Venous thromboembolism (VTE) is potentially a fatal condition resulting in one in five deaths in people who are not treated for the condition It is one of the leading preventable causes of death globally, with a 1-year mortality rate of about 22%.Reference Lozano, Naghavi, Foreman, Lim, Shibuya and Aboyans1,Reference Søgaard, Schmidt, Pedersen, Horváth-Puhó and Sørensen2 It is estimated to affect nearly 10 million people worldwide.Reference Khan, Tritschler, Kahn and Rodger3 VTE-related morbidity is associated with a poorer quality of life and greater healthcare costs.Reference Chuang, Gumbs, van Hout, Agnelli, Kroep and Monreal4 VTE has an incidence of between 2 and 12% among older people within psychiatric in-patient settings.Reference Van Zyl, Wieczorek and Reilly5,Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6 VTE includes deep vein thrombosis (DVT) when a thrombus is formed within the veins of lower limbs, and pulmonary embolism, a serious consequence of DVT. Further, 43% of medically ill patients develop a silent pulmonary embolism and 7–33% have a fatal pulmonary embolism.Reference Anand, Wells, Hunt, Brill-Edwards, Cook and Ginsberg7–Reference Shi, Wang, Yuan, Su, Chen and Huang9 Although precise estimates of death among older psychiatric in-patients within mental health settings is not known, this is likely to be significantly higher than the above-mentioned fatality rates of one in five among all VTE-related deaths.
Risk factors
Surgical risk factors for DVT are well known, and the knowledge of medical risk factors is growing.Reference Lutsey and Zakai10 However, much less is known about risk factors for the development of DVT in psychiatric patients, particularly in older psychiatric in-patients. There is some evidence to link VTE with both psychotropic drugs and mental illness. Antipsychotics are reported to increase risk of VTE three- to four-fold.Reference Lacut, Le Gal, Couturaud, Cornily, Leroyer and Mottier11,Reference Wang, Yang, He, Jiang, Gao and Liu12 Patients who have been physically restrained or have a diagnosis of dementia are also more likely to develop VTE.Reference Fu, Liu, Xu, Wang, Shang and Ke13–Reference Therasse, Persano, Ventura and Tecco15 Additionally, many psychiatric in-patients have comorbidities that increase their risk of VTE.Reference Wilkowska, Kujawska-Danecka and Hajduk16 Although there may be an acute decline of mobility in surgical patients, there is also a progressive reduction of mobility in psychiatric patients with severe mental illness.Reference Therasse, Persano, Ventura and Tecco15 This reduced mobility may predate their hospital admission and their functioning within psychiatric hospital settings.Reference Wilkowska, Kujawska-Danecka and Hajduk16 International guidelines recommend that all mental health in-patients should have a VTE risk assessment on admission.17
We undertook a systematic review of the existing literature to establish current understandings of the specific risk factors and outcomes for VTE in older psychiatric in-patients, with the aims of (a) identifying risk factors for VTE in older psychiatric in-patients, (b) determining whether they are distinct from patients in general medical settings and (c) identifying any risk assessment tools that are specific for this patient group.
Method
Searches
We searched the following databases: Medline (1946–2023), EMBASE (1947–2023), PsycINFO (1984–2023), CINAHL (1976–2023) and the Cochrane Library (1993–2023) using predefined search strategy (Supplementary Appendix 1 available at https://doi.org/10.1192/bjb.2025.9). The search strategy was developed in conjunction with a librarian (Stuart Glover, Librarian at University Hospitals of Leicester NHS Trust). Searches were restricted to studies in English or where the translation in English was available. In addition, reference lists and citation indices of relevant papers were searched, and the PubMed related articles feature used to identify any further articles. This review was registered with PROSPERO under the registration number CRD42022352798.
Abstracts of articles identified by the search were screened independently by two reviewers (T.C., D.C.) and then full texts were independently reviewed (T.C., D.C.). There was only one disagreement within the studies obtained through data searches in relation to a study by Schmidt et al,Reference Schmidt, Horvath-Puho, Thomsen, Smeeth and Sørensen18 and this was resolved after a discussion with a third reviewer (I.S.).
