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.


Lymphocytopenia and Infection Risk in Rheumatoid Arthritis: A Population Based Analysis.

Hoganson2,  Deana D., Matteson1,  Eric L., Fitz-Gibbon3,  Patrick D., Crowson3,  Cynthia S.

Mayo Clinic, Rochester, MN
Mayo Clinic Rochester, Rochester, MN
Mayo Clinic Rochester

Background:

There is an increased susceptibility for infections in patients with rheumatoid arthritis (RA) which contributes to increased mortality. Lymphocytopenia is prevalent in RA patients and may contribute to increased infection risk. The purpose of this study was to examine the association between lymphocytopenia and infection in RA patients during the pre-biologic era and develop a risk score for infections.

Methods:

We utilized a population based cohort of patients with incident RA ascertained between 1955 and 1994 that were followed longitudinally through their complete medical records until 1/1/2000. The outcome measures included all objectively confirmed infections (by microbiology or radiology) and serious infections (requiring hospitalization or IV antibiotics). Data were collected on smoking status, leukopenia, lymphocytopenia, comorbidities (alcoholism, diabetes mellitus (DM), chronic lung disease, cardiovascular disease (CVD)), RA disease characteristics (erosions, extra-articular manifestations (ExRA), rheumatoid factor (RF), nodules, erythrocyte sedimentation rate (ESR)) and medication use. Potential predictors were examined using multivariable Andersen-Gill models (a variation of Cox modeling allowing multiple infections per patient) with time-dependent covariates.

Results:

Among the 584 RA patients (mean age 58 years; 72% female; median followup 9.9 years), 277 had >=1 objectively confirmed infection (706 total infections), and 252 had >=1 serious infection (646 total infections). Significant predictors of both outcomes included age, male sex, leukopenia, lymphocytopenia, alcoholism, DM, chronic lung disease, CVD, ExRA, RF positivity, nodules, ESR and glucocorticoid use. Lymphocytopenia was significantly associated with objectively confirmed (HR=1.7, 95% CI=1.3–2.2; p<0.001) and serious (HR=1.6, 95% CI=1.2–2.2; p<0.001) infections after adjustment for the other risk factors. Using these models, infection risk scores were developed for each outcome. The score discriminated patients with low (5 year risk 13%± 4.1%), medium (5 year risk 23%± 7.4%), and high infection risk (5 year risk 40%± 8.5%) figure.

Figure. Cumulative incidence of objectively confirmed infections in RA patients based on risk score.

Conclusions:

This study reveals that lymphocytopenia is an independent risk factor for infection in RA patients. A risk score may alert clinicians to the potential occurrence of infection in their RA patients. Further research is needed to examine whether this score accurately estimates the infection risk in patients treated with biologics.

To cite this abstract, please use the following information:
Hoganson, Deana D., Matteson, Eric L., Fitz-Gibbon, Patrick D., Crowson, Cynthia S.; Lymphocytopenia and Infection Risk in Rheumatoid Arthritis: A Population Based Analysis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :316
DOI: 10.1002/art.28085

Abstract Supplement

Meeting Menu

2010 ACR/ARHP