[Measurement of quality of life in patients with active ankylosing spondylitis being treated with infliximab-a comparison of SF-36 and SF-12].
BACKGROUND
Quality of life as a part of the WHO definition of health is an important assessment tool for measuring the success in the treatment of chronic diseases. The short form 36 questionnaire (SF-36), which is measuring health related quality of life, was used in a multicentre placebo controlled study in patients with ankylosing spondylitis (AS) treated with the anti-TNF-alpha antibody infliximab. As previously reported, substantial changes of almost all outcome parameters were observed in this study because of the substantial clinical improvement that is known to occur in most patients treated with anti-TNF agents. The short form 12 questionnaire (SF-12) is shorter and quicker to complete as the SF-36. The summary scales of both questionnaires were compared in this study to answer the question whether the SF-12 can also be used in AS patient populations without too much loss of information. Using the shorter from could be an advantage for further studies in patients with AS, for example, the inception cohort for spondyloarthritides within the German Network of competence in rheumatology. Furthermore the data can be compared to the German standard population.


METHODS
In this multicentre placebo controlled study 70 patients with active disease were enrolled: 35 AS patients received placebo, 35 were treated with infliximab, 5 mg/kg at week 0/2/6. Thereafter all patients were treated in an open study with infliximab at 5 mg/kg every 6 weeks. The disease activity (BASDAI), function (BASFI), mobility (BASMI), pain (NRS) and CRP as well as SF-36 were assessed. Data to calculate the SF-12 were extracted from the SF-36 questions and compared concerning agreement of individual levels, correlation with each other and with the BASFI, sensitivity to change and missing values.


RESULTS
All outcome parameters for disease activity as well as all subscales of health related quality of life improved in patients with active AS treated with infliximab. The comparability of the sum components for SF-12 and SF-36 were high (physical health r=0.912 and mental health r=0.957).


CONCLUSIONS
These data suggest that the shorter version of the SF-36, the SF-12, is capable to measure quality of life in clinical studies with AS patients.
Haibel
H
H
Deutsches Rheuma-Forschungszentrum, Berlin. haibel@zedat.fu-berlin.de
Niewerth
M
M
Brandt
J
J
Rudwaleit
M
M
Listing
J
J
Sieper
J
J
Braun
J
J
D000203:Activities of Daily Living / Q000145:classification / Q000523:psychology; D000328:Adult; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005858:Germany; D006801:Humans; D000069285:Infliximab; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000706:statistics & numerical data; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D013167:Spondylitis, Ankylosing / Q000188:drug therapy* / Q000523:psychology; D011795:Surveys and Questionnaires
D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D000069285:Infliximab