Study selection
We included evidence from multiple study types, including longitudinal studies, randomised controlled trials, non-controlled trials, cohort, case–control, cross-sectional studies and observational studies. We included studies on older patients who developed DVT and pulmonary embolism in psychiatric in-patient settings. We defined ‘older’ as a person aged ≥65 years. We recorded the factors significantly associated with the occurrence of venous thrombosis in these studies.
Participants/population
We included studies of older people who had a documented DVT or pulmonary embolism in their records or had DVT/pulmonary embolism during their stay in psychiatric in-patient units, including dementia units and functional assessment units.
Inclusion criteria were as follows: individuals aged ≥65 years; individuals admitted to a psychiatric in-patient unit; individuals who developed DVT or pulmonary embolism, including those with a history of VTE; and individuals on prophylaxis for VTE during their hospital stay.
Exclusion criteria were as follows: individuals aged <65 years; those admitted to surgical wards or from within surgical or orthopaedic settings, as they represent an alternative patient group; and patients with trauma or recent fractures.
Intervention
Studies that evaluated prophylaxis used to prevent VTE, either mechanical or low-molecular-weight heparin, were included. We reviewed studies for presence of VTE (DVT or pulmonary embolism) as main outcomes. We investigated study author, title, year, setting and number of participants. We also examined patient characteristics such as age, gender, comorbidities, prophylaxis and risk assessment.
Data extraction
All articles were initially extracted into a Microsoft Excel spreadsheet. After screening through the titles and abstracts, 81 articles were retrieved for a detailed assessment. We excluded 72 articles for reasons as listed in the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flowchart (Fig. 1). No discrepancies in numerical data were found. Quality assessments were conducted independently by two reviewers (D.C., T.C.), against the Quality Assessment Tool for Observational Cohort and Cross-sectional Studies,Reference Downes, Brennan, Williams and Dean19 and disagreements resolved internally. The PRISMA flow diagram for papers in this review is presented in Fig. 1, and the checklist in Supplementary Fig. 1 available at https://doi.org/10.1192/bjb.2025.9.
Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flowchart.
Results
Search results
The search strategy identified 1030 articles, of which 19 were excluded as not being in English and 65 were duplicates. A total of 946 abstracts were further screened, and 83 articles retrieved. As noted in the PRISMA flowchart, 38 studies were further excluded as they had non-psychiatric patients and 16 studies included younger patients. There were seven reviews, three conference abstracts and eight case reports that did not meet our inclusion criteria. Two studies were not included as, despite all attempts, it was not possible to retrieve them from the searches. Only nine studies met all the criteria and were included in the review. More details of these studies are provided in the tables. Nine studies were initially identified.Reference Van Zyl, Wieczorek and Reilly5,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20–Reference Schmedt and Garbe27 Four other studies were identified through cross-referencing articles.Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6,Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Liu, O'Rourke and Van Nguyen28,Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 In total, we identified 13 studies that met our criteria.
Ten studies included patients from psychiatric in-patient units (summarised in Table 1), and three studies included patients from geriatric (physical health/acute care) units with psychiatric diagnoses (summarised in Table 2). Two studies were prospective in design,Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21,Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 and the rest were retrospective in nature, with cross-sectional assessment of patient records. Two studies were part of local trust audits to assess factors associated with VTE in older in-patients.Reference Van Zyl, Wieczorek and Reilly5,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20 The ten studies from psychiatric units included a total sample size of 101 458 in comparison with 5780 identified from geriatric settings. Schmedt and GarbeReference Schmedt and Garbe27 had the highest sample size of 72 591, followed by Wang et alReference Wang, Yang, He, Jiang, Gao and Liu12 with 12 939, Gaertner et alReference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 with 6218 and Ishida et alReference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22 with 5268. Other studies had lower sample sizes.
Study characteristics of psychiatric in-patients
VTE, venous thromboembolism; HRSD, Hamilton Rating Scale for Depression; HRSA, Hamilton Rating Scale for Anxiety; CE CT, contrast-enhanced computerised tomography.
