{'fraction_non_alphanumeric': 0.05555555555555555, 'fraction_numerical': 0.03648424543946932, 'mean_word_length': 4.731591448931116, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Monitoring patients with ankylosing spondylitis on anti-TNF monotherapy: too much too often?

Guidelines regarding blood test monitoring of tumour necrosis factor inhibitor (TNFi) monotherapy in ankylosing spondylitis (AS) do not exist. Most patients with rheumatoid arthritis (RA) are also taking diseasemodifying anti-rheumatic drugs (DMARDs) such as methotrexate and require monthly monitoring for that drug; in addition, the principal outcome measure in RA (the Disease Activity Score, DAS) requires blood sampling [for C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR)]. Most AS patients use TNFi as monotherapy and the outcome measure (the Bath Ankylosing Spondylitis Disease Activity Index, BASDAI) does not require blood samples. Monitoring must therefore be decided by evaluating the risk posed by that drug alone. Hence, in the absence of firm recommendations testing is arbitrary, ranging from every 1 to 6 months, generally checking full blood count (FBC), liver function tests (LFTs), and renal function. We conducted a 2-year audit to investigate the frequency of abnormal blood tests. All AS patients on anti-TNF therapy, attending three teaching hospitals, were identified (n = 258). The audit was confined to patients who had been on TNFi monotherapy for at least 9 months and in whom all blood test results and medical records were available. Patients on concomitant DMARDswere excluded (see Figure 1). Sixty-seven patients were studied [males = 52/67; median age 44 (IQR 38–51) years]. TNFis used were: adalimumab (n = 46), etanercept (n = 18), infliximab (n = 1), and golimumab (n = 2). Blood tests were correlated to electronic and paper medical records by retrospective analysis. Results putatively associated with TNFi toxicity were studied: FBC, creatinine, and alanine aminotransferase (ALT). Most patients had bloods checked every 3 months. FBC was checked 425 times in the 67 patients during the 2-year study period as monitoring for TNFi therapy. A neutrophil count lower than 1.8 × 10/L was recorded in 36/425 (8%), but in no case was the level less than 1.4 × 10/L (0%). Haemoglobin less than 130 g/L was seen in 26/425 (6%) and platelet count less than 150 × 10/L in 8/425 (2%). Serum creatinine was checked 337 times: a level greater than 110 μmol/L was seen in 15/337 (4%). ALT was checked 363 times and in 18/363 (5%) patients ALT levels were elevated (> 65 U/L).