Archives For November 2012

While working on my current grant application, I was astounded by the prevalence of hearing impairment in the United States. Additionally, this begged a question: Is hearing impairment currently underdiagnosed, overdiagnosed, or neither? After perusing the literature, I found the answer to be fairly complicated. While it is believed that presbycusis (age-related hearing loss) is underdiagnosed in the U.S., the prevalence of hearing loss appears to be fairly high in this country when compared with worldwide statistics (over 30 million in the United States, with about 275 million around the world). Is this due to relatively better diagnosis in the U.S., or is there something else going on? Here, I’ll delve into that question, through the following measures:

  • Statistics on hearing impairment of all types in the United States
  • Statistics on hearing impairment of all types in various other countries
  • Comparison of screening and management in these regions

It is helpful to consider these basic data before moving on to determining any real differences between the countries. When discussing rates of change in prevalence or incidence of disease, it is helpful to first determine the effects of diagnostic bias. Nonetheless, I hope readers will leave with the impression that hearing loss is a major problem, one that will become more apparent as our population ages.

For the purposes of this post, remember that hearing loss is defined as a hearing threshold greater than 25 dB, where 0 dB is defined as the sound pressure at which young, healthy listeners hear that frequency 50% of the time. Functional impairment, however, is that which begins to impair the ability to understand conversational sound levels at 50-60 dB. A recent review of hearing loss in the United States estimated that over 10% of the population has bilateral hearing loss (>25 dB HL), and over 20% are estimated to have at least unilateral hearing loss. This staggering statistic increases to over 55% in those aged at least 70, increasing to nearly 80% by the age of 80. With an aging population in the United States, this becomes a major public health concern.

The causes of hearing impairment include genetic, drug-induced, and noise-induced hearing loss. With the increased use of overloud noise, noise-induced hearing loss has become more prevalent over time. However, nonsyndromic and syndromic genetic hearing loss accounts for about 50% of impairments in children. Remaining environmental causes include “TORCH” organisms and other neonatal infections. Nonetheless, the problem is a vast one, an issue that will grow as this population ages.

Considering the vastness of this problem, how well do we screen for it? The answer is that we do a poor job of it. Only 9% of internists offer screenings to those aged 65 and older, and only 25% of those with hearing impairment that could be treated with hearing aids actually use hearing aids. This is a failure in both screening and management. Thus, we must reiterate the prevalence of this health condition and do what we can to improve the current state of underdiagnosis and undertreatment. Thus, to answer the question above, we still do not do a stellar job in our screening of hearing loss.

How do we compare with other countries? Is hearing loss more prevalent in the United States, even though our screening programs are not ideal? It’s actually the opposite. Hearing loss is more prevalent in middle-income and lower-income countries, but the screening there is so poor that the numbers are staggeringly underreported. Compared with the rate of about 10%-20% in the United States, prevalence increases to over 25% in southeast Asia, 20-25% in sub-Saharan Africa, and over 20% in Latin America.  The WHO reports a value of about 275 million people with moderate to severe hearing impairment (note that the values listed above are for mild hearing impairment) and estimates that approximately 80% of this is in less wealthy nations. If we include all those with any type of hearing impairment (including mild, >25 dB HL), the number rises to 500-700 million people around the world (with 30-40 million in the United States). There is also very little information regarding hearing aid use in low and middle income countries (excluding Brazil), since many of these countries tend toward worse management than what we have in the United States.

When discussing the “global burden of disease,” hearing impairment hits the nail on the head. It is a health condition that affects all countries and in much the same way. Though there is a lower prevalence in high-income countries, consider that 1 in 5 people will succumb to some form of hearing loss. We must therefore implement increased standards for screening and management of this condition.


Flexner and Curricular Reform

November 19, 2012 — 1 Comment

While working with our medical school on curricular reform, an often-mentioned piece of literature is the Flexner Report.  Most, if not all, of those on the committees know what this is and what it entails. However, those with whom I have discussions about the reform outside of the committees are often left dumbfounded. Many understand the need to reform medical curricula, but far less know the history of its structure in the United States.

Prior to the 20th century, American medical education was dominated by three systems. These included an apprenticeship system, a proprietary school system, and a university system. Lack of standardization inevitably resulted in a wide range of expertise. Additionally, the best students left the United States to study in Paris or Vienna. In response, the American Medical Association established the Council on Medical Education (CME) in 1904. The council’s goal was to standardize medicine and to develop an ‘ideal’ curriculum. They requested the Carnegie Foundation for the Advancement of Teaching to survey medical schools across the United States.