Study characteristics, geriatric settings
VTE, venous thromboembolism; 5HT, 5Hydroxy tryptophan.
We performed a quality assessment of the included studies, using the National Institutes of Health (NIH) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.Reference Downes, Brennan, Williams and Dean19 Because of the heterogeneity of the studies included and two studies being retrospective in nature, only 11 studies could be qualitatively assessed. The quality assessment is summarised in Table 3. Because of the cross-sectional nature of the studies, most studies were limited in their quality, with only three studies being good.Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21,Reference Kleijer, Heerdink, Egberts, Jansen and van Marum23,Reference Schmedt and Garbe27
National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies
Rates of VTE
Ten studies provide occurrence rates of VTE in their populations. In psychiatric units, VTE rates ranged from 0.9 to 10.5%.Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21–Reference Kleijer, Heerdink, Egberts, Jansen and van Marum23,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25,Reference Liu, O'Rourke and Van Nguyen28,Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 Delluc et al found the incidence of VTE was higher in patients older than 75 years, at 8.2%, compared with a rate of 3.5% across all age groups. Weil-Engerer et al found VTE incidence was higher in acute in-patient settings compared with long-term units.Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21,Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 Yoshizawa et al found that 10.5% of patients with depression developed VTE, all of whom were asymptomatic.Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6 These high rates may be reflective of the authors screening all the patients for VTE, but may also possibly be a result of their stronger methodological approach. Table 4 shows comparison of sample sizes, VTE rates and risk factors between the studies from psychiatric and geriatric settings.
Comparison between psychiatric and geriatric studies
VTE, venous thromboembolism.
Age
Increasing age is an important risk factor for the development of VTE. Around 80% of studies included in this review note that older patients were at higher risk of developing VTE, and this was across both psychiatric and geriatric in-patient units.Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20–Reference Kleijer, Heerdink, Egberts, Jansen and van Marum23,Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 Weill-Engerer et al found the odds of VTE increased 1.5-fold over 10 years.Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 Some risk factors were age-related, as one study reported dementia as a risk factor for VTE only in patients older than 75 years of age.Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21 Wang et al noted that patients at risk of VTE tended to be older if they were diagnosed as having psychosis.Reference Wang, Yang, He, Jiang, Gao and Liu12 Interestingly, one study reported no association between age and the risk of developing VTE.Reference Liu, O'Rourke and Van Nguyen28 This difference might have been because of its small sample size.
Gender
Results were mixed regarding the association between gender and risk of VTE. Thus, four studies noted that women were at higher risk of developing VTE.Reference Van Zyl, Wieczorek and Reilly5,Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22,Reference Schmedt and Garbe27 Only one study reported higher rates of VTE in men (54%) compared with controls, but this result was not statistically significant.Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 Four studies did not report a link between the gender of patients and their risk of VTE.Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6,Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25,Reference Liu, O'Rourke and Van Nguyen28
Diagnosis
