Reducing medication errors for adults in hospital settings.

ObjectiveTo examine medication safety in two intensive care units (ICU), and to assess the complexity of medication errors and adverse drug events (ADE) in ICUs across the stages of the...

Background. Medication errors and resultant adverse drug events (ADEs) often occur during transitions of care. Up to 67% of in-patients prescriptions have at least one unintentional medication discrepancy with previously prescribed therapy. The proportion of clinically significant medication discrepancies is 1159%. Studies from the developed countries demonstrated the effectiveness of medication reconciliation in reducing medication errors, ADEs and healthcare resource utilization. There is a necessity to conduct medication reconciliation studies within Russian current clinical practice to develop effective medical care quality and patients safety programs. Aims to evaluate the impact of pharmacologist-led medication reconciliation on the frequency and structure of unintentional medication discrepancies and potential ADEs at hospital admission and discharge. Methods. Standard care was compared to medication reconciliation led by a clinical pharmacologist in a prospective randomized trial of 410 elective surgical patients. Medication discrepancies at hospital admission and discharge were identified and reconciled. Clinical outcomes were evaluated by reviewing electronic health records. Results. In the intervention group the frequency of unintentional discrepancies at hospital admission decreased from 32.68 to 16.86%, the proportion of patients with at least one unintentional discrepancy decreased from 64.9 to 44.9%, the number of discrepancies per patient decreased from 1.5 to 0.66. The incidence of discrepancies at hospital discharge decreased from 82.90 to 43.29%, the proportion of patients with discrepancies decreased from 95.61 to 52.68%, the average number of discrepancies per patient decreased from 2.79 to 1.67. Medication reconciliation led by clinical pharmacologist decreased the frequency of unscheduled out-patient visits after discharge from 7.32 to 2.93%. The determined risk factors for unintentional discrepancies at hospital admission were: prescribing of cardiovascular, endocrine drugs and those affecting the central nervous system. Both at admission and discharge medication reconciliation was the significant factor reducing the risk of unintentional discrepancies. Conclusions. Medication reconciliation at hospital admission and discharge reduces the frequency of unintentional discrepancies in drug prescriptions by 16 and 40%, respectively. The implementation of medication reconciliation into clinical practice reduces unscheduled out-patient visits after hospital discharge.

Background and Aims:Medication errors occur at any point of the medication management process, and are a major cause of death and harm globally. The objective of this review was to compare the effectiveness of different interventions in reducing prescribing, dispensing and administration medication errors in acute medical and surgical settings.Methods:The protocol for this systematic review was registered in PROSPERO (CRD42019124587). The library databases, MEDLINE, CINAHL, EMBASE, PsycINFO, Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials were searched from inception to February 2019. Studies were included if they involved testing of an intervention aimed at reducing medication errors in adult, acute medical or surgical settings. Meta-analyses were performed to examine the effectiveness of intervention types.Results:A total of 34 articles were included with 12 intervention types identified. Meta-analysis showed that prescribing errors were reduced by pharmacist-led medication reconciliation, computerised medication reconciliation, pharmacist partnership, prescriber education, medication reconciliation by trained mentors and computerised physician order entry (CPOE) as single interventions. Medication administration errors were reduced by CPOE and the use of an automated drug distribution system as single interventions. Combined interventions were also found to be effective in reducing prescribing or administration medication errors. No interventions were found to reduce dispensing error rates. Most studies were conducted at single-site hospitals, with chart review being the most common method for collecting medication error data. Clinical significance of interventions was examined in 21 studies. Since many studies were conducted in a pre–post format, future studies should include a concurrent control group.Conclusion:The systematic review identified a number of single and combined intervention types that were effective in reducing medication errors, which clinicians and policymakers could consider for implementation in medical and surgical settings. New directions for future research should examine interdisciplinary collaborative approaches comprising physicians, pharmacists and nurses.Lay summaryActivities to reduce medication errors in adult medical and surgical hospital areasIntroduction:Medication errors or mistakes may happen at any time in hospital, and they are a major reason for death and harm around the world.Objective:To compare the effectiveness of different activities in reducing medication errors occurring with prescribing, giving and supplying medications in adult medical and surgical settings in hospital.Methods:Six library databases were examined from the time they were developed to February 2019. Studies were included if they involved testing of an activity aimed at reducing medication errors in adult medical and surgical settings in hospital. Statistical analysis was used to look at the success of different types of activities.Results:A total of 34 studies were included with 12 activity types identified. Statistical analysis showed that prescribing errors were reduced by pharmacists matching medications, computers matching medications, partnerships with pharmacists, prescriber education, medication matching by trained physicians, and computerised physician order entry (CPOE). Medication-giving errors were reduced by the use of CPOE and an automated medication distribution system. The combination of different activity types were also shown to be successful in reducing prescribing or medication-giving errors. No activities were found to be successful in reducing errors relating to supplying medications. Most studies were conducted at one hospital with reviewing patient charts being the most common way for collecting information about medication errors. In 21 out of 34 articles, researchers examined the effect of activity types on patient harm caused by medication errors. Many studies did not involve the use of a control group that does not receive the activity.Conclusion:A number of activity types were shown to be successful in reducing prescribing and medication-giving errors. New directions for future research should examine activities comprising health professionals working together.

