Trend and seasonality in hospitalizations for pulmonary embolism: a time-series analysis

Racial, Biological Sex, and Geographic Disparities of Venous Thromboembolism in the United States, 2016-2019

BACKGROUND

Venous thromboembolism (VTE) stands as the leading cause of preventable death within hospitals in the United States. While there have been some studies investigating incidence rates of VTE, there has yet to be a large-scale study elucidating disparities in sex, race, income, region, and seasons in patients with VTE. The goal of this study was to report the disparities in race, sex, income, region, and seasons in patients with VTE, pulmonary embolism (PE), and deep vein thrombosis (DVT), in hospitalized patients from 2016-2019.

METHODS

We used the United States National Inpatients Sample database to identify inpatients diagnosed with PE, DVT, and PE & DVT from 2016 to 2019. The inpatient incidence per thousand was calculated for sex and race using the weighted sample model. The regional and monthly incidence of DVT and PE per thousand inpatients and risk of incidence were calculated. Patients' characteristics including hospital type, bed size, median length of stay, median total charges, and mortality were also collected.

RESULTS

We examined 455,111 cases of VTE, 177,410 cases of DVT, 189,271 cases of PE, and 88,430 cases of both DVT and PE combined. Over the study period, we observed a statistically significant trend among PE hospitalization incidences. There was a strong and positive correlation between DVT and PE inpatients. Black inpatients had the highest cumulative incidence of hospitalizations in all cohorts with 10.36/1000 in PE, and 9.1/1000 in DVT. Asian and Pacific Islander inpatients had the lowest cumulative incidence with 4.42/1000 in PE and 4.28/1000 in DVT. Females showed the lowest cumulative incidence with 7.47/1000 in PE and 6.53/1000 in DVT. Mountain region was the highest among PE hospitalizations with 9.62/1000. For DVT, Middle Atlantic region was the highest at 8.65/1000. The in-hospital mortality was the highest among the PE hospitalizations with 7.3%. Also, the trend analysis showed significant increases among all groups.

CONCLUSION

Over the study period (2016-2019), we reported the racial, biological sex, and geographical disparities from the National Inpatient Sample database, highlighting that Black inpatients had the highest incidence of PE and DVT, while Asian / Pacific Islander inpatients had the lowest incidence of PE and DVT. Moreover, women had lower incidence compared to men. The observed regional variations indicated that the incidence of PE was highest in the Mountain region, whereas the incidence of DVT was lowest in the Middle Atlantic region. There was an increase in the mortality of inpatients diagnosed with VTE reflecting the growing burden of this condition in the U.S. healthcare system.

Debunking the July Effect in lung transplantation recipients

Objective

The "July Effect" is a theory that the influx of trainees from July to September negatively impacts patient outcomes. We aimed to study this theoretical phenomenon in lung transplant recipients given the highly technical nature of thoracic procedures.

Methods

Adult lung transplant hospitalizations were identified within the National Inpatient Sample (2005-2020). Recipients were categorized as academic Q1 (July to September) or Q2-Q4 (October to June). In-hospital mortality, operator-driven complications (pneumothorax, dehiscence including wound dehiscence, bronchial anastomosis, and others, and vocal cord/diaphragm paralysis, all 3 treated as a composite outcome), length of stay, and inflation-adjusted hospitalization charges were compared between both groups. Multivariable logistic regression was performed to assess the association between academic quarter and in-hospital mortality and operator-driven complications. The models were adjusted for recipient demographics and transplant characteristics. Subgroup analysis was performed between academic and nonacademic hospitals.

Results

Of 30,788 lung transplants, 7838 occurred in Q1 and 22,950 occurred in Q2-Q4. Recipient demographic and clinical characteristics were similar between groups. Dehiscence (n = 922, 4% vs n = 236, 3%), post-transplant cardiac arrest (n = 532, 2% vs n = 113, 1%), and pulmonary embolism (n = 712, 3% vs n = 164, 2%) were more common in Q2-Q4 versus Q1 recipients (all P < .05). Other operator-driven complications, in-hospital mortality, and resource use were similar between groups (P > .05). These inferences remained unchanged in adjusted analyses and on subgroup analyses of academic versus nonacademic hospitals.

