International Wound Journal ISSN 1742-4801 ORIGINAL ARTICLE Heel ulcers do heal in patients with diabetes Hedvig Örneholm1 , Jan Apelqvist2 , Jan Larsson1 & Magnus Eneroth1 1 Department of Orthopaedics, Skåne University Hospital and Lund University, Sweden 2 Department of Endocrinology, Skåne University Hospital and Lund University, Sweden Key words Diabetes; Healing; Heel ulcer; Outcome Örneholm H, Apelqvist J, Larsson J, Eneroth M. Heel ulcers do heal in patients with diabetes. Int Wound J 2016; doi: 10.1111/iwj.12654 Correspondence to H. Örneholm Department of Orthopaedics Skåne University Hospital S-20501 Malmö Lund University Lund Sweden E-mail: hedvig.orneholm@med.lu.se Abstract A heel ulcer is considered to be a serious complication in patients with diabetes, and there is limited information regarding outcome. In most of the literature, a poor prognosis is described. The aim of this study was to investigate a large cohort of ulcers located in the heel in patients with diabetes. Seven hundred and sixty-eight patients [median age 73 (17–98)], presenting with a heel ulcer at a multidisciplinary diabetes foot clinic, fulfilled the inclusion criteria and were followed-up until final outcome. Fifty-eight per cent of the patients healed primarily; 7% healed after major debridement; 9% healed after amputation and 25% died unhealed. Median healing time was 17 weeks. Ulcer progression was seen in 19% of patients. Thirty-one percent of patients had severe peripheral vascular disease. A creatinine level below 91 μmol/l was related to a higher probability for healing without major debridement or amputation, whereas vascular surgery, nephropathy and oedema were related to a lower probability for healing without major debridement or amputation. Two thirds of heel ulcers do heal in patients with diabetes despite patients being elderly and with extensive comorbidity. The extent of peripheral vascular disease, nephropathy, oedema and decreased renal function are important factors influencing outcome. Introduction A heel ulcer is considered to be a serious complication in patients with diabetes and is often described with a poor outcome (1). In the literature, there are few studies that specifically focus on ulcers located on the heel, and many of these report on small numbers or selected cases, and there is no clear consensus on management (2,3). A common opinion is that a patient with diabetes and a heel ulcer almost invariably ends up with an amputation above the ankle. There are also a number of studies detailing different surgical procedures to enhance healing of a heel ulcer (4–7). To our knowledge, there is only one other study, published in 2005 by Chipchase and colleagues (8), reporting on heel ulcers and outcome. The purpose of this study was to evaluate a large cohort of consecutively presenting patients with diabetes and an ulcer located on the heel at a multidisciplinary foot care centre. Patients and methods Design This is a large cohort study of consecutively presenting patients with diabetes and heel ulcers, followed-up © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd doi: 10.1111/iwj.12654 prospectively until final outcome (healing or death). All patients were followed-up according to a preset protocol. Patient data were gathered prospectively as they visited the diabetic foot clinic. Analysis of collected data was performed in 2015 by the first author. Minimum follow-up time was 2 years. Patient population All 4273 patients with diabetes who presented with a foot ulcer at the multidisciplinary diabetes foot clinic (tertiary centre) from 1 January 1983 to 31 December 2013 were considered Key Messages: • heel ulcers do heal in patients with diabetes • vascular disease of such severity as to have required vascular surgery, oedema and decreased renal function were factors negatively influencing outcome • fifty-eight percent (447/768) of patients healed primarily; 7% (57/768) healed after major debridement; 9% (72/768) healed after major amputation and 25% (192/768) died unhealed 1 H. Örneholm et al. Heel ulcers do heal in patients with diabetes Patients with a foot ulcer admitted to the diabetic foot care team, 1983-2013 n = 4273 Ulcer of other location n = 2758 Multiple ulcers n = 671 Patients with heel ulcer n = 844 Not fulfilling inclusion criteria n=7 Included n = 837 Drop-out n = 66 Ongoing treatment n=3 Available for analysis n = 768 Healing without amputation n = 504 Without major debridement n = 447 Deceased unhealed n = 192 Healing after major amputation n = 72 With major debridement n = 57 Figure 1 Outcome of heel ulcers in patients with diabetes. n = number of patients. for inclusion (Figure 1). Inclusion criteria for this study were diabetes and an ulcer located on the heel. If a patient presented with bilateral heel ulcers, the ulcer with the worst outcome was included. Patients with multiple ulcers were not included. During the observation period, 844 patients were originally classified as fulfilling the inclusion criteria (Figure 1). Seven patients were excluded from the analysis after re-evaluation of the data. Sixty-six patients were lost to follow-up, and three patients had ongoing treatment at last follow-up in this study (30 June 2015). Thus, a total of 768 patients (432 males, 336 females) with a median age of 73 (17–98) years remained for analysis in this study. The median duration of diabetes was 17 (0–72), years and 56% of the patients were male (Table 1). Hypertension was present in 67% of patients, and 39% of patients had ischaemic heart disease. Thirty-five percent of patients had evidence of nephropathy, and 12% had end-stage renal disease. Seventy-four percent of patients lived in their own home, and 52% did not have any home assistance (Table 1). In 87% of patients, good concordance was noted. Eleven percent of patients had had an amputation prior to entering the study, either a minor amputation on the same side or an amputation at any level on the contralateral side. Vascular surgery had been performed in 6% of patients prior to entering the study and was performed in 23% of patients during the 2 course of the study. Of the 46 patients who had vascular surgery prior to enrolment, 15 (33%) patients had endovascular surgery, and 31 (67%) patients had open vascular reconstruction. Of the 176 patients who had vascular surgery during the course of the study, 48 (27%) patients had endovascular surgery, and 128 (73%) had open vascular reconstruction. At enrolment, 38% of patients had a history of a previously healed ulcer on either foot (Table 1). Setting/organisation The diabetic foot centre is located at a university hospital with a primary care catchment area of approximately 700 000 people at the end of the study. This centre is the single provider of specialised diabetic foot care in this area, from the year 2000, operating in two geographic locations, and is also a tertiary referral centre for the surrounding regions. The management protocol at the diabetic foot clinic is based on a multidisciplinary approach and has been previously described (9–13). Briefly, it consists of inpatient and outpatient visits, regular podiatric care, individually adjusted footwear, regular ulcer dressings and access to specialists in vascular surgery, orthopaedics and infectious diseases when needed. When presenting with a foot ulcer, the patients were seen by the multidisciplinary foot care team, consisting of a diabetologist, an orthopaedic surgeon, a diabetes © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd H. Örneholm et al. Heel ulcers do heal in patients with diabetes Table 1 Patient characteristics at inclusion and outcome. Values are n (%) or median (range) All patients Primary healing Healing after major debridement, no amputation Healing after amputation Deceased unhealed Primary healing versus all others P value 768 73 (17–98) 432 (56) 17 (0–72) 520 (68) 126 (16) 515 (67) 272 (35) 268 (35) 95 (12) 91 (29–1101) 296 (39) 278 (36) 223 (29) 223 (29) 123 (69–185) 7⋅5 (3⋅4–14⋅9) 571 (74) 397 (52) 86 (11) 46 (6) 176 (23) 447 (58) 71 (19–96) 244 (55) 15 (0–70) 301 (67) 75 (17) 292 (65) 156 (35) 142 (32) 49 (11) 88 (29–978) 159 (36) 142 (32) 110 (25) 111 (25) 126 (70–169) 7⋅5 (4.6–14⋅2) 360 (81) 263 (59) 39 (9) 20 (5) 82 (18) 57 (7) 65 (17–88) 32 (56) 12 (0–55) 39 (68) 9 32 (56) 28 (49) 17 (30) 5 80 (45–808) 15 (26) 11 (19) 16 (28) 16 (28) 129 (74–161) 8⋅4 (4⋅8–14⋅9) 43 (75) 35 (61) 4 5 14 (25) 72 (9) 70 (49–89) 47 (65) 22 (1–72) 51 (71) 16 (22) 54 (75) 33 (46) 40 (56) 16 (22) 121 (37–1101) 33 (46) 29 (40) 28 (39) 24 (33) 111 (69–163) 7⋅6 (4⋅1–12⋅1) 57 (79) 34 (47) 14 (19) 8 39 (54) 192 (25) 79 (40–98) 109 (57) 20 (0–56) 129 (67) 26 (14) 137 (71) 55 (29) 69 (36) 25 (13) 101 (30–632) 89 (46) 96 (50) 69 (36) 72 (38) 120 (84–185) 6⋅9 (3⋅4–14⋅9) 111 (58) 65 (34) 29 (15) 13 (7) 41 (21) <0⋅0001 ns ns ns ns ns 0⋅07 0⋅03 ns 0⋅03 0⋅05 0⋅003 0⋅001 0⋅002 <0⋅0001 ns <0⋅0001 <0⋅0001 0⋅01 0⋅04 0⋅0004 specialist nurse, an orthotist and a chiropodist. The team works in close cooperation with vascular surgeons and also has access to specialists in infectious diseases. The patients were treated by the team both as in- and outpatients and followed-up by the team until final outcome (healing with or without amputation or deceased unhealed). Definitions Number of patients Age Male gender Duration of diabetes (years)* Diabetes treatment with insulin Current smoker Hypertension Retinopathy†(preprolif + prolif) Nephropathy End-stage renal disease Creatinine level‡(μmol/l) Ischaemic heart disease Congestive heart failure Non-ischaemic heart disease Cerebrovascular lesion Haemoglobin level§(g/l) HbA1c at hospital admission¶(%) Living in own home No home care Previous amputation Vascular surgery prior to inclusion Vascular surgery after inclusion|| *Duration of diabetes not known for 133 patients. †No retinal examination performed in 209 patients. ‡No creatinine level recorded for 180 patients. §No haemoglobin level recorded for 206 patients. ¶No HbA1c recorded for 207 patients. ||No record of vascular surgery for 30 patients. Clinical examination At inclusion, all patients were questioned for medical history and examined, and the findings were recorded according to a preset protocol (12,14). The lesions were classified according to the Wagner classification (15). Measurements Systolic toe and ankle blood pressure measurements were obtained using strain gauge and Doppler techniques as previously described (14). In cases where the patient was found to have decreased peripheral blood circulation, the patient was referred to a vascular surgeon for evaluation and, if possible, treatment with vascular surgery. In 274 patients, ankle or toe pressure measurements were not obtained (because of previous amputation, calcified arteries or the patients’ medical condition) or were considered unnecessary (because of palpable foot pulses). © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd General characteristics Duration of diabetes was calculated from the year of diagnosis until presentation with an ulcer at the foot clinic. Nephropathy was defined as persistent urine albumin > 300 mg/l (13). End-stage renal disease (ESRD) was defined as uremia (creatinine level > 300 μmol/l), treatment in dialysis or a previous renal transplantation. Patients were defined as smokers when currently smoking or having stopped smoking for less than one year. Hypertension was defined as blood pressure over 140/90 mm Hg or treatment with antihypertensive agents. Retinopathy was classified as pre-proliferative or proliferative based on retinal photographs by an ophthalmologist. Cardiovascular comorbidity was divided into ischaemic heart disease (angina pectoris or myocardial infarction), non-ischaemic heart disease (e.g. atrial fibrillation or valvular heart disease), or congestive heart failure (13). Cerebrovascular comorbidity was defined as previously described (13). Assisted living was defined as any institutional living outside the patients’ own home. Home care was defined as any assistance the patient had in his or her own home. Good concordance was defined as the ability to keep 50% or more of appointments with the multidisciplinary foot care team (13). 3 H. Örneholm et al. Heel ulcers do heal in patients with diabetes Extremity-related characteristics Severe peripheral vascular disease (SPVD) was defined as toe pressure less than 45 mmHg or ankle pressure less than 80 mmHg. For classification of peripheral vascular disease, the lowest distal blood pressure measurement was used. Pain was defined as rest pain localised to the foot. Oedema was defined as swelling of the foot enough to leave a finger imprint. Previous amputation and previous vascular surgery were defined as having been performed on either side before the patient entered the study. Ulcer-related characteristics An ulcer was defined as a full thickness lesion through all the layers of the skin and classified according to Wagner (15). Superficial skin infection or cellulitis was not reported separately in the protocol (Wagner classification). An increase in Wagner grade from time of inclusion during time of treatment was recorded. Ulcer duration was defined as number of weeks from