To compare the frequency and preventability of adverse drug events and potential adverse drug events in intensive care units (ICUs) and non-ICUs. To evaluate systems factors involving the individual caregivers, care unit teams, and patients involved in each adverse drug event by comparing ICUs with non-ICUs and medical ICUs with surgical ICUs. Prospective cohort study. Participants included all 4,031 adult admissions to a stratified, random sample of 11 medical and surgical units in two tertiary care hospitals over a 6-month period. Units included two medical and three surgical ICUs and four medical and two surgical general care units. Two tertiary care hospitals: Eleven medical and surgical units, including two medical and three surgical ICUs. Adult admissions (n = 4,031). None. Rate of preventable adverse drug events and potential adverse drug events, length of stay, charges, costs, and measures of the unit's environment. Incidents were detected by stimulated self-report by nurses and pharmacists and by daily review of all charts by nurse investigators. Incidents were subsequently classified by two independent reviewers as to whether they represented adverse drug events or potential adverse drug events and as to severity and preventability. Those individuals involved in the preventable adverse drug event and potential adverse drug event underwent detailed interviews by peer case-investigators. The rate of preventable adverse drug events and potential adverse drug events in ICUs was 19 events per 1000 patient days, nearly twice that rate of non-ICUs (p <.01). The medical ICU rate (25 events per 1000 patient days) was significantly (p <.05) higher than the surgical ICU rate (14 events per 1000 patient days). When adjusted for the number of drugs used in the previous 24 hrs or ordered since admission, there were no differences in rates between ICUs and non-ICUs. ICU acuity, length of stay, and severity of the adverse drug event were greater in ICUs than non-ICUs, but there were no differences between medical ICU and surgical ICU patients. Structured interviews indicated almost no differences between ICUs and non-ICUs for many characteristics of the patient, patient care team, systems, and individual caregivers. The rate of preventable and potential adverse drug events was twice as high in ICUs compared with non-ICUs. However, when adjusted for the number of drugs ordered, there was no greater likelihood for preventable adverse drug events and potential adverse drug events to occur in ICUs than in non-ICUs. Preventable adverse drug events and potential adverse drug events occurred in units that functioned normally and involved caregivers who were working under reasonably normal circumstances, not at the extremes of workload, stress, or a difficult environment.

