alone. We considered RCTs that administered niacin for at least six months, reported a clinical outcome, and included adults with or without established CVD. DATA COLLECTION AND ANALYSIS:Two reviewers used pre-piloted forms to independently and in duplicate extract trials characteristics, risk of bias items, and outcomes data. Disagreements were resolved by consensus or third party arbitration. We conducted random-effects meta-analyses, sensitivity analyses based on risk of bias and different assumptions for missing data, and used meta-regression analyses to investigate potential relationships between treatment effects and duration of treatment, proportion of participants with established coronary heart disease and proportion of participants receiving background statin therapy. We used GRADE to assess the quality of evidence. MAIN RESULTS:We included 23 RCTs that were published between 1968 and 2015 and included 39,195 participants in total. The mean age ranged from 33 to 71 years. The median duration of treatment was 11.5 months, and the median dose of niacin was 2 g/day. The proportion of participants with prior myocardial infarction ranged from 0% (4 trials) to 100% (2 trials, median proportion 48%); the proportion of participants taking statin ranged from 0% (4 trials) to 100% (12 trials, median proportion 100%).Using available cases, niacin did not reduce overall mortality (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.97 to 1.12; participants = 35,543; studies = 12; I2 = 0%; high-quality evidence), cardiovascular mortality (RR 1.02, 95% CI 0.93 to 1.12; participants = 32,966; studies = 5; I2 = 0%; moderate-quality evidence), non-cardiovascular mortality (RR 1.12, 95% CI 0.98 to 1.28; participants = 32,966; studies = 5; I2 = 0%; high-quality evidence), the number of fatal or non-fatal myocardial infarctions (RR 0.93, 95% CI 0.87 to 1.00; participants = 34,829; studies = 9; I2 = 0%; moderate-quality evidence), nor the number of fatal or non-fatal strokes (RR 0.95, 95% CI 0.74 to 1.22; participants = 33,661; studies = 7; I2 = 42%; low-quality evidence). Participants randomised to niacin were more likely to discontinue treatment due to side effects than participants randomised to control group (RR 2.17, 95% CI 1.70 to 2.77; participants = 33,539; studies = 17; I2 = 77%; moderate-quality evidence). The results were robust to sensitivity analyses using different assumptions for missing data. AUTHORS' CONCLUSIONS:Moderate- to high-quality evidence suggests that niacin does not reduce mortality, cardiovascular mortality, non-cardiovascular mortality, the number of fatal or non-fatal myocardial infarctions, nor the number of fatal or non-fatal strokes but is associated with side effects. Benefits from niacin therapy in the prevention of cardiovascular disease events are unlikely.
Project description:BACKGROUND: The utility of acupuncture in managing osteoarthritis symptoms is uncertain. Trial results are conflicting and previous systematic reviews may have overestimated the benefits of acupuncture. METHODS: Two reviewers independently identified randomized controlled trials (up to May 2014) from multiple electronic sources (including PubMed/Medline, EMBASE, and CENTRAL) and reference lists of relevant articles, extracted data and assessed risk of bias (Cochrane's Risk of Bias tool). Pooled data are expressed as mean differences (MD), with 95% confidence intervals (CI) (random-effects model). RESULTS: We included 12 trials (1763 participants) comparing acupuncture to sham acupuncture, no treatment or usual care. We adjudicated most trials to be unclear (64%) or high (9%) risk of bias. Acupuncture use was associated with significant reductions in pain intensity (MD -0.29, 95% CI -0.55 to -0.02, I2 0%, 10 trials, 1699 participants), functional mobility (standardized MD -0.34, 95% CI -0.55 to -0.14, I2 70%, 9 trials, 1543 participants), health-related quality of life (standardized MD -0.36, 95% CI -0.58 to -0.14, I2 50%, 3 trials, 958 participants). Subgroup analysis of pain intensity by intervention duration suggested greater pain intensity reduction with intervention periods greater than 4 weeks (MD -0.38, 95% CI -0.69 to -0.06, I2 0%, 6 trials, 1239 participants). CONCLUSIONS: The use of acupuncture is associated with significant reductions in pain intensity, improvement in functional mobility and quality of life. While the differences are not as great as shown by other reviews, current evidence supports the use of acupuncture as an alternative for traditional analgesics in patients with osteoarthritis. SYSTEMATIC REVIEW REGISTRATION: CRD42013005405.
Project description:BACKGROUND:Breathlessness is a cardinal symptom of chronic obstructive pulmonary disease (COPD). Long-term oxygen therapy (LTOT) is given to improve survival time in people with COPD and severe chronic hypoxaemia at rest. The efficacy of oxygen therapy for breathlessness and health-related quality of life (HRQOL) in people with COPD and mild or no hypoxaemia who do not meet the criteria for LTOT has not been established. OBJECTIVES:To determine the efficacy of oxygen versus air in mildly hypoxaemic or non-hypoxaemic patients with COPD in terms of (1) breathlessness; (2) HRQOL; (3) patient preference whether to continue therapy; and (4) oxygen-related adverse events. SEARCH METHODS:We searched the Cochrane Airways Group Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase, to 12 July 2016, for randomised controlled trials (RCTs). We handsearched the reference lists of included articles. SELECTION CRITERIA:We included RCTs of the effects of non-invasive oxygen versus air on breathlessness, HRQOL or patient preference to continue therapy among people with COPD and mild or no hypoxaemia (partial pressure of oxygen (PaO2) > 7.3 kPa) who were not already receiving LTOT. Two review authors independently assessed articles for inclusion in the review. DATA COLLECTION AND ANALYSIS:Two review authors independently collected and analysed data. We assessed risk of bias by using the Cochrane 'Risk of bias tool'. We pooled effects recorded on different scales as standardised mean differences (SMDs) with 95% confidence intervals (CIs) using random-effects models. Lower SMDs indicated decreased breathlessness and reduced HRQOL. We performed subanalyses and sensitivity analyses and assessed the quality of evidence according to the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. MAIN RESULTS:Compared with the previous review, which was published in 2011, we included 14 additional studies (493 participants), excluded one study and included data for meta-analysis of HRQOL. In total, we included in this review 44 studies including 1195 participants, and we included 33 of these (901 participants)in the meta-analysis.We found that breathlessness during exercise or daily activities was reduced by oxygen compared with air (32 studies; 865 participants; SMD -0.34, 95% CI -0.48 to -0.21; I2 = 37%; low-quality evidence). This translates to a decrease in breathlessness of about 0.7 points on a 0 to 10 numerical rating scale. In contrast, we found no effect of short-burst oxygen given before exercise (four studies; 90 participants; SMD 0.01, 95% CI -0.26 to 0.28; I2 = 0%; low-quality evidence). Oxygen reduced breathlessness measured during exercise tests (25 studies; 442 participants; SMD -0.34, 95% CI -0.46 to -0.22; I2 = 29%; moderate-quality evidence), whereas evidence of an effect on breathlessness measured in daily life was limited (two studies; 274 participants; SMD -0.13, 95% CI, -0.37 to 0.11; I2 = 0%; low-quality evidence).Oxygen did not clearly affect HRQOL (five studies; 267 participants; SMD 0.10, 95% CI -0.06 to 0.26; I2 = 0%; low-quality evidence). Patient preference and adverse events could not be analysed owing to insufficient data. AUTHORS' CONCLUSIONS:We are moderately confident that oxygen can relieve breathlessness when given during exercise to mildly hypoxaemic and non-hypoxaemic people with chronic obstructive pulmonary disease who would not otherwise qualify for home oxygen therapy. Most evidence pertains to acute effects during exercise tests, and no evidence indicates that oxygen decreases breathlessness in the daily life setting. Findings show that oxygen does not affect health-related quality of life.
