Remote Monitoring Saves Costs in Outpatient Negative Pressure Wound Therapy

ABSTRACT

Objectives: In the outpatient setting, combining remote therapy monitoring (RTM) with negative pressure wound therapy (NPWT) can support improved adherence to prescribed therapy. A recent study reported that patients receiving NPWT with RTM required fewer therapy days than patients receiving NPWT alone, possibly reducing costs of care. Our objective was to determine whether RTM reduced 90-day costs in patients undergoing NPWT.

Study Design: We conducted a retrospective cohort study of patients receiving NPWT with or without RTM in the postacute setting.

Methods: Patients beginning NPWT between March 2018 and May 2019 were included. Payer claims data were collected and analyzed with t test for continuous variables and χ2 test for categorical variables. Multiple regressions were performed to control for confounding variables.

Results: Of the 1105 patients included the study, 675 (61%) received RTM and 430 (39%) did not. RTM patients were significantly older (P < .0001), had more ulcers (P = .0004), and had higher Charlson Comorbidity Index (CCI) scores (P < .0001). The unadjusted mean 90-day wound-related cost was not significantly higher for non-RTM patients than for RTM patients (P = .0799). After controlling for differences in age, payer type, CCI score, and wound type, there was a significant reduction in 90-day wound-related costs in the RTM group compared with the non-RTM group ($11,119 vs $14,752; P = .0131). The RTM group had higher NPWT costs ($3757 vs $3289; P = .0035) but lower wound-related non-NPWT costs ($7361 vs $11,462; P = .0045).

Conclusions: This study demonstrated the value of RTM in supporting NPWT adherence and decreasing the costs of wound care in these patients.

Am J Manag Care. 2022;28(2):53-58. https://doi.org/10.37765/ajmc.2022.88738

Takeaway Points

In this study, we retrospectively examined health insurance records of patients using negative pressure wound therapy (NPWT) with (n = 675) or without (n = 430) remote therapy monitoring (RTM) between March 2018 and May 2019.

• RTM patients were significantly older, had a higher percentage of ulcers, and had more severe comorbidities.
• After controlling for confounding variables, we report reduced 90-day wound-related costs in the RTM group compared with the non-RTM group.
• The RTM group had higher NPWT costs but lower wound-related non-NPWT costs.
• This study demonstrated the value of RTM in supporting NPWT adherence and decreasing the costs of wound care in these patients.

A 2018 retrospective analysis of Medicare beneficiaries estimated that approximately 8.2 million individuals had at least 1 wound or infection in 2014, with estimates of total Medicare wound care spending ranging from $28.1 billion to $96.8 billion per year.¹ The largest percentage of these costs, accounting for 47% to 58%, were incurred in the outpatient setting, where treatment of nonhealing wounds typically takes place. Chronic wounds cost substantially more to treat than acute wounds because of the increased need for wound care products, longer work time for skilled health care workers, and other expenses involved in long-term care.² As the patient population of developed countries gets older and exhibits increased rates of obesity, diabetes, and other comorbid conditions, chronic wounds will become a key driver of rising health care costs.^3,4

The World Health Organization estimates that adherence to therapy among patients with a chronic illness is 50%, representing a significant obstacle to effective therapy in this population.⁵ Outpatient therapies are appealing in that they allow the patient to return to a comfortable environment, give patients greater control over their care, and possibly save on health care costs. However, this setting also provides opportunities for therapy adherence to wane after discharge from the hospital. For patients with wounds managed with portable negative pressure wound therapy (NPWT), lapsed therapy adherence can compromise wound healing. Effective use of NPWT involves the application of a vacuum (typically –125 mm Hg) to the wound bed via specialized foam dressings. This approach manages wound exudate, reduces the need for daily dressing changes, and has supported better wound healing outcomes over conventional wound care.^6-8 Health care providers may prescribe a portable NPWT unit to be used approximately 22 hours per day in the outpatient setting, with dressing changes performed at least 3 times per week by a clinician.

