In the present study, the probabilities for patient discharge with CWC before healing plateaus were relatively good (> 80%) for VLUs and STWs. The non-VLU group healed significantly slower than the VLU group (estimated median, 152 vs. 87 days for total treatment duration) and less likely to be discharged with CWC (P < .01; OR = 0.41). Venous leg ulcers are caused by dysfunctional venous valves that normally facilitate blood return from the leg, thus decreasing swelling and risk for wound occurrence. Compression therapy is widely recognized as the standardized intervention for patients with VLUs as it normalizes venous circulation, which is abnormal in patients with VLUs.11 Interestingly, treatment duration and the percentage of patients discharged with CWC did not differ in patients with VLUs and STWs in the present study. This finding indicates physical therapy outpatient wound care resulted in similar probabilities of wound closure and total treatment duration of these 2 etiologies. As for the chronic non-VLU wounds of other etiologies, with the exception of STWs, the results indicate that treatments at the present clinic remain unsatisfactory. One possible explanation may be that patients with VLUs or STWs responded better to electric stimulation than wounds of other etiologies, and electric stimulation facilitates angiogenesis and thus better circulation.12
The probabilities for patient discharge with CWC before healing plateaus were dismally low for PUs and arterial wounds, and mediocre (~52%; Figure 3) for DFUs. The pathophysiology of PUs includes prolonged pressure and/or friction over bony prominences,7 but treatment options have been limited to pressure relief and skin protection in traditional wound care practices, which could be difficult, especially for patients with paralysis. Arterial wounds are caused by poor arterial circulation. As a result of the advent of angiography, physicians are able to recanalize middle-sized to large-sized arteries to improve blood circulation. However, microvascular diseases, which are common in patients with arterial wounds, remain a dilemma for clinicians. The chronicity of DFUs is usually due to poor glycemic control.8 Diabetic foot ulcers can be difficult to treat as the process of diabetic complications, such as neuropathy, takes years—if not decades—to occur.8 Consistent with these aforementioned theories,7,8 this study demonstrated that longer total treatment durations were required for PUs, DFUs, and arterial wounds, with a relatively low probability to be discharged with CWC. The protocol of care, which currently involves wound care dressings and therapeutic modalities in the outpatient physical therapy wound care clinic, remains unsatisfactory, and more research studies are needed to develop new treatment strategies for these wounds.
In the present study, the estimated median total treatment duration in patient discharge with CWC was 87, 152, 100, 773, 170 days for VLUs, non-VLUs, STWs, PUs, and DFUs, respectively. Complete wound closure rates with different treatments have been widely reported in the available literature.13-16 In patients with VLUs treated with multilayer compression bandage, CWC rates were 57% at 2 months13 and 83.8% with low molecular weight heparin therapy at 12 months in 1 study.13 To the authors’ knowledge, little information regarding wound healing outcomes in outpatients with chronic surgical or traumatic wounds is available in the literature. For PUs, Brewer et al15 reported the mean treatment durations required for CWC as 21.1 ± 3.7 (n = 26) weeks with conventional care and 10.5 ± 1.3 (n = 30) weeks with an additional arginine-containing supplement. For DFUs, Omar et al16 found that CWC rates at weeks 8 and 20 were 33.3% and 54%, respectively, with extracorporeal shock wave therapy plus standard wound care and 14.28% and 28.5%, respectively, with standard wound care.16 Although these numbers in the literature appear to be more positive than the present study, these studies were prospective clinical trials with strict inclusion and exclusion criteria, together with smaller sample sizes13-16; the present retrospective study reported the results of all-inclusive analyses from an outpatient physical therapy wound care clinic, including patients treated with different dressings and/or modalities. In addition, the total treatment duration in patients with CWC in the present study was usually 1 to 2 weeks longer than the time required for CWC, the actual outcome measure in the aforementioned studies.13-16
In the present study, patients with VLUs accounted for 45.66% of the total patient population (N = 265), and it was the most common wound diagnosis seen in the study. It has been previously reported that VLUs account for 70% to 90% of all leg ulcers.6 As the present study included wounds located in areas other than the leg, the proportion of patients with VLUs in all leg ulcers is expected to be much higher than 45.66% of patients with wounds in general, which included wounds at other body locations. Thus, this study further suggests the high prevalence of VLUs in patients with wounds. Wounds of traumatic or surgical etiology usually heal by primary intention; however, delayed wound healing is not uncommon, especially given the fact that the prevalence of infection ranges from 10% to 30% in secondary intention surgical wound healing.17 In the present study, STWs were the second most common diagnosis (23.77%) of all patients. Fife et al18 reported that nonhealing surgical wounds represented the largest category of wounds (20.8%) among hospital-based outpatient wound centers. The present study’s finding of 23.77% supports that STWs are common in outpatient physical therapy wound care clinics, with higher prevalence than that of PUs or DFUs.18
The results of the present study indicate that patients with VLUs tend to be older, female, overweight or obese, and have more than 1 wound. Age typically plays a role in the development of VLUs, as the venous valve function declines as people age.19 In addition to age, being overweight (BMI ≥ 25) or obese (BMI ≥ 30) appeared to be a risk factor for the development of VLUs in the present study; this is supported by the finding that obesity was related to lower venous peak velocity, mean velocity, velocities amplitude (peak velocity-minimum velocity), and shear stress.20 Sex also may be a confounding factor for the development of VLUs as there are typically more females in the general senior population.21
No difference was found between VLUs and wounds of other common etiologies in marital status, education level, and number of comorbidities, indicating that these factors may not be involved in the development of wounds of specific etiologies. Interestingly, in the present study, although etiologies varied, as compared with VLUs, PUs and DFUs are both more likely to be seen in those who are younger, male, and have a wound duration of no less than 180 days but are less likely to reach CWC. While the pathophysiology of PUs and DFUs is understood, current treatments remain limited in both preventing the occurrence and expediting the healing of PUs and DFUs.22
In general, understanding the differences between VLUs and wounds of other etiologies in terms of wound healing outcomes and wound characteristics provide valuable information for clinicians with respect to plan of care, helping patients better understand the wound healing process, assisting health care policy makers regarding the extensive treatment duration required for CWC and thus an appropriate structure and allocation of medical resources, and educating insurance companies in creating tailored reimbursement structures for different wound etiologies.