Project description:BACKGROUND:Serum procalcitonin (PCT) evaluation has been proposed for early diagnosis and accurate staging and to guide decisions regarding patients with sepsis, severe sepsis and septic shock, with possible reduction in mortality. OBJECTIVES:To assess the effectiveness and safety of serum PCT evaluation for reducing mortality and duration of antimicrobial therapy in adults with sepsis, severe sepsis or septic shock. SEARCH METHODS:We searched the Central Register of Controlled Trials (CENTRAL; 2015, Issue 7); MEDLINE (1950 to July 2015); Embase (Ovid SP, 1980 to July 2015); Latin American Caribbean Health Sciences Literature (LILACS via BIREME, 1982 to July 2015); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCO host, 1982 to July 2015), and trial registers (ISRCTN registry, ClinicalTrials.gov and CenterWatch, to July 2015). We reran the search in October 2016. We added three studies of interest to a list of 'Studies awaiting classification' and will incorporate these into formal review findings during the review update. SELECTION CRITERIA:We included only randomized controlled trials (RCTs) testing PCT-guided decisions in at least one of the comparison arms for adults (? 18 years old) with sepsis, severe sepsis or septic shock, according to international definitions and irrespective of the setting. DATA COLLECTION AND ANALYSIS:Two review authors extracted study data and assessed the methodological quality of included studies. We conducted meta-analysis with random-effects models for the following primary outcomes: mortality and time spent receiving antimicrobial therapy in hospital and in the intensive care unit (ICU), as well as time spent on mechanical ventilation and change in antimicrobial regimen from a broad to a narrower spectrum. MAIN RESULTS:We included 10 trials with 1215 participants. Low-quality evidence showed no significant differences in mortality at longest follow-up (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.65 to 1.01; I2 = 10%; 10 trials; N = 1156), at 28 days (RR 0.89, 95% CI 0.61 to 1.31; I2 = 0%; four trials; N = 316), at ICU discharge (RR 1.03, 95% CI 0.50 to 2.11; I2 = 49%; three trials; N = 506) and at hospital discharge (RR 0.98, 95% CI 0.75 to 1.27; I2 = 0%; seven trials; N = 805; moderate-quality evidence). However, mean time receiving antimicrobial therapy in the intervention groups was -1.28 days (95% CI to -1.95 to -0.61; I2 = 86%; four trials; N = 313; very low-quality evidence). No primary study has analysed the change in antimicrobial regimen from a broad to a narrower spectrum. AUTHORS' CONCLUSIONS:Up-to-date evidence of very low to moderate quality, with insufficient sample power per outcome, does not clearly support the use of procalcitonin-guided antimicrobial therapy to minimize mortality, mechanical ventilation, clinical severity, reinfection or duration of antimicrobial therapy of patients with septic conditions.
Project description:Object:The purpose of this study was to fully assess the role of statins in the primary prevention of coronary heart disease (CHD). Methods:We searched six databases (PubMed, the Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wanfang Database, and Chinese Scientific Journal Database) to identify relevant randomized controlled trials (RCTs) from inception to 31 October 2017. Two review authors independently assessed the methodological quality and analysed the data using Rev Man 5.3 software. Risk ratios and 95% confidence intervals (95% CI) were pooled using fixed/random-effects models. Funnel plots and Begg's test were conducted to assess publication bias. The quality of the evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results:Sixteen RCTs with 69159 participants were included in this review. Statins can effectively decrease the occurrence of angina (RR=0.70, 95% CI: 0.58~0.85, I2 =0%), nonfatal myocardial infarction (MI) (RR=0.60, 95% CI: 0.51~0.69, I2 =14%), fatal MI (RR=0.49, 95% CI: 0.24~0.98, I2 =0%), any MI (RR=0.53, 95% CI: 0.42~0.67, I2 =0%), any coronary heart events (RR=0.73, 95% CI: 0.68~0.78, I2=0%), coronary revascularization (RR=0.66, 95% CI: 0.55~0.78, I2 = 0%), and any cardiovascular events (RR=0.77, 95% CI: 0.72~82, I2 = 0%). However, based on the current evidence, there were no significant differences in CHD deaths (RR=0.82, 95% CI: 0.66~1.02, I2=0%) and all-cause mortality (RR=0.88, 95% CI: 0.76 ~1.01, I2 =58%) between the two groups. Additionally, statins were more likely to result in diabetes (RR=1.21, 95% CI: 1.05~1.39, I2 =0%). There was no evidence of publication biases, and the quality of the evidence was considered moderate. Conclusion:Statins seemed to be beneficial for the primary prevention of CHDs but have no effect on CHD death and all-cause mortality.