onset of ulcer until arrival at the foot clinic. When time of onset could not be established, ulcer duration was categorised as unknown. Healing was defined as macroscopically complete epithelialisation and had to be reconfirmed after 6 months (10). If the ulcer reoccurred during the first 6 months, it was per definition not healed. Healing time was defined as number of weeks from arrival at the foot clinic until healing. After healing is reconfirmed after 6 months, patients are not followed-up at the diabetic foot centre. Patients are recommended regular visits to a podiatrist and regular check-ups at their primary care facility. If a new ulcer develops, patients are referred to the outpatient clinic and treated accordingly. Minor debridement was defined as such the removal of callosities and debris that could be performed in the outpatient clinic without anaesthesia. Major debridement was defined as surgical revision or resection of soft tissues and/or bone, requiring anaesthesia and/or the use of an operation theatre (1). Primary healing was defined as healing with intact skin without amputation and was subdivided into healing with or without major debridement. Off-loading Upon arrival at the foot clinic with an ulcer located on the heel, the patients were immediately prescribed total pressure relief, both prescribed for walking, sitting and bedridden patients. Type of off-loading was adapted to the patients’ individual need and medical condition and was modified as required during the course of treatment. with the specialists concerned (1,9–12). The strategy for management in cases of diabetic foot infections is suggested by a programme written in close cooperation with the department of infectious diseases, including diagnosis, investigations, cultures, microbiology and antimicrobial treatment. When clinical signs of infection were present, oral antibiotics were given. Patients with deep abscess or osteomyelitis were hospitalised, and intravenous antibiotics were administered (16). Analgesia was used related to cause and intensity of pain. Hospitalisation was used in case of the need for acute surgical treatment, parenteral antibiotics or when there was a deterioration of infection despite non-operative treatment. The treatment chosen in each case was based on written guidelines at our institution (in cooperation with the department of infectious diseases), including antibiotic treatment, and changed when decided necessary by the responsible physician (16). Topical treatment was prescribed by the multidisciplinary foot care team according to the individual wound bed condition. Dressing changes were supervised by a registered nurse in primary health care and/or home nursing services. Telephone support during daytime was provided by the team. Surgical treatment Minor debridement was performed as required at the outpatient clinic by a chiropodist. Major debridement and amputation were performed at the discretion of, and by, an orthopaedic surgeon. A non-healing ulcer was not per se considered an indication for amputation (11). Dry and inactive necrosis with or without an underlying osteomyelitis were left for mummification as long as pain and infection would allow. Acute incision and drainage was performed in case of a deep abscess (16). Vascular surgery (including endovascular and open methods) was performed at the discretion of, and by, a vascular surgeon. Major amputation was defined as an amputation proximal to the ankle joint. Statistics Values are given as numbers or median (range) unless otherwise stated. Statistical analysis (chi2 ) was performed for those who healed without major debridement or amputation versus those who healed after major debridement or amputation or were unhealed at death. A stepwise multiple logistic regression model with backward selection, including variables with P < 0⋅1, was performed to determine factors related to outcome. All statistical analysis was performed using IBM SPSS Statistics 21 (SPSS, Chicago, IL). Ethical approval Non-surgical treatment Treatment was carried out in close cooperation with primary care and home care. Individually adjusted off-loading equipment (total contact cast, individually fitted shoes and/or insoles, orthosis) was offered to all patients. Infection, metabolic control, peripheral arterial disease, oedema and comorbidity were managed in close cooperation 4 The Regional Ethical