Seasonal Variation In Mortality Research Articles

Migration mortality in birds

Bird migration is one of the greatest wildlife spectacles, producing massive global changes in the distributions of birds twice each year. To understand the evolution of this phenomenon, it is important to know the costs of these journeys in terms of the mortality they impose. The use of mark/re‐sighting and tracking studies has now made it possible, for some bird species, to separate mortality during migration from mortality during stationary periods. This paper aims to assess this information, based mainly on 31 published studies, most of which concern long‐distance migrations of passerines, large waterfowl and raptors. Most of these studies revealed that mortality rates were greater during migration than at other times – in some species more than 20 times greater. Overall, on the basis of median values, mortality per unit time during autumn journeys was about 3.0 times greater than mortality during stationary periods, during spring journeys about 6.3 times greater, and during autumn and spring journeys combined 4.4 times greater. The greater overall mortality on spring journeys was largely associated with more adverse wind conditions in spring than in autumn. High mortality rates were especially evident in birds crossing large ecological barriers, such as the Sahara Desert or the Gulf of Mexico, and were higher in that part of their journey than when crossing more benign terrain. There was no increase in mortality during migration in the adults of some long‐lived species with high annual survival and predominantly overland journeys; for these birds, much larger samples of year‐round tracked individuals will be needed to reveal any seasonal variations in mortality. Within certain species, birds that travelled long distances experienced greater mortality over the journey than those that travelled short distances, but in other species no such relationship was found. In species in which adults and juveniles were followed over the same journey, juveniles showed greater mortality. To judge from other studies, this difference could be attributed to the inexperience of juveniles, their lower feeding rates and flight efficiency, greater vulnerability to hazards such as weather and predation, or more frequent navigational errors. Broadly speaking, the risks of migration vary with features of the birds themselves, with the terrain to be crossed and with weather at the time. It may be assumed that migration persists in the long term because the costs (in terms of associated mortality) are more than offset by the benefits of breeding and wintering in different areas (in terms of improved overall survival and breeding success). To provide further understanding of migration mortality, suggestions are made on the types of studies required and on how they could best be conducted.

Seasonal variation in mortality in the city of Barnaul based on the Pokrovsky parish registers (1877-1897)

The paper analyzes seasonal fluctuations in mortality among the parish population on the basis of parish registers of the Pokrovsky parish in Barnaul in the last third of the XIX century. The study results show that infant mortality in Barnaul in 1877-1897 was still strongly dependable upon the time of year. Summer and winter peaks suggest a continued role of exogenous causes of death. Infant mortality rates in summer were three times higher than the annual average. The mortality peak is mainly registered in June. Starting from the age of 10-14, the seasonal factor passes from the picture, and deaths are distributed more evenly over the seasons. The analysis of seasonal fluctuations in mortality by cause of death showed that in children, summer peaks are associated with infectious diseases, while winter peaks are due to cold-related diseases. Seasonal fluctuations in mortality by social class are not fundamentally different. It can be assumed that the demographic transition was still in its early stages and yet to be developed even in the upper classes, which had always been at the forefront of demographic modernization. The obtained results and conclusions about seasonal fluctuations in infant and child mortality are consistent with pre-revolutionary and modern research. The existing differences in seasonal fluctuations in infant mortality exemplified by different cities and settlements in Russia with peaks either in July or August, may indicate a wide climatic diversity and socio-economic differences between regions of the country, as well as differences in calculation methods.

The effect of climate warming on the seasonal variation of mortality in European countries

The effect of climate warming on the seasonal variation of mortality in European countries

Learning from the pandemic: mortality trends and seasonality of deaths in Australia in 2020.

