The number needed to treat (NNT) is a simple measure of a treatment’s impact, increasingly reported in randomized trials and observational studies. It has been found to be incorrectly calculated in several studies involving varying follow-up times. We discuss the NNT in these contexts and illustrate the concept using several published studies. The computation of the NNT is founded on the cumulative incidence of the outcome. Instead, several published studies use simple proportions that do not account for varying follow-up times, or use incidence rates per person-time. We show how these approaches can lead to erroneous values of the NNT and misleading interpretations. For example, a trial of 3,845 very elderly hypertensives randomized to a diuretic or placebo reported a NNT of 94 treated for 2 years to prevent one stroke, though the correct approach results in a NNT of 63. We also note that meta-analyses involve trials of differing lengths, but often report a single NNT. For example a meta-analysis of 22 trials of the anticholinergic tiotropium in chronic obstructive pulmonary disease reported a NNT of 16 patients “over one year,” even if the trials varied in duration from 3 to 48 months, with the more specifically computed NNTs varying widely from 72, 15, and 250 for the 3-month, 12-month, and 48-month trials, respectively. Finally, we describe the value of the NNT in assessing benefit–risk, such as low-dose aspirin use in secondary prevention, where prevention of mortality was assessed against the risk of gastrointestinal bleeding. As the “number needed to treat” becomes increasingly used in the comparative effectiveness and safety of therapies, its accurate estimation and interpretation become crucial to avoid distorting clinical, economic, and public health decisions.
Pulmonary edema clearance is necessary for patients with lung injury to recover and survive. The mechanisms regulating edema clearance from the lungs are distinct from the factors contributing edema formation during injury. Edema clearance is effected via vectorial transport of Na+ out of the airspaces which generates an osmotic gradient causing water to follow the gradient out of the cells. This Na+ transport across the alveolar epithelium is mostly effected via apical Na+ and chloride channels and basolateral Na,K-ATPase. The Na,K-ATPase pumps Na+ out of the cell and K+ into the cell against their respective gradients in an ATP-consuming reaction. Two mechanisms contribute to the regulation of the Na,K-ATPase activity:recruitment of its subunits from intracellular compartments into the basolateral membrane, and transcriptional/translational regulation. Na,K-ATPase activity and edema clearance are increased by catecholamines, aldosterone, vasopressin, overexpression of the pump genes, and others. During lung injury, mechanisms regulating edema clearance are inhibited by yet unclear pathways. Better understanding of the mechanisms that regulate pulmonary edema clearance may lead to therapeutic interventions that counterbalance the inhibition of edema clearance during lung injury and improve the lungs’ ability to clear fluid, which is crucial for patient survival.
Feelings of guilt have tormented Holocaust survivors, ranging from immediately after the liberation to later in life, for shorter or longer periods, and persisting for some throughout their entire post-war lives. Descriptions of the guilt experienced by survivors of the Nazi camps occupy an impressive amount of literature: “Why me?” was the question, when a younger and more able family member perished; “Why me?” when more productive members of the community perished; “Why me?” when a million and a half children were deprived of their lives. Many found the answer by retelling their stories, witnesses of what happened. This type of guilt is much different from the recently described phenomenon of survivor syndrome, namely the secondary guilt felt by Nazi-persecuted Jewish writers. Despite successes in all aspects of their life, these writers developed a self-incriminating guilt due to their perceived inadequacy of communicating, particularly in light of the resurging anti-Semitism worldwide. This paper deals with the survival and suicides of Nazi-persecuted Jewish writers and offers a possible explanation for their late self-destructive acts.
During the past 50 years, a dramatic reduction in the mortality rate associated with cardiovascular disease has occurred in the US and other countries. Statistical modeling has revealed that approximately half of this reduction is the result of risk factor mitigation. The successful identification of such risk factors was pioneered and has continued with the Framingham Heart Study, which began in 1949 as a project of the US National Heart Institute (now part of the National Heart, Lung, and Blood Institute). Decreases in total cholesterol, blood pressure, smoking, and physical inactivity account for 24%, 20%, 12%, and 5% reductions in the mortality rate, respectively. Nephrology was designated as a recognized medical professional specialty a few years later. Hemodialysis was first performed in 1943. The US Medicare End-Stage Renal Disease (ESRD) Program was established in 1972. The number of patients in the program increased from 5,000 in the first year to more than 500,000 in recent years. Only recently have efforts for risk factor identification, early diagnosis, and prevention of chronic kidney disease (CKD) been undertaken. By applying the approach of the Framingham Heart Study to address CKD risk factors, we hope to mirror the success of cardiology; we aim to prevent progression to ESRD and to avoid the cardiovascular complications associated with CKD. In this paper, we present conceptual examples of risk factor modification for CKD, in the setting of this historical framework.
Introduction. The current study evaluated the rate of ependymal enhancement and whether its presence influences survival of patients with malignant glioma (GBM).
