Prolonged Seasonality of Respiratory Syncytial Virus Infection among Preterm Infants in a Subtropical Climate

Objective

There is limited epidemiological data on the seasonality of respiratory syncytial virus (RSV) infection in subtropical climates, such as in Taiwan. This study aimed to assess RSV seasonality among children ≤24 months of age in Taiwan. We also assessed factors (gestational age [GA], chronologic age [CA], and bronchopulmonary dysplasia [BPD]) associated with RSV-associated hospitalization in preterm infants to confirm the appropriateness of the novel Taiwanese RSV prophylactic policy.

Study Design

From January 2000 to August 2010, 3572 children aged ≤24-months were admitted to Taipei Mackay Memorial Hospital due to RSV infection. The monthly RSV-associated hospitalization rate among children aged ≤24 months was retrospectively reviewed. Among these children, 378 were born preterm. The associations between GA, CA, and BPD and the incidence of RSV-associated hospitalization in the preterm infants were assessed.

Results

In children aged ≤24 months, the monthly distribution of RSV-associated hospitalization rates revealed a prolonged RSV season with a duration of 10 months. Infants with GAs ≤32 weeks and those who had BPD had the highest rates of RSV hospitalization (P<0.001). Preterm infants were most vulnerable to RSV infection within CA 9 months.

Conclusions

Given that Taiwan has a prolonged (10-month) RSV season, the American Academy of Pediatrics'' recommendations for RSV prophylaxis are not directly applicable. The current Taiwanese guidelines for RSV prophylaxis, which specify palivizumab injection (a total six doses until CA 8–9 months) for preterm infants (those born before 28^6/7 weeks GA or before 35^6/7 weeks GA with BPD), are appropriate. This prophylaxis strategy may be applicable to other countries/regions with subtropical climates.     

Incidence of Hospitalization for Respiratory Syncytial Virus Infection amongst Children in Ontario,Canada: A Population-Based Study Using Validated Health Administrative Data

Importance

RSV is a common illness among young children that causes significant morbidity and health care costs.

Objective

Routinely collected health administrative data can be used to track disease incidence, explore risk factors and conduct health services research. Due to potential for misclassification bias, the accuracy of data-elements should be validated prior to use. The objectives of this study were to validate an algorithm to accurately identify pediatric cases of hospitalized respiratory syncytial virus (RSV) from within Ontario’s health administrative data, estimate annual incidence of hospitalization due to RSV and report the prevalence of major risk factors within hospitalized patients.

Study Design and Setting

A retrospective chart review was performed to establish a reference-standard cohort of children from the Ottawa region admitted to the Children’s Hospital of Eastern Ontario (CHEO) for RSV-related disease in 2010 and 2011. Chart review data was linked to Ontario’s administrative data and used to evaluate the diagnostic accuracy of algorithms of RSV-related ICD-10 codes within provincial hospitalization and emergency department databases. Age- and sex-standardized incidence was calculated over time, with trends in incidence assessed using Poisson regression.

Results

From a total of 1411 admissions, chart review identified 327 children hospitalized for laboratory confirmed RSV-related disease. Following linkage to administrative data and restriction to first admissions, there were 289 RSV patients in the reference-standard cohort. The best algorithm, based on hospitalization data, resulted in sensitivity 97.9% (95%CI: 95.5–99.2%), specificity 99.6% (95%CI: 98.2–99.8%), PPV 96.9% (95%CI: 94.2–98.6%), NPV 99.4% (95%CI: 99.4–99.9%). Incidence of hospitalized RSV in Ontario from 2005–2012 was 10.2 per 1000 children under 1 year and 4.8 per 1000 children aged 1 to 3 years. During the surveillance period, there was no identifiable increasing or decreasing linear trend in the incidence of hospitalized RSV, hospital length of stay and PICU admission rates. Among the Ontario RSV cohort, 16.3% had one or more major risk factors, with a decreasing trend observed over time.

Conclusion

Children hospitalized for RSV-related disease can be accurately identified within population-based health administrative data. RSV is a major public health concern and incidence has not changed over time, suggesting a lack of progress in prevention.     

Clinical Presentation and Birth Outcomes Associated with Respiratory Syncytial Virus Infection in Pregnancy

Background

Respiratory syncytial virus (RSV) is the most important cause of viral pneumonia in children worldwide. A maternal vaccine may protect both the mother and infant from RSV illness. The epidemiology and clinical presentation of RSV in pregnant and postpartum women is not well-described.

