Renal insufficiency is a common comorbidity in patients with inflammatory rheumatic diseases such as rheumatoid arthritis and psoriatic arthritis. Decreased renal function is a limiting factor for the use of non-steroidal anti-inflammatory drugs and disease-modifying antirheumatic drugs. Therefore, the availability of therapeutic alternatives would improve our treatment options for these patients. For tumour necrosis factor α (TNFα) inhibitors, no data about their use in patients with impaired renal function are available, because it has been an exclusion criterion in all major clinical trials.

We therefore retrospectively analysed all patients from our institution who had increased serum creatinine levels before or during treatment with TNFα antagonists. All patients with a serum creatinine ⩾1.1 mg/dl and treatment with infliximab, etanercept or adalimumab were included. We were able to identify nine patients with rheumatoid arthritis, one patient with …