Cardiovascular disease risk assessment tools that do not include severe mental illness as a predictor can significantly underestimate risk, researchers say.

New Zealand researchers used data from the PREDICT general practice database to compare the observed risk of a first CVD event among people with severe mental illness with the risk predicted by algorithms for the general population.

A history of severe mental illness was associated with an increased age-adjusted estimated risk of a cardiovascular event, both for people with diagnoses of schizophrenia or bipolar disorder and for those using specialist mental health services.

On average, the observed risk was 64% higher than the predicted risk among women, 29% higher among men, and 37% higher for men and women combined, the researchers reported.