Background/Purpose : The Bath Ankylosing
Spondylitis Disease Activity Index (BASDAI) is the more frequently used index
for evaluating disease activity in Spondyloarthritis (SpA) in clinical practice. However patients frequently have
questions concerning its wording or need assistance to fill it out. Despite BASDAI
is a patient reported outcome, physicians often ask the questions to the
patients themselves and give their own explanations. Moreover, in patients with
axial SpA a short version of the BASDAI including only questions 1,2,5 and 6
has been proposed (referred here to axial-BASDAI).

These remarks prompted
us to conduct this study aiming to assess the agreement between doctor’s and
patient’s BASDAI and axial-BASDAI in the clinical evaluation of patients with
SpA in daily practice.

Methods:

Study design: this was a cross-sectional
study including patients with axial SpA according to the rheumatologist. Patients
filled out the BASDAI questionnaire in the waiting room. Thereafter, unaware of
the results provided by the patients, the rheumatologist collected another
BASDAI by reading out loud the questions to the patient and giving explanations
if needed.

Statistical analyses: agreement between patient
and physician BASDAI and axial-BASDAI were compared by the intraclass coefficient
of correlation (ICC) and its 95% confidence interval (CI) for continuous
variables and  by the kappa statistics (95%CI) when evaluating the percentage
of patients with high disease activity (e.g. BASDAI > 4).

Results:

Of the 50 enrolled
patients (mean age: 44± 10 years; disease duration: 15 ± 10 years) 32 (64%) were male, 40
(81,6%) were B27 positive and 34 (69,4%) had a radiographic sacroiliitis.

The agreement between
patient’s versus physician’s BASDAI and axial BASDAI were excellent [ICC 0.91 [95% CI, 0.84-0.95]] and ICC
0.94 [95%
CI,
0.90-0.97]] respectively.  Regarding each question of the BASDAI (see table)
the lowest
 agreement was found for Q4 (i.e. referring to enthesitis) with an ICC[95%CI] = 0.51 [0.28 – 0.69].

The agreement between patient and
physician assessment of high disease activity (e.g. BASDAI >
40 yes/no) was better when considering the axial BASDAI in comparison with the
total BASDAI (see table).  

Table 1

Conclusion:

Despite an excellent agreement between the physician’s
and  patient’s total BASDAI scores, these data
suggest that:

a)The
fourth question of the BASDAI (e.g. relative to enthesitis) is the less
concordant.

b)The physician’s
reported total BASDAI resulted in lower number
of patients considered as active patients.

c) Such results should
prompt the scientific community to revise such outcome or at least to provide
clear recommendations on the optimal way to collect it.