Results
At 3 months, the analysis included 12,843 NPWT-V and 713 NPWT-O patients. Mean age for the NPWT-V cohort was 59.2 years and 48.3% of these patients were men (Table 1). Patients in the NPWT-V cohort were significantly younger than NPWT-O patients (59.2 vs 63.6 years, P < 0.01); mean Charlson Comorbidity Index scores between groups did not differ (3.38 vs 3.66). The most common comorbid conditions were diabetes without complications, peripheral vascular disease, and chronic pulmonary disease (Table 1).
Based on ICD-9-CM codes, chronic wound types (ie, PrUs, DFUs [with and without amputation], VLUs, and nonhealing surgical wounds) comprised the majority (82.1%) of the wounds. Open wounds, cellulitis, and necrotizing fasciitis were some of the acute wound groups, although it was difficult to determine whether open wounds were chronic or acute wounds.
Mean total health care costs per patient were calculated and compared for 3 months and 12 months after the initial NPWT claim in an outpatient setting (Figure 1). At 3 months, there were 12,843 patients in the NPWT-V cohort and 713 patients in the NPWT-O cohort. The difference between the mean total costs per patient at 3 months for NPWT-V ($35,498) vs NPWT-O ($39,722) trended lower by $4,224 (11%) per patient for NPWT-V (P = 0.08). At 12 months, there were 7,860 patients in the NPWT-V cohort and 378 patients in the NPWT-O cohort. The 12-month mean total costs (NPWT-V, $80,768 vs NPWT-O, $111,212) (Figure 1) were significantly (P = 0.03) lower for NPWT-V patients by $30,444 (27%).
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Figure 1.
Mean total health care costs per patient. (A) 3 months after initial negative pressure wound therapy (NPWT) claim; and (B) 12 months after initial NPWT claim. NPWT-V: negative pressure wound therapy using a specific product (V.A.C. Therapy, KCI, an Acelity company, San Antonio, TX); NPWT-O: negative pressure wound therapy using other, non-KCI products. ER: emergency room; Graftjacket RTM (KCI, an Acelity company, San Antonio, TX)
At 3 months, wound-related costs represented 37.9% of total costs for NPWT-V and 37.6% of total costs for NPWT-O; at 12 months, wound-related costs represented 25.7% of total costs for both NPWT-V and NPWT-O. Wound-related costs (NPWT-V, $20,801 vs NPWT-O, $28,647) at 12 months were significantly (P = 0.01) lower for NPWT-V by $7,846 (27%). At 12 months, cost savings for NPWT-V were driven by $14,598 (35%) lower inpatient costs (P = 0.01), $4,188 (65%) lower emergency room costs (P < 0.01), and $4,810 (35%) lower home costs (P = 0.05), despite $982 higher NPWT-related costs (P = 0.04.)
Across all wound types, hospital readmission rates for patients treated with NPWT-V vs patients treated with NPWT-O were significantly lower at 3 months (23% vs 31%, respectively; P ≤ 0.01) and at 6 months (31% vs 43%, P ≤ 0.01) (Figure 2). Wound-related readmission rates were also significantly lower for NPWT-V vs NPWT-O patients at 3 months (5% vs 8%, respectively; P ≤ 0.01) and 6 months (6% vs 11%; P ≤ 0.01) (Figure 2).
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Figure 2.
Hospital readmission rates at 3 months and 6 months post initial negative pressure wound therapy claim.
NPWT-V: negative pressure wound therapy using a specific product (V.A.C. Therapy, KCI, an Acelity company, San Antonio, TX); NPWT-O: negative pressure wound therapy using other, non-KCI products.
Mean counts of wound-related inpatient stays and emergency room visits were 53% and 83% lower (P < 0.0001) at 3 months and 6 months for patients in the NPWT-V cohort compared to patients in the NPWT-O cohort (Table 2). For each wound category examined, a similar pattern of lower or significantly lower mean number of inpatient stays and emergency room visits was evident for patients treated with NPWT-V (Table 2). Patients treated with NPWT-V also had lower home costs than those treated with NPWT-O. At 3 months, NPWT-V vs NPWT-O home costs were 32% lower ($4,462 vs $6,588, respectively) and at 12 months, home costs were significantly lower ($8,828 vs $13,638, P = 0.05) (Figure 1).
For all wound types, patients treated with NPWT-O had a 17-fold higher rate of switching to alternate NPWT compared to patients treated with NPWT-V (Figure 3). At 6 months after the initial NPWT claim, rates of switching among NPWT-O patients were 9-fold higher for pressure ulcers, 15-fold higher for nonhealing surgical wounds, and 32-fold higher for open wounds compared to NPWT-V patients (Figure 3).
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Figure 3.
Rate of switching from initial negative pressure wound therapy (NPWT) to alternate NPWT at 6 months after initial NPWT claim. NPWT-V: negative pressure wound therapy using a specific product (V.A.C. Therapy, KCI, an Acelity company, San Antonio, TX); NPWT-O: negative pressure wound therapy using other, non-KCI products.
In the interest of conciseness, the authors have presented data at the most appropriate time points.