Impact of lifetime lactation on the risk and duration of frequent vasomotor symptoms: A longitudinal dose-response analysis.

OBJECTIVE: To examine the association between lifetime lactation and risk and duration of frequent vasomotor symptoms (VMS). DESIGN: Prospective cohort. SETTING: USA, 1995-2008. SAMPLE: 2356 parous midlife women in the Study of Women's Health Across the Nation. METHODS: Lifetime lactation was defined as the duration of breastfeeding across all births in months. We used generalised estimating equations to analyse risk of frequent VMS and Cox regression to analyse duration of frequent VMS in years. MAIN OUTCOME MEASURES: Frequent VMS (hot flashes and night sweats) were measured annually for 10 years, defined as occurring ≥6 days in the past 2 weeks. RESULTS: Overall, 57.1% of women reported hot flashes and 43.0% reported night sweats during follow-up. Lifetime lactation was inversely associated with hot flashes plateauing at 12 months of breastfeeding (6 months: adjusted odds ratio [AOR] 0.85, 95% confidence interval (CI) 0.75-0.96; 12 months: AOR 0.78, 95% CI 0.65-0.93) and was inversely associated with night sweats in a downward linear fashion (6 months: AOR 0.93, 95% CI 0.81-1.08; 18 months: AOR 0.82, 95% CI 0.67-1.02; 30 months: AOR 0.73, 95% CI 0.56-0.97). Lifetime lactation was associated with shorter duration of hot flashes and night sweats in a quadratic (bell-shaped) fashion. The association was strongest at 12-18 months of breastfeeding and significant for hot flashes (6 months: adjusted hazard ratio [AHR] 1.35, 95% CI 1.11-1.65; 18 months: AHR 1.54, 95% CI 1.16-2.03; 30 months: AHR 1.18, 95% CI 0.83-1.68). CONCLUSIONS: Longer lifetime lactation is associated with decreased risk and duration of frequent VMS.

Effect of Clinical Decision Support With Audit and Feedback on Prevention of Acute Kidney Injury in Patients Undergoing Coronary Angiography: A Randomized Clinical Trial.

Importance: Contrast-associated acute kidney injury (AKI) is a common complication of coronary angiography and percutaneous coronary intervention (PCI) that has been associated with high costs and adverse long-term outcomes. Objective: To determine whether a multifaceted intervention is effective for the prevention of AKI after coronary angiography or PCI. Design, Setting, and Participants: A stepped-wedge, cluster randomized clinical trial was conducted in Alberta, Canada, that included all invasive cardiologists at 3 cardiac catheterization laboratories who were randomized to various start dates for the intervention between January 2018 and September 2019. Eligible patients were aged 18 years or older who underwent nonemergency coronary angiography, PCI, or both; who were not undergoing dialysis; and who had a predicted AKI risk of greater than 5%. Thirty-four physicians performed 7820 procedures among 7106 patients who met the inclusion criteria. Participant follow-up ended in November 2020. Interventions: During the intervention period, cardiologists received educational outreach, computerized clinical decision support on contrast volume and hemodynamic-guided intravenous fluid targets, and audit and feedback. During the control (preintervention) period, cardiologists provided usual care and did not receive the intervention. Main Outcomes and Measures: The primary outcome was AKI. There were 12 secondary outcomes, including contrast volume, intravenous fluid administration, and major adverse cardiovascular and kidney events. The analyses were conducted using time-adjusted models. Results: Of the 34 participating cardiologists who were divided into 8 clusters by practice group and center, the intervention group included 31 who performed 4327 procedures among 4032 patients (mean age, 70.3 [SD, 10.7] years; 1384 were women [32.0%]) and the control group included 34 who performed 3493 procedures among 3251 patients (mean age, 70.2 [SD, 10.8] years; 1151 were women [33.0%]). The incidence of AKI was 7.2% (310 events after 4327 procedures) during the intervention period and 8.6% (299 events after 3493 procedures) during the control period (between-group difference, -2.3% [95% CI, -0.6% to -4.1%]; odds ratio [OR], 0.72 [95% CI, 0.56 to 0.93]; P = .01). Of 12 prespecified secondary outcomes, 8 showed no significant difference. The proportion of procedures in which excessive contrast volumes were used was reduced to 38.1% during the intervention period from 51.7% during the control period (between-group difference, -12.0% [95% CI, -14.4% to -9.4%]; OR, 0.77 [95% CI, 0.65 to 0.90]; P = .002). The proportion of procedures in eligible patients in whom insufficient intravenous fluid was given was reduced to 60.8% during the intervention period from 75.1% during the control period (between-group difference, -15.8% [95% CI, -19.7% to -12.0%]; OR, 0.68 [95% CI, 0.53 to 0.87]; P = .002). There were no significant between-group differences in major adverse cardiovascular events or major adverse kidney events. Conclusions and Relevance: Among cardiologists randomized to an intervention including clinical decision support with audit and feedback, patients undergoing coronary procedures during the intervention period were less likely to develop AKI compared with those treated during the control period, with a time-adjusted absolute risk reduction of 2.3%. Whether this intervention would show efficacy outside this study setting requires further investigation. Trial Registration: ClinicalTrials.gov Identifier: NCT03453996.