To support patient therapy adherence and enhance outpatient NPWT performance, a remote therapy monitoring (RTM) program was integrated with existing portable NPWT units to allow the secure transmission of therapy data to a remote health care network. This information is monitored and analyzed by a team of virtual therapy specialists (VTSs) who reach out to patients throughout the duration of NPWT to support adherence.

Since the implementation of the RTM program, several preliminary studies have reported outcome data. In a pilot study of 198 patients, 79% of patients received at least 1 phone call from a VTS regarding low adherence to therapy; therapy adherence improved on the day following the call, increasing by an average of 8.5 hours.⁹ This study was expanded upon by a review of 510 patient records, which found that average usage of NPWT with RTM was 18.6 hours per day, and with increased adherence, the wound size reduction rate also increased.¹⁰ In a study comparing outpatient NPWT with RTM vs NPWT alone, the median length of treatment was significantly shorter for the RTM group, despite these patients also being older and having higher Charlson Comorbidity Index (CCI) scores, which indicate a higher predicted risk of death within 1 year of hospitalization for patients with specific comorbid conditions.¹¹ These studies suggested a potential for cost savings with RTM but required further investigation with larger study populations.

In 2018, health insurer Highmark Inc entered into a partnership with the manufacturer of an NPWT device supported by RTM (3M Company). The partnership created a performance-based payment structure for reducing total wound care costs. We hypothesized that the previously observed association of RTM with shorter length of treatment and greater reduction in wound size would result in reduced costs of care. In this study, we analyzed the Highmark patients undergoing outpatient NPWT and examined the RTM program metrics as well as whether RTM reduced 90-day costs.

METHODS

This evaluation includes Highmark patients receiving NPWT (3M ActiV.A.C. Therapy) in the postacute setting. Patients began therapy between March 2018 and May 2019. This study did not meet the National Institutes of Health criteria for human subject research, so human subjects approval was not sought. Patient consent was obtained by the insurer prior to data collection; only anonymized data were utilized in our analyses.

The application of NPWT is prescribed independently by each patient’s health care provider. The RTM service (iOn Progress Remote Therapy Monitoring System) is provided by the manufacturer of the NPWT device (3M Company). When NPWT with RTM was initiated, patients received a welcome phone call from the VTS team to answer questions, educate patients on NPWT, and provide direct contact information should the patient have any additional questions or concerns. Usage data were transmitted to the care network, which conducted alarm calls, customer care calls, and patient adherence calls as needed. If the remote monitoring dashboard displayed multiple alarms (ie, battery, leak, blockage, or inactive therapy), an alarm call to the patient would be made. Customer care calls were made to obtain information or provide supplies and educational materials. If therapy adherence fell below 16 hours for 2 consecutive days, a VTS reviewed the patient’s therapy history and made a patient adherence call to resolve any obstacles to therapy adherence. If multiple attempts to reach the patient were unsuccessful, or consistent nonadherence was documented, a call was made to the patient’s health care provider to discuss the wound management plan.

Claims data within 90 days of initial NPWT placement were collected and deidentified prior to analysis. Wound-related claims were identified using International Classification of Diseases, Tenth Revision (ICD-10) coding; if a wound ICD-10 code appeared in the top 3 ICD-10 claim codes, the cost for the entire claim was included as “wound-related costs.” Costs for patients with RTM included the additional cost of the program. Wound type was determined using wound ICD-10 codes within 30 days of NPWT placement. The CCI scores were determined using all available ICD-10 codes for each patient. Higher CCI scores correlate with higher risk of death within 1 year of hospitalization.¹² Wound types were categorized into ulcers, nonulcer open wounds, and atypical/other. Ulcers included diabetic ulcers, venous ulcers, arterial ulcers, pressure ulcers, and nonpressure ulcers. Nonulcer open wounds included those coded as open wounds, orthopedic trauma, and nonhealing surgical wounds. The atypical/unknown category included diabetic amputations, nondiabetic amputations, necrotizing fasciitis, cellulitis, and unknown wound types.