Project description:OBJECTIVE:To investigate the effect of whole-body vibration exercise (WBV) on fracture risk in adults ?50 years of age. DESIGN:A systematic review and meta-analysis calculating relative risk ratios, fall rate ratio and absolute weighted mean difference using random effects models. Heterogeneity was estimated using I2 statistics, and the Cochrane Collaboration's risk of bias tool and the GRADE approach were used to evaluate quality of evidence and summarise conclusions. DATA SOURCES:The databases PubMed, Embase and the Cochrane Central Register from inception to April 2016 and reference lists of retrieved publications. ELIGIBILITY CRITERIA FOR SELECTING STUDIES:Randomised controlled trials examining the effect of WBV on fracture risk in adults ?50 years of age. The primary outcomes were fractures, fall rates and the proportion of participants who fell. Secondary outcomes were bone mineral density (BMD), bone microarchitecture, bone turnover markers and calcaneal broadband attenuation (BUA). RESULTS:15 papers (14 trials) met the inclusion criteria. Only one study had fracture data reporting a non-significant fracture reduction (risk ratio (RR)=0.47, 95%?CI 0.14 to 1.57, P=0.22) (moderate quality of evidence). Four studies (n=746) showed that WBV reduced the rate of falls with a rate ratio of 0.67 (95% CI 0.50 to 0.89, P=0.0006; I2=19%) (moderate quality of evidence). Furthermore, data from three studies (n=805) found a trend towards falls reduction (RR=0.76, 95%?CI 0.48 to 1.20, P=0.24; I2=24%) (low quality of evidence). Finally, moderate to low quality of evidence showed no overall effect on BMD and only sparse data were available regarding microarchitecture parameters, bone turnover markers and BUA. CONCLUSIONS:WBV reduces fall rate but seems to have no overall effect on BMD or microarchitecture. The impact of WBV on fractures requires further larger adequately powered studies. This meta-analysis suggests that WBV may prevent fractures by reducing falls. PROSPERO REGISTRATION NUMBER:CRD42016036320; Pre-results.
Project description:Recent trials have assessed the efficacy and safety of novel monoclonal antibodies such as reslizumab and benralizumab. However, the overall efficacy and safety anti-interleukin (IL) 5 treatment in asthma have not been thoroughly assessed.Randomized controlled trials (RCTs) of anti-IL-5 treatment on patients with asthma published up to October 2016 in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) that reported pulmonary function, quality of life scores, asthmatic exacerbation rate, blood and sputum eosinophil counts, short-acting ?-agonist (SABA) rescue use, and adverse events were included. The pooled mean difference, and relative risks (RR), and 95% confidence intervals (CIs) were calculated using random-effects models.Twenty studies involving 7100 patients were identified. Pooled analysis revealed significant improvements in FEV1 (first second forced expiratory volume) (MD = 0.09, 95% CI: 0.06-0.12, I2 = 10%), FEV1% (MD = 3.75, 95% CI: 1.66-5.83, I2 = 19%), Asthma Quality of Life Questionnaire (AQLQ) score (MD = 0.22, 95% CI: 0.15-0.30, I2 = 0%), decreased blood, sputum eosinophils and asthmatic exacerbation (RR = 0.66, 95% CI: 0.59-0.73, I2 = 51%); peak expiratory flow (PEF) (MD = 5.45, 95% CI: -2.83-13.72, I2 = 0%), histamine PC20 (MD = -0.62, 95% CI: -1.92-0.68, I2 = 0%) or SABA rescue use (MD = -0.11, 95% CI: -0.3-0.07, I2 = 30%) were unaffected; adverse events were not increased (RR = 0.93, 95% CI: 0.89-0.98, I2 = 46%). No publication bias was observed (Egger's P = 0.78).Anti-interleukin 5 monoclonal therapies for asthma could be safe for slightly improving FEV1 (or FEV1% of predicted value), quality of life, and reducing exacerbations risk and blood and sputum eosinophils, but have no significant effect on PEF, histamine PC20, and SABA rescue use. Further trials required to establish to clarify the optimal antibody for different patients.
Project description:Importance:Acetaminophen (paracetamol) and ibuprofen are the most widely prescribed and available over-the-counter medications for management of fever and pain in children. Despite the common use of these medications, treatment recommendations for young children remain divergent. Objective:To compare acetaminophen with ibuprofen for the short-term treatment of fever or pain in children younger than 2 years. Data Sources:Systematic search of the databases MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials and the trial registers ClinicalTrials.gov and the Australian New Zealand Clinical Trials Registry from inception to March 2019, with no language limits. Study Selection:Studies of any design that included children younger than 2 years and directly compared acetaminophen with ibuprofen, reporting antipyretic, analgesic, and/or safety outcomes were considered. There were no limits on length of follow-up. Data Extraction and Synthesis:Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline, 2 authors independently extracted data and assessed quality. Data were pooled using a fixed-effects method if I2 was less than 50% and using a random-effects method if I2 was 50% or greater. Main Outcomes and Measures:The primary outcomes were fever or pain within 4 hours of treatment onset. Safety outcomes included serious adverse events, kidney impairment, gastrointestinal bleeding, hepatotoxicity, severe soft tissue infection, empyema, and asthma and/or wheeze. Results:Overall, 19 studies (11 randomized; 8 nonrandomized) of 241?138 participants from 7 countries and various health care settings (hospital-based and community-based) were included. Compared with acetaminophen, ibuprofen resulted in reduced temperature at less than 4 hours (4 studies with 435 participants; standardized mean difference [SMD], 0.38; 95% CI, 0.08-0.67; P?=?.01; I2?=?49%; moderate quality evidence) and at 4 to 24 hours (5 studies with 879 participants; SMD, 0.24; 95% CI, 0.03-0.45; P?=?.03; I2?=?57%; moderate-quality evidence) and less pain at 4 to 24 hours (2 studies with 535 participants; SMD, 0.20; 95% CI, 0.03-0.37; P?=?.02; I2?=?25%; moderate-quality evidence). Adverse events were uncommon. Acetaminophen and ibuprofen appeared to have similar serious adverse event profiles (7 studies with 27?932 participants; ibuprofen vs aceteminophen: odds ratio, 1.08; 95% CI, 0.87-1.33; P?=?.50, I2?=?0%; moderate-quality evidence). Conclusions and Relevance:In this study, use of ibuprofen vs acetaminophen for the treatment of fever or pain in children younger than 2 years was associated with reduced temperature and less pain within the first 24 hours of treatment, with equivalent safety.