Pregnancy complications and risk of preterm birth according to maternal age: A population-based study of delivery hospitalizations in Alberta.

INTRODUCTION: Pregnancy-related medical complications are associated with a 2- to 5-fold increased risk of preterm birth (PTB), but the nature of this etiologic relation in context with maternal factors remains poorly understood. Previous studies have generally treated maternal age as a confounder but overlooked its potential as an effect modifier, whereby the magnitude of the effect of complications on PTB could differ significantly across age groups. We investigated whether advanced maternal age (≥35 years) modified the association between pregnancy complications and PTB, and compared population-attributable fractions of PTB from complications in women older vs younger than 35 years. MATERIAL AND METHODS: We analyzed population-based, cross-sectional data from the Alberta Discharge Abstract Database for women aged 18-50 years with singleton live births in hospital between 2014 and 2017 (n = 152 246). Complications were preeclampsia, gestational diabetes, and placental disorders identified using diagnostic codes. Outcomes were spontaneous (sPTB) or iatrogenic (iPTB) PTB before 37 weeks of gestation. We estimated risk ratios and risk differences using modified Poisson and log binomial regression, respectively, adjusting for confounders (pregnancy history, comorbidities). Population-attributable fractions estimates were calculated from risk ratios. Age modification was tested using interaction terms and Z-tests. RESULTS: Prevalence of advanced maternal age was 19.2%. Pregnancy complications and s/iPTB were more common among women aged ≥35 years. Age modified the risk of PTB from preeclampsia only, with risk differences of 9.9% (95% CI 7.2%-12.6%) in older women vs 6.1% (95% CI 4.8%-7.4%) in younger women (P-interaction = 0.012) for sPTB, and 29.5% (95% CI 26.0%-33.1%) vs 20.8% (95% CI 18.9%-22.6%, P-interaction <0.001) for iPTB. Population-attributable fractions of s/iPTB types for all complications were consistently 2%-5% larger in women aged ≥35 years, and significantly larger for preeclampsia (sPTB: 5.1% vs 2.7%, P = 0.002; iPTB: 18.8% vs 14.0%, P < 0.001) and placental disorders (sPTB: 12.5% vs 8.7%, P < 0.001; iPTB: 13.2% vs 8.9%, P < 0.001). CONCLUSIONS: Of the pregnancy complications studied, advanced maternal age only modified the association between PTB and preeclampsia, such that older women with preeclampsia have a higher risk for s/iPTB than younger counterparts. Pregnancy complications contribute to a sizable proportion of PTBs in Alberta, especially among women aged ≥35 years. Findings may inform clinical risk assessment and population-level policy targeting PTB.

Challenges and potential solutions to the evaluation, monitoring, and regulation of surgical innovations.

BACKGROUND: As it may be argued that many surgical interventions provide obvious patient benefits, formal, staged assessment of the efficacy and safety of surgical procedures has historically been and remains uncommon. The majority of innovative surgical procedures have therefore often been developed based on anatomical and pathophysiological principles in an attempt to better manage clinical problems. MAIN BODY: In this manuscript, we sought to review and contrast the models for pharmaceutical and surgical innovation in North America, including their stages of development and methods of evaluation, monitoring, and regulation. We also aimed to review the present structure of academic surgery, the role of methodological experts and funding in conducting surgical research, and the current system of regulation of innovative surgical procedures. Finally, we highlight the influence that evidence and surgical history, education, training, and culture have on elective and emergency surgical decision-making. The above discussion is used to support the argument that the model used for assessment of innovative pharmaceuticals cannot be applied to that for evaluating surgical innovations. It is also used to support our position that although the evaluation and monitoring of innovative surgical procedures requires a rigorous, fit-for-purpose, and formal system of assessment to protect patient safety and prevent unexpected adverse health outcomes, it will only succeed if it is supported and championed by surgical practice leaders and respects surgical history, education, training, and culture. CONCLUSION: We conclude the above debate by providing a recommended approach to the evaluation, monitoring, and regulation of surgical innovations, which we hope may be used as a guide for all stakeholders involved in interpreting and/or conducting future surgical research.

