Evaluation of seasonal and monthly variation and location of deep vein thrombosis.

Background: Deep vein thrombosis of the lower extremities is associated with a significant burden of comorbidities. Objectives: In this study, our objective was to investigate the presence of seasonal variation in deep vein thrombosis (DVT) and assess the location of the thrombus. Methods: Out of 8177 patients admitted to two university hospitals and referred to outpatient clinics, we included a total of 611 consecutive patients (316 females, 295 males) diagnosed with acute deep vein thrombosis in this retrospective study. The mean age of the patients was 59.35±18.49 years, ranging from 1 to 96 years. Patients were categorized into four groups by age. Results: DVT was found to be more frequent in the summer (n = 190 or 31%, p = 0.003) and specifically in August (n = 65 or 10.6%, p = 0.014), while it was least frequent in the spring (n = 128 or 20.9%) and in May (n = 40 or 6.5%). However, when comparing seasons, no significant differences were observed in terms of seasonal variation (p = 0.062) or monthly variation (p = 0.143). Conclusions: Contrary to previous studies, this study demonstrated a higher occurrence of DVT during the summer, particularly in August. However, it did not reveal a clear seasonal pattern. One plausible explanation for these findings could be the adverse winter conditions and transportation challenges within the province, which may result in fewer DVT patients being able to reach hospitals for timely treatment.