Prevalence and risk factors of deep venous thrombosis of lower extremity in patients with stage Ⅲ and Ⅳ pressure ulcers on admission

Objective To investigate the incidence and risk factors of deep venous thrombosis (DVT) of lower extremity in patients with stage Ⅲ and Ⅳ pressure ulcer on admission.

Methods A retrospective case series study was conducted. A total of 241 patients with stage Ⅲ and Ⅳ pressure ulcers who met the inclusion criteria and were discharged from the Department of Wound Repair of the First People's Hospital of Zhengzhou from January 1, 2015 to December 31, 2019 were enrolled in this study, including 134 males and 107 females, aged 22 to 93 years, with a median age of 68 years; 37 patients were with stage Ⅲ pressure ulcers and 204 patients were with stage Ⅳ pressure ulcers. The DVT occurrence of patients was recorded. According to whether DVT of lower extremity veins was diagnosed by color Doppler ultrasound within 48 h after admission or not, the patients were divided into DVT group (n=37) and non-DVT group (n=204). Data of patients in the two groups were collected and compared, including gender, age, duration of pressure ulcer, time in bed, and combination with diabetes, hypertension, coronary heart disease, cerebral infarction, pneumonia, sepsis/septic shock, and paraplegia, and the plasma D-dimer level and Caprini score within 24 h after admission. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, chi-square test, and Fisher's exact probability test. The indicators with statistically significant differences between the two groups were analyzed with multivariate logistic regression analysis to screen the independent risk factors influencing the DVT of lower extremity in 241 patients with stage Ⅲ and Ⅳ pressure ulcers on admission.

Results The incidence of DVT of lower extremity was 15.4% (37/241), of which 86.5% (32/37) were asymptomatic DVT. Among the DVT of 46 lower limbs, only 29 involved the inferior genicular veins, accounting for 63.0%. There were no statistically significant differences in gender, duration of pressure ulcer, combination with diabetes, hypertension, coronary heart disease, cerebral infarction, pneumonia, and sepsis/septic shock of patients between the two groups (P>0.05), while there were statistically significant differences in age, time in bed, combination with paraplegia, the plasma D-dimer level and Caprini score of patients between the two groups(t=-3.19, Z=-2.04, χ²=4.44, Z=-3.89, t=-2.14, respectively, P<0.05 or P<0.01). Multivariate logistic regression analysis showed that age and plasma D-dimer level were independent risk factors influencing the DVT of lower extremity in 241 patients with stage Ⅲ and Ⅳ pressure ulcers on admission (with odds ratios of 1.03 and 1.18, respectively, with 95% confidence intervals of 1.00-1.06 and 1.05-1.33, respectively, P<0.05 or P<0.01).

Conclusions The patients with stage Ⅲ and Ⅳ pressure ulcers have a higher incidence of DVT on admission, with age and plasma D-dimer level being the independent risk factors for DVT of lower extremity. It is necessary to pay attention to the targeted screening of DVT and education of its prevention.