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Risk assessment important in VTE prophylaxis for medical inpatients

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Hospitalized nonsurgical patients (medical patients and those with acute stroke) should receive pharmacologic venous thromboembolism (VTE) prophylaxis, unless the risk for bleeding outweighs the likely benefit, according to a new Clinical Practice Guideline from the American College of Physicians.

In a telephone interview with Reuters Health, Dr. Amir Qaseem at ACP, who worked on the guideline, said risk assessment is the key.

“The current practice is that the majority of hospitalized medical patients get VTE prophylaxis without going through the risk assessment,” he said. “The ACP is recommending that before you start VTE prophylaxis, it’s important to do the risk assessment for thromboembolism and bleeding in medical patients, including stroke patients. Don’t just give it to everyone. We need to make sure that the benefits outweigh the risk of bleeding.”

The ACP guideline recommends against mechanical prophylaxis. “The reason for that is we found evidence for very clinically important lower extremity skin damage with graduated compression stockings and they were not effective in preventing VTE or reducing mortality,” Dr. Qaseem told Reuters Health.

The ACP guideline on VTE prophylaxis in hospitalized medical patients, appearing in the November 1 issue of Annals of Internal Medicine, is based on a review of studies on the topic published from 1950 through April 2011. The review itself is reported in a companion paper in the journal.

The review found that in hospitalized medical patients, heparin prophylaxis does not reduce death rates in medical patients, but it does lead to fewer pulmonary emboli (odds ratio, 0.69), albeit with an increase in all bleeding events (risk ratio, 1.34).

In hospitalized acute stroke patients, heparin prophylaxis had no statistically significant effect on any outcome except for an increase in major bleeding events (odds ratio, 1.66).

When trials of hospitalized medical patients and those with acute stroke were considered together (18 studies; 36,122 patients), heparin prophylaxis reduced the incidence of pulmonary embolism (odds ratio, 0.70). The absolute reduction was three events per 1,000 patients treated.

However, heparin increased the incidence of all bleeding (risk ratio, 1.28) and major bleeding (risk ratio, 1.61), with an absolute increase of nine bleeding events per 1,000 patients treated, four of which were major bleeds.

A reduction in total mortality approached statistical significance (risk ratio, 0.93) in the combined analysis (absolute decrease, six deaths per 1,000 patients treated).

There was no difference in the benefits or harms with various types of heparin (unfractionated heparin, low-molecular weight heparin, or fondaparinux).

Mechanical leg compression stockings provided no benefit and caused side effects including skin damage (risk ratio, 4.02), an increase of 39 events per 1,000 patients treated.

Based on the findings in this review, Dr. Qaseem and the ACP Clinical Guidelines Committee make the following three recommendations.

1. Assess risk for thromboembolism and bleeding in medical (including stroke) patients prior to initiation of prophylaxis of VTE (Grade: strong recommendation, moderate-quality evidence).

2. Give pharmacologic prophylaxis with heparin or a related drug for VTE in medical (including stroke) patients unless the assessed risk for bleeding outweighs the likely benefit. (Grade: strong recommendation, moderate-quality evidence).

3. Do not use mechanical prophylaxis with graduated compression stockings for prevention of VTE (Grade: strong recommendation, moderate-quality evidence).

In addition, the ACP does not support the application of performance measures in medical (including stroke) patients that promote universal VTE prophylaxis regardless of risk.

“The evidence reviewed for the clinical recommendations in this guideline does not support routine prophylaxis of VTE in all medical patients and emphasizes the tradeoff in harms and benefits,” the report reads.

“Clinicians caring for these patients must assess the risks and benefits before deciding whether to initiate prophylaxis. In some cases, not prescribing VTE prophylaxis may be justified because the estimated tradeoff between potential risks and benefits is small or unclear.”

Performance measures targeting all patients are “inappropriate,” the ACP concludes. “Until we can better identify patients who truly benefit, performance measures that encourage VTE prophylaxis for all medical patients may encourage physicians to use prophylaxis in low-risk patients for whom the risks may exceed the benefit.”

Venous Thromboembolism Prophylaxis in Hospitalized Medical Patients and Those With Stroke: A Background Review for an American College of Physicians Clinical Practice Guideline

Venous Thromboembolism Prophylaxis in Hospitalized Patients: A Clinical Practice Guideline From the American College of PhysiciansAnn Intern Med. 2011;155:602-615,625-632.