Psychiatric illness by itself is associated with higher risk of developing VTE. Rates of VTE occurrence differ based on psychiatric diagnosis. Wang et al noted the occurrence was highest in patients with organic mental illness (5.6%), followed by mood disorder (1.07%), schizophrenia (1.1%) and other mental health diseases, including neurotic disorder and substance-induced mental health disorders.Reference Wang, Yang, He, Jiang, Gao and Liu12 This was also reported by Delluc et al, who found that patients with dementia who were older than 75 years of age are were higher risk of developing VTE, with an incidence ranging from 8.2 to 12.5%.Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21 Additionally, there was an association between dementia in patients on old-age wards and the risk of developing VTE.Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20 In contrast, Liu et al found that wandering behaviour in dementia was associated with reduced risk of VTE, with 0.1% of patients with dementia developing VTE compared with 5.8% of patients without dementia (P < 0.07).Reference Liu, O'Rourke and Van Nguyen28
Depression was found to be associated with VTE in three studies.Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6,Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22,Reference Liu, O'Rourke and Van Nguyen28 Liu et al found patients with depression had higher risk of VTE compared with those without depression (6.3 v. 0.8%, P < 0.043).Reference Liu, O'Rourke and Van Nguyen28 One study reported that the severity of depression as rated by Hamilton Rating Scale for Depression (HRSD) score was associated with high risk of VTE, with an odds ratio of 1.22 (95% CI 1.08–1.3; P < 0.001).Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6 In keeping with this, Wang et al reported that higher HRSD scores were associated with VTE risk, whereas the Hamilton Rating Scale for Anxiety (HRSA) scores were found to be protective factors.Reference Wang, Yang, He, Jiang, Gao and Liu12
Catatonia was associated with increased risk of developing VTE. VTE was observed in 61.1% (11/18) of patients with catatonia, 4.1% (11/270) of restrained patients without catatonia and 1.2% (17/1393) of unrestrained patients without catatonia.Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25 This finding was replicated by Ishida et al, who also reported an association between catatonia and VTE, with an odds ratio of 5.84 (95% CI 2.69–12.70; P < 0.001).Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22 The remaining studies either did not record or did not identify any significant association between other mental illness and the risk of VTE.Reference Kleijer, Heerdink, Egberts, Jansen and van Marum23,Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29
Medication
The association between medication use and DVT reported mixed findings. In terms of antipsychotic use, most studies found no association between the use of antipsychotics and VTE.Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20,Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22,Reference Kleijer, Heerdink, Egberts, Jansen and van Marum23,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25,Reference Liu, O'Rourke and Van Nguyen28,Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 A nested case–control study of 111 818 patients with at least one antipsychotic drug prescription during 1998–2008 reported that current use of antipsychotics was not associated with the risk of VTE (odds ratio 0.9, 95% CI 0.7–1.1). The study found no difference between typical (chlorpromazine, chlorprothixene, periciazine, perphenazine, pipamperone) and atypical antipsychotics (risperidone, olanzapine, clozapine, quetiapine, aripiprazole, tiapride, sulpiride) in terms of risk of VTE.Reference Kleijer, Heerdink, Egberts, Jansen and van Marum23 In contrast, a large study found significantly increased risk of VTE for current antipsychotic use (odds ratio 1.23, 95% CI 1.01–1.50) and concurrent use of second- and first-generation drugs (odds ratio 1.62, 95% CI 1.15–2.27). They also note that the odds ratio was significantly elevated for patients who were newly prescribed antipsychotics within 90 days (odds ratio 1.63, 95% CI 1.10–2.40) of commencement of medication, but not for those who were already using antipsychotics (odds ratio 1.09, 95% CI 0.87–1.36).Reference Schmedt and Garbe27 Similarly, a case report of four patients who developed VTE while on risperidone noted an incidence rate of 5.2% in patients who received risperidone for a variety of psychiatric diagnoses.Reference Gallerani, Imberti, Mari, Marra and Manfredini24
None of the studies included in this review found any association between the use of antidepressants and the risk of VTE.
