Effect of Removing Outliers on Statistical Inference: Implications to Interpretation of Experimental Data in Medical Research

Background Data editing with elimination of “outliers” is commonly performed in the biomedical sciences. The effects of this type of data editing could influence study results, and with the vast and expanding amount of research in medicine, this effect would be magnified. Methods and Results We first performed an anonymous survey of medical school faculty at institutions across the United States and found that indeed some form of outlier exclusion was performed by a large percentage of the respondents to the survey. We next performed Monte Carlo simulations of excluding high and low values from samplings from the same normal distribution. We found that removal of one pair of “outliers”, specifically removal of the high and low values of the two samplings, respectively had measurable effects on the type I error as the sample size was increased into the thousands. We developed an adjustment to the t score that accounts for the anticipated alteration of the type I error (tadj=tobs-2(log(n)^0.5/n^0.5)), and propose that this be used when outliers are eliminated prior to parametric analysis. Conclusion Data editing with elimination of outliers that includes removal of high and low values from two samples, respectively, can have significant effects on the occurrence of type 1 error. This type of data editing could have profound effects in high volume research fields, particularly in medicine, and we recommend an adjustment to the t score be used to reduce the potential for error

Testing Educational Strategies for Shaken Baby Syndrome

Shaken Baby Syndrome (SBS) occurs from the violent shaking of an infant, which may lead to brain damage or death. The goal of this study was to assess educational methods used to teach new mothers about SBS

Postpartum Opioid Use Following Vaginal Deliveries with No or Minor Obstetric Perineal Lacerations

Background: Recommendations for management of pain following vaginal delivery are not specific and do not differentiate patients based on the degree of perineal trauma. Our objective is to describe patterns of postpartum opioid use in women with no or minor perineal trauma. Methods: This is a retrospective cohort study describing the characteristics of opioid analgesia usage among women with no or minor perineal lacerations at the time of vaginal delivery in a university affiliated regional hospital. Results: For the 6-month study period, 433 patients were eligible for inclusion. Of these, 423 (97.69%) were ordered as needed narcotics during their post-partum hospitalization. Of women with an as needed narcotic prescribed, 285 (65.82%) used at least one dose of narcotics while hospitalized. Significant patient characteristics of women using opioids during their inpatient post-partum course included those who used epidural analgesia during labor (p=0.009) and primiparous patients (p=0.05). Thirty-five of the women included in the study received a prescription for opioid analgesics at the time of discharge (8.08%). Significant findings among these women include increasing maternal age (p=0.007). Non-academic physicians with resident coverage were 3.1 times more likely to prescribe opioids at discharge compared to academic physicians with residents and non-academic physicians without resident coverage. Conclusions: Focusing specifically on women with no or minor perineal lacerations at the time of delivery, our findings indicate that if given the option of opioids analgesia during their hospitalization, many women will request at least one dose of opioid analgesia, but rarely require opioids after discharge

Physician and patient barriers to adherence with cholesterol guidelines

Several national studies have shown poor compliance with National Cholesterol Education Program II (NCEP) goals. A study we conducted of patients in the General Internal Medicine Clinic at the Marshall University Joan C. Edwards School of Medicine in Huntington showed that 46% of them were not at NCEP goals. We hypothesized that both patient and physician barriers were responsible for these findings so we administered two surveys about barriers to cholesterol management to 261 random patients identified with hypercholesterolemia and to all 50 residents and faculty at the clinic. We identified insufficient knowledge of low cholesterol foods as a patient barrier (31.6% of patients), and inadequate time to review NCEP guidelines as a physician barrier (45.5% of physicians). We conclude that many patients in our practice lack the knowledge of what foods are low in cholesterol and that our physicians may not use the NCEP guidelines because they are inconvenient to access in our clinic. Future research should explore ways to improve patient knowledge of low cholesterol foods and accessibility of guidelines for use during patient visits

Recognizing Guttate Psoriasis and Initiating Appropriate Treatment

Guttate psoriasis is a less common form of psoriasis. It manifests with numerous small, teardrop shaped, scaly plaques on the trunk and extremities. The etiology includes both environmental and genetic factors. It commonly arises 3-4 weeks following a beta hemolytic streptococcal infection. In some cases, it may be misdiagnosed as an allergy to the antibiotics being used to treat the streptococcal infection. The treatment of guttate psoriasis can vary by severity, but the mainstay treatment includes photo therapy and topical steroids. This case report presents the etiology, clinical findings and current treatment options of guttate psoriasis. It also discusses importance of differentiating guttate psoriasis from an antibiotic allergy. The confusion between the two can often delay and make treatment more difficult

Effect of Removing Outliers on Statistical Inference: Implications to Interpretation of Experimental Data in Medical Research