A Clinical Risk Prediction Tool for 6-Month Mortality After Dialysis Initiation Among Older Adults.

BACKGROUND: Information on an individual's risk for death following dialysis therapy initiation may inform the decision to initiate maintenance dialysis for older adults. We derived and validated a clinical risk prediction tool for all-cause mortality among older adults during the first 6 months of maintenance dialysis treatment. STUDY DESIGN: Prediction model using retrospective administrative and clinical data. SETTING & PARTICIPANTS: We linked administrative and clinical data to define a cohort of 2,199 older adults (age ≥ 65 years) in Alberta, Canada, who initiated maintenance dialysis therapy (excluding acute kidney injury) in May 2003 to March 2012. CANDIDATE PREDICTORS: Demographics, laboratory data, comorbid conditions, and measures of health system use. OUTCOMES: All-cause mortality within 6 months of dialysis therapy initiation. ANALYTICAL APPROACH: Predicted mortality by logistic regression with 10-fold cross-validation. RESULTS: 375 (17.1%) older adults died within 6 months. We developed a 19-point risk score for 6-month mortality that included age 80 years or older (2 points), glomerular filtration rate of 10 to 14.9mL/min/1.73m2 (1 point) or ≥15mL/min/1.73m2 (3 points), atrial fibrillation (2 points), lymphoma (5 points), congestive heart failure (2 points), hospitalization in the prior 6 months (2 points), and metastatic cancer (3 points). Model discrimination (C statistic = 0.72) and calibration (Hosmer-Lemeshow χ2=10.36; P=0.2) were reasonable. As examples, a score < 5 equated to <25% of individuals dying in 6 months, whereas a score > 12 predicted that more than half the individuals would die in the first 6 months. LIMITATIONS: The tool has not been externally validated; thus, generalizability cannot be assessed. CONCLUSIONS: We used readily available clinical information to derive and internally validate a 7-variable tool to predict early mortality among older adults after dialysis therapy initiation. Following successful external validation, the tool may be useful as a clinical decision tool to aid decision making for older adults with kidney failure.

Indications for Use of Damage Control Surgery in Civilian Trauma Patients: A Content Analysis and Expert Appropriateness Rating Study.

OBJECTIVES: To characterize and evaluate indications for use of damage control (DC) surgery in civilian trauma patients. BACKGROUND: Although DC surgery may improve survival in select, severely injured patients, the procedure is associated with significant morbidity, suggesting that it should be used only when appropriately indicated. METHODS: Two investigators used an abbreviated grounded theory method to synthesize indications for DC surgery reported in peer-reviewed articles between 1983 and 2014 into a reduced number of named, content-characteristic codes representing unique indications. An international panel of trauma surgery experts (n = 9) then rated the appropriateness (expected benefit-to-harm ratio) of the coded indications for use in surgical practice. RESULTS: The 1107 indications identified in the literature were synthesized into 123 unique pre- (n = 36) and intraoperative (n = 87) indications. The panel assessed 101 (82.1%) of these indications to be appropriate. The indications most commonly reported and assessed to be appropriate included pre- and intraoperative hypothermia (median temperature <34°C), acidosis (median pH <7.2), and/or coagulopathy. Others included 5 different injury patterns, inability to control bleeding by conventional methods, administration of a large volume of packed red blood cells (median >10 units), inability to close the abdominal wall without tension, development of abdominal compartment syndrome during attempted abdominal wall closure, and need to reassess extent of bowel viability. CONCLUSIONS: This study identified a comprehensive list of candidate indications for use of DC surgery. These indications provide a practical foundation to guide surgical practice while studies are conducted to evaluate their impact on patient care and outcomes.

Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5).

BACKGROUND: Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a ß-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed. STRUCTURE OF STUDY: The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis. POWER CALCULATIONS: A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients. IMPLICATIONS: This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.

Active Negative Pressure Peritoneal Therapy After Abbreviated Laparotomy: The Intraperitoneal Vacuum Randomized Controlled Trial.

