The Epidemiology of MH in the United States and Two New MHAUS Programs of Interest

As I mentioned in my last blog, one of the important questions regarding MH is the incidence of and the mortality from MH. Two recent studies are addressing these questions. One has been published, the other is in review. The first was done by Dr. Eric Rosero and colleagues from the University of Texas Southwestern Medical Center, Dallas and was published in the journal Anesthesiology in January 2009.  The authors utilized a public national database of hospital discharges from a large number of hospitals. They used the database to find patients who were diagnosed with MH according to the standard International Classification of Diseases (ICD-9). The other study in final review is one that examined the NY State Hospital Discharge data base for cases of MH. This study is being done by a team from the Department of Anesthesiology at Columbia University (Drs. Guohua Li, Lena Sun and Ms. Joanne Brady) and myself.

Here are some of the highlights of both of these studies:

• One in every 100,000 hospital discharges is complicated by MH.
• There are about 500-600 MH cases per year in the US.
• MH occurs more often in males than females. 58% in the published study and almost 2/3^rds of cases in the NY state database.
• A significant percentage of the patients are adults. In the national study about 20% of patients with MH were children in the national study, while the NY state data did not reveal a difference in incidence between adults and children.

The study by Rosero and colleagues showed that the mortality from MH is about 5% where the patient was admitted for routine elective surgery.  However, the mortality from MH is 20% when the patient was transferred in to the hospital from either and ambulatory center or another hospital. The mortality from MH was higher in rural hospitals and hospitals located in the South.  These figures are much higher than previously reported.  The mortality from MH was 20% based on the NY State data. The problem with such data though is that one has to take on faith that the diagnosis of MH that is recorded in the patient record truly represents MH. Some physicians interpret a high fever from any cause as being MH.

Last year I presented information at the European MH meeting that supports the data published in Anesthesiology.   I analyzed the hotline reports for January 2006 through May of 2008 and culled out the cases that the hotline consultants thought were highly likely to be MH.  I then looked at the mortality from MH.  What I found was that the mortality from MH when it occurred in a hospital was about 7% (2 deaths in 28 cases), but when the MH cases started out of the hospital the mortality was 20% (3 deaths of 13 cases). Very similar to the study using a national database even though the numbers of cases that I investigated based on the hotline reports was rather low.
 
In other words, although the mortality from MH is higher than we would like in a hospital setting, it is unacceptably high when the episode begins in an outpatient setting.

Because we believe the hotline data, MHAUS, in cooperation with the Ambulatory Surgery Center Foundation, has begun   the development of guidelines for the care and transfer on an MH patient from an ambulatory surgery center or other non-hospital setting to a local acute care hospital.  Creating such a guideline requires input from multiple health care providers: surgeons and anesthesiologists who work in such settings, emergency medical responders (EMTs), emergency medicine physicians and the multiple specialized nurses that work in these facilities. We are well under way in the process using the expertise and experience of Dr. Marilyn Larach, who spearheaded the development of the MH clinical grading scale several years ago using a consensus development process.

However, once the guidelines are created, the educational programs for implementation will be challenging. This undertaking will have to include print material, web broadcasts, lectures and conferences, videos, slide shows and simulations. There are thousands of ambulatory surgery centers across the US. Training of EMTs generally does not include information concerning MH.  As I understand it, the basic EMTs may not give medications of any kind, while the advanced EMTs may do so under the direction of an emergency medicine physician or under protocol. The emergency medicine physicians do not deal with MH very frequently, may not have dantrolene easily available and may not have the treatment protocols for MH at hand.  We do not even know how many of the surgery centers who administer MH trigger agents even have dantrolene available.

Some of the accrediting agencies for ambulatory centers do require stocking of dantrolene and even annual MH drills. But not all such centers are accredited, because accreditation is voluntary. The time, effort and resources to accomplish our goals will be very substantial and will take many months. Nevertheless, the Board of Directors and all those associated with MHAUS are committed to reducing death and disability from MH wherever it may occur.

Furthermore, we are determined to better understand the actual incidence (number of actual cases of MH each year) as well as the prevalence (the number of people who are at risk for MH) through these powerful epidemiologic tools.

I would like to bring to your attention two other projects that we have recently completed.  The first is a video of an MH muscle biopsy.  With the assistance of the MH biopsy center at the Bowman Gray School of Medicine in North Carolina and the help of Dr. Joseph Tobin, the Chairman of the Department of Anesthesia, a hotline consultant and member of the MHAUS Board, a video of an actual muscle biopsy and contracture test will be posted on our web site for medical professionals and patients to use to clarify wheat is involved in an actual test should they be considering testing options for their patients or themselves.  The video will show describe how the muscle is harvested and how the test is performed.  Furthermore, the text will be displayed in multiple languages. Later this year, we will be adding audio to the video clip.  

Another project has been completed in partnership with the Genetic Alliance. Genetic Alliance aims to increase information and awareness of many inherited diseases. Two booklets will be published: one focused on helping MHS individuals and their family members share medical histories, including information related to MH susceptibility; the other focused on explaining genetics and health, with information on many inherited disease, including MH. The booklets are aimed at individuals who are not health care providers and have only a rudimentary knowledge of medical terminology and medical knowledge. Individual copies will be made available free of charge. We hope to receive feedback form the MHS community regarding these booklets.

You will learn more about these offerings through our e-Newsletter published every other month and archived on the MHAUS web site. If you do not currently receive the e-Newsletter, contact the MHAUS office, 607 674 7901 or e mail [email protected].

Thank you for your interest and let me know of your comments.