AimTo assess whether the observed numbers and seasonality of deaths in Australia during 2020 differed from expected trends based on 2015–19 data.MethodsWe used provisional death data from the Australian Bureau of Statistics, stratified by state, age, sex and cause of death. We compared 2020 deaths with 2015-19 deaths using interrupted time series adjusted for time trend and seasonality. We measured the following outcomes along with 95% confidence intervals: observed/expected deaths (rate ratio: RR), change in seasonal variation in mortality (amplitude ratio: AR) and change in week of peak seasonal mortality (phase difference: PD).ResultsOverall 4% fewer deaths from all causes were registered in Australia than expected in 2020 [RR 0·96 (0·95-0·98)] with reductions across states, ages and sex strata. There were fewer deaths from respiratory illness [RR 0·79 (0·76-0·83)] and dementia [RR 0·95 (0·93-0·98)] but more from diabetes [RR 1·08 (1·04-1·13)]. Seasonal variation was reduced for deaths overall [AR 0·94 (0·92-0·95)], and for deaths due to respiratory illnesses [AR 0·78 (0·74-0·83)], dementia [AR 0.92 (0.89-0.95)] and ischaemic heart disease [0.95 (0.90-0.97)].ConclusionsThe observed reductions in respiratory and dementia deaths and the reduced seasonality in ischaemic heart disease deaths may reflect reductions in circulating respiratory (non-SARS-CoV-2) pathogens resulting from the public health measures taken in 2020. The observed increase in diabetes deaths is unexplained and merits further study.

Seasonal variation in mortality and the role of temperature: a multi-country multi-city study.

Although seasonal variations in mortality have been recognized for millennia, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and to examine the contribution of temperature. We compiled daily data on all-cause, cardiovascular and respiratory mortality, temperature and indicators on location-specific characteristics from 719 locations in tropical, dry, temperate and continental climate zones. We fitted time-series regression models to estimate the amplitude of seasonal variation in mortality on a daily basis, defined as the peak-to-trough ratio (PTR) of maximum mortality estimates to minimum mortality estimates at day of year. Meta-analysis was used to summarize location-specific estimates for each climate zone. We estimated the PTR with and without temperature adjustment, with the differences representing the seasonal effect attributable to temperature. We also evaluated the effect of location-specific characteristics on the PTR across locations by using meta-regression models. Seasonality estimates and responses to temperature adjustment varied across locations. The unadjusted PTR for all-cause mortality was 1.05 [95% confidence interval (CI): 1.00-1.11] in the tropical zone and 1.23 (95% CI: 1.20-1.25) in the temperate zone; adjusting for temperature reduced the estimates to 1.02 (95% CI: 0.95-1.09) and 1.10 (95% CI: 1.07-1.12), respectively. Furthermore, the unadjusted PTR was positively associated with average mean temperature. This study suggests that seasonality of mortality is importantly driven by temperature, most evidently in temperate/continental climate zones, and that warmer locations show stronger seasonal variations in mortality, which is related to a stronger effect of temperature.

Seasonal variation in mortality and the role of temperature: a multi-country multi-city study

BACKGROUND AND AIM: Although seasonal variations in mortality have been recognised for a long time, the role of temperature remains unclear. We aimed to assess seasonal variation in mortality and to examine the contribution of temperature. METHODS: We compiled daily data on all-cause, cardiovascular, and respiratory mortality, temperature, and indicators on location-specific characteristics from 719 locations in tropical, dry, temperate and continental climate zones. We fitted time-series regression models to estimate the amplitude of seasonal variation in mortality on a daily basis, defined as the peak-to-trough ratio (PTR) of maximum mortality estimates to minimum mortality estimates at day-of-year. Random-effects multivariate meta-analysis was used to summarise location-specific estimates for each climate zone. We estimated PTR with and without temperature adjustment, with the differences representing the seasonal effect attributable to temperature. We also evaluated the effect of location-specific characteristics on PTR across locations by using random-effects meta-regression models. RESULTS:Seasonality estimates and responses to temperature adjustment varied across locations. Unadjusted-PTR for all-cause mortality was 1.05 (95% confidence interval (CI): 1.00–1.11) in the tropical zone and 1.23 (95% CI: 1.20–1.25) in the temperate zone; adjusting for temperature reduced the PTR estimates to 1.02 (95% CI: 0.95–1.09) and 1.10 (95% CI: 1.07–1.12), respectively. Furthermore, unadjusted-PTR was positively associated with average annual mean temperature, and adjusting for temperature in PTR moved the estimate towards the null. CONCLUSIONS:This study suggests that seasonality of mortality is importantly driven by temperature, most evidently in temperate/continental climate zones, and that warmer locations show stronger seasonal variations in mortality, which is related to a stronger effect of temperature. On behalf of the MCC collaborative research network. KEYWORDS: Seasonality of mortality, temperature, a multi-country multi-city study

