Seasonal Variation in Hospital Admission for Acute Myocardial Infarction in Al-Diwanya City

The effects of environmental variations on the onset and course of cardiovascular events are not yet fully elucidated. A dramatic surge in the incidence of myocardial infarction was observed during early morning hours, accompanied by a notable increase in mortality from myocardial infarction during the winter months. The objective of this study was to ascertain the existence of a seasonal pattern in the admissions to cardiology intensive care units (CICU) for patients with myocardial infarction (MI) and to examine the mortality rate of these patients during their stay. Additionally, the study sought to elucidate the association between the season of admission to CICU for patients with MI and their socio-demographic characteristics and medical history.           

The present study was conducted in accordance with the following methodology.

 A cross-sectional study design was employed. The study population comprised 1,732 patients with myocardial infarction who were admitted to the CICU in four hospitals in Al-Qadisiya Province over the two-year period from 1 December 2023 to 1 Feb 2024.

The results of the study are as follows:

 The proportion of patients admitted to hospital during the winter, spring, summer, and autumn seasons was 36.7%, 19.5%, 21.2% and 22.6%, respectively. The mean age of patients was found to be 63.11 years (± 12.96). The proportion of patients over the age of 60 was 57.6%, the proportion of female patients was 50.3%, and 53.8% of patients resided in urban areas.

 The majority of patients (63.9%) were married, while the majority of those who were not employed (67.7%) were also married.

 As indicated by the patient's medical history, 49.3% of patients exhibited symptoms for a period of three hours prior to admission. Furthermore, 89.4% of patients remained in the CICU for a duration of less than three days. It is noteworthy that 77.7% of patients had not previously been admitted to the CICU. Additionally, 29.0% of patients were smokers, while only 7.3% of patients consumed alcohol. Thirty percent of patients exhibited a family history of IHD, while the mean outcome was as follows: 71.4% were discharged, and 28.6% died.

The present study revealed a significant association between the season of admission to the CICU and the patient's age (P-value < 0.003), sex (P-value < 0.001), and occupational status (P-value < 0.001).

In addition, a substantial correlation was identified between the season of admission and the duration of home-based care for each of the following:

- compliance at home (P-value < 0.001),

- previous admission to the CICU (P-value < 0.001),

- family history of IHD (P-value < 0.001), and

- patient outcome (P-value < 0.001). The findings of this study demonstrate that there is an absence of a statistically significant correlation between the season of admission and the following variables: residence, marital status of the patient, duration of stay in the CICU, and alcohol consumption or smoking.

Conclusion:

A seasonal pattern is evident in the admissions for myocardial infarction in the sample of data collection, with an increase in the number of cases in winter and a decrease in summer. The age of patients has been demonstrated to influence the effect of environmental factors on myocardial infarction. A substantial body of evidence has been found to demonstrate a clear correlation between the season of admission to the hospital and both sex and occupational status. A robust correlation was identified between the season of hospital admission and the duration of symptoms experienced in the home environment. This association remained consistent when controlling for prior admission to the CICU, family history of IHD, and patient outcomes.