Originally published June 9.
NEW YORK (GenomeWeb) – Researchers from Genomind and elsewhere recently published a retrospective cost-effectiveness study reporting that when doctors used results from Genomind's Genecept Assay to help treat psychiatric patients, the patients appeared more adherent to medications, resulting in increased pharmacy costs compared to controls. However, for these more adherent patients, total medical outpatient services costs were lower than those patients treated without any genetic information.
Genecept is a saliva-based test that analyzes pharmacokinetic CYP450 genes, including CYP2D6 and CYP2C19, and pharmacodynamic genes SLC6A4, CACNA1C, DRD2, COMT, and MTHFR. The study, published in May in the American Journal of Managed Care, was funded by the company. "This is the first published study examining the Genecept Assay and its impact on resource utilization and medication adherence," Jay Lombard, CSO of Genomind and lead study author, said in a statement.
Researchers used patients' claims data between September 2010 to September 2012 to identify two cohorts – patients whose doctors ordered the Genecept assay and controls who were treated traditionally without the help of genetic testing. Using an initial group of 111 patients and 222 controls, researchers analyzed medication adherence and healthcare costs. In a replication study of 116 cases and 232 controls, investigators looked at just adherence.
Overall, the comparison showed that patients whose doctors ordered the Genecept Assay seemingly adhered more to their drugs than those in the control arm. The analysis showed that over a four-month follow up period, there was a 9.5 percent, or about $562, per-patient reduction in total medical costs compared to controls. Investigators estimated the cost of medicines and medical care using IMS Health data.
Lombard and colleagues noted in their paper that the design of the study enabled them to track whether patients were dispensing medications, not if they were actually taking them. Furthermore, based on patients' claims data, researchers identified whether doctors ordered the Genecept Assay, not whether they actually used the test results to guide treatment.
"The claims data utilized in this study may be suggestive of adherence, although one inherent limitation of claims analyses is that there is no way to definitively determine if a patient took the dispensed medication," they wrote. "In addition, the ability to assess the implementation of genetic information in clinician decision making was not possible."
Although this study suggests that Genecept may improve psychiatric patients' outcomes and reduce costs, Lombard and colleagues noted the need for a randomized-controlled trial to limit biases, better characterize the impact of genetic testing on patient outcomes, and identify populations that might most benefit from PGx information. The study authors employed statistical analysis (i.e. propensity score matching) to reduce bias since it was not a randomized study.
In the primary analysis, researchers found that over a four-month period those in the genetically-guided cohort had higher pharmacy costs, averaging $886 per patients, compared to $222 for controls. Although the drug costs were higher for cases, the amount of drugs dispensed was nearly 30 percent less than for controls. Over the study period, those who had the genetic test had 1.2 fewer outpatient visits compared to traditionally treated patients, resulting in a savings of $425 per patient at the doctor's office. Over the same period, controls had the same number of outpatient visits and their costs increased an average of $537 per patient.
"While pharmacy costs for cases increased, the utilization of medical services decreased, leading to a reduction in total outpatient costs for cases," Lombard and colleagues wrote in the paper. "The increase in pharmacy costs among cases is likely due to consistent medication fills concomitant with improved medication adherence."
Psychiatric patients with declining mental health tend to have poor adherence to medicines. Studies cited by Genomind report that 31 percent of schizophrenic patients and 33 percent of those with bipolar disorder have poor adherence to their drugs.
Moreover, there is substantial variability in the effectiveness of these agents between patients based on their genetics. Common pharmacogenetic variations in CYP450 and other markers can account for 40 percent of the inter-patient differences in antidepressant response. As many as two-thirds of patients don't respond to first-line anti-depression drugs, while around 30 percent become resistant to treatment.