The Impact of Deep Vein Thrombosis on Outcomes in Critically Ill Patients: A Systematic Review and Meta-Analysis
Authors: Malato Alessandra , Lim Wendy , Siragusa Sergio , Cook Deborah , Crowther Mark A. 
Published: April 2020

Abstract
Background: The clinical consequences of Deep Vein Thrombosis (DVT) have the potential to be serious yet are frequently unrecognized in the Intensive Care Unit (ICU). We hypothesized that both undetected and clinically evident VTE would affect the prognosis of critically ill patients
Purpose: To systematically review whether a diagnosis of DVT in critically ill patients affects clinically important outcomes including length of stay, duration of mechanical ventilation and mortality.
Material and Methods: Data sources used were the MEDLINE, EMBASE and PUBMED databases. Studies selected evaluated one or more of the following outcomes: duration of patient stay in hospital and in ICU, hospital and ICU mortality, and duration of mechanical ventilation. Two investigators independently extracted and reviewed data from each study; including study and patient characteristics and outcomes. Statistical heterogeneity was evaluated using the I2 statistic; Cohen’s Kappa for inter-rater agreement was used to assess inter-rater reliability. Data was pooled using the Mantel-Haenszel method and a random effects model using Review Manager.
Results: Five studies were included in the systematic review. Patients diagnosed with DVT compared to those without DVT had increased ICU and hospital stay (7.3 days (95% confidence interval [CI] 1.4 to 13.2; P= 0.02) and 16.5 days (95% CI 1.51 to 30.59; P= 0.03), respectively. Duration of mechanical ventilation was increased by 3.41 days (95 % CI −1.12 to 7.94; P=0.14). Patients diagnosed with DVT also had increased relative risk (RR) for ICU mortality of 9.19 (95% CI 1.07 to 78.65, P=0.04) and a trend towards increased hospital mortality (RR 14.32 [95% CI 0.59 to 347.96, P = 0.10]).
Conclusions: A diagnosis of DVT upon ICU admission appears to affect clinically important outcomes including length of ICU and hospital stay and ICU mortality. Further research involving larger prospective study designs are warranted.
Outcomes Study Duration of mechanical ventilation in days (DVT/NO DVT) Hospitalization length In days (DVT/NO DVT) ICU Stay In days (DVT/NO DVT) Hospital mortality rate (DVT/NO DVT) n (%) ICU mortality rate (DVT, n/NO DVT, n) Legend PEPP: positive end-expiratory pressur * IQR ** median “ [95%CI]) ^ Necessity for ventilation measured by PEEP ≥10: DVT/no DVT: 11 (42%)/37 (21%) Ibrahim&#x2028; 2002 18.9±19.7/14.6±12.9M&#x2028; p=0.310 31.4±21.7/27.5± 18.2&#x2028; p=0.375 18.6±14.6/15.9±1.04&#x2028; p=0.388 8.9 (34.6%)/26.8(32.1)&#x2028; p=0.815 n/a Velmahos&#x2028; 1998 Not given. ^ 49±32/31±24, p=&lt; 0.05 34±31/19±18, p=&lt;0.05 n/a 31%,8.06/18%,31.2 Major&#x2028; 2003 n/a n/a n/a n/a 17%, 2/2%, 15&#x2028; p=0.03 Patel&#x2028; 2005 n/a 26**&#x2028; (14,49)*/− 6**&#x2028; (3,15)*/− 70**&#x2028; (28.5%) [22.8–34.1])″/− 16.7%,41 [12.0- 21.3]″/− Cook&#x2028; 2005 9** (4,25)*/6 (3,13)* &#x2028; p=0.03 51** (24,73)*/23 **&#x2028; (12,47)*&#x2028; p=&lt;0.001 17.5** (8.5, 30.5)*/9** (5,17)* 17 (53.1%)/85&#x2028; (37.4%)&#x2028; p=0.04 -, 8 **/−, 62**&#x2028; p=0.78