Adverse drug events and medication errors are threats to quality care. Inpatient studies suggest that a pharmacist may reduce these events, but outpatient studies have not been forthcoming. We conducted a pooled analysis of 2 randomized controlled trials to determine the effect of pharmacist intervention on adverse drug events and medication errors. We studied 800 outpatient cases of hypertension stratified into complicated (n = 535) and uncomplicated (n = 265). Patients in the complicated stratum had heart failure or other cardiovascular complication. Computer programs examined 1-year electronic record data to identify events classified as adverse drug events and preventable or potential adverse drug events. Medication errors included preventable and potential adverse drug events. Of the 800 participants (mean [SD] age, 59 [10] years), 484 (90.5%) and 258 (97.4%) participants remained in the complicated and uncomplicated strata, respectively, at 12 months. Compared with the control group, the risk of any event was 34% lower in the intervention group (risk ratio, 0.66; 95% confidence interval [CI], 0.50-0.88), including a lower risk of adverse drug events (risk ratio, 0.65; 95% CI, 0.47-0.90), preventable adverse drug events (risk ratio, 0.52; 95% CI, 0.25-1.09), potential adverse drug events (risk ratio, 0.70; 95% CI, 0.40-1.22), and medication errors (risk ratio, 0.63; 95% CI, 0.40-0.98). This post hoc analysis suggests that pharmacist intervention to improve medication use in outpatients with cardiovascular disease decreases the risk of adverse drug events and medication errors. Further studies are needed to confirm this finding.

Iatrogenic injuries, including medication errors, are an important problem in all hospitalized populations. However, few epidemiological data are available regarding medication errors in the pediatric inpatient setting. To assess the rates of medication errors, adverse drug events (ADEs), and potential ADEs; to compare pediatric rates with previously reported adult rates; to analyze the major types of errors; and to evaluate the potential impact of prevention strategies. Prospective cohort study of 1120 patients admitted to 2 academic institutions during 6 weeks in April and May of 1999. Medication errors, potential ADEs, and ADEs were identified by clinical staff reports and review of medication order sheets, medication administration records, and patient charts. We reviewed 10 778 medication orders and found 616 medication errors (5.7%), 115 potential ADEs (1.1%), and 26 ADEs (0.24%). Of the 26 ADEs, 5 (19%) were preventable. While the preventable ADE rate was similar to that of a previous adult hospital study, the potential ADE rate was 3 times higher. The rate of potential ADEs was significantly higher in neonates in the neonatal intensive care unit. Most potential ADEs occurred at the stage of drug ordering (79%) and involved incorrect dosing (34%), anti-infective drugs (28%), and intravenous medications (54%). Physician reviewers judged that computerized physician order entry could potentially have prevented 93% and ward-based clinical pharmacists 94% of potential ADEs. Medication errors are common in pediatric inpatient settings, and further efforts are needed to reduce them.

Background Medication errors have been identified as a problem in health care that results in adverse drug events. It has been identified as a failure of an intended plan of action or the initiation of a wrong plan of action. Medication errors are pervasive in community dwelling older adults. Strategies that facilitate the prevention of medication errors warrant consideration. Medication reconciliation has been identified as one such a strategy. Objectives The objective of this systematic review was to identify, appraise and synthesize the best available evidence to determine the effectiveness of medication reconciliation strategies on medication errors among community dwelling older adults. Inclusion criteria Types of participants This review included older adults of all races and ethnicities (65 years of age and older) living in the community. Older adults with dementia or who were dependent on family or other individuals for care were not included. Types of intervention(s) This review considered studies that evaluated the effects of medication reconciliation strategies on medication errors in community dwelling older adults. Types of studies This review considered randomized controlled trials, non-randomized controlled trials and quasi-experimental studies. In the absence of the above, other study designs including case control, cross-sectional cohort, and before and after studies were considered. Types of outcomes This review considered the primary outcome measure of the number of medication errors. Medication errors may include but are not limited to: prescribing, labeling, dispensing, medication administration and medication reconstitution. Search strategy This search examined published and unpublished studies from the inception of databases to the present that were in English. Databases included: MEDLINE, CINAHL, The Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Academic Search Premier, PsycINFO, Healthsource Nursing/Academic edition, and PubMed. Gray literature included Science.gov, scricus.com, Robert Wood Johnson Institute, and Dissertations Abstract International. Searches were completed in November 2012. Methodological quality Two independent reviewers evaluated the included studies for methodological quality using the standardized critical appraisal instruments from the Joanna Briggs Institute. Disagreements between the reviewers were resolved with a third reviewer. Data collection Data were extracted using the standardized data extraction tool from the Joanna Briggs Institute. Data synthesis Statistical pooling was not possible due to heterogeneity of the studies; therefore findings were presented as a narrative. Results This review yielded two level one randomized controlled trials and one level three prospective randomized comparative study. Studies presented evidence as to the potential positive outcomes of a pharmacist-led medication reconciliation on medication errors for community dwelling older adults. The way in which the pharmacist conducted the medication reconciliation varied across studies. Conclusions Medication reconciliation is complex and may be implemented in a variety of ways. For older adults residing in community settings, pharmacist-led medication reconciliation may possibly play a role in the reduction of medication errors.