Short-Term Effect of Temperature Change on Non-Accidental Mortality in Shenzhen, China.

Temperature change is an important meteorological indicator reflecting weather stability. This study aimed to examine the effects of ambient temperature change on non-accidental mortality using diurnal temperature change (DTR) and temperature change between neighboring days (TCN) from two perspectives, intra-day and inter-day temperature change, and further, to explore seasonal variations of mortality, identify the susceptible population and investigate the interaction between temperature change and apparent temperature (AT). We collected daily data on cause-specific mortality, air pollutants and meteorological indicators in Shenzhen, China, from 1 January 2013 to 29 December 2017. A Quasi-Poisson generalized linear regression combined with distributed lag non-linear models (DLNMs) were conducted to estimate the effects of season on temperature change-related mortality. In addition, a non-parametric bivariate response surface model was used to explore the interaction between temperature change and AT. The cumulative effect of DTR was a U-shaped curve for non-accidental mortality, whereas the curve for TCN was nearly monotonic. The overall relative risks (RRs) of non-accidental, cardiovascular and respiratory mortality were 1.407 (95% CI: 1.233–1.606), 1.470 (95% CI: 1.220–1.771) and 1.741 (95% CI: 1.157–2.620) from exposure to extreme large DTR (99th) in cold seasons. However, no statistically significant effects were observed in warm seasons. As for TCN, the effects were higher in cold seasons than warm seasons, with the largest RR of 1.611 (95% CI: 1.384–1.876). The elderly and females were more sensitive, and low apparent temperature had a higher effect on temperature change-related non-accidental mortality. Temperature change was positively correlated with an increased risk of non-accidental mortality in Shenzhen. Both female and elderly people are more vulnerable to the potential adverse effects, especially in cold seasons. Low AT may enhance the effects of temperature change.

Seasonality of mortality under a changing climate: a time-series analysis of mortality in Japan between 1972 and 2015

BackgroundAmbient temperature may contribute to seasonality of mortality; in particular, a warming climate is likely to influence the seasonality of mortality. However, few studies have investigated seasonality of mortality under a warming climate.MethodsDaily mean temperature, daily counts for all-cause, circulatory, and respiratory mortality, and annual data on prefecture-specific characteristics were collected for 47 prefectures in Japan between 1972 and 2015. A quasi-Poisson regression model was used to assess the seasonal variation of mortality with a focus on its amplitude, which was quantified as the ratio of mortality estimates between the peak and trough days (peak-to-trough ratio (PTR)). We quantified the contribution of temperature to seasonality by comparing PTR before and after temperature adjustment. Associations between annual mean temperature and annual estimates of the temperature-unadjusted PTR were examined using multilevel multivariate meta-regression models controlling for prefecture-specific characteristics.ResultsThe temperature-unadjusted PTRs for all-cause, circulatory, and respiratory mortality were 1.28 (95% confidence interval (CI): 1.27–1.30), 1.53 (95% CI: 1.50–1.55), and 1.46 (95% CI: 1.44–1.48), respectively; adjusting for temperature reduced these PTRs to 1.08 (95% CI: 1.08–1.10), 1.10 (95% CI: 1.08–1.11), and 1.35 (95% CI: 1.32–1.39), respectively. During the period of rising temperature (1.3 °C on average), decreases in the temperature-unadjusted PTRs were observed for all mortality causes except circulatory mortality. For each 1 °C increase in annual mean temperature, the temperature-unadjusted PTR for all-cause, circulatory, and respiratory mortality decreased by 0.98% (95% CI: 0.54–1.42), 1.39% (95% CI: 0.82–1.97), and 0.13% (95% CI: − 1.24 to 1.48), respectively.ConclusionSeasonality of mortality is driven partly by temperature, and its amplitude may be decreasing under a warming climate.