Takeshima et al converted administered antidepressants in imipramine equivalents into three groups: 0 mg/day, >0 mg and <150/day, or >150 mg/day, and compared them with the risk of VTE, although they did not specify the antidepressants prescribed. Thirty-five patients had received at least one antidepressant, and they found no association between the dose of antidepressant and VTE.Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25 With regards to use of other psychotropic medications, one study reported that the use of antidementia drugs was associated with the risk of VTE, both at day 10 and day 90 of admission, but found no association between the use of anxiolytics and sedatives and VTE. In this study, individual drugs and their doses were not specified.Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21
Mobility
Psychiatric patients can have immobility resulting from psychomotor retardation, catatonia, excess sedation or physical restraint. Three studies did not find any association between reduced physical mobility and the risk of VTE.Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20,Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 Weil-Engerer et al found that restriction of mobility (both the type and duration of immobility) was associated with patients developing VTE.Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 Additionally, Ishida et al noted that catatonia was associated with elevated risk of VTE in psychiatric in-patients.Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22 Takashima et al found that 61.1% (11/18) of patients with catatonia developed VTE, compared with only 4.1% (11/270) of restrained patients without catatonia and 1.2% (17/1393) of non-restrained patients without catatonia who developed VTE.Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25
Risk assessment
Studies included in this review employed different methods in the assessment of risk factors for VTE. One local auditReference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20 used the UK Department of Health VTE risk assessment tool. Liu et alReference Liu, O'Rourke and Van Nguyen28 used a risk assessment tool previously developed by Malý et al.Reference Malý, Masopust, Hosák and Konupcíková30 Liu et al categorised patients into three groups (low, moderate and high, based on VTE scores); 81.8% (157/192) were assessed as low risk and 18.2% (35/192) as medium/high risk.Reference Liu, O'Rourke and Van Nguyen28 Ishida et al developed their own screening tool with risk factors specific to psychiatric patients. This included factors such as age, gender, depressive episode, catatonia, active cancer, previous VTE and transfer from a general hospital, giving a score ranging from 0 to 14. A cut-off value of 2 had a sensitivity of 0.927, a specificity of 0.535 and a negative predictive value of 0.993. They reported that their tool was able to discriminate between patients with moderate to higher risk.Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22 Overall rates of screening and assessment for VTE were quite variable (5.9.24). Ellis et al reported that despite 30.6% of their sample being identified as at risk of VTE, only 4.3% had undergone risk assessment.Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20 This was even lower in an audit, where none of the patients underwent risk assessment at admission.Reference Van Zyl, Wieczorek and Reilly5
Prophylaxis
Most of the studies in this review either did not report use of thromboprophylaxis or the rates were low. In Delluc et al, only 0.4% of patients received prophylactic anticoagulation on the ward, whereas an audit found that none of their patients received any prophylactic measures.Reference Van Zyl, Wieczorek and Reilly5,Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21 The highest rates were noted in a cross-sectional study, where 16.7% (32/192) received VTE prophylaxis. This included thromboembolic deterrent (thrombo–embolus deterrent hose stockings alone, unfractionated heparin/low-molecular-weight heparin, or thrombo–embolus deterrent stockings combined with unfractionated heparin/low-molecular-weight heparin).Reference Liu, O'Rourke and Van Nguyen28
An audit in the UK recorded the reasons for not prescribing VTE prophylaxis for their patients. There were potential contraindications or concerns about prescribing VTE prophylaxis in 14.9% of patients. These included factors such as active self-harm, high risk of self- harm/previous self-harm and self-neglect, among others.Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20
Discussion
We identified 13 studies that assessed the risk of VTE in older psychiatric in-patients. The occurrence and risk factors for VTE are quite heterogeneous. We found that the prevalence of VTE among psychiatric in-patient settings ranged from 1 to 11%, which is higher than those for community-dwelling older adults (range estimates between 0.14 and 0.8%).Reference Wendelboe and Raskob31,Reference Naess, Christiansen, Romundstad, Cannegieter, Rosendaal and Hammerstrøm32 The rates we found were higher than those in a large cohort study that reported a hospital-acquired VTE incidence rate of 1.29%Reference Neeman, Liu, Mishra, Thai, Xu and Clancy33 and a DVT prevalence of 2.4–9.6% in post-surgical patients.Reference Danwang, Temgoua, Agbor, Tankeu and Noubiap34 Our findings are consistent with previous reports that suggest higher VTE rates within hospital patients compared with community-dwelling patients.Reference Heit, Spencer and White35
Age as a risk factor