Methods

Data were collected from a prospective, randomized trial of influenza immunization in pregnant women in rural southern Nepal. Women were enrolled in their second trimester of pregnancy and followed until six months postpartum. Active weekly home-based surveillance for febrile respiratory illness was performed. Mid-nasal swabs collected with episodes of respiratory illness were tested for RSV by real-time polymerase chain reaction.

Results

RSV was detected in 14 (0.4%) illness episodes in 3693 women over 3554 person-years of surveillance from 2011–2014. RSV incidence was 3.9/1000 person-years overall, and 11.8/1000 person-years between September and December. Seven (50%) women sought care for RSV illness; none died. Of the 7 (50%) illness episodes during pregnancy, all had live births with 2 (29%) preterm births and a median birthweight of 3060 grams. This compares to 469 (13%) preterm births and a median birthweight of 2790 grams in women without RSV during pregnancy. Of the 7 mothers with postpartum RSV infection, RSV was detected in 4 (57%) of their infants.

Conclusions

RSV was an uncommon cause of febrile respiratory illness in mothers during pregnancy in Nepal. These data will inform prevention and therapeutic strategies against RSV in resource-limited settings.     

Viral Co-Infections in Pediatric Patients Hospitalized with Lower Tract Acute Respiratory Infections

Background

Molecular techniques can often reveal a broader range of pathogens in respiratory infections. We aim to investigate the prevalence and age pattern of viral co-infection in children hospitalized with lower tract acute respiratory infection (LT-ARI), using molecular techniques.

Methods

A nested polymerase chain reaction approach was used to detect Influenza (A, B), metapneumovirus, respiratory syncytial virus (RSV), parainfluenza (1–4), rhinovirus, adenovirus (A—F), bocavirus and coronaviruses (NL63, 229E, OC43) in respiratory samples of children with acute respiratory infection prospectively admitted to any of the GENDRES network hospitals between 2011–2013. The results were corroborated in an independent cohort collected in the UK.

Results

A total of 204 and 97 nasopharyngeal samples were collected in the GENDRES and UK cohorts, respectively. In both cohorts, RSV was the most frequent pathogen (52.9% and 36.1% of the cohorts, respectively). Co-infection with multiple viruses was found in 92 samples (45.1%) and 29 samples (29.9%), respectively; this was most frequent in the 12–24 months age group. The most frequently observed co-infection patterns were RSV—Rhinovirus (23 patients, 11.3%, GENDRES cohort) and RSV—bocavirus / bocavirus—influenza (5 patients, 5.2%, UK cohort).

Conclusion

The presence of more than one virus in pediatric patients admitted to hospital with LT-ARI is very frequent and seems to peak at 12–24 months of age. The clinical significance of these findings is unclear but should warrant further analysis.     

Incidence and Risk Factors for Respiratory Syncytial Virus and Human Metapneumovirus Infections among Children in the Remote Highlands of Peru

Introduction

The disease burden and risk factors for respiratory syncytial virus (RSV) and human metapneumovirus (MPV) infections among children living in remote, rural areas remain unclear.

Materials and Methods

We conducted a prospective, household-based cohort study of children aged <3 years living in remote rural highland communities in San Marcos, Cajamarca, Peru. Acute respiratory illnesses (ARI), including lower respiratory tract infection (LRTI), were monitored through weekly household visits from March 2009 through September 2011. Nasal swabs collected during ARI/LRTI were tested for RSV, MPV, and other respiratory viruses using real-time RT-PCR. Incidence rates and rate ratios were calculated using mixed effects Poisson regression.

Results

Among 892 enrolled children, incidence rates of RSV and MPV ARI were 30 and 17 episodes per 100 child-years, respectively. The proportions of RSV and MPV ARI that presented as LRTI were 12.5% and 8.9%, respectively. Clinic visits for ARI and hospitalizations were significantly more frequent (all p values <0.05) among children with RSV (clinic 41% and hospital 5.3%) and MPV ARI (38% and 3.5%) when compared with other viral infections (23% and 0.7%) and infections without virus detected (24% and 0.6%). In multivariable analysis, risk factors for RSV detection included younger age (RR 1.02, 95% CI: 1.00-1.03), the presence of a smoker in the house (RR 1.63, 95% CI: 1.12-2.38), residing at higher altitudes (RR 1.93, 95% CI: 1.25-3.00 for 2^nd compared to 1^st quartile residents; RR 1.98, 95% CI: 1.26-3.13 for 3^rd compared to 1^st quartile residents). Having an unemployed household head was significantly associated with MPV risk (RR 2.11, 95% CI: 1.12-4.01).