OBJECTIVE: To determine whether active negative pressure peritoneal therapy with the ABThera temporary abdominal closure device reduces systemic inflammation after abbreviated laparotomy. BACKGROUND: Excessive systemic inflammation after abdominal injury or intra-abdominal sepsis is associated with poor outcomes. METHODS: We conducted a single-center, randomized controlled trial. Forty-five adults with abdominal injury (46.7%) or intra-abdominal sepsis (52.3%) were randomly allocated to the ABThera (n = 23) or Barker's vacuum pack (n = 22). On study days 1, 2, 3, 7, and 28, blood and peritoneal fluid were collected. The primary endpoint was the difference in the plasma concentration of interleukin-6 (IL-6) 24 and 48 hours after temporary abdominal closure application. RESULTS: There was a significantly lower peritoneal fluid drainage from the ABThera at 48 hours after randomization. Despite this, there was no difference in plasma concentration of IL-6 at baseline versus 24 (P = 0.52) or 48 hours (P = 0.82) between the groups. There was also no significant intergroup difference in the plasma concentrations of IL-1ß, -8, -10, or -12 p70 or tumor necrosis factor α between these time points. The cumulative incidence of primary fascial closure at 90 days was similar between groups (hazard ratio, 1.6; 95% confidence interval, 0.82-3.0; P = 0.17). However, 90-day mortality was improved in the ABThera group (hazard ratio, 0.32; 95% confidence interval, 0.11-0.93; P = 0.04). CONCLUSIONS: This trial observed a survival difference between patients randomized to the ABThera versus Barker's vacuum pack that did not seem to be mediated by an improvement in peritoneal fluid drainage, fascial closure rates, or markers of systemic inflammation. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01355094.

Clinical Presentation of Patients With Tension Pneumothorax: A Systematic Review.

OBJECTIVE: To determine whether the reported clinical presentation of tension pneumothorax differs between patients who are breathing unassisted versus receiving assisted ventilation. BACKGROUND: Animal studies suggest that the pathophysiology and physical signs of tension pneumothorax differ by subject ventilatory status. METHODS: We searched electronic databases through to October 15, 2013 for observational studies and case reports/series reporting clinical manifestations of tension pneumothorax. Two physicians independently extracted clinical manifestations reported at diagnosis. RESULTS: We identified 5 cohort studies (n = 310 patients) and 156 case series/reports of 183 cases of tension pneumothorax (n = 86 breathing unassisted, n = 97 receiving assisted ventilation). Hypoxia was reported among 43 (50.0%) cases of tension pneumothorax who were breathing unassisted versus 89 (91.8%) receiving assisted ventilation (P < 0.001). Pulmonary dysfunction progressed to respiratory arrest in 9.3% of cases breathing unassisted. As compared to cases who were breathing unassisted, the adjusted odds of hypotension and cardiac arrest were 12.6 (95% confidence interval, 5.8-27.5) and 17.7 (95% confidence interval, 4.0-78.4) times higher among cases receiving assisted ventilation. One cohort study reported that none of the patients with tension pneumothorax who were breathing unassisted versus 39.6% of those receiving assisted ventilation presented without an arterial pulse. In contrast to cases breathing unassisted, the majority (70.4%) of those receiving assisted ventilation who experienced hypotension or cardiac arrest developed these signs within minutes of clinical presentation. DISCUSSION: The reported clinical presentation of tension pneumothorax depends on the ventilatory status of the patient. This may have implications for improving the diagnosis and treatment of this life-threatening disorder.

Kaplan-Meier Survival Analysis Overestimates the Risk of Revision Arthroplasty: A Meta-analysis.

