Comparison of seasonal pattern in patients with warfarin overdose

Objectives: The most common anticoagulant drug in the world is warfarin. Overdoses of warfarin may follow seasonal patterns, but the information is scarce. This study investigated possible seasonal variations in warfarin overdose among various age groups living in cold climates.Methods: This retrospective study was carried out on ۲۳۵ patients between ۲۰۱۴ and ۲۰۱۹ at Shahid Madani Hospital, Tabriz, Iran. The analysis was performed on the patients who had overdosed on warfarin and had INR (International Normalized Ratio) levels higher than four. After reviewing our database, we found seasonal patterns in admissions for overdoses caused by warfarin. The seasonality of access of patients older and younger than ۶۵ years of age was compared between the two groups. The independent t-test was used to compare the quantitative data, and the Chi-square test was used to compare categorical variables using SPSS V. ۲۰.۰ software.Results: Seasonal patterns were observed in warfarin overdoses. Warfarin overdoses were more common among the patients under ۶۵ years old during winter (P-value = ۰.۰۳), whereas almost identical findings were found among the patients ۶۵ and older, although numerically more cases were seen during the summer season (P-value = ۰.۸). Conclusions: The results of the current study showed that warfarin overdoses in the patients younger than ۶۵ years showed a seasonal pattern peaking in the winter months. However, these findings did not have any relation with older patients. To confirm the results of the present study, larger prospective multicenter studies in a variety of climate settings are needed.

Keywords:

Comparison , Warfarin , Drug overdose , Season Age