Influence of Meteorological Temperature and Pressure on the Severity of Heart Failure Decompensations

Association between ambient temperature exposure and pregnancy outcomes in patients undergoing in vitro fertilization in Shanghai, China: a retrospective cohort study

STUDY QUESTION

Does ambient temperature exposure affect outcomes including clinical pregnancy and live birth in women undergoing IVF?

SUMMARY ANSWER

Both extreme cold and hot ambient temperatures were significantly associated with adverse pregnancy outcomes of IVF cycles.

WHAT IS KNOWN ALREADY

Heat exposure has been linked to adverse pregnancy outcomes worldwide. However, the effect of ambient temperature on infertile women undergoing IVF treatment is unclear.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study was conducted from a database of 3452 infertile women who underwent their first fresh or frozen embryo transfer in the Shanghai First Maternity and Infant Hospital from April 2016 to December 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Daily mean ambient temperature exposure for each patient was obtained based on their residential address. Temperature-stratified multiple logistic regression analysis was performed to investigate associations between temperature exposure and pregnancy outcomes after controlling for confounders. Vulnerable sub-groups were identified using forest plots.

MAIN RESULTS AND THE ROLE OF CHANCE

The clinical pregnancy rate and live birth rate were 45.7% and 37.1%, respectively. Regarding clinical pregnancy, a higher temperature during cold weather was significantly associated with a higher pregnancy rate in the period about 11 weeks before ovarian stimulation (adjusted odds ratio (aOR) = 1.102, 95% CI: 1.012-1.201). Regarding live birth, an increased temperature during cold weather was significantly related to a higher live birth rate in the period after confirmation of clinical pregnancy or biochemical pregnancy, with the aORs of 6.299 (95% CI: 3.949-10.047) or 10.486 (95% CI: 5.609-19.620), respectively. However, a higher temperature during hot weather was negatively associated with the live birth rate in the periods after confirmation of clinical pregnancy or biochemical pregnancy, with the aORs at 0.186 (95% CI: 0.121-0.285) or 0.302 (95% CI: 0.224-0.406), respectively. Moreover, the decline in live birth rates during cold and hot weather was accompanied by increased rates of early miscarriage (P < 0.05). Stratified analyses identified susceptibility characteristics among the participants.

LIMITATIONS, REASONS FOR CAUTION

Climate monitoring data were used to represent individual temperature exposure levels according to the patient's residential address in the study. We were not able to obtain information of personal outdoor activity and use of indoor air conditioners in this retrospective study, which may affect actual temperature exposure.

WIDER IMPLICATIONS OF THE FINDINGS

This study highlights that the ambient temperature exposure should be taken into account during IVF treatment and afterwards. There is a need to be alert to extremes in cold and hot ambient temperatures, especially during the period of follicle development and pregnancy. With this knowledge, clinicians can scientifically determine the timing of IVF treatment and reinforce patients' awareness of self-protection to minimize adverse pregnancy outcomes associated with extreme temperatures.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a grant from the Clinical Research Plan of Shanghai Hospital Development Center [SHDC2020CR4080], a grant from the Science and Technology Commission of Shanghai Municipality [19411960500], and two grants from the National Natural Science Foundation of China [81871213, 81671468]. B.W.M. is supported by a NHMRC Investigator grant (GNT1176437). B.W.M. reports consultancy for ObsEva, and research grants from Merck KGaA, Ferring and Guerbet. The other authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Analysis of the relationship between ambient air pollution and the severity of heart failure decompensations in two Spanish metropolises (Barcelona and Madrid)

OBJECTIVES

To analyze whether the high levels of air pollutants are related to a greater severity of decompensated heart failure (HF).

METHOD

Patients diagnosed with decompensated HF in the emergency department of 4 hospitals in Barcelona and 3 in Madrid were included. Clinical data (age, sex, comorbidities, baseline functional status), atmospheric (temperature, atmospheric pressure) and pollutant data (SO₂, NO₂, CO, O₃, PM₁₀, PM_2.5) were collected in the city on the day of emergency care. The severity of decompensation was estimated using 7-day mortality (primary indicator) and the need for hospitalization, in-hospital mortality, and prolonged hospitalization (secondary indicators). The association adjusted for clinical, atmospheric and city data between pollutant concentration and severity was investigated using linear regression (linearity assumption) and restricted cubic spline curves (no linearity assumption).

RESULTS

A total of 5292 decompensations were included, with a median age of 83 years (IQR=76-88) and 56% women. The medians (IQR) of the daily pollutant averages were: SO₂=2.5μg/m³ (1.4-7.0), NO₂=43μg/m³ (34-57), CO=0.48mg/m³ (0.35-0.63), O₃=35μg/m³ (25-48), PM₁₀=22μg/m³ (15-31) and PM_2.5=12μg/m³ (8-17). Mortality at 7 days was 3.9%, and hospitalization, in-hospital mortality, and prolonged hospitalization were 78.9, 6.9, and 47.5%, respectively. SO₂ was the only pollutant that showed a linear association with the severity of decompensation, since each unit of increase implied an OR for the need for hospitalization of 1.04 (95% CI 1.01-1.08). The restricted cubic spline curves study also did not show clear associations between pollutants and severity, except for SO₂ and hospitalization, with OR of 1.55 (95% CI 1.01-2.36) and 2.71 (95% CI 1.13-6.49) for concentrations of 15 and 24μg/m³, respectively, in relation to a reference concentration of 5μg/m³.

CONCLUSION

Exposure to ambient air pollutants, in a medium to low concentration range, is generally not related to the severity of HF decompensations, and only NO₂ may be associated with an increased need for hospitalization.

Ambient temperature and atmospheric pressure at discharge as precipitating factors in immediate adverse events in patients treated for decompensated heart failure

To investigate the relationship of ambient temperature and atmospheric pressure (AP) at patient discharge after an episode of acute heart failure (AHF) with very early post-discharge adverse outcomes. We analyzed 14,656 patients discharged after an AHF episode from 26 hospitals in 16 Spanish cities. The primary outcome was the 7-day post-discharge combined adverse event (emergency department -ED- revisit or hospitalization due to AHF, or all-cause death), and secondary outcomes were these three adverse events considered individually. Associations (adjusted for patient and demographic conditions, and length of stay -LOS- during the AHF index episode) of temperature and AP with the primary and secondary outcomes were investigated. We used restricted cubic splines to model the continuous non-linear association of temperature and AP with each endpoint. Some sensitivity analyses were performed. Patients were discharged after a median LOS of 5 days (IQR = 1-10). The highest temperature at discharge ranged from - 2 to 41.6 °C, and AP was from 892 to 1037 hPa. The 7-day post-discharge combined event occurred in 1242 patients (8.4%), with percentages of 7-day ED-revisit, hospitalization and death of 7.8%, 5.1% and 0.9%, respectively. We found no association between the maximal temperature and AP on the day of discharge and the primary or secondary outcomes. Similarly, there were no significant associations when the analyses were restricted to hospitalized patients (median LOS = 7 days, IQR = 4-11) during the index event, or when lag-1, lag-2 or the mean of the 3 post-discharge days (instead of point estimation) of ambient temperature and AP were considered. Temperature and AP on the day of patient discharge are not independently associated with the risk of very early adverse events during the vulnerable post-discharge period in patients discharged after an AHF episode.