Conclusion

In rural high altitude communities in Peru, childhood ARI due to RSV or MPV were common and associated with higher morbidity than ARI due to other viruses or with no viral detections. The risk factors identified in this study may be considered for interventional studies to control infections by these viruses among young children from developing countries.     

A prospective, open-label, non-comparative study of palivizumab prophylaxis in children at high risk of serious respiratory syncytial virus disease in the Russian Federation

ABSTRACT: BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LRTIs) in children globally. Predisposing conditions for the development of serious RSV disease include preterm infants and those with cardiopulmonary illness, including congenital heart disease (CHD) and bronchopulmonary dysplasia (BPD). No vaccine is currently approved for the prevention of RSV infection. It is recommended that children at high risk be prophylactically administered palivizumab, a monoclonal antibody that has been shown in a number of clinical studies to reduce hospitalization rates due to serious RSV infection. The objective of the current study was to determine the safety and effectiveness of palivizumab in preventing serious RSV disease in high-risk children in the Russian Federation. Children at high risk of serious RSV disease (ie, born at <=35 wk gestational age and <=6 mo of age, and/or aged <=24 mo with BPD or hemodynamically significant CHD) were enrolled. Subjects were to receive 3 to 5 monthly injections of palivizumab 15 mg/kg (depending on the month of the initial injection) over the RSV season. The primary endpoint was RSV-related hospitalizations. Adverse events (AEs) were reported through 100 days following the final injection. RESULTS: One hundred subjects received >=1 injection of palivizumab; 94 completed their dosing schedule. There were no RSV hospitalizations or deaths. Six of 7 subjects hospitalized for respiratory/cardiac conditions had an RSV test, which was negative in all cases. Three non-serious AEs (acute intermittent rhinitis and rhinitis, 1 subject; atopic dermatitis, 1 subject) were considered possibly related to palivizumab. All other AEs were mild or moderate and considered not related/probably not related to palivizumab. CONCLUSION: Palivizumab was generally well tolerated and effectively prevented serious RSV infection in a mixed population of high-risk children in the Russian Federation.Trial registrationClinicalTrials.gov: NCT01006629.     

Sequencing and Analysis of Globally Obtained Human Respiratory Syncytial Virus A and B Genomes

Background

Human respiratory syncytial virus (RSV) is the leading cause of respiratory tract infections in children globally, with nearly all children experiencing at least one infection by the age of two. Partial sequencing of the attachment glycoprotein gene is conducted routinely for genotyping, but relatively few whole genome sequences are available for RSV. The goal of our study was to sequence the genomes of RSV strains collected from multiple countries to further understand the global diversity of RSV at a whole-genome level.

Methods

We collected RSV samples and isolates from Mexico, Argentina, Belgium, Italy, Germany, Australia, South Africa, and the USA from the years 1998-2010. Both Sanger and next-generation sequencing with the Illumina and 454 platforms were used to sequence the whole genomes of RSV A and B. Phylogenetic analyses were performed using the Bayesian and maximum likelihood methods of phylogenetic inference.

Results

We sequenced the genomes of 34 RSVA and 23 RSVB viruses. Phylogenetic analysis showed that the RSVA genome evolves at an estimated rate of 6.72 × 10^-4 substitutions/site/year (95% HPD 5.61 × 10^-4 to 7.6 × 10^-4) and for RSVB the evolutionary rate was 7.69 × 10^-4 substitutions/site/year (95% HPD 6.81 × 10^-4 to 8.62 × 10^-4). We found multiple clades co-circulating globally for both RSV A and B. The predominant clades were GA2 and GA5 for RSVA and BA for RSVB.

Conclusions

Our analyses showed that RSV circulates on a global scale with the same predominant clades of viruses being found in countries around the world. However, the distribution of clades can change rapidly as new strains emerge. We did not observe a strong spatial structure in our trees, with the same three main clades of RSV co-circulating globally, suggesting that the evolution of RSV is not strongly regionalized.     

