PSD is a frequently observed neuropsychiatric complication among elderly individuals who have suffered a stroke. It is linked to adverse outcomes, including extended hospital stays, higher mortality rates, and delayed recovery. Factors such as advanced age, existing comorbid conditions, and stroke-related complications significantly elevate the risk of PSD, highlighting the importance of tailored preventive and management approaches. A large cohort of elderly stroke patients was examined to determine the incidence and risk factors associated with PSD. Our study determined an overall incidence of post-stroke delirium of 19.5% (Table 2), lower than the reported prevalence in the literature (30%) [21]. Besides, Doris et al. reported a 27.4% prevalence among stroke patients over 50 years old [22]. Discrepancies between studies may arise from limitations in prior research, such as small sample sizes and an overrepresentation of elderly patients. These factors may have led to an inflated estimation of delirium prevalence following acute stroke. Moreover, variations in diagnostic criteria and the accuracy of delirium identification across researchers and institutions may influence the reliability of reported outcomes.

Our study highlights the significant impact of post-stroke delirium on clinical outcomes. Patients with delirium experienced extended hospital stays (5 days vs. 4 days, p < 0.001), increased hospitalization expenses ($44,863 vs. $35,787, p < 0.001), and elevated in-hospital mortality rates (12.6% vs. 7.0%, p < 0.001) (Table 2). These results aligned with prior research indicating that delirium is a prevalent and severe complication in stroke patients, contributing to cognitive and functional decline, prolonged hospitalization, and increased mortality risk [23,24,25].

Our analysis revealed racial disparities, with Black and Asian/Pacific Islander patients demonstrating an increased risk of developing delirium (Table 3). These findings aligned with previous studies emphasizing racial disparities in health outcomes [26,27]. Factors such as cultural, socioeconomic, and healthcare access differences may contribute to these observed disparities. Our results suggest that demographic and clinical factors should be considered in the management of stroke patients to tailor individualized care strategies [28].

Multiple studies on post-stroke delirium have highlighted the critical role of early detection and intervention in managing risk factors to enhance patient outcomes [29,30]. Consequently, understanding these risk factors is essential for developing targeted interventions. Our findings are largely consistent with previous research and provide further insights into the predictors of post-stroke delirium. Logistic regression analysis indicated that individuals aged 80 years or older (OR = 1.237) had a significantly higher likelihood of developing delirium (Table 3). This finding aligned with prior research emphasizing advanced age as a critical risk factor for delirium [38]. The mechanisms underlying this association are complex and may involve age-related physiological changes in brain function, as well as increased susceptibility to metabolic disturbances during stroke recovery [39,40]. Furthermore, the likelihood of delirium was elevated in patients presenting with three or more comorbidities (OR = 2.05) (Table 3). This finding aligned with previous studies indicating that the presence of multiple comorbid conditions correlates with a poorer stroke prognosis [31,32]. Among these comorbidities, alcohol abuse (OR=1.126) and deficiency anemia (OR=1.150) were associated with delirium (Table 4), indicating that these conditions may exacerbate the neurocognitive decline in stroke patients [33,34,35].

As expected, fluid and electrolyte disorders exhibited the strongest association with post-stroke delirium, with an odds ratio (OR=1.902) (Table 4), corroborating prior evidence that fluid and electrolyte disturbances can affect neuronal function, impair the nervous system, and significantly increase the risk of delirium [36,34,37]. Moreover, a prior history of neuropsychiatric disorders, such as psychoses (OR = 1.765) and depression (OR = 1.236), was associated with an elevated risk of delirium (Table 4). This finding underscores the contribution of pre-existing brain pathology to delirium development [41,34,42]. Systemic comorbidities were also identified as independent risk factors. Renal failure (OR=1.059) and congestive heart failure (OR = 1.186) have been previously linked to delirium (Table 4), likely due to their impact on cerebral perfusion and metabolic stability [43,44,45]. These findings emphasize the necessity of optimizing comorbidity management to mitigate delirium risk and enhance the overall prognosis in elderly stroke patients. Although several risk factors, such as advanced age, prior neurological disorders, and psychiatric comorbidities, are non-modifiable, their identification remains clinically significant. Recognizing high-risk patients allows for targeted delirium prevention strategies, such as enhanced monitoring, early mobilization, and cognitive interventions.

Notably, our study identified private insurance as a protective factor against post-stroke delirium (Table 3). A potential explanation is that, among elderly stroke patients, private insurance often correlates with a favorable financial status, which may facilitate timely access to medical care. Delays in treatment are known to increase the risk of delirium, while adequate financial resources likely contribute to both its prevention and management. Moreover, logistic regression analysis identified elective admission as another protective factor (Table 3), as patients admitted electively tend to be in relatively stable condition. Elective admissions provide patients with the opportunity to prepare in advance, alleviating stress and anxiety upon hospital admission. This psychological stabilization may contribute to a lower incidence of delirium.

The occurrence of delirium was significantly influenced by post-stroke complications. Patients experiencing post-stroke complications such as dysphagia, pneumonia, urinary tract infection, and sepsis exhibited a higher risk of delirium (Table 5) [46,47,48]. The literature has consistently shown that other complications in hospitalized stroke patients tend to induce or worsen delirium [38,48]. Our findings suggest that the management of these complications should be prioritized in the prevention of post-stroke delirium [24].

While this research offers critical insights into the incidence and risk factors associated with post-stroke delirium, several inherent limitations must be acknowledged. The study’s retrospective design restricts our ability to establish causal relationships, and the use of administrative data may have contributed to underreporting or inaccuracies in the coding of variables such as delirium. Moreover, the study did not capture detailed information regarding patient-specific delirium management strategies, which could have influenced the observed outcomes. Additional prospective research is required to validate these results and investigate the mechanisms through which factors like age and comorbidities influence the development of post-stroke delirium.