Urinary tract infections in patients with rheumatoid arthritis

Co-morbidity from rheumatoid arthritis (RA) has recently focussed on outcomes of cardiovascular and pulmonary disease, but serious infections are an increasingly well-recognised complication of RA. Recent work has demonstrated how the incidence of pneumonia can be reduced in RA, but little attention has been paid to the incidence of urinary tract infection (UTI) in RA or to the associated co-morbidity. The aim of this study was to describe the incidence of UTI leading to hospitalisation in a large cohort of patients with RA and investigate which factors contributed to this. This study assessed all patients with RA hospitalised over a 12-month period with a discharge diagnosis including UTI. Patients were identified through a PAS records search in a single large centre. Historical case controls without RA matched for age and gender were identified from the literature. Clinical notes were manually examined by two observers. We recorded: age, gender, duration of RA, number of UTI, all RA therapy, co-morbidity, results of urine and blood cultures with antimicrobial sensitivities, readmission rates, treatment and outcome. We calculated the relative risk (RR) of developing UTI in patients with RA and the factors influencing this. From a population of 2,200 RA patients, the overall annual incidence of hospitalisation with UTI amongst RA patients was 2.09 %, as against 0.97 and 0.91 % for two control groups (RR = 2.16 and 2.29). Most patients (90 %) were female, and the group mean age was 76 years. The use of long-term oral steroids as sole therapy was associated with a RR of 6.8 for UTI (p = 0.002) while failure to take disease-modifying anti-rheumatic drugs (DMARDs) was associated with a similar RR of 6.7 (p = 0.001). Positive cultures for Escherichia coli were found in 51 % of RA patients. Relevant co-morbidities included permanent catheters, vaginal prolapse, cancer and diabetes. Recurrence of UTI within a year was common. RA was associated with a higher-than-expected incidence of UTI, particularly among older females. This was associated with the use of long-term oral steroids and the absence of DMARDs. Other factors included female gender, greater age and long disease duration. We recommend avoidance of long-term oral steroids but consideration of low-dose prophylactic antibiotics in those patients with recurrent UTI.