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Interleukin Publishes Large Study Involving PST Test to Stratify Patients at Risk of Gum Disease


The Journal of Dental Research has published data from a large study looking at whether twice-a-year dental checkups for patients deemed to be at low risk of gum disease based on a variety of risk factors, including Interleukin Genetics' genetic test, impacts tooth loss.

In the paper, entitled "Patient Stratification for Preventive Dental Care," researchers led by William Giannobile of the University of Michigan School of Dentistry retrospectively looked at insurance claims from more than 5,000 people over a 16-year period and investigated how smoking, diabetes, and the interleukin-1 genotype impacts tooth loss in patients who make preventive dental visits at various frequencies.

If patients had one or more of the risk factors, the study investigators classified them as being at high-risk of periodontitis, and at low risk if they had no risk factors. Among low-risk patients who visited the dentist twice a year, nearly 14 percent had a tooth loss event, while 22 percent of high-risk patients who had a single visit to the dentist experienced tooth loss.

In low-risk patients, the study authors found that tooth loss wasn't impacted based on whether the patient visited the doctor once or twice annually. "In high-risk patients, two preventative visits per year significantly reduced the number of patients who had events, in contrast to one visit per year," the authors wrote in the paper. In the study, there were 534 patients with two or three of the risk factors, of which approximately 68 percent were IL-1 genotype-positive smokers.

Currently, it is standard practice to recommend that people visit their dentist every six months for an examination and cleaning. Interleukin's PST test is aimed at identifying patients who are at low risk of gum disease and as such can do well by visiting the dentist once a year. By stratifying patients based on risk, Interleukin is hoping to provide a tool with which healthcare providers can manage costs more efficiently.

"Stratified or personalized medicine aims to achieve better outcomes for patients and optimal use of health care resources by integrating genomic, phenomic, and clinical information to predict disease susceptibility, clinical progression, and responses to prevention and treatment regimens; but practical translation requires sufficient clinical validity and utility to produce value for clinical adoption," Giannobile and colleagues wrote in the paper. "The present study may provide a proof-of-principle that resources could be targeted to selected groups for public health gain in the prevention of a chronic disease."

One of the limitations of the current analysis is that the researchers didn't have sufficient information in the insurance claims to discern why a patient had a tooth extracted. "Since tooth loss in adults is attributable primarily to PD and caries, we used dental extraction codes as an outcome that reflects the cumulative effects of both," the study authors noted.

Interleukin has been marketing PST as a lab-developed test since 2003. Quest's Oral DNA group holds a non-exclusive license to market the test.

Interleukin has been working closely with several dental insurance firms to finance the development and commercialization of PST. These insurers are interested in the test's potential to reduce healthcare costs by identifying which patients can forgo two dental visits since they are at low risk for gum disease.

Nationwide dental insurance firm Renaissance Health Service provided funding for the published validation study. Additionally, Delta Dental Plan of Michigan purchased 500,000 shares of Interleukin's preferred stock earlier this summer and Interleukin will use the $2.7 million net proceeds from this transaction to further commercialize PST (PGx Reporter 7/3/2012).