Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Urinary Tract Infections in Rheumatoid Arthritis.

Edgerton1,  Colin C., Michaud3,  Kaleb D., Wolfe2,  Frederick

Eisenhower Army Medical Center, Evans, GA
Natilonal Data Bank for Rheumatic Disease, Wichita, KS
Univ of Nebraska Med Ctr, Omaha, NE

Purpose:

Recent interest in urinary tract infections in rheumatoid arthritis (RA) has stemmed from the assessment of risk of infection with biologic agents. There have been little data about community acquired urinary tract infections (UTI) until a recent report gave an incidence rate (IR) of ~3% (1). By contrast, an epidemiology study in the general population reported an IR at 10.8% (95% CI 9.4. 12.1) in women (2). We used a large prospective data bank to investigate these differences and to understand risk factor for UTI in RA.

Methods:

We used general estimating equations to evaluate the risk of UTI in 17,139 RA patients and 107,546 semiannual observations. Patients self-reported the number of urinary tract infections in the previous 6 months. We evaluated the role of age, sex, antirheumatic drug use, education, BMI, household income, smoking, comorbidity, and the tendency to over-report symptoms. We also calculated the misclassification rate for self-reported events based on 76,493 cases that evaluated for validation.

Results:

The estimated IR for UTI, adjusted for 10% over-reporting, was 8.9% (8.6, 9.2) overall and 11.4% (11.0, 11.8) in women and 3.3% (2.9, 3.7) in men. Serious events, resulting in hospitalization or requiring intravenous antibiotics was reported in 0.39%. In multivariable analyses, UTI was associated with diabetes, OR 1.2 (95% CI 1.0, 1.3), corticosteroid use OR 1.1 (1.0, 1.2), but not to biologic use, OR 1.0 (0.9, 1.1). Among other factors, UTI was associated with less household income and multiple comorbidities, but not with smoking, BMI, education level or estrogen use. When the study variables were applied to serious infection, the OR increased for prednisone use, 1.9 (1.6, 2.4) and diabetes, 2.0 (1.5, 2.6), but remained non-significant, 0.9 (0.7, 1,1) for biologics. Overall, prednisone was used at 34.9% of observations and biologics at 38.2%.

Conclusions:

Based on increased risk associated with prednisone and comorbidity, as well as increased IC compared with the community epidemiology study, we estimate that UTI is slightly increased in RA. These results are 3 times higher than a previous study (1). The Observed rate of serious urinary tract infection was consistent with data from the British Biologics registry (3).

References:

1.Greenberg, JD, Reed, G, Kremer, JM, Tindall, E, Kavanaugh, A & Zheng, C, et al. Association of Methotrexate and TNF antagonists with risk of infection outcomes including opportunistic infections in the CORRONA registry. Ann Rheum Dis. 2009

2.Foxman, B, Barlow, R, D'Arcy, H, Gillespie, B & Sobel, J. Urinary Tract Infection: Self-Reported Incidence and Associated Costs. Annals of epidemiology. 2000;10(8):509-15.

3.Dixon, WG, Watson, K, Lunt, M, Hyrich, KL, Silman, AJ & Symmons, DP. Rates of serious infection, including site-specific and bacterial intracellular infection, in rheumatoid arthritis patients receiving anti-tumor necrosis factor therapy: results from the British Society for Rheumatology Biologics Register. Arthritis Rheum. 2006;54(8):2368-76.

To cite this abstract, please use the following information:
Edgerton, Colin C., Michaud, Kaleb D., Wolfe, Frederick; Urinary Tract Infections in Rheumatoid Arthritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :346
DOI: 10.1002/art.28115

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