Review Board approved the study. Results The median ulcer duration at inclusion was 4 (0⋅5–166) weeks (Table 2). There was no correlation between ulcer duration and outcome (data not shown). © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd H. Örneholm et al. Heel ulcers do heal in patients with diabetes Table 2 Local characteristics at inclusion and outcome. Values are n (%) or median (range). Number of patients Foot oedema Ulcer duration at inclusion* (weeks) Wagner grade at inclusion Precipitating factors 1 (superficial ulcer) 2 (deep ulcer) 3 (abscess and/or osteomyelitis) 4 (gangrene of portion of foot) 5 (gangrene of greater part of foot) Intrinsic ulcer Pressure ulcer Cracked skin Miscellaneous Severe peripheral vascular disease (toe pressure < 45 or ankle pressure < 80 mm Hg) No severe peripheral vascular disease (toe pressure < 45 or ankle pressure < 80 mm Hg) No distal pressure measurement Toe pressure (mm Hg) Ankle pressure (mm Hg) Local foot pain Healing after amputation Deceased unhealed Primary healing versus all others P value <0⋅0001 0⋅04 All patients Primary healing Healing after major debridement, no amputation 768 284 (37) 4 (0⋅5–166) 447 (58) 130 (29) 4 (0⋅5–166) 57 (7) 21 (37) 5 (0⋅5–41) 72 (9) 43 (60) 4 (0⋅5–157) 192 (25) 90 (47) 4 (0⋅5–53) 653 (85) 82 (11) 18 (2) 415 (64) 26 (32) 4 38 (6) 11 (13) 8 50 (8) 15 (18) 2 150 (23) 30 (37) 4 8 2 0 1 5 7 0 0 4 3 90 (12) 331 (43) 96 (13) 251 (33) 237 (31) 62 (69) 146 (44) 76 (79) 163 (65) 118 (26) 9 18 (5) 5 25 (10) 11 (19) 7 31 (9) 4 30 (12) 33 (46) 12 (13) 136 (41) 11 (11) 33 (13) 75 (39) 257 (33) 168 (38) 35 (61) 17 (24) 37 (19) 274 (36) 161 (36) 11 (19) 22 (31) 80 (42) 53 (5–224) 60 (10–224) 95 (10–290) 104 (23–290) 185 (24) 86 (19) 70 (15–210) 128 (45–225) 9 40 (10–140) 39 (5–135) 73 (10–214) 65 (15–220) 24 (33) 66 (34) 0.002 <0⋅0001 0⋅001 <0⋅0001 *Ulcer duration is not known for 111 patients. Superficial ulcers (Wagner grade 1) were the most commonly presenting ulcers (85% of ulcers), and a pressure ulcer was the most common precipitating factor (43% of ulcers; Table 2). In patients with a pressure ulcer as the precipitating factor, the primary healing rate was 44% (146/331). In patients with cracked skin, intrinsic ulcer or miscellaneous cause as the precipitating factor, the primary healing rate was 79% (76/96), 69% (62/90) and 65% (163/251), respectively. Patients with a pressure ulcer had a higher mortality rate (41%) than patients with other precipitating factors (P < 0⋅0001). For the 33 patients (4% of all included patients) in our study who had an ulcer classified as Wagner grade 3 or higher upon arrival at the foot clinic, six healed without surgery or amputation; eight healed after major debridement; seven healed after major amputation; and 12 were unhealed at death. SPVD was present in 31% of patients. Foot oedema was present in 284 patients (37%), and 185 patients (24%) had presence of pain. Progress of Wagner grade was seen in 19% of patients. Outcome Sixty-six per cent of patients (504/768) achieved healing without (n = 447) or with (n = 57) major debridement; 9% (72/768) healed after an amputation and 25% (192/768) died unhealed © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd Table 3 Outcome according to period at inclusion. Values are n (%) Outcome Healing (without major debridement or amputation) Healing (with major debridement, no amputation) Healing after amputation Deceased unhealed 1983–2000 2001–2013 P value 120 (54) 327 (60) ns 39 (18) 18 (3) 0⋅001 18 (8) 45 (20) 54 (10) 147 (27) ns 0⋅05 (Figure 1). Of the 57 patients who healed after major debridement, four patients had a resection, and another four patients had a skin transplant. Primary healing in surviving patients was 78% (447/576). Patients included after the year 2000 had a lower healing rate with major debridement and a higher frequency of patients who died unhealed (Table 3). Median healing time from inclusion was 17 (1–416) weeks. Healing time for those who healed following major debridement (28 weeks) or amputation (24 weeks) was longer than for those who had neither major debridement nor amputation (14 weeks, P < 0⋅0001). No correlation could be found between ulcer duration and healing time (data not shown). 