Vaccine Induced Herd Immunity for Control of Respiratory Syncytial Virus Disease in a Low-Income Country Setting

Background

Respiratory syncytial virus (RSV) is globally ubiquitous, and infection during the first six months of life is a major risk for severe disease and hospital admission; consequently RSV is the most important viral cause of respiratory morbidity and mortality in young children. Development of vaccines for young infants is complicated by the presence of maternal antibodies and immunological immaturity, but vaccines targeted at older children avoid these problems. Vaccine development for young infants has been unsuccessful, but this is not the case for older children (> 6m). Would vaccinating older children have a significant public health impact? We developed a mathematical model to explore the benefits of a vaccine against RSV.

Methods and Findings

We have used a deterministic age structured model capturing the key epidemiological characteristics of RSV and performed a statistical maximum-likelihood fit to age-specific hospitalization data from a developing country setting. To explore the effects of vaccination under different mixing assumptions, we included two versions of contact matrices: one from a social contact diary study, and the second a synthesised construction based on demographic data. Vaccination is assumed to elicit an immune response equivalent to primary infection. Our results show that immunisation of young children (5–10m) is likely to be a highly effective method of protection of infants (<6m) against hospitalisation. The majority benefit is derived from indirect protection (herd immunity). A full sensitivity and uncertainty analysis using Latin Hypercube Sampling of the parameter space shows that our results are robust to model structure and model parameters.

Conclusions

This result suggests that vaccinating older infants and children against RSV can have a major public health benefit.     

Metamizole-Associated Adverse Events: A Systematic Review and Meta-Analysis

Background

Metamizole is used to treat pain in many parts of the world. Information on the safety profile of metamizole is scarce; no conclusive summary of the literature exists.

Objective

To determine whether metamizole is clinically safe compared to placebo and other analgesics.

Methods

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and several clinical trial registries. We screened the reference lists of included trials and previous systematic reviews. We included randomized controlled trials that compared the effects of metamizole, administered to adults in any form and for any indication, to other analgesics or to placebo. Two authors extracted data regarding trial design and size, indications for pain medication, patient characteristics, treatment regimens, and methodological characteristics. Adverse events (AEs), serious adverse events (SAEs), and dropouts were assessed. We conducted separate meta-analyses for each metamizole comparator, using standard inverse-variance random effects meta-analysis to pool the estimates across trials, reported as risk ratios (RRs). We calculated the DerSimonian and Laird variance estimate T² to measure heterogeneity between trials. The pre-specified primary end point was any AE during the trial period.

Results

Of the 696 potentially eligible trials, 79 trials including almost 4000 patients with short-term metamizole use of less than two weeks met our inclusion criteria. Fewer AEs were reported for metamizole compared to opioids, RR = 0.79 (confidence interval 0.79 to 0.96). We found no differences between metamizole and placebo, paracetamol and NSAIDs. Only a few SAEs were reported, with no difference between metamizole and other analgesics. No agranulocytosis or deaths were reported. Our results were limited by the mediocre overall quality of the reports.

Conclusion

For short-term use in the hospital setting, metamizole seems to be a safe choice when compared to other widely used analgesics. High-quality, adequately sized trials assessing the intermediate- and long-term safety of metamizole are needed.     

End of Life Care for Patients Dying of Stroke: A Comparative Registry Study of Stroke and Cancer

Background

Although stroke is a significant public health challenge and the need for palliative care has been emphasized for these patients, there is limited data on end-of-life care for patients dying from stroke.

Objective

To study the end-of-life care during the last week of life for patients who had died of stroke in terms of registered symptom, symptom management, and communication, in comparison with patients who had died of cancer.

Design

This study is a retrospective, comparative registry study.

Methods

A retrospective comparative registry study was performed using data from a Swedish national quality register for end-of-life care based on WHO`s definition of Palliative care. Data from 1626 patients who had died of stroke were compared with data from 1626 patients who had died of cancer. Binary logistic analyses were used to calculate odds ratios, with 95% CI.

Results

Compared to patients who was dying of cancer, the patients who was dying of stroke had a significantly higher prevalence of having death rattles registered, but a significantly lower prevalence of, nausea, confusion, dyspnea, anxiety, and pain. In addition, the stroke group had significantly lower odds ratios for health care staff not to know whether all these six symptoms were present or not. Patients who was dying of stroke had significantly lower odds ratio of having informative communication from a physician about the transition to end-of-life care and of their family members being offered bereavement follow-up.

