Inferior vena cava filters may be overused in managed care populations, study suggests

Humana Inc. today announced research findings that suggest inferior vena cava (IVC) filters may be overused in managed care populations, and that filters may not always be removed after they are no longer needed.

The study, published in the Journal of Thrombosis and Thrombolysis, compared health outcomes between patients who received IVC filters and patients who were potentially eligible for filters but did not receive them.

IVC filters were developed for patients who are at risk of deep vein thrombosis (DVT) (a thrombosis is a blood clot) but are unable to receive anticoagulants for preventive treatment, either because they aren't effective for these patients or because of recent surgery or other contraindications.

During the procedure, the filter is placed in the inferior vena cava vein, the body's largest vein, and serves to catch clots migrating from other parts of the body before they can get to the heart or lungs and potentially cause a life-threatening condition called a pulmonary embolism (PE).

Though the filters are only recommended for patients who cannot use anticoagulants, the study found that anticoagulant use was actually greater in patients who had undergone filter placement than in patients who had not received filters. This finding implies that IVC filters are frequently used in cases that do not meet the criteria of clinical practice guidelines.

This is a cause for concern, as the study also found that patients who received filters experienced higher rates of subsequent hospitalization and hospital readmission than those without filters. Other publications in the medical literature reveal that many experts believe that IVC filters are used too often.

In general, IVC filters are designed to be removed when they are no longer needed. Removal is important because the filters themselves can eventually cause DVT. Complications such as filter migration are also possible.

In agreement with previous research on removal rates, the study found that filters were removed in only a small percentage of patients. Removal occurred in six percent of patients who received filters because of a history of DVT or PE, and 16 percent of those who had filters to prevent DVT or PE following surgery.

"Given that IVC filters were associated with greater rather than diminished use of anticoagulants, our research suggests that IVC filters may be overused," said Mitchel Seleznick, MD, MPH, lead author of the study and medical director, CarePlus, a Humana affiliate. "In addition, the low rates of filter removal indicate that patients may be at unnecessary risk of filter-induced DVT."

"These real-world findings confirm what previous research has reported for patients in academic medical centers," said Laura Happe, PharmD, MPH, director of research and publications at Humana. "This study, which joins a growing body of research, underscores the need for closer compliance with clinical practice guidelines for IVC filters."

In the United States, one or two of every 1,000 individuals develops either DVT or PE each year, and approximately one third of these cases will experience another DVT or PE within 10 years.

The study evaluated a managed care population with Humana health care coverage from 2013 to 2014. This included 435 recipients of prophylactic IVC filters, 4,376 recipients of therapeutic IVC filters, and two control groups, each matched to filter recipients.