BASDAI Score Calculator - Disease Activity

The Bath Ankylosing Spondylitis Disease Activity Index, abbreviated BASDAI, is a six-question patient-reported measure used in axial spondyloarthritis and ankylosing spondylitis care. It asks about fatigue, spinal pain, peripheral joint pain or swelling, localized tenderness, the severity of morning stiffness, and the duration of morning stiffness during the previous week. Each response is recorded on a 0 to 10 scale, with higher numbers representing worse symptoms. The scoring method gives the two morning-stiffness questions a combined weight equal to one other question. First, the severity and duration ratings are averaged. That average is added to the first four ratings, and the total is divided by five. The final BASDAI therefore ranges from 0 to 10. For example, ratings of 6, 7, 4, 3, 8, and 6 produce a stiffness average of 7, a sum of 27, and a BASDAI of 5.4. A score of 4 or higher is commonly used as one indicator of active disease and has historically appeared in eligibility or response criteria for some therapies. It is not a universal diagnostic cutoff and should not be interpreted in isolation. Treatment guidelines, payer requirements, and research protocols may combine BASDAI with other measures, documented inflammation, previous treatment response, and clinician judgment. A result below 4 does not mean that symptoms are unimportant or that disease is absent. Consistency improves comparisons over time. Answer each question for the same recall period, use the full scale, and base ratings on the past week rather than only the best or worst day. For the duration question, clinical forms usually anchor 0 as no stiffness and 10 as stiffness lasting two hours or longer. If a clinician or study provides a specific questionnaire layout or anchor wording, follow that version so repeated scores remain comparable. BASDAI reflects the patient's experience, which is valuable, but symptoms can also be influenced by mechanical pain, sleep, mood, infection, fibromyalgia, medication changes, and other conditions. It does not directly measure structural damage or laboratory inflammation. Clinicians may review it alongside examination, C-reactive protein, imaging, function measures, and an alternative disease activity score such as ASDAS. Use this calculator for accurate arithmetic and symptom tracking, not for self-diagnosis or independent changes to medication. Discuss persistent, worsening, or concerning symptoms with a qualified healthcare professional.