Methods. A retrospective review of all patients who were treated in our institution from 2005 to 2011 was conducted. Data extracted from the medical records included age, date of diagnosis, co-morbidities, treatment regimen, and time of death. Magnetic resonance images (MRI) were evaluated for the presence of ependymal enhancement and its extent, and the correlation to survival was investigated.
Results. Between 2005 and 2011, 230 patients were treated for GBM. Eighty-nine patients were excluded from the study due to insufficient data, leaving 141 patients for analysis. Median age at diagnosis was 60 years. Sixty-seven (40.6%) patients had evidence of ependymal enhancement on MRI (group A), and 70 (42.4%) patients did not have evidence of enhancement. The assessment of ependymal enhancement was inconclusive due to mass effect and ventricular compression that precluded accurate assessment for 28 (17%) patients (group C). Median survival was 14 months for group A (range, 12–16 months), 15.9 months for group B (range, 14.28–17.65 months), and 11.7 months for group C (range, 6.47–16.92 months) (P>0.05). A multivariate analysis to predict survival indicated that male gender (P=0.039), hypertension (P=0.012), and biopsy only compared to complete gross tumor resection (P=0.001) were significant for poor survival.
Conclusions. Pretreatment ependymal enhancement on MRI was not found to be associated with poorer survival. These results might be due to better treatments options compared to prior reports.
Medicine is developing through biomedical technology and innovations. The goal of any innovation in medicine is to improve patient care. Exponential growth in technology has led to the unprecedented growth of medical technology over the last 50 years. Clinician-scientists need to understand the complexity of the innovation process, from concept to product release, when working to bring new clinical solutions to the bedside. Hence, an overview of the innovation process is provided herein. The process involves an invention designed to solve an unmet need, followed by prototype design and optimization, animal studies, pilot and pivotal studies, and regulatory approval. The post-marketing strategy relative to funding, along with analysis of cost benefit, is a critical component for the adoption of new technologies. Examples of the road to innovation are provided, based on the experience with development of the transcatheter aortic valve. Finally, ideas are presented to contribute to the further development of this worldwide trend in innovation.
I appreciate Dr Walsh’s feedback regarding my recent article, “Teaching and Assessing Profession-alism in Medical Learners and Practicing Physicians.” I agree with Dr Walsh that quality improvement is a topic of importance within the professionalism domain. ...
Catheter ablation is a first-line treatment for many cardiac arrhythmias and is generally performed under X-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with sub-optimal success rates and prolonged radiation exposure. Pre-procedure 3-D magnetic resonance imaging (MRI) has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedures. A particular strength of MRI compared to other imaging modalities is the ability to visualize ablation lesions. Post-procedure MRI is now being applied to assess ablation lesion location and permanence with the goal of identifying factors leading to procedure success and failure. In the future, intra-procedure real-time MRI, together with the ability to image complex 3-D arrhythmogenic anatomy and target additional ablation to regions of incomplete lesion formation, may allow for more successful treatment of even complex arrhythmias without exposure to ionizing radiation. Development of clinical grade MRI-compatible electrophysiology devices is required to transition intra-procedure MRI from preclinical studies to more routine use in patients.
An anniversary is not only a point of memory—it provides the opportunity for self-examination and paves the way to the future. Every anniversary marks a starting-point that was preceded by a vision. The beginning of any vision is a personal dream—someone wants to improve or repair the world as far as he is able. The vision motivates action; in its aftermath comes the reality. This is the 21st issue of Rambam Maimonides Medical Journal. This issue is particularly important as it marks the completion of five years of creative work pursuing our vision for a high-caliber scientific medical journal. Our vision has become reality.
Background: Following the announcement of actress Angelina Jolie’s prophylactic bilateral mastectomies and subsequent prophylactic oophorectomy, there has been a dramatic increase in interest in BRCA testing and prophylactic surgery.
Objective: To review current medical literature on the benefits of prophylactic mastectomy and oophorectomy among BRCA-positive women and its permissibility under Jewish law.
Results: Recent literature suggests that in BRCA-positive women who undergo prophylactic oophorectomy the risk of dying of breast cancer is reduced by 90%, the risk of dying of ovarian cancer is reduced by 95%, and the risk of dying of any cause is reduced by 77%. The risk of breast cancer is further reduced by prophylactic mastectomy. Prophylactic oophorectomy and prophylactic mastectomy pose several challenges within Jewish law that call into question the permissibility of surgery, including mutilation of a healthy organ, termination of fertility, self-wounding, and castration. A growing number of Jewish legal scholars have found grounds to permit prophylactic surgery among BRCA carriers, with some even obligating prophylactic mastectomy and oophorectomy.
Conclusion: Current data suggest a significant reduction in mortality from prophylactic mastectomy and oophorectomy in BRCA carriers. While mutilation of healthy organs is intrinsically forbidden in Jewish law, the ability to preserve human life may contravene and even mandate prophylactic surgery.