Conclusions

The "July Effect" is not evident in US lung transplantation recipient outcomes during the transplant hospitalization. This suggests that current institutional monitoring systems for trainees across multiple specialties, including surgery, anesthesia, critical care, nursing, and others, are robust.

Calendar month variation in the diagnosis and severity of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is the third-leading cause of cardiovascular death in the United States, and several studies suggest PE shows seasonal variation. Variation in monthly PE diagnosis may be due to pathophysiologic factors or confounding/bias. However, severe PE may be less prone to diagnostic bias. To address this gap, we analyzed two registries from 1/2013-12/2018 with the aim of describing temporal trends in PE diagnosis and severity.

METHODS

We performed a retrospective analysis of two existing databases containing: (1) consecutive patients diagnosed with PE in the emergency departments (EDs) of two large, urban teaching hospitals, and (2) severe PEs requiring PE Response Team (PERT) activation at one of the above hospitals. The primary outcome was to assess variation in PE diagnosis and severity by calendar month. Separate analysis of these two databases sought to control for workup bias by trainee experience across the academic year. One-way ANOVA and Poisson regression were performed to assess for cyclical variation across calendar months, using Stata v16.1.

RESULTS

The PE diagnosis database contained 1324 patients over 36 months. One-way ANOVA did not reveal a statistically significant (p = 0.713) association between calendar month and PE number. The PERT activation database contained 1082 patients over 72 months. One-way ANOVA revealed a statistically significant (p = 0.024) association between calendar month and activations, repeated year-on-year.

CONCLUSION

Our results indicate correlation between calendar month and PERT activation; however, this pattern was not observed for PE diagnoses. This finding warrants further investigation into the causes of calendar month variation of PERT activations.

Insight on Cardiac Chronobiology and Latest Developments of Chronotherapeutic Antihypertensive Interventions for Better Clinical Outcomes

Cardiac circadian rhythms are an important regulator of body functions, including cardiac activities and blood pressure. Disturbance of circadian rhythm is known to trigger and aggravate various cardiovascular diseases. Thus, modulating the circadian rhythm can be used as a therapeutic approach to cardiovascular diseases. Through this work, we intend to discuss the current understanding of cardiac circadian rhythms, in terms of quantifiable parameters like BP and HR. We also elaborate on the molecular regulators and the molecular cascades along with their specific genetic aspects involved in modulating circadian rhythms, with specific reference to cardiovascular health and cardiovascular diseases. Along with this, we also presented the latest pharmacogenomic and metabolomics markers involved in chronobiological control of the cardiovascular system along with their possible utility in cardiovascular disease diagnosis and therapeutics. Finally, we reviewed the current expert opinions on chronotherapeutic approaches for utilizing the conventional as well as the new pharmacological molecules for antihypertensive chronotherapy.

Low ambient temperature might trigger the symptom onset of pulmonary embolism: A nationwide case-crossover study at hourly level in China

BACKGROUND

Pulmonary embolism (PE) is an important cause of death and its seasonality has long been observed. Very few epidemiological studies have explored the potential role of ambient temperature in PE symptom onset, especially at the hourly level.

METHODS

We conducted a time-stratified case-crossover study among 17,903 PE patients with hourly onset of symptom from 1590 hospitals across China between January 2015 and September 2020. Conditional logistic regression model combined with distributed lag non-linear models were used to explore the associations between hourly ambient temperature and PE symptom onset. The attributable fractions due to non-optimum temperature were calculated.

