Click here to listen to a recording of Dr. Nang's presentation.
Dr. Nang presented a large trial of warfarin vs. apixaban which was designed to prove the non-inferiority of apixaban for preventing stroke in atrial fibrillation. The primary efficacy outcome was a compound of stroke and systemic embolism, and the primary safety outcome was bleeding. They also analyzed their results for subtypes of stroke (ischemic vs. hemorrhagic) and bleeding (e.g. gastroinestinal, intracranial, etc.). The study was large, multi-centered, and used a randomized, double dummy design. The baseline demographic data they reported indicated highly successful randomization, and analysis was by intention to treat.
Their results showed that in their sample, apixiban was non-inferior to warfarin both in terms of reducing the risk of the primary outcome (HR 0.79 (0.66-0.95), P = 0.01) and in reducing the rate of major bleeding (HR 0.69 (0.6-0.8), P= <0.001). The reduced incidence of stroke appeared to accrue primarily from a reduction in hemorrhagic stroke relative to warfarin (HR 0.42 (0.30-0.58) P = <0.001).
Some important points were raised during the discussion. Dr. Flattery and Dr. Feeney both pointed out that, while the trial design and execution appear fairly impeccable based on the article, one should not ignore the extremely close involvement of the manufacturers. Primary analysis were performed at Bristol-Myers-Squibb, its representatives had a say in trial design, participated in the study design, and the investigators had an enormous variety of relations to an inordinate number of pharmaceutical companies, including BMS and Pfizer. Dr. Rose pointed out some sleight-of-hand at the end of the article: the trial was designed to prove non-inferiority; however, the investigators report that "apixiban was superior to warfarin in preventing stroke or systemic embolism, caused less bleeding, and resulted in lower mortality." All of these conclusions would require another study powered for superiority to demonstrate.
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| Fig 1. Hazard Ratios. Prevalence is on the Y axis, time on the X. |
Dr. Jafari: Association of Hospitalist Care with Medical Utilization After Discharge: Evidence of Cost Shift from a Cohort Study.
Click here to listen to a recording of Dr. Jafari's presentation
Dr. Jafari presented a retrospective cohort study which looked at length of stay, hospital charges, and post-discharge healthcare usage among Medicare patients who were cared for by hospitalists and those who were cared for by their primary care providers (PCP) while in the hospital.
The statistical analysis, which was rather baroque, appeared to show that the patients cared for by hospitalists stayed in the hospital for around a day less, that their hospitalization was cheaper by about $282.00, and that their post-discharge healthcare costs were higher by about $332.00 compared to patients whose PCP cared for them in the hospital. Moreover, hospitalist care was associated with a marginal risk of re-admission (OR 1.08), ED visits (OR 1.18) and a reduced chance of discharge home (OR 0.82).
Dr Green-Yeh noted that while these results may have some validity, time is not moving backwards and PCPs are not coming back into the hospital. She suggested that this study is more useful as a foil for policy discussion than an argument for returning to the "traditional" model of hospital practice. Dr. Remler saw a number of problems with the study, one of the foremost being that most of the included hospitals were teaching hospitals; this, he argued, disorts the results significantly, since the hospitalist movement began in community hospitals and has primarily flourished there.
Dr. Rose and Dr. Singh both pointed out that there was no analysis by severity of illness, which would seem to be a critical feature to consider given that general internists increasingly defer management of the sickest patients to hospitalists. Dr. Rose also pointed out that the present Medicare system reimburses hospitalization at a set rate based on DRG, whereas Medicare outpatient visits are reimbursed on a fee-for-service basis, creating an obvious incentive to shorten hospitalization at the expense of outpatient service utilization.
Dr. Flattery and Dr. Sackrin commented that another limitation of this study is that it doesn't account for the lost daytime productivity of a PCP working in a hospital. Dr. Feeney concluded by emphasizing that what this study really demonstrates is how important it is, when working in an inpatient environment, to strive for continuity of care with patients' outpatient doctors.
Dr. Ha: Venous Thromboembolism Prophylaxis in Hospitalized Patients: A Clinical Practice Guideline From the American College of Physicians
Click here to watch a recording of Dr. Ha's presentation - unfortunately, there's no audio.
Dr. Ha presented both a new guideline from the ACP on VTE prophylaxis, and the background evidence review which supports it. The new guideline (below) is based on a systematic review of the literature on heparin (unfractionated and low-molecular-weight) for the prophylaxis of VTE in medical patients and patients suffering from acute stroke.
The guideline contradicts conventional wisdom and many hospital's internal performance standards in questioning the utility and safety of generalized VTE prophylaxis with heparin products. However, the background paper is, as Dr. Feeney noted, even more pessimistic than the guideline. The authors conclude:
When considering medical patients and those with stroke together, low dose heparin prophylaxis may have reduced PE and increased risk for bleeding and major bleeding events and had no statistically significant effect on mortality. We interpret these findings as indicative of little or no net benefit.There were some other interesting features of the guideline and review. First, the authors make an implicit judgment about the cost-efficacy of low-molecular weight heparin as opposed to unfractionated. While they did observe an increased incidence of heparin-induced thrombocytopenia among patients given unfractionated heparin (which is generally given as the main reason to use low-molecular weight heparin), the incidence in both groups was so low that they suggested the decision as to which product to use should be made on the basis of "ease of use, adverse effect profile, and cost". Second, they found insufficient evidence to support the use of pneumatic compression devices to prevent DVT. Finally, the absolute effect sizes derived from their review were infinitessimal. The estimated that the number-needed-to-treat to prevent one pulmonary embolus in medical and stroke patietns considered ogether was around 333, and the number needed to cause a major bleed was 250. This suggests that for the vast, vast majority of medical patients, heparin products do absolutely nothing.
Dr. Green-Yeh commented that what is clearly needed, and unfortunately does not yet exist, is a validated tool for establishing VTE risk in medical inpatients based on risk factors. Some patients must benefit much more than others - but how the "assessment of the risk of VTE" recommended by the ACP is to be carried out is not at all clear. She also pointed out that this guideline ought to have major implications for pay-for-performance measures involving VTE prophylaxis, which presently are based on the nebulous and apparently wrong sense that heparin prophylaxis should be standard of care unless contra-indicated.
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