BACKGROUND: Although Kaplan-Meier survival analysis is commonly used to estimate the cumulative incidence of revision after joint arthroplasty, it theoretically overestimates the risk of revision in the presence of competing risks (such as death). Because the magnitude of overestimation is not well documented, the potential associated impact on clinical and policy decision-making remains unknown. QUESTIONS/PURPOSES: We performed a meta-analysis to answer the following questions: (1) To what extent does the Kaplan-Meier method overestimate the cumulative incidence of revision after joint replacement compared with alternative competing-risks methods? (2) Is the extent of overestimation influenced by followup time or rate of competing risks? METHODS: We searched Ovid MEDLINE, EMBASE, BIOSIS Previews, and Web of Science (1946, 1980, 1980, and 1899, respectively, to October 26, 2013) and included article bibliographies for studies comparing estimated cumulative incidence of revision after hip or knee arthroplasty obtained using both Kaplan-Meier and competing-risks methods. We excluded conference abstracts, unpublished studies, or studies using simulated data sets. Two reviewers independently extracted data and evaluated the quality of reporting of the included studies. Among 1160 abstracts identified, six studies were included in our meta-analysis. The principal reason for the steep attrition (1160 to six) was that the initial search was for studies in any clinical area that compared the cumulative incidence estimated using the Kaplan-Meier versus competing-risks methods for any event (not just the cumulative incidence of hip or knee revision); we did this to minimize the likelihood of missing any relevant studies. We calculated risk ratios (RRs) comparing the cumulative incidence estimated using the Kaplan-Meier method with the competing-risks method for each study and used DerSimonian and Laird random effects models to pool these RRs. Heterogeneity was explored using stratified meta-analyses and metaregression. RESULTS: The pooled cumulative incidence of revision after hip or knee arthroplasty obtained using the Kaplan-Meier method was 1.55 times higher (95% confidence interval, 1.43-1.68; p < 0.001) than that obtained using the competing-risks method. Longer followup times and higher proportions of competing risks were not associated with increases in the amount of overestimation of revision risk by the Kaplan-Meier method (all p > 0.10). This may be due to the small number of studies that met the inclusion criteria and conservative variance approximation. CONCLUSIONS: The Kaplan-Meier method overestimates risk of revision after hip or knee arthroplasty in populations where competing risks (such as death) might preclude the occurrence of the event of interest (revision). Competing-risks methods should be used to more accurately estimate the cumulative incidence of revision when the goal is to plan healthcare services and resource allocation for revisions.

Assessing the association between occupancy and outcome in critically Ill hospitalized patients with sepsis.

BACKGROUND: Sepsis has a high prevalence, mortality-rate and cost. Sepsis patients usually enter the hospital through the Emergency Department (ED). Process or structural issues related to care may affect outcome. METHODS: Multi-centered retrospective observational cohort study using administrative databases to identify adult patients (> = 18 years) with sepsis and severe sepsis admitted to Alberta Health Services Calgary zone adult multisystem intensive care units (ICU) through the ED between January 1, 2006 and September 30, 2009. We examined the association between ICU occupancy and hospital outcome. We explored other associations of hospital outcome including the effect of ED wait time, admission from ED during weekdays versus weekends and ED admission during the day versus at night. RESULTS: One thousand and seven hundred seventy patients were admitted to hospital via ED, 1036 (58.5 %) with sepsis and 734 (41.5 %) with severe sepsis. In patients with sepsis, ICU occupancy > 90 % was associated with an increase in hospital mortality even after adjusting for age, sex, triage level, Charlson index, time of first ED physician assessment and ICU admission. No differences in hospital mortality were found for patients who waited more than 7 h, were admitted during the day versus night or weekdays versus weekends. CONCLUSIONS: In patients with sepsis admitted via the ED, increased ICU occupancy was associated with higher in-hospital mortality.

Multicentre implementation of a quality improvement initiative to reduce delirium in adult intensive care units: An interrupted time series analysis.

PURPOSE: The ABCDEF bundle may improve delirium outcomes among intensive care unit (ICU) patients, however population-based studies are lacking. In this study we evaluated effects of a quality improvement initiative based on the ABCDEF bundle in adult ICUs in Alberta, Canada. MATERIAL AND METHODS: We conducted a pre-post, registry-based clinical trial, analysed using interrupted time series methodology. Outcomes were examined via segmented linear regression using mixed effects models. The main data source was a population-based electronic health record. RESULTS: 44,405 consecutive admissions (38,400 unique patients) admitted to 15 general medical/surgical and/or neurologic adult ICUs between 2014 and 2019 were included. The proportion of delirium days per ICU increased from 30.24% to 35.31% during the pre-intervention period. After intervention implementation it decreased significantly (bimonthly decrease of 0.34%, 95%CI 0.18-0.50%, p < 0.01) from 33.48% (95%CI 29.64-37.31%) in 2017 to 28.74% (95%CI 25.22-32.26%) in 2019. The proportion of sedation days using midazolam demonstrated an immediate decrease of 7.58% (95%CI 4.00-11.16%). There were no significant changes in duration of invasive ventilation, proportion of partial coma days, ICU mortality, or potential adverse events. CONCLUSIONS: An ABCDEF delirium initiative was implemented on a population-basis within adult ICUs and was successful at reducing the prevalence of delirium.