Patient and wound characteristics were extracted from the claims data and compared between non-RTM and RTM patients with t test for continuous variables and χ² test for categorical variables. Multiple linear regressions were performed to control for significant baseline differences in age, insurance type, CCI score, and wound category (ulcers, nonulcer open wounds, and atypical/other). Least-squares means for RTM and non-RTM were computed at the mean values for covariates and compared from the multiple regression analyses. Statistical significance was determined at the α = .05 level. All analyses were conducted with SAS version 9.4 (SAS Institute).

RESULTS

A total of 1105 patients initiated NPWT treatment in an outpatient setting between March 2018 and May 2019. Of these, 675 received NPWT with RTM. These patients received a mean of 3.2 (range, 1-21) patient adherence support calls per patient. The mean therapy time on the day prior to the adherence call was 8.2 hours. The day after the call, therapy increased to a mean of 20.4 hours per day.

The 1105 NPWT patients were divided into 2 cohorts for comparison: 675 patients (61%) receiving NPWT with RTM and 430 (39%) receiving NPWT alone. There was no significant difference in sex distribution among the groups. Patients in the RTM cohort were significantly older (P < .0001), had higher CCI scores (P < .0001), and were more likely to have Medicare Advantage insurance (P < .0001). The RTM cohort had significantly higher rates of congestive heart failure, peripheral vascular disease, cerebrovascular disease, chronic obstructive pulmonary disease, diabetes with complications, and renal disease (Table 1). The most common wound types for both cohorts were open wound (46.8%) and diabetic ulcer (20.6%). The cohort receiving NPWT with RTM also had a higher percentage of patients with ulcers of any type (Table 2).

Upon initial examination, the unadjusted mean 90-day wound-related costs were slightly higher for non-RTM patients than for RTM patients ($15,360 vs $12,464; P = .0799), although this was not a significant difference. After multiple regression analysis to adjust for differences in age, payer type, CCI score, and wound type, there was a significant reduction in 90-day wound-related costs in the RTM group compared with the non-RTM group ($11,119 vs $14,752; P = .0131) (Figure 1). The RTM group had higher NPWT costs ($3757 vs $3289; P = .0035) (Figure 2); this included the added costs of participation in the RTM program. However, the RTM group had lower wound-related non-NPWT costs ($7361 vs $11,462; P = .0045). Non–wound-related costs remained the same in both groups (P = .9393). Overall total costs, including both wound-related and non–wound-related costs, were increased for the non-RTM group, although not significantly ($23,288 vs $27,041; P = .0838).

To examine whether our definition of “wound-related costs” affected these outcomes, we conducted sensitivity analyses using definitions of wound-related costs as “wound as first code only” and “wound as any code.” Using the “wound as first code only” definition resulted in a shift of $2602 from wound-related costs to non–wound-related costs ($2663 for RTM and $2507 for non-RTM). For unadjusted costs, this resulted in significantly lower costs for the RTM group for wound-related costs ($9801 vs $12,853; P = .0366) and wound-related non-NPWT costs ($5680 vs $8919; P = .0241). All other cost differences remained nonsignificant. When the analysis was adjusted for baseline differences between groups, the RTM group had lower wound-related costs ($8992 vs $12,243; P = .0104) and wound-related non-NPWT costs ($5235 vs $8953; P = .0029), and higher NPWT costs ($3757 vs $3289; P = .0035). Using the “wound as any code” definition resulted in no shift in costs compared with the top-3 approach.

DISCUSSION

Our results are consistent with the existing literature on postacute NPWT with RTM and expand on the current knowledge of RTM outcomes. Initial studies of NPWT with RTM revealed that adherence steadily declined in the days leading up to an adherence call, but adherence increased by a mean of 8.5 hours the day after the call.⁹ Unsurprisingly, a greater reduction in wound volume and surface area was associated with higher adherence to therapy.¹⁰ The outcomes of these early studies were reflected in a pilot cost savings analysis, which found a moderate, but not statistically significant, reduction in costs among patients undergoing NPWT with RTM compared with NPWT alone.¹¹ We hypothesized that a difference may be obscured by the RTM patients being significantly older and sicker than the non-RTM group and that further study with a larger patient population was required.