Mortality Pattern of Broiler Rabbits in an Organized Farm in Bihar, India

Background: The pre and post-weaning mortality in broiler rabbit limits the production potential and lower the income generation through rabbit farming. Therefore, mortality pattern of animals in a farm is very essential clue for future strategy to combat the incidences of various diseases and prevention. Considering the above fact the present study was undertaken to find out the incidences of various rabbit diseases and mortality in an organized institutional farm.Methods: ICAR Research Complex for Eastern Region, Patna was maintaining a broiler rabbit farm with 364 rabbit comprising Newzealand White (194) and Soviet Chinchilla (170) rabbit breed. During the three years (October, 2011 to September, 2014) study period in total 364 rabbits were under observation. The seasonal variation viz. (pre-monsoon, monsoon, post-monsoon and winter, in regards to mortality, disease incidences, young and adults, sex variation, breed, housing system etc were recorded. The incidences of disease and mortality of rabbits were diagnosed through pathological examination and postmortem findings. The descriptive statistics and ÷2 test were used to explain the statistical significance.Result: During the three years study period out of 364 broiler rabbits (Soviet Chinchilla and Newzealand white) in total 63 rabbits (17.31%) were died due to various diseases. The coccidiosis (3.02%), green slime disease (2.20%), haemorrhagic tracheitis (1.92%), enteritis (1.65%), pneumonia (1.37%) and peritonitis (1.37%) were affected more than the other diseases. Apart from these the other ailments that affected broiler rabbits were ear cancer (0.82%), gastroenteritis (0.82%), stomach infection (0.82%), cardinogenic shock (0.55%), stomach impaction (0.55%), kidney infection (0.55%), limb injury (0.27%), ascites (0.27%), cystitis (0.27%), abscess in abdominal cavity (0.27%), rupture of liver and gall bladder (0.27%) as well as injury of eye and blindness (0.27%). The Soviet Chinchilla rabbits were less (7.14%) affected than the Newzealand white (10.16%). It was observed that mortality of male rabbits (6.04%) were less than the female rabbits (11.26%) and mortality of young were higher (11.54%) than the adult rabbits (5.77%). The seasonal variations in mortality of broiler rabbits were observed in present study. In monsoon season mortality was maximum i.e. 6.32% whereas, in post-monsoon it was 5.49%, pre-monsoon 3.02% and in winter season mortality was only 2.47%. The Soviet Chinchilla rabbits were less susceptible and comparatively better performer in regards to disease resistance. It may be concluded that in broiler rabbit farm coccidiosia is a major concern along with other parasitic and bacterial diseases. However, proper hygiene and sanitation along with periodic treatment with coccidiostat and deworming reduces mortality of rabbits.

Modelling seasonal mortality with individual data

Most studies of seasonal variation in mortality rely on aggregated death counts at population level. In this paper, we use individual data to present a series of models for different aspects of seasonal variation. The models are fitted to a variety of international pensioner data sets and suggest a high degree of commonality across countries with different climates and different health systems. The power of individual life-history survival modelling allows the detection of seasonal patterns in even modest-sized portfolios. We measure the tendency for seasonal fluctuations to increase with age, and we again find strong similarities between geographically distinct populations. We further find that seasonal effects are generally uncorrelated with gender, but that low-income pensioners can suffer greater seasonal swings than high-income ones. Finally, we propose a single-parameter measure for the extent to which winter mortality is a spike and summer mortality is a shallower trough, and show results for a variety of data sets.

