Partnerships, IT Solutions Improve Infectious Disease Diagnostic Stewardship

Appropriate use of testing is becoming a greater challenge, given the growing number of available diagnostic tests and their increasing complexity. While unnecessary or inappropriate testing can lead to wasted resources, unneeded tests can impact patient outcomes too, with potentially downstream repercussions including invasive medical workups or unneeded courses of antibiotics.

There is currently particular focus on the inappropriate use of testing tied to diagnosis and management of infectious diseases in hospitalized patients. Given concerns over antibiotic resistance, so called diagnostic stewardship—the process of ordering, performing, and reporting diagnostic tests to improve the treatment of infections and other conditions—is an area where laboratories, infectious disease clinicians, pharmacists, and leaders of antibiotic stewardship programs are working together to find solutions to improve test utilization management and interpretation of test results.

Diagnostic stewardship represents a convergence of interventions—preanalytic through postanalytic—that often rely heavily on information technology (IT) capabilities, such as clinical decision support, electronic ordering, and integration of laboratory results into electronic health records (EHRs).

DTET examined a recent sampling of studies demonstrating the impact of IT on laboratory test management.

EHR Alerts Can Change Physicians’ Ordering

Programming a hospital’s EHR to both inform providers on appropriate use of a costly gastrointestinal panel and to block unnecessary orders can substantially cut inappropriate testing, according to a study published April 23 in Infection Control & Hospital Epidemiology. Use of a simple hard stop alert in the EHR also was associated with significant cost savings.

Researchers hardwired University of Nebraska Medical Center’s EHR to provide informational best practice alerts, as well as a hard stop that prevented inappropriate orders for the FilmArray Gastrointestinal Panel (GIPP; BioFire; Salt Lake City, Utah). Alternative stand-alone testing is offered, if necessary, but an override of the GIPP hard stop requires approval of the microbiology laboratory director. Test order patterns were compared among patients hospitalized with diarrhea for whom GIPP testing was ordered pre- and post- implementation of the EHR intervention.

The GIPP test panel is useful for new patients who may have been exposed to a wider variety of pathogens, and holds the potential to improve antibiotic stewardship and cut back on serial testing, as well as labor-intensive stool culture methods. However, it may be overused in the inpatient setting, where the authors say, pathogens other than C. difficile and norovirus are uncommon. Inappropriate GIPP ordering was defined as more than one GIPP per admission or in patients hospitalized for more than 72 hours.

The researchers found that in the pre-intervention period, 1,587 GIPP tests were ordered over 212,212 patient days (a rate of 7.48 per 1,000 patient days) versus 1,165 GIPP tests over 222,343 patient days during the post-intervention period (5.24 per 1,000 patient days), yielding a 30 percent reduction in total GIPP ordering rates between the 2 periods. Additionally, the rate of inappropriate tests ordered decreased significantly from 21.5 percent to 4.9 percent. Over the 15 months, the estimated cost savings reached up to $168,000.

“Consistent with published literature, we found that stool testing in patients hospitalized for more than 72 hours or those who have previously been tested is unlikely to be clinically relevant, which suggests that restricting repeat GIPP testing in the inpatient setting is reasonable,” write the authors led by Jasmine R. Marcelin, M.D. “Our results highlight the value of diagnostic stewardship in antimicrobial stewardship programs and collaboration with the microbiology laboratory.”

Order Entry Format Impacts Urine Culture Testing

Computerized physician order entry (CPOE) format can play an important role in reducing the burden of unnecessary urine cultures, according to a study published in the March issue of Infection Control & Hospital Epidemiology.

Urinalysis and urine culture tests are often ordered for patients without clinical suspicion of urinary tract infection, leading to unnecessary testing, increased hospital costs, and unnecessary antibiotic treatment. Previous research shows that treatment of asymptomatic bacteriuria does not affect patient outcomes.

Researchers from Barnes-Jewish Hospital in St. Louis evaluated the impact of changes to urine testing orderables in the hospital’s CPOE system on urine culturing practices. A staged intervention to clarified test names and made changes to the urine reflex test panel. Urine culture rates were compared pre- and post-intervention among hospitalized adults who had at least one urine culture performed during their stay.

The researchers found that over the study period, 18,954 inpatients had 24,569 urine cultures ordered (11,780 during the pre-intervention versus 7,174 during the post-intervention period)— a 45.1 percent unadjusted decrease in the rate of inpatient urine cultures performed. In the post-intervention period, the urine culturing rate decreased significantly overall and for all specimen types, but the reduction in the urine culture rate was most marked for the catheterized (75.6 percent) versus clean-catch specimens (37.8 percent).

Overall, just over one-fourth of urine cultures (27 percent) were positive. There was a 16.4 percent increase in the proportion of positive urine cultures and a 6.9 percent decrease in the proportion of isolated urine cultures obtained.

“Our intervention resulted in an estimated cost savings of ~$104,000 for inpatient laboratory costs after implementation. This represents a fraction of the total costs and does not reflect the costs saved based on the medical decisions (e.g., delayed hospital discharge) and antimicrobial therapy,” write the authors led by Satish Munigala, from Washington University in St. Louis, Mo. “In an era of reducing reimbursement for clinical laboratory testing, the prudent use of common diagnostic tests in patient care is increasingly important.”

Partnership With Antimicrobial Stewardship Program Cuts C. Diff Testing

Implementation of a clinical review and preauthorization protocol led by antimicrobial stewardship program (ASP) can decrease inappropriate testing, according to a study published in the March issue of Infection Control & Hospital Epidemiology. Further, the multidisciplinary, multifaceted intervention reduced the hospital-onset (HO) C. difficile infection incidence rate (HO-CDI-IR) and antibiotic consumption.

Screening for C. difficile in asymptomatic patients is not recommended by consensus guidelines, in part because highly sensitive diagnostic technologies, such as nucleic acid amplification tests (NAATs) have a difficult time differentiating carriers from active infections. These false positives can drive unnecessary antibiotic treatment in asymptomatic patients.

The researchers from Northwestern Memorial Hospital evaluated whether a diagnostic stewardship initiative consisting of ASP preauthorization paired with education was effective at reducing false-positive, HO-CDI among patients admitted between Oc.1, 2016, and April 30, 2018. Patients admitted to the stem cell transplant unit were not included in the intervention and served as a control group.

ASP preauthorization occurred for hospitalized patients for whom a computerized provider order entry order for an NAAT was placed and a specimen was sent for testing to the clinical microbiology laboratory. The intervention required the prescriber to attest that diarrhea has met CDI clinical criteria, to confirm no medication could cause the diarrhea, and confirm no recent C. diff polymerase chain reaction test had been ordered. Data were compared 33 months before and 19 months after implementation.

The researchers found that over the entire 52-month period, the mean facility-wide HO-CDI-IR was 7.8 per 10,000 PD. The mean HO-CDI-IR significantly decreased from baseline during the intervention, while HO-CDI-IR in the noninterventional control unit did not change.

“Our findings demonstrate that ASP preauthorization coupled with individual provider education can meaningfully reduce clinical false-positive NAAT results while also decreasing antibiotic overuse,” conclude the authors led by Alyssa B. Christensen, Pharm.D., from Rosalind Franklin University in Chicago, Ill.

Takeaway: IT solutions are having an impact on infectious disease diagnostic stewardship. While system-wide benefits are seen, labs may notice decreased volumes post-implementation of these EHR-based solutions.