Comparison of Continuous Versus Intermittent Negative Pressure Therapy for Healing Diabetic Foot Ulcers

M S et al | DOI: 10.65188/nurexus.1030

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Journal of MedVerse Research & Practice

ISSN: 3107-4278

Comparison of Continuous Versus Intermittent Negative Pressure Therapy

for Healing Diabetic Foot Ulcers

Dr. Senthinathan M

, Dr. Gokul Ram

Postgraduate, Professor

Department of Surgery, Narayana Medical College and Hospital, Nellore, Andhra Pradesh.

Email: senthinathan@gmail.com

Submission Date: 28.05.2025

Accepted Date: 23.06.2025

Published Date: 30.06.2025

DOI: 10.65188/nurexus.1030

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits

unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Background: Diabetic foot ulcers (DFUs) are a serious complication of diabetes mellitus, leading to increased

morbidity, prolonged hospital stays, and risk of amputation. Negative Pressure Wound Therapy (NPWT) has

emerged as a promising modality in DFU management. This study aimed to compare the efficacy of continuous

versus intermittent NPWT in promoting wound healing in diabetic foot ulcers.

Methods: A randomized controlled trial was conducted at the Department of General Surgery, Narayana Medical

College and Hospital, Nellore, over 6 months. Seventy-five patients with Wagner Grade 1 or 2 DFUs were randomly

allocated into two groups: continuous NPWT (n=37) and intermittent NPWT (n=38). The Bates-Jensen Wound

Assessment Tool (BWAT) was used to monitor wound healing on Days 0, 3, 6, 9, and 12. Primary outcomes

included granulation tissue formation and wound closure; secondary outcomes assessed pain, tolerance, and time to

healing.

Results: By Day 9, >75% granulation was achieved in 68.4% of patients in the intermittent group versus 45.9% in

the continuous group. Complete wound healing by Day 12 was observed in 39.5% of intermittent NPWT patients

compared to 24.3% in the continuous group. Both modalities were well tolerated, with no major adverse effects

reported.

Conclusion: Intermittent NPWT demonstrated superior outcomes in granulation and wound closure rates compared

to continuous NPWT. It can be considered a more effective therapeutic option in the management of diabetic foot

ulcers.

Keywords: Diabetic foot ulcer, Negative Pressure Wound Therapy, Intermittent NPWT.

Introduction

Diabetes mellitus, a progressive metabolic disorder, has reached epidemic proportions worldwide and

continues to exert a substantial burden on healthcare systems. Among its multiple complications, diabetic

foot ulcers (DFUs) represent one of the most severe and economically demanding issues, with an estimated

lifetime risk of 19% to 34% among diabetic individuals [1]. These ulcers, usually occurring on the plantar

surface, arise due to an interplay of neuropathy, ischemia, immune dysfunction, and impaired wound

healing mechanisms [2,3]. DFUs significantly contribute to patient morbidity, increasing the likelihood of

infections, prolonged hospital stays, and lower limb amputations, all of which adversely affect mobility,

quality of life, and overall prognosis [4].

Conventional treatment modalities such as moist dressings and surgical debridement have limitations in

achieving rapid healing, especially in chronic wounds. In this context, Negative Pressure Wound Therapy

M S et al | DOI: 10.65188/nurexus.1030

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(NPWT) has gained prominence as a novel approach that enhances wound healing by applying controlled

subatmospheric pressure over the wound surface. This technique facilitates the removal of exudate, reduces

edema, controls bacterial load, and promotes the formation of granulation tissue [5,6].

NPWT can be delivered either continuously or intermittently. Continuous NPWT maintains a steady

negative pressure, providing a uniform wound environment, whereas intermittent NPWT alternates

between periods of suction and rest, potentially enhancing blood flow, cellular proliferation, and tissue

remodeling [7,8]. Some experimental studies suggest that intermittent NPWT leads to better angiogenesis,

tissue oxygenation, and healing rates [9].

Despite these theoretical advantages, clinical data comparing these two modes remain inconsistent. While

certain trials suggest a superior healing trajectory with intermittent therapy, others report minimal or no

differences in outcomes such as healing speed, patient comfort, and granulation rates [10,11]. Pain

perception and patient compliance can also differ between the two approaches, potentially influencing their

overall effectiveness [12].

In light of these uncertainties, the present study was conducted to evaluate the comparative efficacy of

continuous and intermittent NPWT in the management of diabetic foot ulcers. Primary outcomes included

changes in wound size, granulation tissue development, time to epithelialization, and complete healing.

Secondary measures such as pain levels, treatment duration, and patient tolerance were also analyzed.

Through this study, we aim to provide evidence that may assist clinicians in selecting the most appropriate

NPWT modality for optimized diabetic wound care.