Seasonal variations in cause-specific mortality and transition to renal replacement therapy among patients with end-stage renal disease

Despite some studies showing seasonal variations in mortality and the transition to renal replacement therapy in patients with end-stage renal disease, detailed evidence is still scarce. We investigated seasonal variations in patients with end-stage renal disease using a large Japanese database for dialysis patients. We compared the fractions of all-cause and cause-specific mortality and the transition to renal replacement therapy among seasons and performed a mixed-effects Poisson regression analysis to compare the mortality among seasons after adjustment for some variables. The initiation of hemodialysis was highest in winter and lowest in summer. Seasonality in the initiation of peritoneal dialysis and transition to kidney transplantation differed from hemodialysis. All-cause mortality was highest in the winter and lowest in the summer. Death from coronary artery disease, heart failure, cerebral hemorrhage, and infectious pneumonia had similar seasonality, but death from cerebral infarction, septicemia, or malignant tumor did not have similar seasonality. In conclusion, the initiation of hemodialysis, all-cause mortality, and mortality from coronary heart disease, heart failure, cerebral hemorrhage, and infectious pneumonia were significantly highest in winter and lowest in summer. However, the initiation of peritoneal dialysis, transition to kidney transplantation, or mortality from cerebral infarction, septicemia, or malignant tumor did not have similar seasonal variations.

P2822Seasonal variation in in-hospital cardiac arrest and associated mortality

Abstract Background Previous reports have documented seasonal variation in out-of-hospital cardiac arrest (OHCA), with peak incidence in winter months, regardless of geographical region. However, seasonal variation in in-hospital cardiac arrest (IHCA) has not been well studied. Purpose To assess seasonal variation in incidence of in-hospital cardiac arrest, as well as gender and mortality differences. Methods We queried the 2014 National Inpatient Service (NIS) database for the total numbers of inpatient hospitalizations and in-hospital cardiac arrests for each month, as identified by ICD-9 codes (99.60 and 99.63). The trend for each month was plotted to assess seasonal variations in hospitalizations, IHCA, and mortality. Seasonal Variations in IHCA Results The mean age of the study population was 57.3±0.2 years and 58.9% were female. Out of 29,717,872 total inpatient hospitalizations in 2014, the overall IHCA event for the year was 0.38%. Females were more likely to be hospitalized; however, males were more likely to have IHCA. These gender differences persisted throughout the year. Overall, more hospitalizations and IHCA were seen in the winter compared to the summer, and this trend was seen in both men and women. The highest incidence of in-hospital cardiac events occurred in January and the lowest incidence occurred in June. There was no seasonal variation in mortality in both male and female patients who suffered IHCA. Conclusion(s) In this observational study, seasonal variation is present in in-hospital cardiac arrest. Cardiac events are highest in the winter months as compared to the summer months; however, the mechanism of this variation is unknown and warrants further study. Acknowledgement/Funding None

A Hermite-spline model of post-retirement mortality

ABSTRACTWe present a model for post-retirement mortality where differentials automatically reduce with increasing age, but without the fitted mortality rates for subgroups crossing over. Selection effects are catered for, as are age-modulated time trends and seasonal variation in mortality. Central to the model are Hermite splines, which permit parsimonious modelling of complex risk factors in even modest-sized portfolios. The model is therefore suitable for the stand-alone analysis of experience data for reinsurance, bulk annuities and longevity swaps. We also illustrate the contrast between the statistical significance of a risk factor and its financial significance and discuss reasons why one might include risk factors like season that are not directly financially significant.

Seasonal variation of mortality from external causes in Hungary between 1995 and 2014.

