The Effect of Timing of Instillation Therapy on Outcomes and Costs for Patients Receiving Negative Pressure Wound Therapy

Introduction: Negative pressure wound therapy with instillation and dwell time (NPWTi-d) involves the periodic instillation of topical solution into a wound followed by the application of negative pressure to remove the topical solution. Although the addition of instillation therapy to negative pressure wound therapy (NPWT) has been associated with improved patient outcomes, questions remain regarding the timing of its use.

The objective of this study was to examine the effect of the timing of NPWTi-d* initiation on patient outcomes and costs.

Methods: This retrospective analysis used data from Premier, a large, national all-payer hospital database†. The study population included patients with an inpatient visit in 2019 treated with NPWTi-d as indicated by hospital billing data. Clinical outcomes and costs were compared for patients with diverse wound types receiving early (within 1 day of NPWT application) and late (within 2-7 days following NPWT application) NPWTi-d initiation. A matched cohort of 514 patients (257 per group) based on demographics, comorbidities, and wound characteristics was created using propensity scoring. Differences in outcomes between groups were compared using t-tests and chi-square tests.

Results: On average, patients with early NPWTi-d initiation spent 4.4 fewer days using conventional NPWT (7.0 vs. 11.4 days, P< .0001) and 2.9 fewer days in the hospital (13.4 vs. 16.3, P< .0001) when compared to patients with late NPWTi-d initiation. Early NPWTi-d initiation was also associated with fewer debridements (1.3 vs. 1.7, P=.0221), operating room visits during hospitalization (3.1 vs. 4.1, P=.0002), operating room visits while receiving NPWT (1.7 vs. 2.9, P< .0001), days until final operating room procedure (9.6 vs. 12.2, P=.0008), 30-day wound-related readmissions (6 [2.3%] vs. 16 [6.2%], P=.0293), and 60-day wound-related readmissions (10 [3.9%] vs. 24 [9.3%], P=.0130).

Additionally, patients with early NPWTi-d initiation had a $10,877 lower ($34,161 vs. $45,038, P< .0001) cost of index admission, which also included lower NPWT costs ($1,020 vs. $1,955, P=.0001).Discussion: In these patients with wounds, these data suggest that early NPWTi-d initiation may be optimal for helping to improve patient outcomes and reducing cost of care.