RESULTS

The exposure-response relationship curve was inverse and almost linear. Lower temperature was significantly associated with higher risk of PE symptom onset when temperature was below 18 °C. This risk occurred immediately at the same hour, attenuated thereafter, and became nonsignificant at approximately 72 h after exposure. Compared with the referent temperature (P₉₉, 34.1 °C), the odds ratio of PE symptom onset associated with extremely low temperature (P₁, -16.1 °C) over lag 0-72 h was 1.63 (95%CI: 1.23, 2.16). Low temperature may account for 16.19 % of the symptom onset nationally with higher proportion in the south of China. The effects were stronger in older adults, males, and cold seasons.

CONCLUSIONS

We provided the first-hand robust evidence that transient exposure (at the hourly level) to low temperature might trigger the symptom onset of PE and constitute a considerable burden for PE patients. Targeted protections and health education are needed for susceptible populations.

Clinical and hemodynamic features of acute pulmonary embolism patients diagnosed in cold weather predicts adverse clinical outcome

Background

Acute pulmonary embolism (APE) is associated with peak incidence and mortality rate in winter. The present study sought to characterize the clinical and hemodynamic features of cold weather on APE patients.

Methods

All enrolled 224 APE patients underwent clinical and hemodynamic evaluation and baseline parameters were collected. Recruited patients were grouped by weather pattern on admission into cold and warm weather group. The correlation and prognostic values among cold weather and other variables were analyzed.

Results

Compared to warm weather group, patients in cold weather group present with more severe cardiac function, with adverse WHO-functional class (P = 0.032) and higher NT-proBNP concentration [1,853.0 (398.0, 5,237.0) pg/ml vs. 847.5 (56.8, 3,090.5) pg/ml, P = 0.001]. The cold weather group also displayed much critical hemodynamic status and heavier thrombosis load, with higher mPAP (29.1 ± 11.2mmHg vs. 25.6 ± 14.2mmHg, P = 0.045), higher PVR [3.3 (1.7, 6.0) wood units vs. 1.8 (0.9, 3.8) wood units, P &lt; 0.001], higher Miller index (21.4 ± 5.9 vs. 19.1 ± 8.0, P = 0.024), and higher D-dimer levels [2,172.0 (854.5, 3,072.5) mg/L vs. 1,094.5 (210.5, 2,914.5) mg/L, P = 0.008]. Besides, cold weather showed well correlation with the above variables. Survival analysis showed APE patients in cold weather had significantly higher clinical worsening event rate (P = 0.010) and could be an independent predictor of adverse clinical outcome in the multivariate analysis (HR 2.629; 95% CI 1.127, 6.135; P = 0.025).

Conclusion

APE patients in cold weather were associated with thrombus overload, cardiac dysfunction, hemodynamic collapse and higher clinical worsening event rate. Cold weather proves to be an independent predictor of adverse clinical outcome.

Prediction of congenital heart disease for newborns: comparative analysis of Holt-Winters exponential smoothing and autoregressive integrated moving average models

OBJECTIVE

To describe the temporal trend of the number of new congenital heart disease (CHD) cases among newborns in Jinhua from 2019 to 2020 and explored an appropriate model to fit and forecast the tendency of CHD.

METHODS

Data on CHD from 2019 to 2020 was collected from a health information system. We counted the number of newborns with CHD weekly and separately used the additive Holt-Winters ES method and ARIMA model to fit and predict the number of CHD for newborns in Jinhua. By comparing the mean square error, rooted mean square error and mean absolute percentage error of each approach, we evaluated the effects of different approaches for predicting the number of CHD in newborns.

RESULTS

A total of 1135 newborns, including 601 baby girls and 534 baby boys, were admitted for CHD from HIS in Jinhua during the 2-year study period. The prevalence of CHD among newborns in Jinhua in 2019 was 0.96%. Atrial septal defect was diagnosed the most frequently among all newborns with CHD. The number of CHD cases among newborns remained stable in 2019 and 2020. There were fewer cases in spring and summer, while cases peaked in November and December. The ARIMA(2,1,1) model relatively offered advantages over the additive Holt-winters ES method in predicting the number of newborns with CHD, while the accuracy of ARIMA(2,1,1) was not very ideal.