ObjectiveTo analyze trends in external mortality in Hungary between 1995 and 2014 by sex.MethodsData on the numbers of deaths due to external causes were obtained from the published nationwide population register. Negative binomial regression was applied to investigate the yearly trends in external-cause mortality rates. Cyclic trends were investigated using the Walter-Elwood method.ResultsSuicide and accidents accounted for approximately 84% of the all-external-cause of deaths in Hungary. Annual suicide, unintentional falls and traffic accidents mortality declined significantly (p-value for annual trend: p < 0.001) from 30.5 (95% CI: 29.5–31.5) to 15.8 (15.1–16.5), from 31.2 (30.2–32.2) to 12.2 (11.7–12.8) and from 17.2 (16.4–18) to 5.4 (5–5.8) per 100 000 persons per year, respectively, during the study period. A significant declining trend in annual mortality was also found for assault, cold/heating-related accidents and accidents caused by electric current. However, the declining trend for drowning-related accidents was significant only for males. Significant winter-peak seasonality was found in the mortality rates from accidental falls, cold/heat-related accidents, other accidents caused by submersion/obstruction and other causes. Seasonal trends with a peak from June to July were observed in death rates from suicide/self-harm, accidental drowning/submersion and accidents caused by electric current. A significant seasonal variation with a peak in September was revealed in the mortality due to traffic accidents.ConclusionsThis Hungarian study suggests that there was a significant seasonal effect on almost all kinds of deaths from external causes between 1995 and 2014. Environmental effects are involved in the aetiology of suicide and accidents.

Observational evidence of the seasonal and demographic variation in experienced temperature from 77 743 UK Biobank participants.

Exposure to cold is known to be associated with severe health impacts. The primary epidemiological evidence for this is the seasonal variation in mortality. However, there is a paucity of directly measured data for personal cold temperature exposure. This paper develops the concept of experienced temperature, and reports how it varies with season, demographics and housing factors. This study uses data from 77 743 UK Biobank participants. A novel method to directly measure participant's exposure to low temperatures using a thermistor in a wrist-worn activity monitor is described. These readings are combined with demographic and housing factor variables in a multiple regression model to understand underlying relationships. The study reveals a significant difference in experienced temperature of ~1.8°C between the periods of coldest and hottest external temperature. A number of demographic differences were also observed-such as people of Chinese ethnic background experiencing 0.65°C lower temperatures than other groups. This paper presents primary evidence for a seasonal variation in experienced temperature. This variation likely contributes to cold related mortality and morbidity. It is hypothesized that this relationship would be less strong in countries which suffer fewer impacts of cold winter temperatures.

Seasonal variation of mortality, detectability, and body condition in a population of the adder (Vipera berus).

We analyzed seasonal variation in mortality rates in adult males and females of the European adder (Vipera berus), using data collected during a 13‐year capture–recapture study (2005–2017) in a large population. We concurrently obtained quantitative information on the seasonal variation in the detectability and body condition of adders. Our results show strong seasonality in body condition, encounter, and capture rates of adult adders, and these patterns differ markedly between sexes and between breeding and nonbreeding females. Seasonal variation in mortality rates was however virtually nonexistent in males and moderately low in both breeding and nonbreeding females. In addition, we found no evidence for among‐year differences in the seasonal mortality schedules of males and females. During periods of intensive basking, both males and pregnant females are highly visible for humans, but are not subject to strong natural mortality. This low susceptibility to predation is presumably induced by various factors, including the limitation of overt exposure to short periods of time and specific microhabitats, the dorsal coloration pattern that provides cryptic protection and possibly also an aposematic warning signal, and presumed seasonal differences in the foraging behavior and food requirements of natural predators. Our data provide some evidence that female adders, but not males, are relatively vulnerable to predation during the seasonal migrations between the hibernation and feeding habitats. Mortality in the females was not much elevated during their breeding years, but was notably highest in the spring of the ensuing nonbreeding year. After giving birth, reproductive females are extremely emaciated and have a weakened general condition. They then run the risk of dying from starvation either before, during, or after hibernation. The higher mortality after giving birth, that is sustained over a period of ca. 9 months, should be considered as an indirect and delayed survival cost of reproduction.