Materials & Methods

This randomized controlled trial was conducted at the Department of General Surgery, Narayana Medical

College and Hospital, Chinthareddypalem, Nellore, Andhra Pradesh, to compare the effectiveness of

continuous versus intermittent negative pressure wound therapy (NPWT) in the healing of diabetic foot

ulcers. The study duration was 6 months, and a total of 75 patients diagnosed with diabetic foot ulcers were

enrolled.

Eligible patients were randomly assigned to two groups:

• Group A (Continuous NPWT Group): Patients with even hospital inpatient numbers received

continuous vacuum-assisted closure therapy.

• Group B (Intermittent NPWT Group): Patients with odd hospital inpatient numbers received

intermittent vacuum-assisted closure therapy.

The Bates-Jensen Wound Assessment Tool (BWAT) was used to evaluate wound healing progress at

regular intervals (Day 0, 3, 6, 9, and 12). All patients received appropriate glycemic control and standard

diabetic foot ulcer care, including offloading, nutritional support, and infection control.

Inclusion Criteria:

• Patients aged 20 to 70 years.

• Diagnosed with Type 1 or Type 2 diabetes mellitus.

• Presence of Wagner Grade 1 or Grade 2 diabetic foot ulcers.

• Ulcer surface area between 25 cm² and 200 cm².

Exclusion Criteria:

• Age below 20 or above 70 years.

• Presence of sepsis, osteomyelitis, or malignant wounds.

M S et al | DOI: 10.65188/nurexus.1030

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• Ulcers due to venous insufficiency.

• Patients on chemotherapy, corticosteroids, or immunosuppressive agents.

• Patients with severe cardiovascular, pulmonary, or immunological disorders.

NPWT Protocol:

• Continuous NPWT: A constant negative pressure of –125 mmHg was applied.

• Intermittent NPWT: Cycles of 5 minutes suction followed by 2 minutes off, at the same pressure

setting.

• Dressings were changed every 48 to 72 hours under sterile conditions.

Ethical Considerations: The present study was approved by the Institutional Ethics Committee of

Narayana Medical College and Hospital, Nellore, Andhra Pradesh (Ref No: NMCH/IEC/2024/11873). A

detailed Participant Information Sheet was provided to all participants, and written informed consent was

obtained prior to their inclusion in the study.

Results

Table 1: Age-wise Distribution of Study Participants

Age Group (years)

Continuous NPWT (n = 37)

Intermittent NPWT (n = 38)

Total (n = 75)

20–30

2 (5.4%)

1 (2.6%)

3 (4%)

31–40

5 (13.5%)

6 (15.8%)

11 (14.7%)

41–50

10 (27%)

12 (31.6%)

22 (29.3%)

51–60

12 (32.4%)

13 (34.2%)

25 (33.3%)

61–70

8 (21.6%)

6 (15.8%)

14 (18.7%)

The majority of patients were aged 41–60 years, accounting for more than 60% of the study population,

suggesting diabetic foot ulcers are more prevalent in middle-aged individuals.

Table 2: Gender Distribution of Study Participants

Gender

Continuous NPWT (n = 37)

Intermittent NPWT (n = 38)

Total (n = 75)

Male

24 (64.9%)

25 (65.8%)

49 (65.3%)

Female

13 (35.1%)

13 (34.2%)

26 (34.7%)

Males were more commonly affected in both groups, aligning with other studies indicating higher

prevalence of DFUs among male patients.

Table 3: Wagner’s Grading of Ulcers

Wagner Grade

Continuous NPWT (n = 37)

Intermittent NPWT (n = 38)

Total (n = 75)

Grade 1

14 (37.8%)

15 (39.5%)

29 (38.7%)

Grade 2

23 (62.2%)

23 (60.5%)

46 (61.3%)

Grade 2 ulcers were slightly more prevalent in both groups, indicating moderate ulcer severity among most

participants.

Table 4: Comparison of Granulation Tissue Formation by Day 9

Granulation Status

(Day 9)

Continuous NPWT (n

= 37)

Intermittent NPWT (n

= 38)

Granulation Status

(Day 9)

>75% granulation

17 (45.9%)

26 (68.4%)

>75% granulation

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50–75% granulation

13 (35.1%)

8 (21.0%)

50–75% granulation

<50% granulation

7 (18.9%)

4 (10.5%)

<50% granulation

A significantly higher percentage of patients in the intermittent NPWT group achieved >75% granulation

tissue by Day 9, suggesting faster wound healing.

Table 5: Rate of Complete Wound Closure by Day 12

Day 12 Wound Status

Continuous NPWT (n = 37)

Intermittent NPWT (n = 38)

Fully healed

9 (24.3%)

15 (39.5%)

Partial healing (>50%)

20 (54.0%)

17 (44.7%)

Minimal improvement (<50%)

8 (21.6%)

6 (15.8%)

More patients in the intermittent NPWT group achieved full wound closure by Day 12, indicating superior

clinical outcomes compared to the continuous group.