CONCLUSIONS

The diagnosis of CHD is related to many risk factors, therefore, when using temporal models to fit and predict the data, we must consider such factors' influence and try to incorporate them into the models.

Time series analysis of the in-hospital diagnostic process in suspected pulmonary embolism evaluated by computed tomography: An explorative study

PURPOSE

This retrospective study aims to analyze the distribution of demand and the duration of the diagnostic workup of suspected pulmonary embolism (PE) using computed tomography pulmonary angiography (CTPA).

METHODS

Time data from physical examination to report creation were identified for each CTPA in 2013 and 2018 at a tertiary hospital. Multivariable multinomial logistic and linear regression models were used to evaluate differences between 3 time intervals (I1: 6am-2pm, I2: 2pm-10pm, I3: 10pm-6am). A cosinor model was applied to analyze the amount of CTPA per hour.

RESULTS

The relative demand for CTPA from the emergency room was lower in l1 compared to l2 and l3 (I1/I2: odds ratio (OR) 0.84, 95 % confidence interval (CI) 0.78-0.91; I1/I3: OR 0.80, 95 % CI 0.72-0.89; peak 4:23 pm). Requests for in-patients displayed a tendency towards I1 (I1/2: OR 1.15, 95 % CI 1.06-1.24; l1/l3: OR 1.19, 95 % CI 1.07-1.33; peak 1:54 pm). The time from CTPA request to study was shorter in I3 compared to I1 and I2 in 2013 (I1/I3: ratio 5.23, 95 % CI 3.38-8.10; I2/I3: ratio 3.50, 95 % CI 2.24-5.45) and 2018 (I1/I3: ratio 2.27, 95 % CI 1.60-3.22; I2/I3: ratio 2.11, 95 % CI 1.50-2.97). This applied similarly to fatal cases (I1/I3: ratio 2.91, 95 % CI 1.78-4.75; I2/I3: ratio 2.45, 95 % CI1.52-3.95).

CONCLUSIONS

The temporal distribution of demand for CTPA depends on the sector of patient care and the processing time differs substantially during the day. Time series analysis can reveal such coherences and may help to optimize workflows in radiology departments.

Seasonal Variation in Demand for Smoking Cessation Treatment and Clinical Outcomes

INTRODUCTION

Smoking behaviour shows seasonal variation, with cigarette consumption and youth smoking onset highest in summer and smoking-related web searches and sales of nicotine replacement products highest in winter. Variation in demand for clinical care and in outcomes has not been explored.

AIMS AND METHODS

We measure seasonal variation in enrolments, total clinical visits, visits per enrolment, and treatment outcome (7-day abstinence at 6-month follow-up) from 2015 to 2018 in a large (n = 85 869) clinical cohort from 454 clinics across Ontario, Canada. We model seasonality using harmonic logistic and negative binomial regression. For individual-level outcomes, we adjust for variables, selected a priori, known to be associated with treatment use or outcomes. Data are nearly complete for 3 outcomes, but 6m abstinence is missing for 45% of participants. We use multiple imputation to adjust for missing data.

RESULTS

All four outcomes showed significant seasonal variation (all p <.001). Total enrolments and visits were 20%-25% higher in January-April than in June-September. Visits per enrolment varied slightly, with lowest levels from May-July. Abstinence at 6 months was lowest among individuals enrolled from February-May and highest for those enrolled from July-November, with an absolute peak-trough difference of 4.3% (95% CI = 3.2% to 5.5%).

CONCLUSIONS

There is meaningful seasonal variation in demand for, and outcomes of, smoking cessation treatment. Climate and weather may be indirectly responsible. Seasonal differences underscore the general importance of contextual factors in smoking cessation, may be useful in program promotion, and may explain some variability in outcomes in evaluation and research.