Errors occurring during different steps of the medication process can lead to adverse drug events (ADEs). Surgical patients are expected to have an increased risk for ADEs during hospitalization. However, detailed information about ADEs in the surgical patient is lacking. In this study, we aim to measure the incidence and nature of (preventable) ADEs, potential risk factors for and outcome parameters of (preventable) ADEs in surgical patients. Observational multicentre cohort study in which eight surgical wards participated from three Dutch hospitals, all using computerized physician order entry (CPOE) systems with clinical decision support. Electively admitted surgical patients of the participating wards were included from March until June 2009. ADEs were measured using a standardized method with expert judgment. Incidence, severity, preventability and accountable medication were assessed. Poisson regression analysis was applied to determine the associations between possible risk factors and the occurrence of ADEs, expressed as incidence rate ratio (IRR). Also outcomes of ADEs in surgical patients were measured. The incidence and nature of (preventable) ADEs in surgical patients. A total of 567 surgical patients were included. We found an incidence of 27.5 ADEs and 4.2 preventable ADEs (pADEs) per 100 admissions (15.4 %). A quarter of the pADEs were severe or life-threatening. Opioids and anti-coagulation medication play a major role in the occurrence of ADEs and pADEs respectively. Univariate analysis revealed an American Society of Anesthesiologists classification of III or more as a risk factor for ADEs. Patients older than 65 years [IRR 2.77 (1.14-6.72)], with cardiovascular comorbidity [IRR 2.87 (1.13-7.28)], or undergoing vascular surgery [IRR 2.32 (1.01-5.32)] were at risk for pADEs. Patients experiencing an ADE had a significant longer duration of admission than patients without an ADE. Surgical patients are at considerable risk of experiencing one or more ADEs during their admission, also in CPOE-hospitals. Risk factors for pADEs are age older than 65 years, cardiovascular comorbidity, and vascular surgery. Intensified monitoring may be needed in patients with a higher than average risk for pADEs.

Medication errors are a major concern of health care professionals and medical institutions, especially errors involving children. Studies in adults have shown that computerized physician order entry (CPOE) systems reduce medication errors and adverse drug events (ADEs). The effect of CPOE implementation in a pediatric population has not been reported. The objective of this study was to evaluate the impact of CPOE on the frequency of errors in the medication ordering process in a pediatric critical care unit (PCCU). A prospective trial was conducted of 514 pediatric patients who were admitted to a 20-bed PCCU in a tertiary-care children's hospital before and after implementation of CPOE. Medication errors were identified after review of all orders during the study period and then further classified as potential ADEs, medication prescribing errors (MPE), and rule violations (RV). A total of 13 828 medication orders were reviewed. Before implementation, potential ADEs occurred at a rate of 2.2 per 100 orders, MPEs at a rate of 30.1 per 100 orders, and RVs at a rate of 6.8 per 100 orders. After implementation, the rate of potential ADEs was reduced to 1.3 per 100 orders, MPEs to 0.2 per 100 orders, and RVs to 0.1 per 100 orders. The overall error reduction was 95.9%. Potential ADEs were reduced by 40.9%, and MPEs and RVs were reduced by 99.4% and 97.9%, respectively. The implementation of CPOE resulted in almost a complete elimination of MPEs and RVs and a significant but less dramatic effect on potential ADEs.

