Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Ischemic Stroke in RAa Cohort Study of Risks, Relative Risks and Predictors.

Holmqvist1,  Marie, Gransmark2,  Emma, Jonsson3,  Solveig Wållberg, Jacobsson4,  Lennart TH, Alfredsson1,  Lars, Askling5,  Johan

Karolinska Institutet, Stockholm, Sweden
Clinical Epidemiology Unit, Dept of Medicine, Karolinska Institutet, Stockholm, Sweden
Dept of Rheumatology, Umeå, Sweden
Section of Rheumatology, Malmo, Sweden
Clinical Epidemiology Unit, Dept of Medicine, Karolinska Institutet, Solna, Sweden

Background/Purpose:

To investigate the risk of ischemic stroke (IS) in rheumatoid arthritis (RA) relative to the risk in the general population; to find out when after RA-diagnosis the risk is increased; to explore predictors of IS in the RA population.

Methods:

RA-patients included in the Swedish Rheumatology Quality Register (SRQ) between 1 Jan 1995 and 1 Jan 2010 who had a symptom duration <=12months when included and were free from ischemic stroke prior to inclusion were matched on sex, calendar period, county, and age to an ischemic stroke free general population comparator. 9,412 RA-patients and 46,242 general population comparators were identified. An index date was assigned to all individuals; date of inclusion in SRQ for RA-patients and corresponding in the matched comparators. Information on all first time hospitalizations for IS and potential predictors was retrieved from the Swedish Inpatient register. Information on deaths was retrieved from the census register. Follow-up with respect to hospitalization for IS ended at event, death, emigration or 31 Dec 2009. To estimate the relative risk (RR) and calculate 95% confidence intervals (CI), Cox models were constructed using time since RA-diagnosis as time scale. The models accounted for the matched design. To assess the impact of comorbidities such as hypertension (HT), diabetes mellitus (DM), atrial fibrillation/flutter (AF), peripheral venous events including deep venous thrombosis and pulmonary embolism (DVT/PE) and ischemic heart disease (IHD) on the risk of having an IS, Cox models were constructed and each potential predictor assessed separately using time-dependent covariates adjusted for age at index date and sex.

Results:

Median follow-up was 4.7 years in RA and in comparators. Mean age at index date was 57.9 years in RA and 57.8 years in the comparators. 65.3% of the patients with RA were seropositive. 2.7% of RA-patients and 2.4% of the comparators were hospitalized with an IS after index date, corresponding to an age- and sex-adjusted RR of 1.14 (95% CI 0.99, 1.31). Women with RA had a significantly increased risk of IS compared to the general population (RR= 1.2, 95% CI 1.01, 1.44) but men did not. The risk increased compared to the general population after 10 years with RA (table). HT, IHD AF were statistically significant predictors of IS in RA. DVT/PE did not predict IS in RA but did in the general population (table).

Relative risk of ischemic stroke in RA stratified on time since RA-diagnosis

 <1 year since RA diagnosis1–4 years since RA diagnosis5–10 years since RA diagnosis10–15 years since RA diagnosis
Relative risk (95% CI)1.19 (0.84, 1.67)1.06 (0.86, 1.30)1.08 (0.84, 1.40)2.00 (1.24, 3.22)
N events in RA/comp45/190110/51673/33627/78
 Time-dependent covariates adjusted for age at index date and sex
 RA-patients RR (95% CI)Comparators RR (95% CI)
Hypertension1.74 (1.30, 2.32)2.20 (1.92, 2.52)
Diabetes mellitus1.34 (0.86, 2.10)2.18 (1.82, 2.61)
Ischemic heart disease1.64 (1.22, 2.22)1.54 (1.33, 1.79)
Atrial fibrillation/flutter1.91 (1.32, 2.75)2.61 (2.22, 3.07)
Peripheral venous emboli0.97 (0.55, 1.70)1.32 (1.00, 1.75)

Conclusion:

The risk of IS is increased in RA but first after 10 years with RA. Traditional risk factors might have a weaker association with IS in RA than in the general population, prompting us to search for other, RA-specific, predictors of IS.

To cite this abstract, please use the following information:
Holmqvist, Marie, Gransmark, Emma, Jonsson, Solveig Wållberg, Jacobsson, Lennart TH, Alfredsson, Lars, Askling, Johan; Ischemic Stroke in RAa Cohort Study of Risks, Relative Risks and Predictors. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1162
DOI:

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