Image: PD. West Nile Virus
In this section, we will highlight the key high-impact studies, updates, and analyses published in medicine during the past week.
Targeting of Low-Dose CT Screening According to the Risk of Lung-Cancer Death
Analysis of data from the National Lung Screening Trial (NLST), a randomized trial comparing the efficacy of low-dose CT for lung-cancer screening with that of chest radiography in smokers, showed that low-dose CT screening has disproportionately greater benefits in preventing lung cancer deaths in patients at highest risk of lung-cancer deaths. The number of lung-cancer deaths per 10,000 person-years prevented by low-dose CT screening increased significantly across risk quintiles (0.2, 3.5, 5.1, 11.0, 12.0 for risk quintiles 1-5 respectively, P=0.01 for trend) with the number needed to screen to prevent one lung-cancer death decreasing from 5276 among the 20% of patients at lowest risk to 161 among the 20% at highest risk. Risk factors that were used to determine a participant’s lung-cancer death risk included age, BMI, family history of lung cancer, pack-years of smoking, years since smoking cessation, and emphysema diagnosis. These results speak to the benefits of a risk-based strategy for low-dose CT lung cancer screening.
Alpha Emitter Radium-223 and Survival in Metastatic Prostate Cancer
Radium-223 is an alpha emitter that selectively targets bone metastases. This phase 3 RCT, the Alpharadin in Symptomatic Prostate Cancer Patients (ALSYMPCA) study, included 921 patients who received 6 injections of radium-223 or placebo in addition to standard of care treatment. The intervention arm demonstrated significantly improved overall survival (median, 14.9 months vs. 11.3 months; hazard ratio, 0.70; 95% CI, 0.58 to 0.83; P<0.001), confirming previous results from an interim analysis. Results also showed benefit across all other secondary end points including time to first symptomatic skeletal event, time to increase in total alkaline phosphatase level, and time to increase in PSA level. Radium-223 displayed similar or fewer adverse events compared to placebo.
Medicare Part D utilizes private plan drug formularies whereas the Veterans Affairs uses its own formulary. This retrospective cohort study, which included 1,061,095 Medicare Part D beneficiaries and 510,485 veterans with diabetes, found that the rate of brand-name drug use in Medicare was 2-3 times that in the VA among these similar patient groups (35.3% versus 12.7% for oral hypoglycemics, 50.7% versus 18.2% for statins, 42.5% versus 20.8% for ACE inhibitors or ARBs, and 75.1% versus 27.0% for insulin analogues) with an estimated $1.4 billion (39%) in Medicare savings in 2008 if brand-name drug use rates had matched those of the VA.
This randomized trial, involving 268 patients with cardiac arrest, demonstrated that in comparison to patients receiving epinephrine and saline placebo during CPR, patients who received vasopressin, epinephrine, and methylprednisolone during CPR and stress-dose hydrocortisone in post-resuscitation shock had an improved rate of return of spontaneous circulation. The improvement lasted 20 minutes or longer (83.9% vs. 65.9%; OR, 2.98; 95% CI, 1.39-6.40; P = .005). Survival to hospital discharge was also improved in the vasopressin group.
This longitudinal trial included 47,979 intervention patients from 167 different ambulatory practices in Massachusetts that had adopted electronic health records (EHR) systems. It compared monthly healthcare costs for these patients with those of matched patients in similar clinic settings that had not adopted an EHR system. There was no significant difference in cost (pre- to post-implementation difference in monthly trend change, −0.30 percentage point; P = 0.135) but results favored savings (95% CI, $21.95 projected savings per member per month (PMPM) in savings to $1.53 PMPM in higher costs) in the EHR group. There was also a significant slowing in ambulatory cost growth (difference in monthly trend change, −0.35 percentage point; P = 0.012) with the most significant slowing being in radiology costs (−1.61 percentage points, CI, −2.26 to −0.95 percentage points; P < 0.001). The authors note that intervention communities were not randomly selected and that this study may therefore represent a best-case scenario.
Androgen Deprivation Therapy and Risk of Acute Kidney Injury in Patients with Prostate Cancer
This nested case-control analysis included 10,250 men with newly diagnosed non-metastatic prostate cancer. Cases were defined as patients found to have acute kidney injury (AKI) during follow-up after androgen deprivation therapy (ADT). Use of any ADT (gonadotropin-releasing hormone agonists, oral anti-androgens, combined androgen blockade, bilateral orchiectomy, estrogens, and combination of the above) was associated with a significantly increased risk of AKI (OR, 2.48, 95% CI, 1.61-3.82) with a rate difference of 4.43/1000 persons per year (95% CI, 1.54-7.33).
HERA is a randomized trial that included 5102 patients with HER2-positive early breast cancer who received adjuvant treatment with trastuzumab for 1 or 2 years after standard neoadjuvant chemotherapy, adjuvant chemotherapy, or both. There was no significant benefit between treating with 1 year vs. 2 years of adjuvant trastuzumab. Patients treated with 1-year of therapy had 367 events of disease-free survival out of 1552 patients. The 2-year therapy group recorded 367 events in 1553 patients (hazard ratio [HR] 0.99, 95% CI 0·85—1·14, p=0.86).
The 2012 West Nile Encephalitis Epidemic in Dallas, Texas
This investigation reports the epidemiologic, meteorological, and geospatial characteristics of the 2012 Dallas West Nile virus epidemic, which featured a large increase in incidence of West Nile neuroinvasive disease (incidence of 7.30 per 100,000 residents). The number of human cases was predicted by increased mosquito vector indices and more warm winter days with cases demonstrating a geographical distribution similar to that of previous years. These trends may be relevant for predicting outbreaks and guiding future prevention efforts.
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