We found that age is the most important risk factor in the development of DVT, with older patients being at higher risk in all in-patient settings. Advancing age was found to be an important risk factor for VTE, and risk increased exponentially with age, as reported in few community-based studies.Reference Naess, Christiansen, Romundstad, Cannegieter, Rosendaal and Hammerstrøm32,Reference Danwang, Temgoua, Agbor, Tankeu and Noubiap34,Reference Heit, Spencer and White35 In a population-based study, the incidence tripled every 15 years.Reference Naess, Christiansen, Romundstad, Cannegieter, Rosendaal and Hammerstrøm32 Weill-Engerer et al found that the odds of developing VTE increased by 1.5 times every 10 years.Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 The differences could be attributed to factors such as prolonged immobility in older populations, more cardiovascular comorbidities, malignancy and greater length of hospital stay for older patients.Reference Engbers, van Hylckama Vlieg and Rosendaal36–Reference Mackman40 Only one study, did not find any association between the age of the patient and risk of DVT, and this was from a single site and had a relatively small population sample size.Reference Liu, O'Rourke and Van Nguyen28
Diagnosis as a risk factor
Depression was found to be associated with higher risk of VTE in older patients, with severity of depression being proportionately linked with development of VTE. Similar results were found in other community-based studies.Reference Goldhaber8,Reference Lee, Liao, Lin, Liang, Sung and Kao41,Reference Kunutsor, Seidu and Khunti42 A metanalysis found that patients with depression were 1.31 times more likely to develop DVT. The higher risk for developing DVT in patients with depression may be attributable to factors like immobility, dehydration, poor nutrition and the use of antidepressants, although our review did not find risk associated with antidepressant drug use.Reference Kunutsor, Seidu and Khunti42 Our review establishes the association of catatonia with the risk of developing VTE, a finding noted elsewhere too, albeit in smaller case reports.Reference Lachner and Sandson43,Reference Sapota-Zaręba and Nasierowski44 However, these reports were for younger patients, and further research is needed to ascertain the relationship between catatonia and VTE in older patients.
Three studies report that patients with dementia were at higher risk of developing VTE.Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20,Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21 Previous studies have reported that patients with dementia are at higher risk of VTE, and it is a leading cause of mortality in these patients; this may be attributable to prolonged immobility and pre-existing comorbidities.Reference Nuñez, Villalba, Cebrián, Visoná, Lopez-Jimenez and Núňez45 Only one study found that dementia was associated with reduced risk of VTE, with wandering behaviour acting as a protective factor.Reference Liu, O'Rourke and Van Nguyen28
Although there are possible reported links between psychosis and VTE in the literature, these studies did not stratify patients according to their age groups.Reference Wilkowska, Kujawska-Danecka and Hajduk16 Our review in older patients shows only one study reporting such a link between the presence of psychotic symptoms and risk of developing VTE.Reference Wang, Yang, He, Jiang, Gao and Liu12 This was the only study that specifically looked for association of psychiatric diagnosis (such as organic mental disorders, dementias, affective disorders and psychosis) with VTE.
Medication use and VTE
The association between the use of antipsychotics and VTE risk is mixed. Two large-scale studies align with the findings of most of studies in this review, supporting that the use of antipsychotics is not associated with the risk of developing VTE.Reference Wolstein, Grohmann, Rüther and Hippius46,Reference Ray, Mamdani and Yeo47 On the other hand, two studies found a relationship between antipsychotic use and a possible risk of developing pulmonary embolism, and note an increased risk of VTE in patients treated with antipsychotics.Reference Gallerani, Imberti, Mari, Marra and Manfredini24,Reference Schmedt and Garbe27 Some of the previous community-based studies noted that the risk of VTE is higher in older patients using atypical antipsychotics or combination of antipsychotics.Reference Parker, Coupland and Hippisley-Cox48,Reference Liperoti, Pedone, Lapane, Mor, Bernabei and Gambassi49 A meta-analysis not specifically for older mental health in-patients concluded that irrespective of the type, use of antipsychotic increased the risk of developing VTE two-fold compared with the control population.Reference Zhang, Dong, Shao, Tan and Ying50 It is possible that mixed findings regarding the risk of VTE may be because the studies had patients with psychosis, which may be a standalone risk factor for VTE, and thus causes overestimation of the association between antipsychotic use and VTE. In their review, Zhang et al also included studies with patients who were younger, with high heterogeneity, possibly leading to such differing results. It is also likely that younger patients with psychosis may be on higher dose of antipsychotics, leading to a dose–effect relationship between use of antipsychotics and the risk of VTE.Reference Zhang, Dong, Shao, Tan and Ying50
None of the studies in this review found any association between the use and/or dose of antidepressants and the risk of VTE.Reference Yoshizawa, Takeshima, Ishino, Ogasawara, Fujiwara and Itoh6,Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25,Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 This is in contrast to the finding that patients on antidepressants have a 1.22-fold risk of developing VTE, but the studies that reported such findings included a younger population or female patients only, and found it to be a class-specific effect.Reference Kunutsor, Seidu and Khunti42,Reference Parkin, Balkwill, Sweetland, Reeves, Green and Beral51 The studies included in this review did not compare the types and classes of antidepressant and the risk of VTE. One study reported that the use of antidementia drugs was associated with the risk of VTE.Reference Delluc, Montavon, Canceil, Carpentier, Nowak and Mercier21 It is unclear whether this is an independent risk factor or a result of factors such as severity of dementia, presence of behavioural and psychological symptoms in dementia or the type of dementia itself.
