A single centre prospective longitudinal cohort study was conducted on 88 patients with diabetic foot ulcers from August 2018 to August 2020 dividing equally 44 patients in each group in a tertiary care hospital. The study was initiated after Institutional Ethical Committee clearance, IEC 1624 dated 27/2/2019. Sample size was calculated based on a study conducted by Donaghue VM et al., on the efficacy and safety of a collagen-alginate topical wound dressing (FIBRACOL Collagen-Alginate Wound Dressing) in the treatment of diabetic foot ulcers was compared with that of regular gauze moistened with normal saline, which showed standard deviation of alginate dressings (s1) and saline dressings (s2) as 6 and 26, respectively while mean of alginate dressings (μ₁) and saline dressings (μ₂) as 80.6 and 61.1, respectively, which when applied on n=2(z_γ+z_1-β)² (s₁²+s₂²)/(μ₁-μ₂)² gave sample size as 39.30 (40) which when calculated with 10% of dropouts finalised as 44 in each group [13]. Simple randomisation was done. Diabetic foot ulcer patients aged between 12 to 75 years giving consent were included in the study and were explained in their native language about the study in detail. The patients with peripheral vascular diseases, skin malignancies, venous or arterial ulcers, immunocompromised patients or with underlying osteomyelitis were excluded from the study. All the dressings were done by the same group of doctors working in the same surgical unit in order to avoid any discrepancies and were followed-up on a daily basis. The work has been reported in line with the STROCSS criteria [14].

A total of 88 patients were included in the study, one group was managed using alginate dressings [Table/Fig-1], while the other group using conventional saline dressings [Table/Fig-2]. After bedside debridement of the wound without anaesthesia, initial wound assessment was made using PUSH before starting the patient on dressings [Table/Fig-3] [15]. The patients were started on saline or alginate dressing depending on group code and were monitored at two week and at the end of four weeks. The components of the PUSH score include, length×width in square centimetres (wound area), exudate amount and tissue type. These components are further given a sub score. Wound area is given a score from 0 to 10 based on size of the ulcer in Cm Sq. Based on the amount of exudate from the ulcer, it is sub scored from 0 to 3 as none, mild, moderate and severe. Based on the tissue type, it is sub scored from 0 to 4 with 0 as closed, 1 for epithelial tissue, 2 for granulation tissue, 3 for slough and 4 for necrotic tissue.

[Table/Fig-1]:

Alginate application (Group-1).

[Table/Fig-2]:

Saline dressings (Group-2).

The statistical analysis were done using SPSS software version 21. The statistics were done using Levene’s test (for equality of variances and t-test for equality of means), Pearson Chi-square test and Mann-Whitney test and Wilcoxon test.

A total of 88 patients were included in the study out of which 56 were males and 32 were females. In males, 24 patients were included in alginate group and 32 in saline group. In females, 20 patients were included in alginate group and 12 patients were included in saline group.

At two weeks, the mean (SD) of alginate group was reduced from 9.07 (1.634) to 6.89 (1.434) while the mean (SD) of the saline group was reduced from 9.25 (2.059) to 8.00 (1.905). At four weeks, the mean (SD) of alginate group was further reduced to 4.68 (1.272) while the mean (SD) of the saline group was reduced to 6.50 (1.650) [Table/Fig-4].

The mean (SD) of the alginates at two weeks were reduced from 2.02 (0.505) to 1.09 (0.473) in comparison to saline group from 1.98 (0.590) to 1.43 (0.625). The mean (SD) of the alginates at four weeks were further reduced to 0.14 (0.347) in comparison to saline group from 0.75 (0.615) [Table/Fig-5].

The mean (SD) was found to be reduced from 2.30 (0.701) to 0.16 (0.370) for the alginate group in comparison to 2.32 (0.740) to 0.77 (0.743) for the saline group at the end of four weeks [Table/Fig-6].

On evaluation of the wound cultures 19 out of 44 patients (43.2%) were culture positive in the alginate group while 43 out of 44 patients (97.7%) were culture positive from the saline group at two weeks. At the end of four weeks; 6 out of 44 patients (13.6%) were culture positive in the alginate group while 30 out of 44 patients (68.2%) were culture positive from the saline group [Table/Fig-7].