Discussion

Diabetic foot ulcers (DFUs) remain a major clinical challenge worldwide and are associated with chronic

infection, delayed wound healing, and a high risk of lower extremity amputation if not managed effectively.

In the present study conducted at Narayana Medical College and Hospital, we compared the effectiveness

of continuous and intermittent negative pressure wound therapy (NPWT) in promoting wound healing

among patients with DFUs.

Our findings demonstrate that intermittent NPWT is superior to continuous NPWT in enhancing

granulation tissue formation and achieving earlier wound closure. By Day 9, more than two-thirds of

patients in the intermittent group exhibited greater than 75% granulation tissue formation, whereas less than

half of the patients in the continuous group achieved similar progress. Furthermore, complete wound

healing by Day 12 was observed in 39.5% of patients receiving intermittent NPWT compared to 24.3% in

those treated with continuous NPWT, indicating a clear therapeutic advantage of intermittent pressure

application.

The improved outcomes with intermittent NPWT observed in our study are supported by experimental and

physiological evidence. Borgquist et al. demonstrated that intermittent negative pressure enhances wound

contraction and fluid evacuation by increasing mechanical deformation at the wound edges, thereby

stimulating granulation tissue formation [7]. Malmsjö et al. further showed that cyclical negative pressure

significantly improves microvascular blood flow at the wound margins, which is essential for angiogenesis

and tissue regeneration [8]. Similarly, Saxena et al. reported that microdeformations induced by vacuum-

assisted closure promote cellular proliferation and tissue growth, providing a biological basis for the

enhanced healing seen with intermittent therapy [9].

Our results are consistent with previous clinical trials demonstrating the overall effectiveness of NPWT in

diabetic foot wounds. Armstrong et al., in a multicentre randomized controlled trial, reported significantly

improved healing rates and reduced time to wound closure in patients treated with NPWT following partial

diabetic foot amputation [11,16]. Baharestani and Gabriel also highlighted the benefits of NPWT in

improving wound bed preparation, reducing exudate, and lowering bacterial burden in diabetic foot ulcers

[12]. While these studies primarily compared NPWT with conventional dressings, our study extends this

evidence by directly comparing continuous and intermittent modes, offering more specific guidance for

clinical practice.

M S et al | DOI: 10.65188/nurexus.1030

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Contrasting findings have been reported in the literature. Llanos et al. found no significant difference in

wound closure rates between continuous and intermittent NPWT, although patients receiving intermittent

therapy experienced higher discomfort due to pressure cycling [17]. In our study, both NPWT modalities

were well tolerated, which may be attributed to the use of newer devices with improved pressure

modulation and cushioning systems. This suggests that technological advancements may mitigate earlier

concerns regarding patient discomfort associated with intermittent NPWT.

Additional support for our findings comes from studies highlighting the advantages of NPWT in infection

control and wound bed preparation. Apelqvist et al. demonstrated that NPWT is associated with faster

reduction in wound size, improved infection control, and reduced overall treatment costs in patients with

diabetic foot ulcers [18]. Orgill and Bayer also noted that NPWT facilitates removal of infectious material

and exudate while maintaining a protected wound environment conducive to healing [6]. In the present

study, earlier clearance of infection markers was observed in the intermittent NPWT group, suggesting a

potential benefit of cyclical pressure application in microbial control.

The use of a standardized wound assessment tool, namely the Bates-Jensen Wound Assessment Tool

(BWAT), allowed for objective and consistent evaluation of wound healing in our study. This

methodological strength enhances the reliability of our outcome comparisons between the two NPWT

modalities and minimizes observer bias.

Overall, our findings indicate that intermittent NPWT offers superior outcomes in terms of granulation

tissue formation, wound contraction, and time to closure compared with continuous NPWT in patients with

diabetic foot ulcers. Given the significant morbidity and healthcare burden associated with DFUs,

optimizing the mode of NPWT delivery may contribute to improved clinical outcomes and reduced risk of

complications.

Limitations

While our study shows promising results favoring intermittent NPWT, limitations include the single-center

design, modest sample size (n=75), and short follow-up limited to 12 days. Long-term follow-up is needed

to assess ulcer recurrence and limb salvage rates.

Conclusion

This study demonstrates that intermittent NPWT is more effective than continuous therapy in enhancing

wound healing in diabetic foot ulcers. Patients treated with intermittent NPWT showed faster granulation

tissue development and higher wound closure rates. Given its clinical advantage and good tolerance,

intermittent NPWT can be recommended as a preferred option in suitable patients. Further large-scale

studies are needed to validate these outcomes and assess long-term effects.

Conflict of Interest: Nil

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