In the present study, we found similar initial results. The patients receiving NPWT with RTM were significantly older, had higher CCI scores, and had a higher proportion of ulcers than patients with NPWT alone. These differences had to be accounted for in our data analysis, as increased age, wound type, and the presence of multiple comorbidities have been shown to increase costs of wound care.^11,13,14 Not only do older patients with multiple comorbidities have a higher prevalence of chronic wounds such as ulcers, but multimorbidity can have an amplifying effect on health care costs.¹⁵ For example, complications of diabetic foot ulcers can lead to amputation, rapidly escalating the cost of care.² Once we controlled for these group differences, we found a significant reduction in wound-related costs with RTM. The cost of NPWT was $468 higher per patient in the RTM group due to the additional costs of RTM participation. However, these costs were offset by a savings of $4101 per patient in wound-related non-NPWT costs. The total cost savings, including both wound-related and non–wound-related costs, in the RTM group were $3753 per patient. These results highlight the need to factor in the cost savings of wound-related care, which can overcome initially higher up-front costs of advanced therapy strategies.

This study concludes in the midst of the worldwide COVID-19 pandemic, in which fears of disease transmission have depressed visits to ambulatory practices.¹⁶ Safety measures and physical distancing have highlighted a need for wider telemedicine availability, and a survey by the American College of Emergency Physicians reported that 30% of respondents had actively delayed or avoided seeking medical care over concerns of contracting the virus, indicating an impending secondary crisis of underaddressed health concerns during and following the pandemic.¹⁷ Wound care strategies that provide active management while limiting face-to-face interactions may become more necessary in the postacute environment, especially for patients who are vulnerable and have chronic wounds.¹⁸ By maintaining a supportive connection with patients, the VTS team can increase patient confidence in outpatient NPWT, enhance the benefits of care through improved adherence, and, ideally, shorten the duration of therapy. In an exit survey of patients using NPWT with RTM, 94% of patients expressed satisfaction with the monitoring services provided, 87% responded that VTS support increased usage, and 91% wanted to use RTM again if they needed NPWT in the future.¹⁹ In the patient population included in the present study, 281 of the patients who used NPWT with RTM were surveyed and 98% reported overall satisfaction with the program.

Limitations

This study is limited in that it is a nonblinded, retrospective comparison and therefore does not have the rigor of a randomized clinical trial. The information collected from claims data lacks clinical verification and does not control for the possibility of data entry errors or unknown systemic biases of the health care practitioners or institutions providing patient care. This study also did not collect or control for some demographic data that may affect quality of care, such as race, ethnicity, and socioeconomic status. Future studies including clinical progress reports and detailed per-claim cost analyses would provide valuable additional insight into expanding RTM use among a greater patient population.

CONCLUSIONS

RTM influenced the proper use of NPWT via continuous patient engagement, filling a gap in the home care environment and thereby saving on non-NPWT wound-related costs. This decrease in total wound-related costs also lead to a marginally significant decrease in overall cost, which included both wound-related and non–wound-related costs. This exercise emphasizes the importance of evaluating total cost of care and total cost of wound care rather than only the cost of the device and service. This successful partnership between Highmark and 3M demonstrated that a significant decrease in costs could be obtained despite the additional investment required for the RTM service. This benefit of NPWT with RTM may become even more evident in the future, especially as an aging, comorbid population brings increasing economic challenges to the health care industry.

Author Affiliations: 3M Company (LPG, MMS), San Antonio, TX.

Source of Funding: The authors are employees of 3M Company, which manufactures the mobile negative pressure wound therapy unit studied in this manuscript.

Author Disclosures: Ms Griffin and Dr Sifuentes are employees of 3M Company and hold employee stock.

Authorship Information: Concept and design (LPG, MMS); acquisition of data (LPG); analysis and interpretation of data (LPG); drafting of the manuscript (LPG, MMS); critical revision of the manuscript for important intellectual content (LPG, MMS); statistical analysis (LPG); and administrative, technical, or logistic support (MMS).

Address Correspondence to: Leah P. Griffin, MS, 3M Company, 12930 W Interstate 10, San Antonio, TX 78249. Email: lpgriffin@mmm.com.

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