Epidemiological studies of leg ulcers in Auckland, New Zealand

Abstract

A leg ulcer is generally considered to be any break in the skin on the lower leg (below the knee) or on the foot, which has been present for more than six weeks. Typically the condition is a consequence of disease of the circulatory system, and can cause considerable disability. The Auckland leg ulcer study is a community-based study of leg ulceration conducted in the North Auckland and Central Auckland health districts of New Zealand. The study aimed to determine the prevalence and incidence of leg ulcers in the community and investigate several possible risk factors for the condition. Cases were identified through notifications from health professionals and by self-notification. Cases aged between 40 and 99 years and on the electoral roll for the study region were invited to participate in a case-control study. Controls were individuals without leg ulcers and were selected from the electoral roll using a stratified random sampling process. Controls were also aged between 40 and 99 years and had to be resident within the study region to be eligible. Four hundred and twenty-six cases with current leg ulcers were identified during the 12-month study period, with 241 cases and 224 controls interviewed for the case-control study. Overall, the occurrence of leg ulcers in the general population was low, however, the prevalence and cumulative incidence increased dramatically with age, and changed according to gender and region. The average age at ulcer onset in interviewed cases was 65 years. Leg ulcers took approximately 12 months on average to heal, and recurrence occurred in 59% of cases. Treatment strategies were variable, and almost a quarter of all cases had been admitted to hospital within the last five years because of their ulcers. The average length of hospital stay was 34 days. Results from the case-control study indicated that deep vein thrombosis, lower limb surgery, leg fracture, and varicose veins were strong risk factors for the development of leg ulcers, Furthermore, nulligravida increased the risk of ulcer development while prolonged breast-feeding decreased risk, suggesting a hormonal component to the development of leg ulcers in women. These data have important implications for the prevention of this chronic condition.