Treat-to-target Strategy in Ankylosing Spondylitis Using Etanercept and Conventional Synthetic DMARDs

The test for CRP is a laboratory measurement for evaluation of an acute phase reactant of inflammation through the use of an ultrasensitive assay. A decrease in the level of CRP indicates reduction in inflammation and therefore improvement.

ESR is a laboratory test that provides a non-specific measure of inflammation. The test assesses the rate at which red blood cells fall in a test tube. Normal range is 0-30 millimeter/hour (mm/hr). A higher rate is consistent with inflammation.

The BASDAI score was determined using a simple, self-reported questionnaire that consists of 6 questions on disease activity. Each question is scored from 0 to 10 (0 = no symptoms, 10 = very severe symptoms).

The ASDAS tool is a self-administered questionnaire plus an objective laboratory evaluation. The questionnaire covers disease activity, back pain, and peripheral pain/swelling assessed on a visual analogue scale (from 0 (normal) to 10 (extreme pain or disability) cm) and duration of morning stiffness on a numerical rating scale (from 0 to 10, with 0 being none and 10 representing a duration of 2 hours or longer). The laboratory parameter is a measurement of C-reactive protein (mg/L) (CRP) or erythrocyte sedimentation rate (mm/h) (ESR). Data from five variables (disease activity, back pain, duration of morning stiffness, peripheral pain/swelling, and either CRP or ESR values) are combined to yield a score ranging from 0 to no defined upper limit. Higher scores indicate higher disease activity. Remission is defined as ASDAS score <1.3. Clinically important improvement is defined as a change >= 1.1 units, and major improvement is defined as a change >= 2.0 units.

BASFI is a validated self assessment tool that determines the degree of functional limitation in AS. Participants answered 10 questions, consisting of 8 specific questions regarding function in AS and 2 questions reflecting the participant's ability to cope with everyday life. Each question was answered on a 0-10 scale (0 being no problem and 10 being the worst problem), the sum of which (divided by 10) resulted in the BASFI score (0-10).

EQ 5D is a participant rated questionnaire to assess health-related quality of life. Health State Profile component assesses level of current health for 5 domains: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression; 1 indicates better health state (no problems); 3 indicates worst health state (extreme problems).

The Medical Outcome Study health measure SF-36 questionnaire is a well-validated and widely used quality-of-life instrument. It is a self-administered survey that consists of 8 multi-item scales: The 4 subscales of the SF-36 comprises the PCS (physical functioning, role-physical, bodily pain, and general health) score and the 4 subscales of the SF-36 comprises the MCS (vitality, social functioning, role-emotional, and mental health) score. PCS and MCS are scored from 0 to 100 with higher scores indicating better health (worst value is 0 and best value is 100), which are scored using a norm-based system where linear transformations are performed to transform scores to a mean of 50 and standard deviation of 10.

SPARCC score for the sacroiliac joint was based on 6 consecutive coronal slices from posterior to anterior. Each joint was divided into 4 quadrants. Each quadrant was assigned a score of 0 = no lesion/1 = increased signal. For each slice, the score is increased by 1 for each joint that exhibits an intense signal in any quadrant. Also, for each slice, an additional score of 1 will be given for each joint that includes a lesion demonstrating continuous increased signal of a depth ≥1 cm from the articular surface. The maximum possible score is 72.

Any untoward medical occurrence in a participant who received study regents was considered an AE, without regard to possibility of relationship. An AE resulting in any of the following outcomes, or deemed to be significant for any other reason, was considered to be a SAE: death; initial or prolonged inpatient hospitalization; a life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly.