The unmet need for anti-tumour necrosis factor (anti-TNF) therapy in ankylosing spondylitis

Anti-tumour necrosis factor (anti-TNF) therapy is effective in the treatment of ankylosing spondylitis (AS), but guidelines are needed because of the cost. The primary aim of this study was to evaluate the proportion of patients with AS who meet the criteria for anti-TNF therapy as well as to explore the relationship between disease activity, health status and quality of life in patients with AS who would potentially meet the criteria compared with those who would not.

All patients with a confirmed diagnosis of AS were identified via a search through the clinic correspondence database and sent postal questionnaires. Data captured included demographics, disease activity, aspects of functional impairment, activity limitation and quality of life using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), pain scores (using a visual analogue scale), the Bath Ankylosing Spondylitis Functional Index (BASFI), Health Assessment Questionnaire (HAQ), short-form 36 (SF-36) and the Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire. The unpaired Student's t-test, chi(2) test and Mann-Whitney U-test were performed for comparisons of groups where appropriate.

Out of 325 mailed questionnaires, 246 (76%) were returned. The mean age of the patients who replied to the questionnaire was 52 yr (+/-12 yr) and 25% (62) were females. Mean BASDAI was 49 (+/-24) and 64% had a BASDAI > or = 40. There were significant differences between the groups with a BASDAI above and below 40 in pain by VAS, functional ability (BASFI, HAQ), health status (SF-36) and quality of life (ASQoL). Almost two-thirds (64%) of patients would meet the criteria for anti-TNF therapy under recommended guidelines.

Patients with AS demonstrated poor functional status and poor quality of life. There is a large unmet need for effective therapy in AS, with almost two-thirds of patients meeting the proposed criteria for biological therapy. Patients with a BASDAI > or = 40 had a worse functional status and quality of life than those who have a BASDAI of <40. These results indicate that the need for effective intervention for AS is a priority area.