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Systematic reviews of observational studies of risk of thrombosis and bleeding in urological surgery (ROTBUS): introduction and methodology.

Tikkinen KA, Agarwal A, Craigie S, Cartwright R, Gould MK, Haukka J, Naspro R, Novara G, Sandset PM, Siemieniuk RA, Violette PD, Guyatt GH - Syst Rev (2014)

Bottom Line: Additional studies known to experts and studies cited in relevant review articles were added.The results will be incorporated in the upcoming European Association Urology Guideline on Thromboprophylaxis.PROSPERO CRD42014010342.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland. kari.tikkinen@gmail.com.

ABSTRACT

Background: Pharmacological thromboprophylaxis in the peri-operative period involves a trade-off between reduction in venous thromboembolism (VTE) and an increase in bleeding. Baseline risks, in the absence of prophylaxis, for VTE and bleeding are known to vary widely between urological procedures, but their magnitude is highly uncertain. Systematic reviews and meta-analyses addressing baseline risks are uncommon, needed, and require methodological innovation. In this article, we describe the rationale and methods for a series of systematic reviews of the risks of symptomatic VTE and bleeding requiring reoperation in urological surgery.

Methods/design: We searched MEDLINE from January 1, 2000 until April 10, 2014 for observational studies reporting on symptomatic VTE or bleeding after urological procedures. Additional studies known to experts and studies cited in relevant review articles were added. Teams of two reviewers, independently assessed articles for eligibility, evaluated risk of bias, and abstracted data. We derived best estimates of risk from the median estimates among studies rated at the lowest risk of bias. The primary endpoints were 30-day post-operative risk estimates of symptomatic VTE and bleeding requiring reoperation, stratified by procedure and patient risk factors.

Discussion: This series of systematic reviews will inform clinicians and patients regarding the trade-off between VTE prevention and bleeding. Our work advances standards in systematic reviews of surgical complications, including assessment of risk of bias, criteria for arriving at best estimates of risk (including modeling of timing of events and dealing with suboptimal data reporting), dealing with subgroups at higher and lower risk of bias, and use of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate certainty in estimates of risk. The results will be incorporated in the upcoming European Association Urology Guideline on Thromboprophylaxis.

Systematic review registration: PROSPERO CRD42014010342.

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Related in: MedlinePlus

Proportion of cumulative risk (%) of venous thromboembolism (VTE) and major bleeding by week since surgery during the first 4 post-operative weeks[19],[20],[24].
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Fig2: Proportion of cumulative risk (%) of venous thromboembolism (VTE) and major bleeding by week since surgery during the first 4 post-operative weeks[19],[20],[24].

Mentions: We provided procedure-stratified estimates for both risk of VTE and bleeding requiring reoperation in urological surgery. We chose one and four-week time frames for estimates of risks of thrombosis and bleeding because these are feasible and frequently chosen time frames for, respectively, shorter and longer term prophylaxis. For studies that did not report VTE estimates using these intervals, we modeled estimates—based on a literature search (Additional file 3)—using large-scale population-based studies (Amin, Beral, and Sweetland, personal communications) [19, 20] that have provided data regarding the timing of post-surgical VTE. These results are consistent with recent report using nationwide cystectomy data from the United States [21]. To calculate absolute risk of VTE by post-operative day, we calculated the mean values (of VTE risk) from the available studies [19, 20]. After assessing mean values for both studies and when calculating the final model for VTE (Figures 1 and 2), interpolated values were calculated using natural cubic spline interpolation [22] and R data analysis language [23]. When creating the model for timing of VTE (Figure 1), we used the thromboprophylaxis estimates from the population-based US study [17] where 81.4% had used either mechanical or pharmacological prophylaxis until discharge (i.e., 81.4% used for median of 4.5 days) and that 1.5% used from discharge (median discharge time 4.5 days) until median time of 35 days.Figure 1


Systematic reviews of observational studies of risk of thrombosis and bleeding in urological surgery (ROTBUS): introduction and methodology.