Diagnostic accuracy of computed tomographic angiography for blunt cerebrovascular injury detection in trauma patients: a systematic review and meta-analysis.

OBJECTIVE: To compare the diagnostic accuracy of computed tomographic angiography (CTA) with digital subtraction angiography (DSA) for blunt cerebrovascular injury (BCVI) detection in trauma patients. BACKGROUND: Controversy exists as to whether the diagnostic performance of CTA compares favorably with the reference-standard, DSA. METHODS: We searched electronic databases (1950 to May 22, 2012), article bibliographies, conference proceedings (2008-2011), and clinical trial registries for studies comparing the accuracy of CTA with DSA for BCVI detection in trauma patients. Pooled estimates of sensitivity, specificity, and positive and negative likelihood ratios were calculated using bivariate random effects models. RESULTS: Eight studies that examined 5704 carotid or vertebral arteries in 1426 trauma patients met inclusion criteria. The pooled sensitivity and specificity for BCVI detection with CTA versus DSA was 66% (95% CI, 49%-79%; I = 80.4%) and 97% (95% CI, 91%-99%; I = 94.6%), respectively. Corresponding pooled positive and negative likelihood ratios were 20.0 (95% CI, 6.9-58.4; I = 87.7%) and 0.35 (95% CI, 0.22-0.56; I = 74.9%), respectively. Although pooled sensitivity varied with the number of available CT slices, the training of interpreting radiologists, and in a pattern suggestive of differences in diagnostic threshold for judging CTA positivity, it remained 80% or less among studies that used scanners with 16 or more slices per rotation and where the CTA was read by neuroradiologists. CONCLUSIONS: Existing evidence suggests that the diagnostic performance of CTA varies considerably across studies, likely due to an implicit variation in diagnostic threshold across trauma centers. Moreover, although CTA appears to lack sensitivity to adequately rule out BCVI, it may be useful to rule in BCVI among trauma patients with a high pretest probability of injury.

Rationale for the prevention of syncope trial IV: assessment of midodrine.

BACKGROUND: Vasovagal syncope is a common problem associated with a poor quality of life, which improves when the frequency of syncope is reduced. Effective pharmacological therapies for vasovagal syncope have been elusive. Midodrine is a pro-drug whose primary metabolite is an alpha-1 adrenoreceptor agonist. A few studies have suggested that it may be beneficial in syncope, but all have had significant methodological limitations. A placebo-controlled clinical trial of midodrine for the prevention of vasovagal syncope is needed. STRUCTURE OF STUDY: The prevention of syncope trial IV (POST 4) is a multicenter, international, randomized, placebo-controlled study of midodrine in the prevention of vasovagal syncope. The primary end point is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive midodrine 10-30 mg/day or matching placebo, and followed for 1 year. Secondary end points include syncope frequency, presyncope, and quality of life. Primary analysis will be performed with an intention-to-treat approach, with a secondary on-treatment analysis. POWER CALCULATIONS: A total sample size of 112, split equally between the two groups, achieves 85 % power to detect a 50 % relative risk reduction when the event rates are 55 and 27.5 % in the placebo and midodrine arms. Allowing for 20 % dropout, we propose to enroll 140 patients. REGISTRATION: POST 4 is registered with http://www.clinicaltrials.gov (NCT01456481). IMPLICATIONS: This study will be the first adequately powered trial to determine whether midodrine is effective in preventing vasovagal syncope. If it is effective, then midodrine may become the first-line pharmacological therapy for this condition.

Measuring the value of total hip and knee arthroplasty: considering costs over the continuum of care.