Abraham Flexner, a secondary school teacher and principal not associated with medicine, led the project. In one and a half years, Flexner visited over 150 U.S. medical schools, examining their entrance requirements, the quality of faculty, the size of endowments and tuition, the quality of laboratories, and the teaching hospital (if present). He released his report in 1910. It was found that most medical schools did not adhere to a strict scientific curriculum. Flexner concluded that medical schools were acting more as businesses to make money rather than to educate students:

“Such exploitation of medical education […] is strangely inconsistent with the social aspects of medical practice. The overwhelming importance of preventive medicine, sanitation, and public health indicates that in modern life the medical profession is an organ differentiated by society for its highest purposes, not a business to be exploited.”

In response, the Federation of State Medical Boards was established in 1912. The group, with the CME, enforced a number of accreditation standards that are still in use today. They implemented a curriculum with two years of basic science curriculum followed by two years of clinical rotations as their ‘ideal’ curriculum. The quality of faculty and teaching hospitals were to meet certain standards, and admissions requirements were standardized. As a result, many of these schools shut down. Prior to the formation of the CME, there were 166 medical schools in the United States. By 1930, there were 76. The negative consequence was an immediate reduction in new physicians to treat disadvantaged communities. Those with less privilege in America also found it more difficult to obtain medical education, creating yet another barrier for the socioeconomically disadvantaged in America. Nonetheless, the report and its followup actions were key in reshaping medical curricula in the United States to embrace scientific advancement.

Today, medical schools across the country embrace the doctrines established 100 years ago. Most schools continue to follow the curriculum previously imposed. Scientific rigor is a key component. However, medical educators are currently realigning curricula to embrace modern components of medicine and to focus on the service component of medicine that is central to the doctor-patient relationship.

In 2010, the Commission on Education of Health Professionals for the 21st Century was launched, one century after the release of the Flexner Report. By the turn of the 21st century, gaps within and between countries were glaring. Health systems struggle to keep up with new infectious agents, epidemiological transitions, and the complexities and costs of modern health care. Medical education has once again become fragmented. There is a mismatch between aptitude and needs of populations. We focus on hospitals over primary care. Leadership in medicine is lacking. The interdisciplinary structure of medicine requires that we no longer act in isolated professions. As a result, a redesign of the curriculum is required.

The Commission surveyed the 2420 medical schools and 467 public health schools worldwide. The United States, India, Brazil, and China, each having over 150 medical schools, were the most heavily sampled. In contrast, 36 countries had no medical schools. Across the globe, it cost approximately US$116000 to train each medical graduate and $46000 for each nurse, though the number is greatest in North America. There is little to no standardization between countries, similar to the disjointed nature within the United States in the early 20th century. The globalization of medicine thus requires reform.

Reform of medical education did not stop with Flexner. After the science-based curriculum introduced by the report, the mid-20th century saw a focus on problem-based learning. However, a new reform is now required that seeks a global perspective. A number of core professional skills were recommended by the Commission, and these must be implemented in medical curricula across the globe.

Within the United States, medical educators seek to reform curricula to be more in-line with the global perspective of the modern era, focusing more on global health initiatives and service learning. Additionally, health care reform in America will bring with it new challenges, and medical school curricula must keep up. How this will be accomplished is still under heavy discussion.

When considering any reform, it is helpful to remind oneself of its historical context. In this case, the disjointed structure within the United States at the time of Flexner parallels the disjointed global structure of the world seen today. Though changes will be of a very different nature, motivations remain the same.

For those not aware, peer review is the process by which members of a field evaluate the work of other members in the same field as a form of regulation. This increases credibility and presumably quality within the field. For example, this can refer to review of manuscripts for publication, review of teaching methods by other educators, or the creation and maintenance of health care standards within the medical profession. In particular, scholarly peer review will be the main focus. The term is thus not very specific. I will focus on methods of peer review in publication and in the clinical setting for the purposes of this post. Issues relating to technical peer review in fields like engineering or standardization within education will not be discussed here. However, remember that “peer review” is a broad term encompassing many fields.

In 1665, Henry Oldenburg created the first scientific journal that underwent peer review, the Philosophical Transactions of the Royal Society. Peer review in this journal differed from the peer review we see today. Whereas professionals in the same field and often in competing labs will review today’s articles for publication, articles in this journal were reviewed by the Council of the Society. This journal created a foundation for the papers we see today, disseminating peer-reviewed work and archiving it for later reference. Peer review later developed in the 18th century as one where other professionals, often experts in the field, would perform the review as opposed to the editorial review of the aforementioned journal. This form of scholarly peer review did not become institutionalized until closer to the 20th century. However, professional peer review, such as that performed by physicians, dated back to the 9th and 10th centuries, where one physician would comment on the ethical decisions or procedures of another.