Conclusions

The results indicate on differences in end-of-life care between patients dying of stroke and those dying from cancer. To improve the end-of-life care in clinical practice and ensure it has consistent quality, irrespective of diagnosis, education and implementation of palliative care principles are necessary.     

The Different Association between Serum Ferritin and Mortality in Hemodialysis and Peritoneal Dialysis Patients Using Japanese Nationwide Dialysis Registry

Background/Aims

Monitoring of serum ferritin levels is widely recommended in the management of anemia among patients on dialysis. However, associations between serum ferritin and mortality are unclear and there have been no investigations among patients undergoing peritoneal dialysis (PD).

Methods

Baseline data of 191,902 patients on dialysis (age, 65 ± 13 years; male, 61.1%; median dialysis duration, 62 months) were extracted from a nationwide dialysis registry in Japan at the end of 2007. Outcomes, such as one-year mortality, were then evaluated using the registry at the end of 2008.

Results

Within one year, a total of 15,284 (8.0%) patients had died, including 6,210 (3.2%) cardiovascular and 2,707 (1.4%) infection-related causes. Higher baseline serum ferritin levels were associated with higher mortality rates among patients undergoing hemodialysis (HD). In contrast, there were no clear associations between serum ferritin levels and mortality among PD patients. Multivariate Cox regression analysis of HD patients showed that those in the highest serum ferritin decile group had higher rates of all-cause and cardiovascular mortality than those in the lowest decile group (hazard ratio [HR], 1.54; 95% confidence interval [CI], 1.31–1.81 and HR, 1.44; 95% CI, 1.13–1.84, respectively), whereas associations with infection-related mortality became non-significant (HR, 1.14; 95% CI, 0.79–1.65).

Conclusions

Using Japanese nationwide dialysis registry, higher serum ferritin values were associated with mortality not in PD patients but in HD patients.     

Increased Risk of Wheeze and Decreased Lung Function after Respiratory Syncytial Virus Infection

Background

A relationship between hospitalization for respiratory syncytial virus (RSV) bronchiolitis and asthma development has been suggested in case-control studies.

Objective

The aim of this study was to assess the risk of current wheeze, asthma, and lung function at school age in infants previously hospitalized for RSV bronchiolitis compared to non-hospitalized children.

Methods

For this study, data from a prospective birth cohort of unselected, term-born infants (n = 553), of whom 4 (0.7%) were hospitalized for RSV bronchiolitis, and a prospective patient cohort of 155 term infants hospitalized for RSV bronchiolitis were used. Respiratory outcomes at age 6 in children hospitalized for RSV bronchiolitis were compared to non-hospitalized children.

Results

The risk of current wheeze was higher in hospitalized patients (n = 159) compared to non-hospitalized children (n = 549) (adjusted odds ratio (OR) 3.2 (95% CI 1.2–8.1). Similarly, the risk of current asthma, defined as a doctor’s diagnosis of asthma plus current symptoms or medication use, was higher in hospitalized patients (adjusted OR 3.1 (95% CI 1.3–7.5). Compared to non-hospitalized children, RSV bronchiolitis hospitalization was associated with lower lung function (mean difference FEV1% predicted −6.8 l (95% CI (−10.2 to −3.4).

Conclusions and Clinical Relevance

This is the first study showing that hospitalization for RSV bronchiolitis during infancy is associated with increased risk of wheezing, current asthma, and impaired lung function as compared to an unselected birth cohort at age 6.     

Bacteremia in Children Hospitalized with Respiratory Syncytial Virus Infection

Background

The risk of bacteremia is considered low in children with acute bronchiolitis. However the rate of occult bacteremia in infants with RSV infection is not well established. The aim was to determine the actual rate and predictive factors of bacteremia in children admitted to hospital due to confirmed RSV acute respiratory illness (ARI), using both conventional culture and molecular techniques.

Methods

A prospective multicenter study (GENDRES-network) was conducted between 2011–2013 in children under the age of two admitted to hospital because of an ARI. Among those RSV-positive, bacterial presence in blood was assessed using PCR for Meningococcus, Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, in addition to conventional cultures.