BACKGROUND: Controlling escalating costs of hip (THA) and knee arthroplasty (TKA) without compromising quality of care has created the need for innovative system reorganization to inform sustainable solutions. QUESTIONS/PURPOSES: The purpose of this study was to inform estimates of the value of THA and TKA by determining: (1) the data sources data required to obtain costs across the care continuum; (2) the data required for different analytical perspectives; and (3) the relative costs across the continuum of care. METHODS: Within the context of a pragmatic randomized controlled trial comparing alternative care pathways, we captured healthcare resource use: (1) 12 months before surgery; (2) inpatient; (3) acute recovery; and (4) long-term recovery 3 and 12 months postsurgery. We established a standardized costing model to reflect both the healthcare payer and patient perspectives. RESULTS: Multiple data sources from regional health authorities, administrative databases, and patient questionnaire were required to estimate costs across the care continuum. Inpatient and acute care costs were approximately 60% of the total with the remaining 40% incurred 12 months presurgery and 12 months postsurgery. Regional health authorities bear close to 60%, and patient costs are approximately 30% of the mean total costs, most of which were incurred after the acute inpatient stay. CONCLUSIONS: To fully understand the value of an orthopaedic intervention such as THA and TKA, a broader perspective than one limited to the payer should be considered using a standardized measurement framework over a relevant time horizon and from multiple viewpoints to reflect the substantial patient burden and support sustainable improvement over the care continuum. LEVEL OF EVIDENCE: Level III, economic and decision analyses study. See Guidelines for Authors for a complete description of levels of evidence.

Functional outcomes for 2 years comparing hip resurfacing and total hip arthroplasty.

This prospective observational study of 499 patients with hip resurfacing and 255 patients with total hip arthroplasty compared outcomes for 2 years. We used propensity scores to identify matched cohorts of 118 patients with hip resurfacing and 118 patients with total hip arthroplasty. We used these cohorts to compare improvements in the Western Ontario and McMaster University (WOMAC) osteoarthritis index and Medical Outcomes Short-Form 36 physical function component (SF-36 PF) scores at 3 months and at 1 and 2 years postsurgery. Both groups demonstrated significant improvements from baseline in WOMAC and SF-36 PF. Improvements in SF-36 PF were greater for patients with hip resurfacing than for patients with total hip arthroplasty 1 and 2 years postsurgery; improvements in WOMAC were similar for both groups. The clinical significance of this observation needs further investigation.

Association of lifetime lactation and age at natural menopause: a prospective cohort study.

OBJECTIVE: The aim of this study was to examine the association between duration of lifetime lactation and age at natural menopause. METHODS: In this prospective cohort study, we analyzed parous premenopausal women in the multiethnic Study of Women's Health Across the Nation who were followed approximately annually for 10 years (1995-2008). Lifetime lactation was defined as the duration of breastfeeding across all births in months. Age at natural menopause was defined as age in years after 12 consecutive months of amenorrhea after the final menstrual period for no other reported cause. We used Cox proportional hazard models to analyze time to natural menopause with age as the underlying time scale. Multivariable models controlled for education, race/ethnicity, parity, smoking, body mass index, and oral contraceptive use. RESULTS: Among 2,377 women, 52.6% experienced natural menopause during follow-up and reported a valid final menstrual period date. The small, crude association between lifetime lactation up to 24 months and later age at natural menopause attenuated to nonsignificance in adjusted models (6 months: adjusted hazard ratio [AHR], 0.96; 95% confidence interval (CI), 0.87-1.06; 12 months: AHR, 0.95; 95% CI, 0.82-1.11; 18 months: AHR, 0.96; 95% CI, 0.82-1.13; 24 months: AHR, 0.99; 95% CI, 0.84-1.16). CONCLUSIONS: Duration of lifetime lactation was not associated with age at natural menopause after controlling for sociodemographic characteristics.

A multi-region assessment of population rates of cardiac catheterization and yield of high-risk coronary artery disease.

BACKGROUND: There is variation in cardiac catheterization utilization across jurisdictions. Previous work from Alberta, Canada, showed no evidence of a plateau in the yield of high-risk disease at cardiac catheterization rates as high as 600 per 100,000 population suggesting that the optimal rate is higher. This work aims 1) To determine if a previously demonstrated linear relationship between the yield of high-risk coronary disease and cardiac catheterization rates persists with contemporary data and 2) to explore whether the linear relationship exists in other jurisdictions. METHODS: Detailed clinical information on all patients undergoing cardiac catheterization in 3 Canadian provinces was available through the Alberta Provincial Project for Outcomes Assessment in Coronary Heart (APPROACH) disease and partner initiatives in British Columbia and Nova Scotia. Population rates of catheterization and high-risk coronary disease detection for each health region in these three provinces, and age-adjusted rates produced using direct standardization. A mixed effects regression analysis was performed to assess the relationship between catheterization rate and high-risk coronary disease detection. RESULTS: In the contemporary Alberta data, we found a linear relationship between the population catheterization rate and the high-risk yield. Although the yield was slightly less in time period 2 (2002-2006) than in time period 1(1995-2001), there was no statistical evidence of a plateau. The linear relationship between catheterization rate and high-risk yield was similarly demonstrated in British Columbia and Nova Scotia and appears to extend, without a plateau in yield, to rates over 800 procedures per 100,000 population. CONCLUSIONS: Our study demonstrates a consistent finding, over time and across jurisdictions, of linearly increasing detection of high-risk CAD as population rates of cardiac catheterization increase. This internationally-relevant finding can inform country-level planning of invasive cardiac care services.