IMPLICATIONS

Demand for tobacco cessation treatment and clinical outcomes vary seasonally. This underscores the importance of context in substance-related problems, and implies that some variability in research and evaluation results may be due to the time of year data were collected. Promotion efforts might usefully consider seasonal effects to smooth out demand and possibly improve outcomes.

Sex-specific and age-related seasonal variations regarding incidence and in-hospital mortality of pulmonary embolism in Germany

Background

Studies have reported seasonal variations regarding the incidence and the short-term mortality of pulmonary embolism (PE). The aim of this study was to identify sex-specific and age-related differences in seasonal patterns regarding hospitalisations and mortality of PE patients.

Methods

We analysed the impact of seasons on incidence and in-hospital mortality of male and female hospitalised PE patients in Germany (2005-2015) based on the German nationwide inpatient sample.

Results

The German nationwide inpatient sample comprised 885 806 hospitalisations due to PE (2005-2015). Seasonal variations of both incidence (p=0.021) and in-hospital mortality (p<0.001) were of significant magnitude. Quarterly annual incidence (25.5 versus 23.7 of 100 000 citizens per year, p=0.021) and in-hospital mortality (17.0% versus 16.7%, p=0.008) were higher in winter than in summer. Risk of in-hospital mortality in winter was slightly higher (OR 1.03 (95% CI 1.01-1.06), p=0.015) compared to summer, independently of sex, age and comorbidities. Additionally, we observed sex-specific differences during seasons: the highest number of hospitalisations of PE patients of both sexes was during winter, whereas the nadir of male patients was in spring and that of female patients was in summer. Both sexes showed a maximum of in-hospital mortality in spring. Seasonal variation regarding incidence and mortality was pronounced in older patients.

Conclusion

Incidence and the in-hospital mortality of PE patients showed a significant seasonal variation with sex-specific differences. Although it has to be hypothesised that the seasonal variation of PE is multifactorially dependent, variation in each season was not explained by seasonal differences regarding age, sex and the prevalence of important comorbidities.

Seasonal variation in the frequency of venous thromboembolism: An updated result of a meta-analysis and systemic review

Objective

Venous thromboembolism, including deep vein thrombosis and pulmonary embolism, is likely to cause the death of both medical and surgical patients. Despite some evidence of seasonal variation in the incidence of venous thromboembolism, the existing studies obtain contradictory results. A temporal pattern for pulmonary embolism is known, but data on deep vein thrombosis are inconclusive. The purpose of this study is to make a meta-analysis and systematically review the literature about seasonal variations of pulmonary embolism and/or deep vein thrombosis in order to objectively diagnose venous thromboembolism.

Methods

According to dichotomous data, risk ratios (RRs) and 95% confidence intervals (CIs) were used to compare the incidence of venous thromboembolism in different seasons. The research was classified according to pulmonary embolism mortality, pulmonary embolism/deep vein thrombosis incidence, latitude/elevation/climatic types, and monthly incidence for four subgroup comparisons. There were a total of 23 eligible studies, in which 40,309 patients with venous thromboembolism were compared.

Results

The pooled total venous thromboembolism incidence was 27.2% in winter, 23.1% in spring, 24.6% in summer, and 25.1% in autumn. According to the results of pooled analysis, the incidence of venous thromboembolism in winter was much higher than that in summer (RR = 1.12, 95% CI: 1.01–1.24, adjusted P = .04), especially deep vein thrombosis. Moreover, the incidence of venous thromboembolism in summer and autumn was lower than that in winter in low-latitude (<200 m) areas and median low-latitude (0–50°-N) areas. Interestingly, the frequency of pulmonary embolism mortality was the largest in spring and smallest in summer (spring > winter ≈ autumn > summer). For monthly data, a statistically significantly lower incidence of venous thromboembolism was observed in May and July than in October.

