Using diagnostic stewardship to reduce rates, healthcare expenditures and accurately identify cases of hospital-onset Clostridioides difficile infection

Abstract

Objective: Lack of judicious testing can result in the incorrect diagnosis of Clostridioides difficile infection (CDI), unnecessary CDI treatment, increased costs and falsely augmented hospital-acquired infection (HAI) rates. We evaluated facility-wide interventions used at the VA San Diego Healthcare System (VASDHS) to reduce healthcare-onset, healthcare-facility-associated CDI (HO-HCFA CDI), including the use of diagnostic stewardship with test ordering criteria.

Design: We conducted a retrospective study to assess the effectiveness of measures implemented to reduce the rate of HO-HCFA CDI at the VASDHS from fiscal year (FY)2015 to FY2018.

Interventions: Measures executed in a stepwise fashion included a hand hygiene initiative, prompt isolation of CDI patients, enhanced terminal room cleaning, reduction of fluoroquinolone and proton-pump inhibitor use, laboratory rejection of solid stool samples, and lastly diagnostic stewardship with C. difficile toxin B gene nucleic acid amplification testing (NAAT) criteria instituted in FY2018.

Results: From FY2015 to FY2018, 127 cases of HO-HCFA CDI were identified. All rate-reducing initiatives resulted in decreased HO-HCFA cases (from 44 to 13; P ≤ .05). However, the number of HO-HCFA cases (34 to 13; P ≤ .05), potential false-positive testing associated with colonization and laxative use (from 11 to 4), hospital days (from 596 to 332), CDI-related hospitalization costs (from $2,780,681 to $1,534,190) and treatment cost (from $7,158 vs $1,476) decreased substantially following the introduction of diagnostic stewardship with test criteria from FY2017 to FY2018.

Conclusions: Initiatives to decrease risk for CDI and diagnostic stewardship of C. difficile stool NAAT significantly reduced HO-HCFA CDI rates, detection of potential false-positives associated with laxative use, and lowered healthcare costs. Diagnostic stewardship itself had the most dramatic impact on outcomes observed and served as an effective tool in reducing HO-HCFA CDI rates.

Fig. 1.

Timeline of interventions implemented to reduce C. difficile infection rates at the VA San Diego Healthcare System. Abbreviations: CDI = C. difficile Infection, FY = Fiscal Year.

Fig. 2.

Number of diagnosed HO-HCFA CDI cases identified using stool C. difficile toxin B gene NAAT from FY 2015 to FY 2018 including false positives associated with the initiation or escalation of laxatives. *P ≤ .05 or NS, no statistical significance by Mann Whitney U test comparing the number of monthly HO-HCFA cases identified in FY2015 to FY2017 and FY2017 to FY2018 (pre and post diagnostic stewardship intervention). Abbreviations: HO-HCFA CDI = Healthcare Onset, Healthcare Facility Associated C. difficile Infection, FY = Fiscal Year, NAAT = Nucleic Acid Amplification Test.