Since that time, scholarly peer review has become a mainstay of academic publication. It is amazing to think that this regulatory process has only been so strong for less than a century. However, the procedure does not come without significant criticism. (Though what topic in science is not heavily criticized?)

First, though, let us consider the benefits of scholarly peer review. Mentioned above was the improved quality of published work. Simply put, this works by first presenting a barrier that authors must overcome in order to get published, and critiques from reviewers are then addressed by authors to improve the quality of a manuscript. These suggestions may include additional experiments that will further test the work. The process filters out scientific error, thus improving accuracy of published information. Poor-quality work is rejected by the peer-review process. Additionally, work is stratified by journal quality, and this process routes papers to the correct tier. In total, peer review is at the heart of scientific critique.

One of the most common critiques of peer review is that it remains untested, as purported by a 2002 article in JAMA. The Cochrane Collaboration in 2003 (and reconfirmed in 2008) concluded that there existed “little empirical evidence to support the use of editorial peer review as a mechanism to ensure quality of biomedical research, despite its widespread use and costs.” Additionally, a study in BMJ took an article about to be published, purposely added a number of errors, and measured the error detection rate to be about 25%, with no reviewer correcting more than 65% of the errors. Finally, single-blinded peer review is open to bias. This could be bias against nationality, language, specialty, gender, or competition. Additionally, there is a common trend of bias toward positive results. Double-blinded review may help to overcome this critique.

Alternatives to single-blind review include double-blind review, post-publication review, and open review. In double-blind review, neither the authors nor the reviewers know the other party, and this would presumably reduce aforementioned bias. Surveys had shown a preference to double-blind review. Post-publication review would be an excellent supplement to the current review system to improve the rate of error correction in publications. Finally, open peer review, where the reviewer is known, would also possibly reduce the bias. However, one may be less willing to critique work by a senior author in the field, and the pilot by Nature in 2006 was far from successful.

At this stage, the system is the best we have, and problems lie less in the peer review process and more in the access to scholarly work without a costly subscription. Discontent in the field does not translate to a desire for one of the alternative methods described. Nonetheless, we should be critical of our process, much in the same way the process itself is critical.

Another kind of flood

November 2, 2012 — Leave a comment

Earlier this week, a large storm, whose pressure was at the level we would expect from a category four hurricane, threatened the east coast of the United States. This storm turned inland toward the coast of New Jersey, and its northern winds flooded the city of New York. The Jersey coast is still in disrepair, homes are flooded, power is down, many have been injured or killed, and thousands have been displaced.

Disasters occur every day. However, this particular one was enough to shut down the largest public transportation system in the United States, and an entire state has been pummeled. During a time when we see a country divided, I worried about the consequences of this storm. Would politicians use it for political gain? Would those in unaffected regions ignore the calamity and complain that their local grocery was out of poppyseed bagels? Would the cities be unable to handle such a situation? While some may fall into this category, the majority have not.

Hurricane Sandy brought with it torrential downpours and surges that flooded an entire region. However, the aftermath brought a flood of a different nature. Residents from around the region, country, and world helped in whatever way they could. I spoke with a few people who were in the British and Australian Red Cross divisions, who were visiting for vacation. They stopped the trip short and used their past experience to help us. Friends and classmates dedicated countless hours to volunteer at shelters, hospitals, and various cleanup efforts. Those with more than their share gave their excess clothing and money to those displaced by the storm. Politicians crossed the isle and worked together. Medical students sacrificed a few hours of study time to triage patients. Graduate students did what they could to comfort patients at our local hospitals. People from all walks of life came together and found their way to do what they were able to do best. I was amazed at the self segregation of volunteers based upon expertise or past disaster relief experiences. This demonstrated, in a surge of realization, the flood of humanity that outpoured when neighbors were in need.

For those who are currently affected, please know that you are not alone. For those that are not, call your friends and family. I need not say this, but it couldn’t hurt to remind everyone.

I will not write about my experiences in this storm other than to say that I am safe and that I am humbled by those who have been with me the past few days. I am proud of my neighbors, my city, and my country in times like this.

I will also not add any information on the science or educational aspects of the storm. I hope this will give readers a chance to reflect in the same way this post was a reflection.

The blog will return to its regular programming shortly.