Tikkinen KA, Agarwal A, Craigie S, Cartwright R, Gould MK, Haukka J, Naspro R, Novara G, Sandset PM, Siemieniuk RA, Violette PD, Guyatt GH - Syst Rev (2014)

Proportion of cumulative risk (%) of venous thromboembolism (VTE) and major bleeding by week since surgery during the first 4 post-operative weeks[19],[20],[24].
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4307154&req=5

Fig2: Proportion of cumulative risk (%) of venous thromboembolism (VTE) and major bleeding by week since surgery during the first 4 post-operative weeks[19],[20],[24].
Mentions: We provided procedure-stratified estimates for both risk of VTE and bleeding requiring reoperation in urological surgery. We chose one and four-week time frames for estimates of risks of thrombosis and bleeding because these are feasible and frequently chosen time frames for, respectively, shorter and longer term prophylaxis. For studies that did not report VTE estimates using these intervals, we modeled estimates—based on a literature search (Additional file 3)—using large-scale population-based studies (Amin, Beral, and Sweetland, personal communications) [19, 20] that have provided data regarding the timing of post-surgical VTE. These results are consistent with recent report using nationwide cystectomy data from the United States [21]. To calculate absolute risk of VTE by post-operative day, we calculated the mean values (of VTE risk) from the available studies [19, 20]. After assessing mean values for both studies and when calculating the final model for VTE (Figures 1 and 2), interpolated values were calculated using natural cubic spline interpolation [22] and R data analysis language [23]. When creating the model for timing of VTE (Figure 1), we used the thromboprophylaxis estimates from the population-based US study [17] where 81.4% had used either mechanical or pharmacological prophylaxis until discharge (i.e., 81.4% used for median of 4.5 days) and that 1.5% used from discharge (median discharge time 4.5 days) until median time of 35 days.Figure 1

Bottom Line: Additional studies known to experts and studies cited in relevant review articles were added.The results will be incorporated in the upcoming European Association Urology Guideline on Thromboprophylaxis.PROSPERO CRD42014010342.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland. kari.tikkinen@gmail.com.

ABSTRACT

Background: Pharmacological thromboprophylaxis in the peri-operative period involves a trade-off between reduction in venous thromboembolism (VTE) and an increase in bleeding. Baseline risks, in the absence of prophylaxis, for VTE and bleeding are known to vary widely between urological procedures, but their magnitude is highly uncertain. Systematic reviews and meta-analyses addressing baseline risks are uncommon, needed, and require methodological innovation. In this article, we describe the rationale and methods for a series of systematic reviews of the risks of symptomatic VTE and bleeding requiring reoperation in urological surgery.

Methods/design: We searched MEDLINE from January 1, 2000 until April 10, 2014 for observational studies reporting on symptomatic VTE or bleeding after urological procedures. Additional studies known to experts and studies cited in relevant review articles were added. Teams of two reviewers, independently assessed articles for eligibility, evaluated risk of bias, and abstracted data. We derived best estimates of risk from the median estimates among studies rated at the lowest risk of bias. The primary endpoints were 30-day post-operative risk estimates of symptomatic VTE and bleeding requiring reoperation, stratified by procedure and patient risk factors.

Discussion: This series of systematic reviews will inform clinicians and patients regarding the trade-off between VTE prevention and bleeding. Our work advances standards in systematic reviews of surgical complications, including assessment of risk of bias, criteria for arriving at best estimates of risk (including modeling of timing of events and dealing with suboptimal data reporting), dealing with subgroups at higher and lower risk of bias, and use of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate certainty in estimates of risk. The results will be incorporated in the upcoming European Association Urology Guideline on Thromboprophylaxis.

Systematic review registration: PROSPERO CRD42014010342.

Show MeSH
Related in: MedlinePlus