Monthly Variation in Finnish Total Mortality During 1891-2017, Temperature and Discussions

Seasonal variations in mortality resulting from cardiovascular diseases (CVD) have been demonstrated in many countries, with the highest levels observed during the coldest months of the year [1].

Trends in Hospitalizations for Sickle Cell Disease Related-Complications in USA 2004 - 2012.

BackgroundSickle cell disease (SCD) affects 100,000 patients in the USA. However, no recent data was available for annual national trends in hospitalization rates, in-hospital mortality, hospital length of stay (LOS) and costs of SCD admissions due to its complications.MethodsThis study was conducted to study the trends of hospitalization rates, in-hospital mortality, LOS and hospital charges due to SCD-related complications in African American (AA) patients from 2004 to 2012 in the USA. Complications included acute chest syndrome, splenic sequestration, bacterial pneumonia, sepsis, stroke, deep vein thrombosis (DVT) or pulmonary embolism, retinal circulation complications, priapism, disorders related to biliary stones, or those required blood transfusions. We obtained the study population from the Nationwide Inpatient Sample.ResultsHospital admission rate rose steadily from 106 per 100,000 AA population in 2004 to 137 in 2012. Seasonal and trend decomposition revealed the highest hospitalization rate in January. Hospital LOS decreased from 7.1 ± 7.65 days in 2004 to 6.23 ± 6.42 days in 2012. Hospital charges increased from 15.35 (8.99 - 27.57) thousand dollars per admission in 2004 to 24.78 (14.37 - 45.24) in 2012. Medicaid remained the primary payer in the highest number of patients in 9 years. In-hospital mortality did not change significantly, being 1.03% in 2004 and 1.02% in 2012, with no significant seasonal variation in mortality. Most common complications were acute pain crisis and blood transfusion requirement. Biliary pathology was the only complication that decreased over time. Admissions for each complication were initially uprising with a decline from 2010 to 2012, except for DVT/pulmonary embolism with a significant uptrend.ConclusionsOverall, from 2004 to 2012, hospital admission rates and charges increased, and hospital LOS decreased, while in-hospital mortality remained unchanged.

Associations of postoperative mortality with the time of day, week and year.

Studies that have investigated circadian, weekday and seasonal variation in postoperative mortality have been relatively small or have been for scheduled surgery. We retrospectively tested a large mixed surgical cohort from a German tertiary care university hospital for the presence of cyclical variation in all-cause in-hospital mortality after operations performed between 2006 and 2013. We analysed mortality rates after 247,475 operations, adjusted for age, sex, comorbidities, location, urgency and duration of the surgery, and intra-operative blood transfusions. The mortality odds ratio (95%CI) after operations started in the morning (08:00-11:00) were lowest, 0.73 (0.66-0.80), p < 0.001 and highest for operations started in the afternoon (13:00-17:00), 1.29 (1.18-1.40), p < 0.001. Mortality at the weekend was the same as during the week. There was no seasonal variation in mortality, p = 0.12. However, the interference of four-yearly and ten-monthly cycle amplitudes resulted in higher mortality odds ratio (95%CI) in winter 2008-2009, 1.41 (1.18-1.69), p < 0.001, and lower mortality in spring 2011 and 2012, 0.70 (0.56-0.85) and 0.67 (0.53-0.85), p < 0.001 and p = 0.001, respectively. The ability to predict cyclical phenomena would facilitate the design of interventional studies, aimed at reducing mortality following surgery in the afternoon and when cycles interfere constructively.

Seasonal variations in exacerbations and deaths in patients with COPD during the TIOSPIR&lt;sup&gt;&amp;reg;&lt;/sup&gt; trial

BackgroundAlthough 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 methodsTIOSPIR 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.ResultsTIOSPIR 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.ConclusionAlthough 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 numberNCT01126437.