5 H. Örneholm et al. Heel ulcers do heal in patients with diabetes Table 4 Stepwise multiple regression analysis with backward selection of factors related to outcome between patients who healed without surgical intervention and patients who healed after major debridement or amputation Odds ratio (95% CI) P value 3⋅8 (1⋅9–7⋅2) 2⋅5 (1⋅3–4⋅9) 2⋅4 (1⋅3–4⋅4) 2⋅1 (1⋅1–4⋅2) <0⋅0001 0⋅007 0⋅007 0⋅03 No vascular surgery No nephropathy No oedema Creatinine < 91 μmol/l Factors related to outcome A number of patient and local characteristics were found to be related to outcome when bivariate analysis (chi2) was performed (Tables 1 and 2). When a stepwise multiple regression analysis with backward selection was performed, vascular surgery (P < 0⋅0001), nephropathy (P = 0⋅007) and oedema (P = 0⋅007) were factors related to a lower probability for healing without major debridement or amputation, and a creatinine level below 91 μmol/l (P = 0⋅03) was found to be related to a higher probability for healing without major debridement or amputation (Table 4). Discussion This is, to our knowledge, the largest study to date on a cohort of patients with diabetes and an ulcer located on the heel and followed-up until final outcome. An ulcer located on the heel in patients with diabetes is a serious complication. In a larger cohort of foot ulcers, regardless of ulcer location, heel ulcers made up 10% of all foot ulcers (17). In our study, ulcers located on the heel in patients with diabetes make up 20% of foot ulcers. Most studies regarding ulcers located on the heel in patients with diabetes have small numbers or a selected category of patients (1–8,18,19). In this study of 768 consecutively presenting diabetes patients with a heel ulcer, 66% healed without an amputation; 9% healed after an amputation, and 25% died unhealed. In surviving patients, 78% healed without an amputation. Reported healing rates of heel ulcers in patients with diabetes vary between 51% and 95%, including between 12 and 100 patients (5,6,8,19). In agreement with Chipchase et al. (8), our results contradict the prevailing belief that most heel ulcers will require an amputation above the ankle joint. Such a belief might well act as a self-fulfilling prophecy and thereby maintain itself. A team approach to this group of patients, early referral to a centre with expertise in caring for diabetic foot ulcers and adequate pressure relief are key elements in our treatment strategy and might have played a role in the favourable outcome. The price to pay is often a long healing time. In a previously published work on plantar forefoot ulcers in patients with diabetes (20), the overall healing rate without amputation was 79%. We consider a healing rate without amputation of 66% in patients with heel ulcer a good outcome, especially as these patients are older and often have more extensive comorbidity than those with plantar forefoot ulcers. In this study, the ulcer duration was relatively short, with a median of 4 weeks at inclusion. Eighty-five percent of heel 6 ulcers were superficial upon arrival at the foot clinic. In most of the published data on ulcers located on the heel, the ulcers are deeper at inclusion (4–7,19,21). This indicates that our patients are referred to the multidisciplinary centre at an early stage in ulcer management. This early referral to a multidisciplinary centre, before the ulcer has progressed to exposed bone, and total off-loading may be important regarding outcome. In the present study, 25% of the patients died unhealed. This is higher in comparison to most other studies where mortality ranges between 5% and 21% (4–8,18,19,21). The patients in our study had a higher age and extensive comorbidity. There was also no set time limit to follow-up, but all patients were followed-up to final outcome. The mortality rate in patients with a pressure heel ulcer (43%, 331/768 patients) was considerably higher than in patients with other precipitating factors. This could be because of these patients having more comorbidities. The findings in our study indicate that ulcers located on the heel in patients with diabetes overall do not have a poor outcome. However, pressure ulcers may be considered a separate entity with a potentially poorer prognosis. For 111 patients, ulcer duration could not be established. Among these patients, 52% (58/111) healed without major debridement;6% (7/111) healed after major debridement; 13% (14/111) healed after major amputation and 29% (32/111) died unhealed. Two previous studies have indicated a relationship between ulcer