Background Data editing with elimination of “outliers” is commonly performed in the biomedical sciences. The effects of this type of data editing could influence study results, and with the vast and expanding amount of research in medicine, this effect would be magnified. Methods and Results We first performed an anonymous survey of medical school faculty at institutions across the United States and found that indeed some form of outlier exclusion was performed by a large percentage of the respondents to the survey. We next performed Monte Carlo simulations of excluding high and low values from samplings from the same normal distribution. We found that removal of one pair of “outliers”, specifically removal of the high and low values of the two samplings, respectively had measurable effects on the type I error as the sample size was increased into the thousands. We developed an adjustment to the t score that accounts for the anticipated alteration of the type I error (tadj=tobs-2(log(n)^0.5/n^0.5)), and propose that this be used when outliers are eliminated prior to parametric analysis. Conclusion Data editing with elimination of outliers that includes removal of high and low values from two samples, respectively, can have significant effects on the occurrence of type 1 error. This type of data editing could have profound effects in high volume research fields, particularly in medicine, and we recommend an adjustment to the t score be used to reduce the potential for error

Cardiomyopathy Secondary to Thyroid and Parathyroid Dysfunction: Case Report and Literature Review

Heart failure due to metabolic derangements is not common in clinical practice. However, outcome is usually positive given that the precipitating factor is recognized and treatment is initiated in a timely fashion. We report an unusual case of reduced left ventricular systolic function as a result of hypocalcemia and long standing untreated primary hypothyroidism in a patient without structural heart disease. Delay in seeking appropriate medical attention for both disorders has culminated in cardiac dysfunction that was favorably altered with correction of underlying etiologies. Therefore, early recognition and expedient management of hypocalcemia and hypothyroidism can result in an imminent improvement of cardiac function

Delaying Chemotherapy in the Treatment of Stage IV Non-Small Cell Lung Cancer Does Not Adversely Affect Survival Outcome

Background: Whether a delay in the initiation of chemotherapy for advanced non-small cell lung cancer (NSCLC) can affect overall survival is not well studied. We aim to evaluate the effect of the time interval between diagnosis and initiation of chemotherapy on overall survival in patients with stage IV NSCLC. Methods: A retrospective review of newly diagnosed stage IV NSCLC patients who received chemotherapy between 1995 and 2012 was conducted. Demographics, histology and site(s) of metastases of patients were reviewed. Time interval between the date of diagnosis and the date of starting chemotherapy was calculated in days. Patients were divided in two groups based on median time interval: Group A \u3c 46 days and group B \u3e 46 days. The primary end point was the difference in overall survival between the two groups. Results: A total of 172 patients were reviewed. Each group had 86 patients. Median age for both groups was 61 years. The most common histology was adenocarcinoma in A and B (43% vs. 45%, respectively). The sites of metastases in A and B were: brain (25% vs. 28%), liver (20% vs. 9%), bone (30% vs. 30%), respectively. Performance status of ECOG (Eastern Cooperative Oncology Group) :( 0-1) was 82% vs. 76% in A and B, respectively. The median overall survival for A was 7 months vs.12 months for B (p=0.04). Conclusion: In this single institution review, delayed chemotherapy for stage IV NSCLC more than 46 days did not have a detrimental effect on overall survival and even suggested a better outcome. Further larger and prospective studies are warranted to validate these findings

The Tri-State Experience: Outcome Analysis of Patients with Triple Negative Breast Cancer Treated at Marshall University

Breast cancer is the most frequently diagnosed malignancy in women in the United States. It is the second most common malignancy to cause death, with approximately 39,000 women dying of breast cancer in the United States in 2013. Triple negative breast cancer is defined as the absence of estrogen, progesterone and human epidermal growth factor receptor 2 receptors. It has been associated with a higher incidence in African American women, a younger age and a more advanced stage at diagnosis, and an inferior overall survival. To recognize the differences of our West Virginia community population when compared to the national average, we conducted a retrospective review of all patients diagnosed with breast cancer from 2000-2012

Effect of Student Involvement on Patient Perceptions of Ambulatory Care Visits

OBJECTIVE: To determine if patient satisfaction with ambulatory care visits differs when medical students participate in the visit. DESIGN: Randomized controlled trial. SETTING: Academic general internal medicine practice. PARTICIPANTS: Outpatients randomly assigned to see an attending physician only (N = 66) or an attending physician plus medical student (N = 68). MEASUREMENTS AND MAIN RESULTS: Patient perceptions of the office visit were determined by telephone survey. Overall office visit satisfaction was higher for the “attending physician only” group (61% vs 48% excellent), although this was not statistically significant (P = .16). There was no difference between the study groups for patient ratings of their physician overall (80% vs 85% excellent; P = .44). In subsidiary analyses, patients who rated their attending physician as “excellent” rated the overall office visit significantly higher in the “attending physician only” group (74% vs 55%; P = .04). Among patients in the “attending physician plus medical student” group, 40% indicated that medical student involvement “probably” or “definitely” did not improve their care, and 30% responded that they “probably” or “definitely” did not want to see a student at subsequent office visits. CONCLUSIONS: Although our sample size was small, we found no significant decrement in patient ratings of office visit satisfaction from medical student involvement in a global satisfaction survey. However, a significant number of patients expressed discontent with student involvement in the visit when asked directly. Global assessment of patient satisfaction may lack sensitivity for detection of dissatisfaction. Future research in this area should employ more sensitive measures of patient satisfaction