Immobility as a risk factor
Physical immobility is a recognised risk factor for the development of DVT in medical and surgical patients, and is usually not associated with mobile psychiatric patients. Reduced mobility was identified as risk factor in three of our studies,Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25,Reference Weill-Engerer, Meaume, Lahlou, Piette, Saint-Jean and Sachet26 whereas three studies found no such association.Reference Wang, Yang, He, Jiang, Gao and Liu12,Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20,Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 A study reviewed listed various factors such as physical restraint, catatonia and psychomotor retardation as important risk factors for the development of VTE in psychiatric in-patient settings.Reference Van Neste, Verbruggen and Leysen52 One study found a close association between physical restraints and bedridden status with the risk of VTE and aspiration pneumonia. They found an association between retarded type of catatonia and risk of VTE, probably because of the combination of immobility and sedation.Reference Funayama and Takata53 Two studies in this review identified catatonia as a potential risk factor for the development of VTE, especially if patients were also physically restrained.Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25
Risk assessment and use of prophylaxis
In this review, we note that risk screening tools for VTE varied between settings. Two studies used existing VTE risk assessment tools, whereas one developed their own tools specifically for psychiatric patients.Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20,Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22,Reference Liu, O'Rourke and Van Nguyen28 Screening tools like the Wells score, which have been quite useful in medical settings, were found to be less reliable in psychiatric settings. One study noted that 84% of VTE-positive patients were considered as low risk by their Wells score.Reference Gaertner, Piémont, Faller, Bertschy, Hallouche and Mirea29 Hence using a tool designed with psychiatry-specific risk factors in mind might be more useful. Ishida et al developed a tool that reportedly has a high sensitivity and negative predictive value, but its specificity is limited, and it needs wider research within mental health settings.Reference Ishida, Shibahashi, Sugai, Abe, Hamabe and Kashiyama22
The VTE screening rates in the studies varied from 0 to 17.9%, and is in keeping with quite variable screening rates ranging between 18 and 38% reported in older adult wards.Reference Van Zyl, Wieczorek and Reilly5,Reference Takeshima, Ishikawa, Shimizu, Kanbayashi and Shimizu25,Reference Croxford, Clare and McCurdy54,Reference Powell and Jenkinson55 This is in contrast to 95% screening rates for National Health Service (NHS) acute care provider wards and 98% for independent sector providers as reported by NHS England figures.56 Although guidelines recommend that all mental health patients have VTE risk assessments on admission, the rates of assessment for DVT on the wards remain low, and this was recognised by the National Institute for Health and Care Excellence (NICE) in its technology appraisal of 2018.17 Factors cited for low uptake include ward pressures, staff changes and practicalities of pro forma use or lack of awareness among staff.Reference Croxford, Clare and McCurdy54
The rate of use of prophylactic anticoagulants reported in the studies conducted within mental health settings was very low (between 0 and 17.6%) in comparison with studies undertaken within acute care settings, where in more than one in two patients received DVT prophylaxis.Reference Bosson, Labarere, Sevestre, Belmin, Beyssier and Elias57 In one of the studies, 14.9% of patients within mental health settings had potential contraindications or concerns about prescribing VTE prophylaxis despite 20.8% of these patients being considered as having increased VTE risk. Unlike in acute care settings, contraindications like risk of self-harm and self-neglect are unique to psychiatric settings.Reference Ellis, Grubb, Mustoe, Watkins, Codling and Fitch20 Another reason for such low rates is limited knowledge of pulmonary embolism compared with DVT.Reference Croxford, Clare and McCurdy54 This differs from acute health care settings, where clinicians are more likely to be aware of cumulative risk factors, and hence more likely to administer prophylactic measures.Reference Samama58 This highlights the fact that that psychiatric patients warrant an individualised approach in screening and prophylaxis.
