Cost-effectiveness of Urinary Dipsticks to Screen Asymptomatic Catheter-associated Urinary Infections in an Intensive Care Unit

Objective: To assess the cost-effectiveness of urinary dipsticks (UDs) to screen asymptomatic catheterized patients for quantitative urine.

Design: Prospective comparison of UD with quantitative urine culture (QUC) (reference technique) and cost-effectiveness analysis performed from the hospital's perspective.

Setting: Medical intensive care unit (ICU) of the Besançon University Hospital (France).

Patients And Participants: All consecutive, asymptomatic, catheterized patients.

Interventions: Urinary dipsticks (Multistix 8-SG) were analyzed by the reflectance spectrophotometric method (Clinitek 50). Sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of four combinations of the leukocyte (L) test pad and the nitrite (N) test pad were calculated: L and N, L or N, L alone and N alone. A micro-costing technique was used to determine the direct medical cost of each strategy. The calculated cost-effectiveness ratio was the incremental cost-effectiveness (ICE) ratio.

Measurements And Results: Three hundred thirty-nine urine samples taken from 144 patients were analyzed. The incidence of asymptomatic catheter-associated urinary tract infections (CAUTIs) was 31.3% (> or =10(5) organisms/ml). The L or N combination was the best detector of asymptomatic CAUTI: Se=87.2%, Sp=61.6%, PPV=30.6% and NPV=96.1%. The cost of QUC strategy and UD strategy was EUR 21.5 and EUR 12.6 per test, respectively. The ICE ratio of QUCs was EUR 69.5 per case of detected CAUTI.

Conclusion: The UD is a cost-effective test for screening asymptomatic catheterized patients for quantitative urine culture in a medical ICU.