Conclusions

The study revealed a significantly higher incidence of venous thromboembolism and deep vein thrombosis in winter than in summer. Pulmonary embolism mortality occurred more frequently in spring than during other seasons. A statistically significantly lower incidence of venous thromboembolism was observed in May and July compared with that in October.

Venous Thromboembolism in Denmark: Seasonality in Occurrence and Mortality

Background  Many cardiovascular conditions exhibit seasonality in occurrence and mortality, but little is known about the seasonality of venous thromboembolism.

Methods  Using Danish registries, we identified all patients with deep vein thrombosis, pulmonary embolism, splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis during 1977–2016. We tallied monthly deaths occurring within 90 days of the venous thromboembolism diagnosis. We estimated peak-to-trough ratios and timing of the peak of both diagnoses and deaths summed over all years of the study period. The departure from 1.0 of the peak-to-trough ratio measures the intensity of any seasonal pattern.

Results  We estimated a peak-to-trough ratio of 1.09 (95% confidence interval: 1.07–1.11) for deep vein thrombosis and 1.22 (1.19–1.24) for pulmonary embolism occurrence. The peak-to-trough ratios for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis occurrence were 1.10 (1.01–1.20), 1.19 (1.00–1.40), and 1.12 (1.07–1.17), respectively. The occurrence of all conditions peaked during winter or fall. In time trend analyses, the peak-to-trough ratio increased considerably for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis occurrence. In associated mortality, the peak-to-trough ratio for deep vein thrombosis was larger (1.15, 1.07–1.23) than that for pulmonary embolism (1.04, 1.01–1.08).

Discussion  Excess winter risks were modest, but more marked for pulmonary embolism occurrence than for deep vein thrombosis occurrence. The seasonal pattern intensified throughout the study period for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis. The winter peak in mortality following pulmonary embolism was smaller than that for deep vein thrombosis.

Sex-specific differences regarding seasonal variations of incidence and mortality in patients with myocardial infarction in Germany

BACKGROUND

Seasonal variation regarding the incidence and the short-term mortality of acute myocardial infarction (MI) was frequently reported, but data about sex-specific differences are sparse.

METHODS

We analysed the impact of seasons and temperature on incidence and in-hospital mortality of patients with acute MI in Germany between 2005 and 2015.

RESULTS

The nationwide sample comprised 3,008,188 hospitalizations of MI patients (2005-2015). The incidence was 334.7/100,000 citizens/year. Incidence inclined from 316.3 to 341.6/100,000 citizens/year (β 0.17 [0.10 to 0.24], P < 0.001), while in-hospital mortality rate decreased from 14.1% to 11.3% (β -0.29 [-0.30 to -0.28], P < 0.001). Overall, 377,028 (12.5%) patients died in-hospital. Seasonal variation of both incidence and in-hospital mortality was of substantial magnitude. Seasonal incidence (86.1 vs. 79.0/100,000 citizens/year, P < 0.001) and in-hospital mortality (13.2% vs. 12.1%, P < 0.001) were higher in winter than in summer. Risk to die in winter was elevated (OR 1.080 (95% CI 1.069-1.091), P < 0.001) compared to summer season independently of sex, age and comorbidities. Reperfusion treatment with drug eluting stents and coronary artery bypass graft were more often used in summer. We observed sex-specific differences regarding the seasonal variation of in-hospital mortality: males showed lowest mortality in summer, while females during fall. Low temperature dependency of mortality seems more pronounced in males.

CONCLUSION

Incidence of acute MI increased 2005-2015, while in-hospital mortality rate decreased. Seasonal variation of incidence and in-hospital mortality were of substantial magnitude with lowest incidence and lowest mortality in the summer season. Additionally, we observed sex-specific differences regarding the seasonal variation of the in-hospital mortality.