Results

66 children with positive RSV respiratory illness were included. In 10.6% patients, bacterial presence was detected: H. influenzae (n = 4) and S. pneumoniae (n = 2). In those patients with bacteremia, there was a previous suspicion of bacterial superinfection and had received empirical antibiotic treatment 6 out of 7 (85.7%) patients. There were significant differences in terms of severity between children with positive bacterial PCR and those with negative results: PICU admission (100% vs. 50%, P-value = 0.015); respiratory support necessity (100% vs. 18.6%, P-value < 0.001); Wood-Downes score (mean = 8.7 vs. 4.8 points, P-value < 0.001); GENVIP scale (mean = 17 vs. 10.1, P-value < 0.001); and length of hospitalization (mean = 12.1 vs. 7.5 days, P-value = 0.007).

Conclusion

Bacteremia is not frequent in infants hospitalized with RSV respiratory infection, however, it should be considered in the most severe cases.     

The Effects of Intra-Aortic Balloon Pumps on Mortality in Patients Undergoing High-Risk Coronary Revascularization: A Meta-Analysis of Randomized Controlled Trials of Coronary Artery Bypass Grafting and Stenting Era

Background

Intra-aortic balloon pumps (IABP) have generally been used for patients undergoing high-risk mechanical coronary revascularization. However, there is still insufficient evidence to determine whether they can improve outcomes in reperfusion therapy patients, mainly by percutaneous coronary intervention (PCI) with stenting or coronary artery bypass graft (CABG). This study was designed to determine the difference between high-risk mechanical coronary revascularization with and without IABPs on mortality, by performing a meta-analysis on randomized controlled trials of the current era.

Methods

Pubmed and Embase databases were searched from inception to May 2015. Unpublished data were obtained from the investigators. Randomized clinical trials of IABP and non-IABP in high-risk coronary revascularization procedures (PCI or CABG) were included. In the case of PCI procedures, stents should be used in more than 80% of patients. Numbers of events at the short-term and long-term follow-up were extracted.

Results

A total of 12 randomized trials enrolling 2155 patients were included. IABPs did not significantly decrease short-term mortality (relative risk (RR) 0.66; 95% CI, 0.42–1.01), or long-term mortality (RR 0.79; 95% CI, 0.47–1.35), with low heterogeneity across the studies. The findings remained stable in patients with acute myocardial infarction with or without cardiogenic shock. But in high-risk CABG patients, IABP was associated with reduced mortality (71 events in 846 patients; RR 0.40; 95%CI 0.25–0.67).

Conclusion

In patients undergoing high-risk coronary revascularization, IABP did not significantly decrease mortality. But high-risk CABG patients may be benefit from IABP. Rigorous criteria should be applied to the use of IABPs.     

Gender-Specific Differences in Low-Dose Haloperidol Response for Prevention of Postoperative Nausea and Vomiting: A Register-Based Cohort Study

Background

Postoperative nausea and vomiting (PONV) is one of the most common and distressing complications after general anesthesia and surgery, with young non-smoking females receiving postoperative opioids being high-risk patients. This register-based study aims to evaluate the effect of low-dose haloperidol (0.5 mg intravenously) directly after induction of general anesthesia to reduce the incidence of PONV in the postoperative anesthesiological care unit (PACU).

Methods

Multivariable regression models were used to investigate the association between low-dose haloperidol and the occurrence of PONV using a patient registry containing 2,617 surgical procedures carried out at an university hospital.

Results

Haloperidol 0.5 mg is associated with a reduced risk of PONV in the total collective (adjusted odds ratio = 0.75, 95% confidence interval: [0.56, 0.99], p = 0.05). The results indicate that there is a reduced risk in male patients (adjusted odds ratio = 0.45, 95% confidence interval: [0.28, 0.73], p = 0.001) if a dose of 0.5 mg haloperidol was administered while there seems to be no effect in females (adjusted odds ratio = 1.02, 95% confidence interval: [0.71, 1.46], p = 0.93). Currently known risk factors for PONV such as female gender, duration of anesthesia and the use of opioids were confirmed in our analysis.

Conclusion

This study suggests that low-dose haloperidol has an antiemetic effect in male patients but has no effect in female patients. A confirmation of the gender-specific effects we have observed in this register-based cohort study might have major implications on clinical daily routine.