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.


Stroke in Rheumatoid Arthritis: (When) Is There an Increased Risk?

Holmqvist1,  Marie E., Jacobsson3,  Lennart T. H., Alfredsson1,  Lars, Askling2,  Johan

Karolinska Institutet
Karolinska University Hospital
Malmö University Hospital

We recently showed that the risk of ischemic heart disease, known to be elevated in established RA, increases rapidly after RA onset (1). Data on risk of cerebrovascular disease are conflicting and risks in relation to RA disease duration are lacking. Few have assessed the risk of ischemic and hemorrhagic stroke separately or stratified on serostatus.

Objective:

To assess the risk of stroke in patients recently diagnosed with RA with short symptom duration at diagnosis, as a function of time since diagnosis, and stratified on serostatus.

Methods:

From the Swedish RA register, ongoing since 1995, we identified 7,176 patients with recently diagnosed RA (<18 months of symptoms at inclusion). As a comparator cohort, 5 individuals from the general population were selected for each RA patient, matched on age, sex, calendar year, residential area and marital status (n=35,171). Information on all hospitalizations listing stroke was retrieved from the nationwide Swedish Hospital Discharge Register (through 2006). We assessed stroke overall, as well as ischemic and hemorrhagic stroke separately. One individual could contribute first events to both subgroup outcomes, as well as to the overall outcome. Start of follow-up was date of RA diagnosis in RA patients. Comparators were given the same start date as their matched RA patient. Incidence rates were calculated. Relative risks (RR) and 95% confidence intervals (CI) of stroke after RA-diagnosis were estimated using Cox proportional hazards regression.

Results:

Mean age at start of follow-up was 57 years. 70% were women. Follow-up amounted to 31,318 person-years in the RA cohort and 153,180 person-years in the general population cohort. Median follow-up was 3.9 years (range 12 years) in both cohorts. 2.6% of all patients with RA and of all comparators had any cerebrovascular event during follow up (incidence rate 6/1000 person-years in both cohorts) which corresponded to an overall RR of 1.0 (95% CI 0.9, 1.2). The incidence rates of ischemic (4.8/1000 person-years in RA and 4.1 in comparators) and hemorrhagic stroke (0.9/1000 person-years in RA and 1.2 in comparators) were similar in both cohorts, corresponding to RRs of 1.1 (95% CI 0.9, 1.3) and 0.7 (95% CI 0.5, 1.1) respectively. During this time-frame, no increased risk of stroke was observed, neither overall nor by stroke subtype nor time since RA-diagnosis. When stratified by serostatus no heterogeneities were detected (data not shown).

 <1 year since RA diagnosis1–4 years since RA diagnosis5–12 years since RA diagnosis
Cerebrovascular event1.1 (0.7, 1.5)0.9 (0.8, 1.2)1.2 (0.9, 1.6)
 34/15496/48960/255
Ischemic stroke*1.3 (0.9, 2.0)1.0 (0.8, 1.3)1.1 (0.8, 1.6)
 29/10280/35244/190
Hemorrhagic stroke*0.3 (0.1, 1.2)0.6 (0.4, 1.2)1.4 (0.7, 2.7)
 2/3415/11313/44
*The sum of ischemic and hemorrhagic strokes does not equal cerebrovascular events since some of the cerebrovascular events cannot be classified as neither ischemic nor hemorrhagic. *Cox proportional hazards model adjusted for age at diagnosis, sex, residential area, calendar year of inclusion, and marital status.

Conclusion:

In contrast to the rapid increase in IHD risk, the risk of stroke, ischemic or hemorrhagic, is not elevated in RA within 12 years of RA duration. Stratification by serostatus did not alter these results. This does, however, not preclude an increased risk of stroke in RA patients with longer disease duration but may point to distinct aetiologies behind IHD and stroke in early RA.

References:

1Gunnarsson, M. et al. Ann Rheum Dis 2009;68(Suppl3):78

To cite this abstract, please use the following information:
Holmqvist, Marie E., Jacobsson, Lennart T. H., Alfredsson, Lars, Askling, Johan; Stroke in Rheumatoid Arthritis: (When) Is There an Increased Risk? [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1057
DOI: 10.1002/art.28824

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