Strengths and limitations of the study
To our knowledge, this is the only systematic review to explore the risk factors associated with VTE in older psychiatric in-patients. This review also included patients from different countries, and so may be more representative. Despite a robust review of literature, we could identify only nine studies that looked at patients in psychiatric settings. Most studies had mixed younger and older patients, and the results were not age-stratified. Three of the studies were from single centres, and their results may not be generalisable. Two of the studies were part of local Trust quality improvement studies, and they did not detail the important risk factors.
To conclude, there appears to be a complex relationship between various factors in the development of VTE in elderly psychiatric in-patients. The only risk factor that is consistent is advancing age. Diagnosis and psychotropic medication use were inconsistent risk factors. Studies that show an association of VTE with psychotropic medication use suggest that the greatest risk is within the first 90 days of drug treatment, and this increases with combination treatment. There is some evidence that other than the standard risk profiles already described for VTE, depression in older psychiatric in-patients and the presence of catatonia may be additional independent risk factors within older people's mental health in-patient settings. For patients with dementia, physical restraint may pose an added risk of VTE. Screening tools for VTE in older patients in mental health hospital settings are used at variable rates. Questionnaire-based tools used in medical and surgical settings have low positive predictive value in psychiatric settings, but using blood investigations like a D-dimer assay and imaging modalities in a mental health setting may be neither practical nor cost-efficient. Future research may involve the development of a screening tool tailored to screen the risk of VTE in psychiatric in-patients, as they represent a very specific group and are distinct from patients in medical and surgical units.
About the authors
Damodar Chari is a specialist registrar in old age psychiatry at Leicestershire Partnership NHS Trust, Leicester, UK. Tamara Chithiramohan is a senior house officer in psychiatry at Leicestershire Partnership NHS Trust, Leicester, UK. Ina Sawhney is a consultant psychiatrist at Leicestershire Partnership NHS Trust, Leicester, UK. Elizabeta B. Mukaetova-Ladinska is a consultant psychiatrist at Leicestershire Partnership NHS Trust, Leicester, UK; and Professor of Old Age Psychiatry in the School of Psychology and Visual Sciences, University of Leicester, UK. Lucy Beishon is a higher specialist trainee in geriatric medicine at University Hospitals of Leicester NHS Trust, Leicester, UK; and an academic clinical lecturer in the Department of Cardiovascular Sciences, University of Leicester, UK. Hari Subramaniam is a consultant psychiatrist at Leicestershire Partnership NHS Trust, Leicester, UK; and an honorary senior lecturer in the School of Psychology and Visual Sciences, University of Leicester, UK.
Supplementary material
Supplementary material is available online at https://doi.org/10.1192/bjb.2025.9
Data availability
Data is available from the corresponding author, H.S., on reasonable request.
Acknowledgements
We thank Stuart Glover, Librarian at University Hospitals of Leicester NHS Trust, for his help with the literature searches.
Author contributions
H.S. conceived the project and the study design, and provided supervision. H.S., E.B.M.-L. and L.B. contributed to the literature review and writing the manuscript. L.B. and E.B.M.-L. were also involved in assessing the risk of bias and interpretation of the results. D.C. and T.C. did the literature review. D.C. did data extraction, assessed risk of bias, carried out the analysis and contributed to writing the manuscript. I.S. was involved in study selection, data extraction and analysis.
Funding
L.B. is an academic clinical lecturer funded by the National Institute for Health Research (NIHR). The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR, NHS or the UK Department of Health and Social Care.
Declaration of interest
None.
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