2 Minute Medicine Rewind February 13, 2017

Thromboprophylaxis after Knee Arthroscopy and Lower-Leg Casting

The use of thromboprophylaxis to prevent venous thromboembolism (VTE) after knee arthroscopy or casting of the lower leg is controversial. The purpose of this study was to compare the incidence of symptomatic venous thromboembolism after these procedures in patients who received no anticoagulation versus patients who received anticoagulant therapy. The authors conducted a two parallel, pragmatic, multicenter, randomized, placebo- controlled, open-label trials: 1) the POT-KAST trial which included 1451 patients undergoing knee arthroscopy and 2) POT-CAST trial which included 1435 patients treated with casting of the lower leg.  The primary outcome of interest included the overall incidence of symptomatic VTEs and major bleeding within three months after the procedure. Patients were assigned to receive either a prophylactic dose of low molecular weight heparin (LMWH) or no anticoagulant therapy. VTE occurred in 5 of the 731 (0.7%) in the treatment group and 3 of 720 (0.4%) patients in control arm of the POT-KAST trial (RR: 1.6; 95% CI: 0.4 to 6.8). Major bleeding occurred in 1 patient in the treatment group and 1 patient in the control group (95% CI: -0.6 to 0.7). VTE occurred in 10 of the 719 (1.4%) patients in the treatment group and 13 of the 716 (1.8%) patients in the control group (RR: 0.8; 95% CI: 0.3 to 1.7). No major bleeding events occurred in both trials. The authors concluded that prophylaxis with LMWH for eight days after knee arthroscopy or casting was not effective for the prevention of symptomatic VTE.

Comparative Effectiveness of Vancomycin and Metronidazole for the Prevention of Recurrence and Death in Patients with Clostridium difficile infection

Metronidazole is considered first-line therapy for patients with Clostridium difficile infection (CDI) but may not be as effective as vancomycin for durable cure. The purpose of this study was to evaluate the risk of recurrence and all-cause 30-day mortality in patients receiving either vancomycin or metronidazole for the treatment of mild to moderate and severe CDI. This is a retrospective cohort study which included data for 47,471 patients from the VA Healthcare System from 2005 to 2012. Of the total patients, 2,968 were treated with vancomycin and were matched to 8,069 patients treated with metronidazole. The patients were then subdivided into cohorts by severity of disease (5,452 patients with mild to moderate disease and 3,130 patients with severe disease). There was no difference in the risk of recurrence between patients treated with vancomycin compared to those treated with metronidazole in any of the disease severity cohorts. Among patients with any disease severity, those treated initially with vancomycin had a decreased risk of death (aRR 0.86; 95% CI:0.74 to 0.98). Vancomycin also significantly reduced the risk of all-cause 30 day mortality among patients with severe CDI (aRR 0.79; 95%CI: 0.65 to 0.97). The authors concluded that while recurrence rates were similar among patients treated with vancomycin and metronidazole, the 30-day mortality was significantly reduced among patients who received vancomycin. As a result, the authors justify the use of vancomycin as initial therapy for severe CDI.

Nicotine, Carcinogen, and Toxin Exposure in Long Term E-Cigarette and Nicotine Replacement Therapy Users: A Cross-sectional study

Because the use of e-cigarettes has been increasing, the purpose of this study was to compare exposure to nicotine, tobacco-related carcinogens, and toxins among 1) smokers of only combustible cigarettes, 2) former smokers with long-term e-cigarette use, 3) former smokers with only long term nicotine replacement therapy (NRT) use, 4) long term dual users of both combustible cigarettes and e-cigarettes, and 5) long term users of both combustible cigarettes and NRT. This was a cross-sectional study performed in London from January 2014 to June 2014 where researchers collected data from 181 participants divided into the aforementioned five groups (n=36 to 37 per group). The authors assessed sociodemographic and smoking characteristics in the five groups using a questionnaire. All participants also provided urine and saliva samples to be analyzed for nicotine, tobacco-specific-N-nitrosamines (TSNAs), and volatile organic compounds (VOCs). The authors found that metabolite levels for TSNAs were significantly lower in the e-cigarette use only or NRT only users compared to the three other groups (p<0.001). Levels of VOCs were also significantly lower in users of e-cigarette only or only NRT compared to the other three groups (p<0.001). The authors concluded that former smokers with long term e-cigarette only or NRT only were found to have generally similar levels of nicotine but had considerably reduced levels of measured carcinogens and toxins compared to users of combustible cigarettes. As a result, while e-cigarettes may be useful as an aid for smokers who have struggled to quit by other means, health benefits may not be obtained unless smoking of combustible cigarettes is completely ceased.