Purpose: Patients in the intensive care unit (ICU) are at an increased risk for medication errors (MEs) and adverse drug events from multifactorial causes. ME rate ranges from 1.2 to 947 per 1,000 patient days in the medical ICU (MICU). Studies with the implementation of electronic health records (EHR) have concluded that it significantly reduced overall prescribing errors and the number of errors that caused patient harm decreased. However, other types of errors, such as wrong dose and omission of required medications increased after EHR implementation. We sought to compare the number of MEs before and after EHR implementation in the MICU, with additional evaluation of error severity. Patients and methods: Prospective, observational, quality improvement study of all patients admitted to a single MICU service at an academic medical center. Patients were evaluated during four periods over 2 years: August–September 2010 (preimplementation; period I), January–February 2011 (2 months postimplementation; period II), August–September 2012 (21 months postimplementation; period III), and January–February 2013 (25 months postimplementation; period IV). All medication orders and administration records were reviewed by an ICU clinical pharmacist and ME was defined as a deviation from established standards for prescribing, dispensing, administering, or documenting medication. The frequency and classification of MEs were compared between groups by chi square; p <0.05 was considered significant. Results: There was a statistically significant increase in the number of MEs per 1,000 patient days during time periods II (N=2,592; p <0.001) and III (N=2,388; p =0.0023) compared to baseline (N=1,972). However, over time there was a significant reduction in medication errors during period IV compared to baseline (N=1,669; p =0.0008). Conclusion: In the short-term, EHR did not lead to a reduction in medication errors in the ICU; however, there was a significant decrease in medication errors after 2 years. Keywords: electronic health record, intensive care unit, medication error, patient safety, computerized physician order entry, quality improvement

To assess incidence and preventability of adverse drug events (ADEs) and potential ADEs. To analyze preventable events to develop prevention strategies. Prospective cohort study. All 4031 adult admissions to a stratified random sample of 11 medical and surgical units in two tertiary care hospitals over a 6-month period. Units included two medical and three surgical intensive care units and four medical and two surgical general care units. Adverse drug events and potential ADEs. Incidents were detected by stimulated self-report by nurses and pharmacists and by daily review of all charts by nurse investigators. Incidents were subsequently classified by two independent reviewers as to whether they represented ADEs or potential ADEs and as to severity and preventability. Over 6 months, 247 ADEs and 194 potential ADEs were identified. Extrapolated event rates were 6.5 ADEs and 5.5 potential ADEs per 100 nonobstetrical admissions, for mean numbers per hospital per year of approximately 1900 ADEs and 1600 potential ADEs. Of all ADEs, 1% were fatal (none preventable), 12% life-threatening, 30% serious, and 57% significant. Twenty-eight percent were judged preventable. Of the life-threatening and serious ADEs, 42% were preventable, compared with 18% of significant ADEs. Errors resulting in preventable ADEs occurred most often at the stages of ordering (56%) and administration (34%); transcription (6%) and dispensing errors (4%) were less common. Errors were much more likely to be intercepted if the error occurred earlier in the process: 48% at the ordering stage vs 0% at the administration stage. Adverse drug events were common and often preventable; serious ADEs were more likely to be preventable. Most resulted from errors at the ordering stage, but many also occurred at the administration stage. Prevention strategies should target both stages of the drug delivery process.

BackgroundOne of the most critical steps in the medication process on paediatric wards is the drug prescription.1 Studies have shown that the use of electronic systems may improve the quality...

