HIT Testing, In House vs. External Testing
The two most significant contributing factors to heparin-induced thrombocytopenia (HIT) are cardiopulmonary bypass surgery and hemodialysis, two diseases with vastly different treatment options and therefore vastly different treatment settings. Cardiology & Heart Surgery hospitals represent 9.9% of the hospitals in the United States and the rate of hospitals that might carry out HIT testing in the US, leaving the other 90% of U.S. hospitals to out-of-hospital testing and treatment.
We first looked at data on heparin-induced thrombocytopenia and U.S. hospital testing procedures to find out if this would shed any light on which hospital facilities if any, might be outsourcing their HIT testing. Our search led us to the American Heart Association's HIT in Cardiac Surgery report, and a HIT and in-hospital mortality rate article, as well as an article on the treatment and prevention of HIT from the CHEST Journal. These articles are used since these are the most recent and most relevant information available which discussed HIT testing in detail.
Next, we broadened our search to look at HIT and its testing labs. We chose this strategy to discover if non-hospital laboratories were performing HIT testing, and found two laboratories for testing HIT: LabCorp and ARUP Labs. These are U.S. based, off-site laboratories that test for HIT and explain their laboratory procedures, thus lending credence to the idea that there are hospital facilities that do not do HIT testing.
We also searched for hematology laboratories and the US markets to get an idea of the size of the non-hospital affiliated laboratory business market in the region. We hoped that this might give an idea of the number of hospitals or clinics using these facilities. A GlobeNewswire article reported the worth of the Clinical Laboratory, and a MarketWatch article predicted the market growth. However, neither of the reports went into detail about the number of hospitals or clinics that use the services of clinical laboratories.
In order to get the nearest possible number of U.S. hospitals that perform HIT testing in house, we calculated the number of HIT occurrences in the United States, obtained from using the research done on the prevalence of HIT occurrence rates in one hospital, Froedtert Memorial Luthern Hospital in Milwaukee, WI, and expanded that to all 6,210 hospitals in the United States. After determining the occurrence rate was approximately four per U.S. hospital, we then took the data from the Froedtert medical study, citing the primary causes of HIT as cardiopulmonary bypass surgery and hemodialysis. We used each illness and their treatment methods as a proxy to determine the rate of in-hospital or out-of-hospital treatment for HIT testing.
Our findings helped us to establish, through the occurrence rate and distribution of the major illnesses associated with HIT that, only a small percentage of HIT testing was carried out in hospitals, while the vast majority of HIT testing took place outside of U.S. hospitals. We thus concluded that the number of hospitals which perform HIT testing might be based on the prevalence of HIT. However, we were unable to find exact data on hospital procedures regarding heparin-induced thrombocytopenia, i.e., if the hospitals send out testing or if there is no testing done at all. All the source that we found went into detail about the testing procedures and testing results, but not where the testing was performed.
RATE OF HIT OCCURRENCE PER US HOSPITAL
Using the approximation that 1 in 1,500 hospital admissions are HIT-related, we obtain approximately 24,340 HIT contractions out of the total 36,510,207 US hospital admissions (36,510,207/1500).
Spreading the total number of US hospital admissions (36,510,207) over 6,210 hospitals equals approximately 5,880 admissions per hospital per year (36,510,207/6,210). For the 5,880 admissions per hospital divided by the rate of HIT occurrence equals 3.92 or approximately 4 HIT occurrences for every United States hospital per year (5,880/1500).
PERCENTAGE OF IN-HOSPITAL HIT TESTING
Since Heparin complication rates following cardiopulmonary bypass surgery represented the highest HIT according to the Froedtert Memorial Luthern Hospital study, it is proposed as a proxy for performing HIT testing in-house, on the assumption that cardiopulmonary procedures pose a particular HIT risk that would require monitoring and testing.
Of the 6,210 Hospitals, there are 613 Cardiology & Heart Surgery hospitals throughout the U.S., representing 0.0987 or approximately 9.9% [(613/6,210) x 100%], which conduct in-hospital testing for HIT. Thus, the vast majority of U.S. hospitals (90%), may send their out for the HIT test, i.e., [100% — 9.99% = 90.01%].
Hemodialysis care centers are proposed as a potential non-hospital source of HIT testing due to the Froedtert Memorial Luthern Hospital study which cites hemodialysis procedures as the second most significant contributor of heparin-induced thrombocytopenia.
NUMBER OF HOSPITALS IN THE UNITED STATES
According to the survey conducted by the American Hospital Association, there are 6,210 Hospitals in the United States and a total of 36,510,207 hospital admissions as of 2017. From the total number of US hospitals, there are 613 Cardiology & Heart Surgery hospitals.
NUMBER OF HOSPITALS TESTING FOR HIT
Patient data from Froedtert Memorial Luthern Hospital, Milwaukee, WI., reviewed heparin-induced thrombocytopenia (HIT) patients between 2009 and 2013 and identified 97,566 HIT patients out of over 150 million discharges, which constitutes approximately 1 in every 1,500 hospital admission. Of those patients, those that did a cardiopulmonary bypass had the highest rate of HIT (7,702 out of 1,230,362 patients). Patients undergoing hemodialysis had the second highest rate of HIT, with 23,012 out of 4, 908, 100 patients.
NON-HOSPITAL TESTING FOR HIT
There are approximately 4 HIT cases for every hospital in the US per year, and most of them are sent out for testing, as 90% of US hospitals do not conduct testing of HIT, and only 9.9% do.