[Table/Fig-7]:

Wound culture (p-value 0.001, calculated using Pearson Chi-square test).

In overall comparison among the groups, the PUSH score on admission for both saline and alginate group was 13.57 and 13.45, respectively, which after four weeks were found to be reduced to 8.02 and 4.98 respectively. On further statistical evaluation with Mann-Whitney and Wilcoxon tests, alginate dressing group were found to be statistically significant [Table/Fig-8].

The treatment of diabetic foot ulcers in highly exuding cavity wounds is a challenge. The treatment in such wounds includes debridement of the wound, managing the infection, revascularisation procedures if needed and off-loading of the ulcers [16]. There are several dressing modalities available at present that aids not only in protecting the wound but also promote faster wound healing. An ideal dressing material must be able to remove exudates and toxic components, should maintain a moist environment at wound-dressing interface, should be impermeable to micro-organisms, allowing gaseous exchange, should be removed easily and most importantly should be cost-effective [17]. The use of alginate dressings for cavity wounds was found to be efficacious in many aspects. In terms of wound surface area, in this study, there was marked reduction in the size of the wound in patients who were subjected to alginate dressings when compared to that of saline dressings which was statistically significant. Donaghue VM et al., in evaluating the efficacy and safety of collagen-alginate topical wound dressing (FIBRACOL Collagen Alginate wound dressing) in the treatment of diabetic foot ulcers found the reduction in wound surface area was statistically significant (p=0.0049) with alginate dressings and concluded that collagen-alginate dressings is more effective than the conventionally used saline dressings [13].

In promoting the wound healing by reducing the exudate amount or by increasing the absorption of the exudate, alginates showed marked improvement with reduction in mean of 2.02 to 0.14 within a span of four weeks when compared to that of a reduction from 1.98 to 0.75 in case of saline dressings. In a study conducted by Jones V concluded that alginates are considered to be a comfortable and cost-effective alternative dressing to other dressings especially in cases of moderate to heavily exuding wounds. The ability of the alginates to absorb large amounts (15-20 times its weight) of exudate and fill irregularly shaped cavity wounds was emphasised in this study [11]. In contrast to the above mentioned study, Dumville JC et al., in his research paper stated no significant research evidence to prove alginate dressing to be more efficacious than other dressings, yet they concluded that decision makers may wish to consider certain aspects such as dressing cost and wound management properties like exudate management in alginate dressings [18].

Another important entity that has been compared as per PUSH scaling system is the improvement in the tissue type. In this study, several ulcers which were initially covered with necrotic tissues or slough were either resurfaced completely or healed with epithelial tissues after application of alginate dressings over a period of four weeks. The patients with saline dressings were still granulating over a 4-week period without epithelisation. This was confirmed on PUSH score with reduction in mean from 2.30 to 0.16 for alginate dressings and 2.32 to 0.77 for saline dressings. In addition to these three attributes of PUSH scale, the 4^th entity that has been compared in this study is the reduction or nullification of the bacterial load. The wound swabs taken at the time of admission of 88 patients forming the study population were positive with growth of a variety of organisms. On follow-up wound swabs at two weeks, only 43% of the patients in alginate group were positive while 97% in saline group were still positive for organisms. After four weeks about 13.6% (6) patients in alginate group were culture positive in comparison to 68.2% (30) patients culture positivity in saline dressing group. In a study conducted by Naik BM et al., comparing the efficacy between alginate dressings and povidone iodine dressings, wound culture swabs were compared but there was no statistical significance between the groups [19].

The strength of the study is the sample size with statistically significant results and all the dressings were done by the team of doctors working in the same surgical unit. Alginates are capable of absorbing 15-20 times of its own weight and are useful in highly exuding cavity wounds. We recommend the routine use of alginate dressings in non-healing highly exuding cavity wounds.

The limitations of the study was, firstly alginate dressings were compared with conventional saline dressings and not with proven advanced biological substitutes or negative pressure wound therapy and secondly cost-analysis was not done.

Alginates dressings are superior to saline dressings in terms of reduction in the size of the ulcer and control of microbial activity in diabetic foot. Alginates absorb large amounts of exudates and fill in irregular shaped cavities which are ideal in treating cavity wounds in diabetic foot syndrome.