Evidence for use of damage control surgery and damage control interventions in civilian trauma patients: a systematic review.

BACKGROUND: Although damage control (DC) surgery is widely assumed to reduce mortality in critically injured patients, survivors often suffer substantial morbidity, suggesting that it should only be used when indicated. The purpose of this systematic review was to determine which indications for DC have evidence that they are reliable and/or valid (and therefore in which clinical situations evidence supports use of DC or that DC improves outcomes). METHODS: We searched 11 databases (1950-April 1, 2019) for studies that enrolled exclusively civilian trauma patients and reported data on the reliability (consistency of surgical decisions in a given clinical scenario) or content (surgeons would perform DC in that clinical scenario or the indication predicted use of DC in practice), construct (were associated with poor outcomes), or criterion (were associated with improved outcomes when DC was conducted instead of definitive surgery) validity for suggested indications for DC surgery or DC interventions. RESULTS: Among 34,979 citations identified, we included 36 cohort studies and three cross-sectional surveys in the systematic review. Of the 59 unique indications for DC identified, 10 had evidence of content validity [e.g., a major abdominal vascular injury or a packed red blood cell (PRBC) volume exceeding the critical administration threshold], nine had evidence of construct validity (e.g., unstable patients with combined abdominal vascular and pancreas gunshot injuries or an iliac vessel injury and intraoperative acidosis), and six had evidence of criterion validity (e.g., penetrating trauma patients requiring > 10 U PRBCs with an abdominal vascular and multiple abdominal visceral injuries or intraoperative hypothermia, acidosis, or coagulopathy). No studies evaluated the reliability of indications. CONCLUSIONS: Few indications for DC surgery or DC interventions have evidence supporting that they are reliable and/or valid. DC should be used with respect for the uncertainty regarding its effectiveness, and only in circumstances where definitive surgery cannot be entertained.

Variation in use of damage control laparotomy for trauma by trauma centers in the United States, Canada, and Australasia.

BACKGROUND: It is unknown how frequently damage control (DC) laparotomy is used across trauma centers in different countries. We conducted a cross-sectional survey of trauma centers in the United States, Canada, and Australasia to study variations in use of the procedure and predictors of more frequent use of DC laparotomy. METHODS: A self-administered, electronic, cross-sectional survey of trauma centers in the United States, Canada, and Australasia was conducted. The survey collected information about trauma center and program characteristics. It also asked how often the trauma program director estimated DC laparotomy was performed on injured patients at that center on average over the last year. Multivariable logistic regression was used to identify predictors of a higher reported frequency of use of DC laparotomy. RESULTS: Of the 366 potentially eligible trauma centers sent the survey, 199 (51.8%) trauma program directors or leaders responded [United States = 156 (78.4%), Canada = 26 (13.1%), and Australasia = 17 (8.5%)]. The reported frequency of use of DC laparotomy was highly variable across trauma centers. DC laparotomy was used more frequently in level-1 than level-2 or -3 trauma centers. Further, high-volume level-1 centers used DC laparotomy significantly more often than lower volume level-1 centers (p = 0.02). Nearly half (48.4%) of high-volume volume level-1 trauma centers reported using the procedure at least once weekly. Significant adjusted predictors of more frequent use of DC laparotomy included country of origin [odds ratio (OR) for the United States vs. Canada = 7.49; 95% confidence interval (CI) 1.39-40.27], level-1 verification status (OR = 6.02; 95% CI 2.01-18.06), and the assessment of a higher number of severely injured (Injury Severity Scale score > 15) patients (OR per-100 patients = 1.62; 95% CI 1.20-2.18) and patients with penetrating injuries (OR per-5% increase = 1.27; 95% CI 1.01-1.58) in the last year. CONCLUSIONS: The reported frequency of use of DC laparotomy was highly variable across trauma centers. Those centers that most need to evaluate the benefit-to-risk ratio of using DC laparotomy in different scenarios may include high-volume, level-1 trauma centers, particularly those that often manage penetrating injuries.