Ramadan and the risk of recurrent major adverse cardiovascular events — a nationwide cohort study
B Hummel, N Wilmes, N Kallouch, B Horreh, B Scheenstra, F Demirel, D Schalwijk, S Altintas, R de Boer, I van Valkengoed, C Ghossein-DohaAbstract
Introduction
The month of Ramadan, during which fasting is practiced by Muslims worldwide, may pose unique challenges for Muslim patients with cardiovascular disease (CVD). Changes in health-related behaviours, such as dietary habits, medication adherence, and sleep patterns, are known to influence the recurrence of major adverse cardiovascular events (MACE). However, current clinical guidelines do not address Ramadan, highlighting a significant knowledge lacuna.
Purpose
This study aimed to investigate whether Muslim patients with CVD residing in the Netherlands have a higher risk of MACE compared to non-Muslim patients, and whether this association is modified by Ramadan exposure.
Methods
We conducted a nationwide retrospective cohort study using data from Statistics Netherlands. Adults aged 30–75 years who were first hospitalized with MACE between 2013 and 2020 were included. Individuals originating from predominantly Islamic countries (Morocco, Turkey, Pakistan, and Egypt; countries with a prevalence of 90% Islamic religious affiliation) were classified as being presumed Muslim (PM), while individuals originating from the Netherlands with both parents originating from the Netherlands were classified as presumed non-Muslim (PNM). Individuals were followed for two years after the index event for the main outcome of recurrent MACE, defined as hospitalisation for ischemic heart disease, stroke, heart failure, or cardiovascular death, with administrative censoring after that time. The Ramadan period for each year was based on the Lunar phases. Age- and sex-adjusted Cox regression analyses assessed the association of Ramadan as a time-dependent variable with recurrent MACE, with an interaction term between Ramadan and religious affiliation to determine association differences between PM and PNM. Sensitivity analyses were performed in a subgroup using religious affiliation based on questionnaires.
Results
Among 451,138 individuals included in the primary analysis, 174,425 recurrent MACE events were observed during a mean of 1.3 person-years of follow-up. PM (n=18,283) had a significantly higher (HR 1.12 (95% CI 1.09–1.15)) overall baseline risk of recurrent MACE compared to PNM (n=432,855, p<0.001) outside the Ramadan period. Ramadan was not associated with an increased risk of recurrent MACE in PM (HR 0.99 (95% CI 0.93-1.05)) or in PNM (HR 1.01 (95% CI 0.93–1.05). Sensitivity analyses in a subgroup with better defined religious affiliation showed similar findings (n = 20,593, 8,477 events, interaction term p = 0.35).
Conclusion
Although baseline recurrence risk of MACE is higher in the presumed Muslim group than presumed non-Muslim group, this risk was not further increased during the month of Ramadan.