duration and outcome (22,23). In this study, we could not find any correlation between duration of ulcer and outcome or healing time, consistent with the findings in another study (20). The median healing time in our study was 17 weeks. A longer healing time was seen for patients who had an amputation or major debridement than for those who healed primarily. In studies where healing time is reported, the healing time was between 10–33 weeks (4,5,8,19,21,24). Comparing healing times between studies is not easy as there are no clear definitions, and healing is not always defined. In this study, all patients are followed-up to final outcome, and unlike in many other studies, there is no set time limit to follow-up. Another important difference from most other studies is that time to heal is registered from the date of arrival at the foot clinic, not from the date of surgery. In the literature, there are some studies that look at factors related to outcome. Treiman and colleagues (18) found that normal renal function, a palpable foot pulse, functioning posterior tibial artery and the number of functioning tibial arteries predicted the healing of heel ulcers. Bakheit and colleagues (19) found that short duration of diabetes, adequate circulation and a superficial wound were factors associated with healing, while Chipchase and colleagues (8) found that a larger ulcer and presence of peripheral arterial disease predicted a worse outcome. In a large mixed cohort study of diabetic foot ulcers comorbidity, severe PAD, infection and extent of tissue involvement were factors associated with outcome (1,25). Multivariate analysis in the present study showed that vascular surgery, nephropathy and oedema were the most important factors related to poor outcome, whereas a creatinine level below 91 μmol/l was the only factor related to a higher probability for healing without major debridement or amputation. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd H. Örneholm et al. This is a study of a large, well defined patient material in which all patients are followed according to a standardised protocol. All patients are followed-up to final outcome, both as inpatients and outpatients, by the multidisciplinary foot care team. There are, however, some potential weaknesses to consider in interpreting the data. In this study, we included patients with an ulcer located on the heel. Patients classified as having multiple ulcers were not included. Among the patients admitted to our centre, 671 were classified as having multiple ulcers. In this group of patients, there could be a number of heel ulcers as well. Discerning which of these patients had a heel ulcer as well is not possible. Analysis of patients with multiple ulcers admitted to our centre showed that these patients had a higher mortality rate (33%) and a lower primary healing rate (21%) than patients with ulcers located on the heel. One possible reason for this is that patients with multiple ulcers have more severe disease and comorbidity (12). This cohort spans over three decades, and undoubtedly, there have been changes and evolvement in treatment over the years. When analysing the data according to time period, patients included after the year 2000 had a lower healing rate after major debridement and a higher frequency of patients who died unhealed. The reason for this is not known. When following-up patients over a longer period of time, it is inevitable that there will be changes in daily practice, which has to be taken into consideration when evaluating cohorts over time. Ulcers in this study were classified according to Wagner. This classification has a weakness; it does not describe ulcer area or extent of infection. Unfortunately, it is not possible to reclassify the ulcers to more recent systems retrospectively as the older records lack information on, for example, ulcer size and classification of infection. Major conclusions The most important finding in our study is that ulcers located on the heel in patients with diabetes have a high probability for healing. Evidence of vascular disease of such severity as to have required vascular surgery, oedema and decreased renal function were factors negatively influencing the outcome. Heel ulcers do heal in patients with diabetes 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. References 1. 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