To evaluate the incidence and preventability of adverse drug events (ADEs) and to determine the yield of several strategies for identifying them. Prospective cohort study. Seven units, including two medical, two surgical, and two obstetric general care units and a coronary intensive care unit in an urban tertiary care hospital. All patients on these units over a 37-day period (2,967 patient-days). None. Events were identified in three ways: 1) logs were placed on each unit and satellite pharmacy for nurses and pharmacists to record incidents; 2) a research nurse solicited reports of incidents twice daily on each unit; and 3) the nurse reviewed all charts at least daily. Incidents were classified by two independent reviewers as ADEs or potential ADEs. The rate of drug-related incidents was 73 in 2,967 patient-days; 27 incidents were judged ADEs, 34 potential ADEs, and 12 problem orders. Fifty different drugs were involved. Physicians were primarily responsible for 72% of the incidents, with the remainder divided evenly between nursing, pharmacy, and clerical personnel. Of the 27 ADEs, five were life-threatening, nine were serious, and 13 were significant. Fifteen (56%) of the 27 were judged definitely or probably preventable. Incidents were discovered about equally often from the logs and by chart review. However, when the incidents in which an ADE was present were compared with the remainder of incidents, the authors found that 67% (18 of 27) of the ADEs were identified only by chart review (p < 0.001), and physicians were more often judged responsible than other personnel (p < 0.001). The authors conclude that ADEs are not infrequent, often preventable, and usually caused by physician decisions. In this study, solicited reporting by nurses and pharmacists was inferior to chart review for identifying ADEs, but was effective for identifying potential ADEs. Optimal prevention strategies should cover many types of drugs and target physicians' ordering practices.

Background: Adverse drug events (ADEs) in the elderly frequently occur because of their multiple chronic diseases and complexity of drug therapy. To better understand adverse drug events, the prevalence and characteristics of adverse drug events in elderly South Korean patients were assessed. Methods: The National Health Insurance databases for 2015 and 2016 were used for the analysis. We included patients aged ≥65years that had at least one claim with the diagnosis codes 'drug-induced,' 'poisoning by drug,' and 'vaccine-associated' each year for the base-case analysis. To minimize the underestimation of adverse drug event prevalence, we also used an extended definition analysis by adding the 'adverse drug event very likely' codes. We estimated the prevalence of adverse drug events by sex, age group, and type of insurance and examined the frequent types of adverse drug events in 2015 and 2016. Results: In the base-case analysis, adverse drug event prevalence in individuals aged 65years and older was 2.75% in 2015 and 2.77% in 2016. With advanced age, the prevalence of adverse drug event tended to increase, peaking in the age group of 75-79years. In addition, the adverse drug event prevalence was higher in females and Medical Aid enrollees. The most frequently occurring adverse drug event was 'allergy, unspecified,' followed by 'other drug-induced secondary parkinsonism,' and 'generalized skin eruption due to drugs and medicaments.' When we examined the extended definition analysis, the prevalence of adverse drug events was 4.47% in 2015 and 4.52% in 2016, which significantly increased from those estimated in the base-case analysis. Conclusion: Among the older adults, the prevalence of adverse drug event was higher in advanced age, females, and Medical Aid enrollees. In particular, allergy and drug-induced secondary parkinsonism frequently occurred. This study provides evidence that health policies addressing the prevention and management of adverse drug events should be a priority for the most vulnerable elderly patients.