Seasonal variations in exacerbations and deaths in patients with COPD during the TIOSPIR® trial

Background

Although COPD exacerbations are known to occur more frequently in winter, there is little information on hospitalizations and cause-specific mortality. This study aimed to examine seasonal variations in mortality and exacerbations in patients with COPD during the TIOtropium Safety and Performance In Respimat^® (TIOSPIR^®) trial.

Patients and methods

TIOSPIR was a large-scale, multicenter trial, which assessed the safety and efficacy of tiotropium delivered via HandiHaler^® (18 μg once daily) or Respimat^® Soft Mist™ (2.5 or 5 μg once daily) inhaler in patients with COPD. Patients were aged ≥40 years, with a smoking history ≥10 pack-years, and post-bronchodilator forced expiratory volume in 1 second ≤70% and forced expiratory volume in 1 second/forced vital capacity ≤0.70. COPD exacerbations and deaths were monitored throughout the trial. The data were pooled to examine seasonal patterns. Southern hemisphere data were shifted by 6 months to align with northern hemisphere seasons.

Results

TIOSPIR was conducted in 43 northern (n=15,968) and 7 southern (n=1,148) hemisphere (n=1,148) countries. The median duration of treatment was 835 days, with a mean follow-up of 2.3 years. Among 19,494 exacerbations, there were clear seasonal differences (winter, 6,646 [34.1%]; spring, 4,515 [23.2%]; summer, 3,198 [16.4%]; autumn, 5,135 [26.3%]). Exacerbations peaked in early winter (December in the northern hemisphere and June in the southern hemisphere), respiratory hospitalizations in midwinter, and respiratory deaths in early spring.

Conclusion

Although winter poses a 2-fold hazard for COPD exacerbations vs summer, respiratory deaths peak in early spring. These data suggest that seasonal intensification of preventive treatments may impact COPD morbidity and mortality.

Trial registration number

NCT01126437.

Seasonality in the adverse outcomes in weight loss surgeries

BACKGROUND

Weight loss surgery is a common procedure in the United States.

OBJECTIVE

As weight loss surgery is largely an elective procedure for which patients and physicians can choose the timing, it could be helpful to explore the seasonality pattern of its perioperative adverse outcomes to help decide the timing of this surgery.

SETTING

United States.

METHODS

We used an obese adult sample (age ≥20 yr) of patients who underwent weight loss surgeries from the Premier Healthcare Database from 2011 to 2014. The International Classification of Diseases, Ninth Revision Clinical Modification procedure codes were used to identify weight loss surgery cases. Binary variables are used for 4 adverse outcomes, including hospital mortality, sepsis, deep vein thrombosis (DVT), and pulmonary embolism. The associations between the adverse outcomes and season of surgery were examined using logistic regressions, adjusting for age, sex, race, marital status, surgery types, body mass index, the Charlson co-morbidity index, and region.

RESULTS

A total of 69,365 weight loss surgeries were identified for the analytic sample. The overall rate was .27% for hospital mortality, .16% for DVT, .10% for pulmonary embolism, and .20% for sepsis. For DVT, adjusted odds ratio for the fall was 2.68 (95% confidence interval: 1.39-5.19) and the odds ratio for the winter was 2.26 (95% confidence interval: 1.09-4.27) compared with the summer. For sepsis, adjusted odds ratio for the spring was 1.83 (95% confidence interval: 1.07-3.12) compared with that of the summer. The seasonality pattern was not statistically significant for hospital mortality and pulmonary embolism.

CONCLUSION

DVT and sepsis are more likely to occur in colder seasons compared with the summer season, although the crude rates of these adverse events were low.

Pulmonary embolism: Does the seasonal effect depend on age? A 12-year nationwide analysis of hospitalization and mortality

BACKGROUND

Circannual variations in the incidence and mortality of pulmonary embolism (PE) have been previously described although conflicting observations have been reported. However, the association between age and seasonal variations of incidence and mortality rates is not established. This nationwide study aimed to assess the seasonal pattern in hospitalizations and mortality for PE along with the effect of age.

