IVC Filters May Increase Mortality Risk in Patients With PE

Diana Phillips

December 11, 2018

Use of inferior vena cava (IVC) filters appears to offer no mortality benefit — and may confer a mortality risk — in older adults with pulmonary embolism (PE), a study has shown.

The results of the study, conducted by Behnood Bikdeli, MD, from the Division of Cardiology, Department of Medicine, New York–Presbyterian Hospital, Columbia University Medical Center, New York City, and colleagues, were published online December 10 in a research letter in JAMA Internal Medicine. The findings contradict those from previous analyses of administrative databases in which there was limited adjustment for potential confounders, they write.

The increased risk for death is consistent with the findings of an observational study that assessed 30-day mortality associated with the use of IVC filters in patients with venous thromboembolism (VTE), as reported by Medscape Medical News.

IVC filters are frequently placed in adults who have experienced acute PE or VTE to prevent a subsequent event, but evidence on the safety and efficacy of the practice is limited, the authors explain.

To determine whether mortality benefits observed in reviews of administrative databases persist after adjusting for baseline characteristics, they used Medicare inpatient claims data and ICD-9-CM diagnostic codes to identify and compare the outcomes of older patients with a principle discharge diagnosis of PE who had received an IVC filter and similar patients who had not. The researchers used an inverse probability weighted (IPW) adjustment scheme to account for potential imbalances in baseline characteristics. They created a matched cohort for patients with PE who had received an IVC filter and for those who had not, matching each of the individual characteristics exactly.

Of 214,579 Medicare fee-for-service beneficiaries (mean age, 77.8 years) who had been hospitalized for acute PE during the study period, 13.4% received an IVC filter. Compared with the no-filter group, the adjusted odds ratio of 30-day mortality in the filter group was 1.02 (95% confidence interval [CI], 0.98 - 1.06). The findings from the IPW analysis were statistically significant (OR, 1.16; 95% CI, 1.12 - 1.21).

Among the patients who survived longer than 30 days after admission, 20.5% in the filter group died within 1 year, compared with 13.4% in the no-filter group. After adjusting for patient characteristics, the odds ratio for 1-year mortality in the filter group was 1.35 (95% CI, 1.31 - 1.40). In the IPW model, the adjusted odds ratio was 1.56 (95% CI, 1.52 - 1.61).

In the individually matched cohort, 18.2% of the 76,198 beneficiaries who were hospitalized with acute PE received a filter. In mixed models in which IVC filter was used as the dependent variable, 30-day mortality was higher in the filter group (OR, 1.61; 95% CI, 1.50 - 1.73), as was 1-year mortality (OR, 2.19; 95% CI, 2.06 - 2.33).

The findings across each of the statistical adjustment methods do not indicate an association between IVC filter use and lower mortality, the authors report. "Instead, our study showed hypothesis-generating findings for increased risk."

Despite limitations imposed by the inherent uncertainty associated with the use of administrative claims for gauging the efficacy of health interventions and the potential "immortal time" bias, "these findings in combination with the paucity of evidence from trials raise concerns about the widespread use of these IVC filters," the authors write. More and better studies are needed to evaluate the efficacy and safety of IVC filters across various patient subgroups, they conclude.

The study was partially supported by grants from the National Heart, Lung, and Blood Institute and the National Institutes of Health. The authors have disclosed multiple relationships with government, academic, and advocacy organizations, which are listed on the journal website.

JAMA Intern Med. Published online December 10, 2018. Abstract

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