Prevalence, determinants, and prognostic impact of polyvascular disease in patients hospitalised for atherosclerosis in Slovenia: a nationwide, retrospective cohort study.

Background: Polyvascular disease (PVD) is an increasingly recognised form of atherosclerotic cardiovascular disease (ASCVD) with heightened prognostic implications. This study aimed to comprehensively assess the prevalence, risk factors, and prognosis of PVD in Slovenia. Methods: We conducted an observational retrospective cohort study using national-level reimbursement data from The Health Insurance Institute of Slovenia between January 1, 2015, and December 31, 2023. The study considered all adults who were hospitalised for coronary, cerebrovascular, or lower extremity peripheral arterial disease with diagnoses defined using ICD-10 codes. Multivariate logistic regression was used to identify cardiovascular risk factors for PVD. Patients were grouped by the number of affected vascular beds. The primary outcomes were all-cause death, major adverse cardiovascular events (MACE), major adverse limb events (MALE), and major bleeding. In outcome analysis, a landmark of 90 days was considered. Cause-specific survival analysis was performed, and associations with the primary outcomes was assessed using univariate and multivariate Cox proportional hazards models, adjusting for demographics, cardiovascular risk factors, comorbidities, and prescribed medication. Findings: The study included 91,917 adults hospitalised for ASCVD. Of these, 85,703 (93.2%) had atherosclerosis in one vascular bed, 5878 (6.4%) in two, and 336 (0.4%) in three; the latter two groups (6214; 6.8%) were classified as having PVD. Traditional cardiovascular risk factors were strongly associated with PVD, with chronic kidney disease (odds ratio [OR] 1.96; 95% CI 1.81-2.11; p < 0.0001), diabetes (OR 1.57; 95% CI 1.48-1.66; p < 0.0001), and chronic obstructive pulmonary disease - a surrogate indicator of tobacco use (OR 1.56; 95% CI 1.40-1.74; p < 0.0001) emerging as the strongest predictors. Compared to patients with ASCVD in one vascular bed, patients with two affected beds had adjusted hazard ratios (HRs) of 1.24 (95% CI 1.09-1.42) for all-cause death, 1.51 (95% CI 1.24-1.83) for MACE, 2.52 (95% CI 2.08-3.05) for MALE, and 1.27 (95% CI 1.05-1.54) for major bleeding. Patients with three affected beds had adjusted HRs of 1.69 (95% CI 1.40-2.03), 2.70 (95% CI 2.23-3.28), 4.24 (95% CI 3.49-5.14), and 2.31 (95% CI 1.45-3.68), respectively. Interpretation: Patients with PVD face a high overall disease burden, with adverse event rates increasing in proportion to the number of affected vascular beds. Accurate assessment of individual risk profiles is essential, as patients with the highest baseline risk are most likely to benefit from intensified preventive strategies. Potential underreporting inherent in administrative claims data, along with our selective criteria for defining leading diagnoses, may have somewhat limited the number of identified patients with PVD. Nonetheless, even after adjusting for group size, comorbidities, and prescribed medication, PVD independently predicted not only all-cause death and ischaemic events but also major bleeding. Further research is needed to define optimal treatment strategies in this high-risk population. Funding: The Slovenian Research and Innovation Agency (ARIS).