Heart attack risk increases rapidly after rheumatoid arthritis is diagnosed

Swedish researchers followed 7,469 patients diagnosed with rheumatoid arthritis (RA) between 1995 and 2006, together with 37,024 matched controls without RA to determine the risk of ischaemic heart disease, with particular reference to myocardial infarction (heart attack). The maximum follow-up was 12 years and the median was just over four years.

"Our findings emphasise the importance of monitoring a patient's heart risk from the moment they are diagnosed with rheumatoid arthritis, as the risk rises rapidly in the first few years" says lead author Marie Holmqvist from the Karolinska Institutet.

Key findings of the study included:

• Average age at diagnosis was just under 57 years and 71 per cent of the patients with RA were women. The median time from the appearance of RA symptoms to diagnosis was 6.2 months.
• 67 per cent of the patients had a positive rheumatoid factor (RF), an immunological marker found in a number of acute and chronic conditions. The difference in increased heart attack risk between the RF positive and negative subgroups was not statistically significant -- 70 per cent higher in RF positive patients and 60 per cent higher in RF negative patients.
• Having RA increased the risk of any ischaemic heart disease by 50 per cent one to four years after diagnosis, staying at that level in years five to 12. The risk increased during the first year after diagnosis, but did not reach statistical significance for 12 months.
• The risk of an acute heart attack rose by 60 per cent one to four years after diagnosis, remaining at the same level in years five to 12. Again, the level increased in year one, but was not statistically significant for the first 12 months.

"Our study confirms the increased risk of heart disease and heart attacks that patients with RA face" says Marie Holmqvist. "However it also adds three important observations to previous research."

These are:

• The increased heart attack risk was apparent very soon after RA diagnosis, despite the fact that the median duration of symptoms before diagnosis was just over six months.
• Although RA has been caught earlier and treated more aggressively in the last decade, increased heart attack risks were still seen in patients diagnosed in the last five to ten years.
• Both rheumatoid factor positive and rheumatoid factor negative were associated with an increased heart attack risk.

"Our research underlines the importance of clinicians monitoring patients diagnosed with rheumatoid arthritis for an increased risk of heart problems, in particular heart attacks" concludes Marie Holmqvist. "It is also very clear that more research is needed to determine the mechanisms that link these two health conditions."