Project description:OBJECTIVES:Solid organ transplant recipients are at increased risk of skin cancer, affecting more than 50% of recipients. We aimed to determine the effectiveness of interventions for behavioural change for sun protection or skin cancer prevention in solid organ transplant recipients. DESIGN:Systematic review. DATA SOURCES:We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) and CINAHL from inception to November 2019. ELIGIBILITY CRITERIA:We included randomised controlled trials that evaluated the effect of behavioural or pharmaceutical interventions on behavioural change or skin cancer prevention in solid organ transplant recipients. DATA EXTRACTION AND SYNTHESIS:Risks of bias and evidence certainty were assessed using Cochrane and the Grading of Recommendations Assessment Development and Evaluation framework. RESULTS:Twenty trials (n=2295 participants) were included. It is uncertain whether behavioural interventions improve sun protection behaviour (n=3, n=414, standardised mean difference (SMD) 0.89, 95%?CI -0.84 to 2.62, I2=98%) and knowledge (n=4, n=489, SMD 0.50, 95%?CI 0.12 to 0.87, I2= 76%) as the quality of evidence is very low. We are uncertain of the effects of mammalian target of rapamaycin inhibitors on the incidence of non-melanocytic skin cancer (n=5, n=1080, relative risk 0.46, 95%?CI 0.28 to 0.75, I2 =72%) as the quality of evidence is very low. CONCLUSIONS:Behavioural and pharmaceutical preventive interventions may improve sun protective behaviour and knowledge, and reduce the incidence of non-melanocytic skin cancer, but the overall quality of the evidence is very low and insufficient to guide decision-making and clinical practice. PROSPERO REGISTRATION NUMBER:CRD42017063962.
Project description:Previous systematic reviews and meta-analyses of randomized controlled trials have reported controversial findings regarding the effects of melatonin on pain reduction. The aim of this study was to evaluate the efficacy of melatonin on pain among adults using a meta-analysis of randomized, double-blind, placebo-controlled trials (RDBPCTs). PubMed, EMBASE, the Cochrane Library, and the bibliographies of relevant articles were searched up to February 2020. Two of the authors independently evaluated eligibility of the studies based on the pre-determined criteria and extracted data. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) for the pain score change were calculated using a random-effects meta-analysis. Out of 463 that met the initial criteria, a total of 30 trials, which involved 1967 participants with 983 in an intervention group and 984 in a control group, were included in the final analysis. In a random-effects meta-analysis, the use of melatonin reduced chronic pain in all the trials (5 studies, SMD -0.65, 95% CI -0.96 to -0.34, I2 = 57.2%) and high-quality trials (4 studies, SMD -0.62, 95% CI -1.01 to -0.23, I2 = 49.3%). Moreover, the use of melatonin significantly reduced acute postoperative pain (11 studies, SMD -0.82, 95% CI -1.40 to -0.25, I2 = 93.0%). However, the subgroup meta-analysis of high-quality RDBPCTs showed no significant association between them (6 studies, SMD -0.21, 95 % CI -0.66 to 0.24, I2 = 82.4%). The current study suggests that melatonin might be used in treatment of chronic pain, while there is no sufficient evidence for acute postoperative or procedural pain. Further trials are warranted to confirm its analgesic effect.