This meta-analysis is hindered by the suboptimal quality and homogeneity of studies available for assessment. Hospitalists should be aware of the limitations of the data and literature, as well as the empirical arguments raised by Dr. DeVita, when considering involvement in or designing RRS. TH
Kapoor AS, Kanji H, Buckingham J, et al. Strength of evidence for perioperative use of statins to reduce cardiovascular risk: systematic review of controlled studies. BMJ. 2006 Nov 6;333(7579):1149.
Recent literature and randomized trials have claimed statins decrease morbidity and mortality from cardiovascular events in patients with or at high risk of coronary artery disease. This meta-analysis sought to determine the strength of evidence leading to the recommendations that perioperative statins be used to reduce perioperative cardiovascular events.
The literature search and exclusion criteria identified 18 studies. Two were randomized controlled trials (n=177), 15 were cohort studies (n=799,632), and one was a case-control study (n=480). Of these, 12 studies enrolled patients undergoing noncardiac vascular surgery, four enrolled patients undergoing coronary bypass surgery, and two enrolled patients undergoing various surgical procedures. The 16 nonrandomized studies were rated good. The two randomized trials were rated five and two out of five using the Jadad quality scores.
The results showed that in the randomized trials the summary odds ratio (OR) for death or acute coronary syndrome during the perioperative period with statin use was 0.26 (95% confidence interval 0.07 to 0.99), but this was based on only 13 events in 177 patients and cannot be considered conclusive. In the cohort studies, the OR was 0.70 (95% confidence interval 0.57 to 0.87). Although the pooled cohort data provided a statistically significant result, these cannot be considered conclusive because the statins were not randomly allocated and the results from retrospective studies were more impressive (OR 0.65, 95% confidence interval 0.50 to 0.84) than those in the prospective cohorts (OR 0.91, 95% confidence interval 0.65 to 1.27) and dose, duration, and safety of statin use were not reported.
Limitations of this meta-analysis include that none of the studies reported patient compliance or doses of statins or cholesterol levels before and after surgery, and few reported the duration of therapy before surgery or the which statin was used. Thus, the authors were unable to demonstrate a dose-response association. They were also unable to ascertain if the benefits seen with statins in the observational studies were exaggerated owing to inclusion of patients in the nonstatin group who had their statins stopped prior to surgery, because acute statin withdrawal may be associated with cardiac events.
The authors concluded that although their meta-analysis—which included data from more than 800,000 patients—suggests considerable benefits from perioperative statin use, the evidence from the randomized trials is not definitive. They advocate only that statins be started preoperatively in eligible patients (e.g., patients with coronary artery disease, multiple cardiac risk factors, elevated LDL) who would warrant statin therapy for medical reasons independent of the proposed operation.
Electronic Alerts to Prevent Hospital-acquired VTE
Kucher N, Koo S, Quiroz R, et al. Electronic alerts to prevent venous thromboembolism among hospitalized patients. N Engl J Med. 2005 Mar 10;352(10):969-977
Surveys conducted in North America and Europe have shown that prophylaxis against deep venous thrombosis (DVT) has been consistently underused in hospitalized patients despite consensus guidelines. Studies involving continuing medical education and computerized electronic alerts have shown that physician use of prophylaxis improves when such processes are in place, but have not demonstrated that they can reduce the rate of DVT.