Factors associated with healing leg ulceration with high compression

Age and Ageing, Sept, 1995 by Peter J. Franks, Christine J. Moffatt, Marjorie Connolly, Nick Bosanquet, Margaret I. Oldroyd, Roger M. Greenhalgh, Charles N. McCollum

Introduction

Chronic venous ulceration is a major cause of morbidity in the elderly population of the UK and other western countries [1-3]. In Britain it has been estimated that approximately 75-90 000 patients have an open leg wound at any time, with approximately 2% of women over the age of 80 affected [1,2].

Recent innovations in the treatment of leg ulceration in the community have led to improved healing despite the poor healing thought to be characteristic of leg ulcer patients [4]. A district-wide service providing care for a population of 280 000 in West London achieved healing rates of 69% within 12 weeks using a system of high compression bandaging, rising to 83% after 24 weeks. The assessment and treatment followed a standard regimen [4,5]. The aim of this study was to observe factors which were associated with complete healing.

Patients and Methods

Community leg ulcer clinics were established in six health centres throughout Riverside Health District in West London as part of a project funded by the King Edward's Hospital Fund to deliver innovations in ulcer treatment to the community [4]. Patients were assessed on the day of presentation by clinical nurse specialists. Assessments included factors either known to be important in the healing of leg ulceration or which were associated with the development of venous disease [5]. The area of each ulcer was traced on clear acetate sheets which were later measured using computer planimetry. Ankle brachial pressure indices (ABPI) were measured for all ulcerated limbs, and only those patients with ABPI > 0.8 received high compression bandaging [5]. Ulcerated limbs were bandaged weekly by community nursing staff trained by the vascular surgical service at Charing Cross Hospital, London.

Patients' mobility was classified into three categories; able to walk unaided, walk with aid and chair/bedbound. Duration of ulceration was categorized as less than I month, 1-6 months and >6 months. Body mass index was divided into < 25kg/[m.sup.2], 25-30 kg/[m.sup.2] and 30kg/[m.sup.2]. For multivariate analysis the reference value was the first in each of the categories. For univariate analysis all categories were compared with the-reference category. Table I lists the factors examined in this study.

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In keeping with recommended practice [6] the primary end-point for all analyses was time to complete healing. Likelihoods of healing were estimated up to time of complete healing, and compared using x2 without Yates' correction or for trend where appropriate. For patients with bilateral ulceration the limb with the larger area of ulceration was taken as the reference. Univariate and multivariate relative risks and 95% confidence intervals were calculated and the Cox proportional hazards model was used to identify independent factors associated with ulcer healing [7]. When the `relative-risk' (RR) was greater than unity, the factor was associated with improved healing, and conversely, when the RR was below unity this meant that the factor was associated with delayed healing.

Results

The Riverside project was designed to serve all patients with leg ulceration in the district. Over the first 2 years from the first community clinic opening in February 1989, 475 patients were seen by district nurses in collaboration with a Clinical Nurse Specialist from Charing Cross Hospital [4]. These patients presented a total of 5 54 ulcerated legs, and 477 ulcers (411 patients) were considered to be venous. The remaining ulcers were either arterial with ABPI < 0.8 (56; 10%), associated with rheumatoid arthritis (8; 1%), diabetes (7; 1%) or skin cancer (4; 0.5%).

The cumulative healing rate in patients with ulceration treated by high compression was 69% at 12 weeks rising to 83% by 24 weeks of treatment [4]. Patients with significant arterial disease (0.8 > ABPI >0.5) treated with reduced compression also performed well (56% healed at 12 weeks,75% at 24 weeks). The 12 week healing rate varied between clinics from 62% to 83%.

The patients were old (median age 75.3 years), but most were mobile and only 28 (7%) were chair-or bedbound (Table I). The median duration of ulceration was 3 months though 150 (26%) had been present for longer than 1 year. The median ulcer size was 4.2 [cm.sup.2], with 128 (28%) being greater than l0 [cm.sup.2]. The results of the univariate analysis of risk factors for venous ulceration are shown in Table II. There was a significant reduction in cumulative healing rate in men (24-week healing rates 79% vs. 83%), but no difference associated with patients' body mass index. Smoking was not significantly associated with healing and nor was history of diabetes or hypertension. Previous deep-vein thrombosis was a significant predictor of poor healing as was large ulcer size and long duration of ulceration. Similarly, poor general mobility and poor limb mobility were significantly associated with poorer ulcer healing. On univariate analysis treatment at home was also associated with delayed ulcer healing.

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The independent factors identified by the Cox model are given in Table III. The independent risk factors were ulcer size, fixed limb join .s, ulcer duration and general mobility. After adjustment for these factors the patient's sex, place of treatment and history of deep-vein thrombosis were no longer significantly associated with prolonged ulcer healing.

Table III.Stepwise proportional hazards model to determine independent factors associated with ulcer healing: variables are given in order of fit into the model

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Discussion

This study was an attempt to determine factors associated with prolonged healing of leg ulcers treated with high compression bandaging in a health district service providing for a population of 280 000 people in London. It has long been recognized that it is impossible to treat all patients with leg ulceration in acute services and over three-quarters are treated by community nursing staff alone [1,8]. The methods which have been used in this study were standardized throughout and tested in an outpatient setting prior to introduction to the community service [5].