The choice of the appropriate perioperative thromboprophylaxis for people with cancer depends on the relative benefits and harms of different anticoagulants. To systematically review the evidence for the relative efficacy and safety of anticoagulants for perioperative thromboprophylaxis in people with cancer. This update of the systematic review was based on the findings of a comprehensive literature search conducted on 14 June 2018 that included a major electronic search of Cochrane Central Register of Controlled Trials (CENTRAL, 2018, Issue 6), MEDLINE (Ovid), and Embase (Ovid); handsearching of conference proceedings; checking of references of included studies; searching for ongoing studies; and using the 'related citation' feature in PubMed. Randomized controlled trials (RCTs) that enrolled people with cancer undergoing a surgical intervention and assessed the effects of low-molecular weight heparin (LMWH) to unfractionated heparin (UFH) or to fondaparinux on mortality, deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding outcomes, and thrombocytopenia. Using a standardized form, we extracted data in duplicate on study design, participants, interventions outcomes of interest, and risk of bias. Outcomes of interest included all-cause mortality, PE, symptomatic venous thromboembolism (VTE), asymptomatic DVT, major bleeding, minor bleeding, postphlebitic syndrome, health related quality of life, and thrombocytopenia. We assessed the certainty of evidence for each outcome using the GRADE approach (GRADE Handbook). Of 7670 identified unique citations, we included 20 RCTs with 9771 randomized people with cancer receiving preoperative prophylactic anticoagulation. We identified seven reports for seven new RCTs for this update.The meta-analyses did not conclusively rule out either a beneficial or harmful effect of LMWH compared with UFH for the following outcomes: mortality (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.63 to 1.07; risk difference (RD) 9 fewer per 1000, 95% CI 19 fewer to 4 more; moderate-certainty evidence), PE (RR 0.49, 95% CI 0.17 to 1.47; RD 3 fewer per 1000, 95% CI 5 fewer to 3 more; moderate-certainty evidence), symptomatic DVT (RR 0.67, 95% CI 0.27 to 1.69; RD 3 fewer per 1000, 95% CI 7 fewer to 7 more; moderate-certainty evidence), asymptomatic DVT (RR 0.86, 95% CI 0.71 to 1.05; RD 11 fewer per 1000, 95% CI 23 fewer to 4 more; low-certainty evidence), major bleeding (RR 1.01, 95% CI 0.69 to 1.48; RD 0 fewer per 1000, 95% CI 10 fewer to 15 more; moderate-certainty evidence), minor bleeding (RR 1.01, 95% CI 0.76 to 1.33; RD 1 more per 1000, 95% CI 34 fewer to 47 more; moderate-certainty evidence), reoperation for bleeding (RR 0.93, 95% CI 0.57 to 1.50; RD 4 fewer per 1000, 95% CI 22 fewer to 26 more; moderate-certainty evidence), intraoperative transfusion (mean difference (MD) -35.36 mL, 95% CI -253.19 to 182.47; low-certainty evidence), postoperative transfusion (MD 190.03 mL, 95% CI -23.65 to 403.72; low-certainty evidence), and thrombocytopenia (RR 3.07, 95% CI 0.32 to 29.33; RD 6 more per 1000, 95% CI 2 fewer to 82 more; moderate-certainty evidence). LMWH was associated with lower incidence of wound hematoma (RR 0.70, 95% CI 0.54 to 0.92; RD 26 fewer per 1000, 95% CI 39 fewer to 7 fewer; moderate-certainty evidence). The meta-analyses found the following additional results: outcomes intraoperative blood loss (MD -6.75 mL, 95% CI -85.49 to 71.99; moderate-certainty evidence); and postoperative drain volume (MD 30.18 mL, 95% CI -36.26 to 96.62; moderate-certainty evidence).In addition, the meta-analyses did not conclusively rule out either a beneficial or harmful effect of LMWH compared with Fondaparinux for the following outcomes: any VTE (DVT or PE, or both; RR 2.51, 95% CI 0.89 to 7.03; RD 57 more per 1000, 95% CI 4 fewer to 228 more; low-certainty evidence), major bleeding (RR 0.74, 95% CI 0.45 to 1.23; RD 8 fewer per 1000, 95% CI 16 fewer to 7 more; low-certainty evidence), minor bleeding (RR 0.83, 95% CI 0.34 to 2.05; RD 8fewer per 1000, 95% CI 33 fewer to 52 more; low-certainty evidence), thrombocytopenia (RR 0.35, 95% CI 0.04 to 3.30; RD 14 fewer per 1000, 95% CI 20 fewer to 48 more; low-certainty evidence), any PE (RR 3.13, 95% CI 0.13 to 74.64; RD 2 more per 1000, 95% CI 1 fewer to 78 more; low-certainty evidence) and postoperative drain volume (MD -20.00 mL, 95% CI -114.34 to 74.34; low-certainty evidence) AUTHORS' CONCLUSIONS: We found no difference between perioperative thromboprophylaxis with LMWH versus UFH and LMWH compared with fondaparinux in their effects on mortality, thromboembolic outcomes, major bleeding, or minor bleeding in people with cancer. There was a lower incidence of wound hematoma with LMWH compared to UFH.