The Relationship of Obesity to Hospice Use and Expenditures: A Cohort Study

Although it is well known that obesity complicates medical care in severe illness with increased risk for hospitalization, higher use of intensive care units, and shorter life expectancy, its effect on hospice use and Medicare expenditures however remains unknown. The purpose of this study was to describe the association between body mass index (BMI) and hospice use/Medicare expenditures in the last six months of life. This retrospective cohort study of 5677 community dwelling Medicare fee-for-service beneficiaries who passed away from 1998-2012 studied the relationship between BMI and hospice enrollment, days enrolled in the hospice, in-home death, and Medicare expenditures was examined. The authors found that for decedents with BMI of 20kg/m2, the predicted probability of hospice enrolled was 38.3% (95% CI: 36.5% to 40.2%), hospice duration was 42.8 days (CI: 42.3 to 43.2 days) , probability of in-home death was 61.3% (CI:5934% to 63.2%), and total Medicare expenditures were $43,803 ( CI: $41,085 to $44,521). For patients with BMI and 30 kg/m2 and 40kg/m2 the predicted probability of hospice enrollment decreased by 6.7 percentage points (95% CI: -9.3 to -4 percentage points) and 15.2 percentage points (95% CI: -19.6 to -10.9 percentage points) respectively, hospice duration decreased by 3.8 days (95% CI: -4.4 to -3.1 days) and 4.3 days (95% CI: -5.7 to -2.9 days) respectively, and in-home death decreased by 3.2 percentage points (95% CI: -6.0 to -0.4 percentage points) and  6.3 percentage points (95% CI: -11.2 to -1.5 percentage points) respectively compared to decedents with BMI of 20kg/m2. In addition, patients with BMI of 40kg/m2 had mean total predicted expenditures that were $3471 (95% CI: $955 to $5988) higher than participants with BMI of 20kg/m2. The authors concluded that obesity was associated with reduced hospice use and in-home death and higher Medicare expenditures in the last six months of life.

Nd:YAG and pulsed dye laser therapy in infantile hemangiomas: a retrospective analysis of 271 treated hemangiomas in 149 children

Infantile hemangiomas (IH) are the most common benign vascular tumors in infancy. Although they often resolve spontaneously, some may require treatment due to ulceration or cosmetic impairment. While propranolol has been traditionally used in these cases, laser therapy may be a safe topical alternative. The purpose of this study was to assess the efficacy of combined Nd:YAG/pulsed dye laser (PDL) or PDL alone for therapy of IH. This was a retrospective study which evaluated the use of PDL and Nd:YAG/PDL in the treatment of 149 infants with 271 IH (84 IH treated with PDL and 187 IH treated with Nd:YAG/PDL). PDL was performed for solitary superficial hemangiomas while Nd:YAG/PDL was utilized for deeper lesions and clinical outcomes were evaluated by three different physicians based on improvement in clearance, color, thickness, or vascularization. Remissions were categorized as 0–25% (I), 26–50% (II), 51–75% (III) and 76–100% (IV). The authors showed that IH treated with laser demonstrated moderate-to-strong improvement in 92.4% of cases (91.1% in Nd:YAG/PDL and 95.6% in PDL). The relapse rate was 2% and the failure rate was 3.6%. In addition, an average of 1.74 treatments per IH were necessary (Nd:YAG/PDL: 1.95, PDL: 1.26). The most common adverse effect was blistering and crusting which was observed in 21.2% and 8.3% of cases respectively.

Image: PD

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