METHODS

Comprehensive records from the French hospital discharge databases between 2002 and 2013 and death certificates between 2000 and 2010 were used. For each outcome and separately for each sex, monthly event counts were analyzed using quasi-Poisson models with tensor-products of regression splines, including a seasonal component and controlling for the underlying time trend, age of patients and population size changes.

RESULTS

During the period studied, 599,432 patients with PE were hospitalized and 150,404 death certificates mentioned a PE. Compared with summer months, the winter peak was associated with 25% increasing rates in hospitalizations and mortality. The rates ratio of hospitalizations between the winter peak and the summer trough increased with age. The winter excess of incidence raised from 10%, IC 95% [5-16] in 30-year-old men to 33% [31-35] in 75year-old men. In the same way, the incidences at the peak time was 13% [9-18] and 34% [31-36] higher in 30 and 75-year-old women respectively.

CONCLUSION

Based on large nationwide study, our study showed a clear seasonal pattern both on PE incidence and mortality. In addition, our data supported an association of age on the PE seasonal variations.

Analysis of environmental risk factors for pulmonary embolism: A case-crossover study (2001-2013)

BACKGROUND

The relationship between environmental factors and pulmonary embolism (PE) has received little attention. The aim of this study was to estimate the influence of climatological factors and air pollution levels on PE in Spain from 2001 to 2013.

METHODS

We carried out a retrospective study. Data were collected from the Minimum Basic Data Set (MBDS) and the State Meteorological Agency (AEMET) of Spain. A case-crossover analysis was applied to identify environmental risk factors related to hospitalizations and deaths. For each patient, climatic and pollutant factors were assigned using data from the meteorological station closest to his/her postal code.

RESULTS

A seasonal effect for PE hospital admission was observed, with more frequent admissions noted during Spain's colder seasons with peaks in autumn and winter. Lower temperatures as well as higher concentrations of NO2 and O3 at the time of admission (when 2weeks and 3weeks respectively were used as controls) were significant risk factors for hospital admissions with PE.

CONCLUSIONS

Pulmonary embolism epidemiology was adversely influenced by colder climatological factors (absolute temperature, and seasonality) and higher concentrations of ambient air pollution (NO2, O3).

Pulmonary embolism, acute coronary syndrome and ischemic stroke in the Spanish National Discharge Database

BACKGROUND

Venous and arterial thrombosis share a number of pathogenic mechanisms, but the burden of pulmonary embolism (PE) has not been consistently compared with that in other arterial diseases.

METHODS

We used the Spanish National Discharge Database to compare the frequency, clinical characteristics and mortality rate of all patients with PE, acute coronary syndrome (ACS) or ischemic stroke admitted from 2001 to 2010. Patients were classified as having primary diagnosis (the process leading to hospital admission) or secondary diagnosis (it appeared during hospital stay for other reasons)

RESULTS

During the study period, 31,949,739 patients were discharged. Of these, 165,229 (0.52%) were diagnosed with PE, 562,837 (1.76%) with ACS and 495,427 (1.55%) with ischemic stroke. Overall, 31% of patients with PE, 8.4% with ACS and 13% with ischemic stroke had secondary diagnoses. The most common reasons for admission in patients with secondary PE were: cancer (21%), acute respiratory failure (11%), acute heart failure (6.4%) and stroke (5.5%). Mean hospital stay was: 14 ± 13 days in PE patients, 9.7 ± 9.7 in those with ACS and 13 ± 14 days in those with stroke. In-hospital mortality rate was: 10.5%, 10.1% and 12.3% respectively in patients with primary diagnosis, and 36%, 34% and 29% in those with secondary diagnosis.

CONCLUSIONS

Patients hospitalized with PE were 3-4 times less frequent than those with ACS or stroke, but had a higher mortality. One in every 3 patients with PE (but only one in every 10 with ACS or stroke) had secondary diagnosis, and these patients had the highest mortality.