RCTs underestimate comorbidity in AS patients

Australian patients with ankylosing spondylitis (AS) who are starting biological therapy in routine clinical practice have more comorbidities than those who have met the inclusion criteria for clinical trials, Australian rheumatologists say. They compared the baseline characteristics of almost 400 AS patients in the Australian Rheumatology Association Database (ARAD) with participants enrolled in published randomised controlled trials (RCTs) of biological DMARDs for AS. Two thirds of the AS patients in ARAD had at least one comorbid condition and almost half (46%) had more than one, the authors reported in the International Journal of Rheumatology. The level of comorbidity was similar to that of patients with rheumatoid arthritis enrolled in ARAD even though, on average, the AS patients were younger. Almost 7% of the AS patients had a history of malignancy. Higher comorbidity in the 'real world' ARAD patients probably reflected the fact that they were older, had a longer duration of disease and more severe disease compared to trial participants. These features were likely to be a result of the ‘stringent’ PBS requirements for the use of bDMARDS for AS in Australia. The authors noted the general difficulty in achieving comparable efficacy between RCTs and clinical practice. In the case of AS the differences were probably accentuated by a lack of effective treatment options prior to the introduction of bDMARD therapy for AS, leading to a cohort of community-treated patients with long-standing and relatively severe disease. The findings highlighted the importance of systematically collecting postmarketing longitudinal outcome data in routine care, they concluded. International Journal of Rheumatology 2010...