Antibodies to cardiolipin in stroke: association with mortality and functional recovery in patients without systemic lupus erythematosus

Abstract

Antibodies to cardiolipin were measured in 100 consecutive patients with first ever stroke, on admission and at three and six months after the acute event. One hundred healthy, age- and sex-matched, British elderly individuals were also screened for antibodies to cardiolipin as a control group. Elevated levels of anticardiolipin antibody (i.e. 5 SD above the laboratory control mean) were present in none of the control group, but in 21 per cent of the patients with stroke. Thirteen of these 21 patients (62 per cent) died within three months, compared to 17 (21.5 per cent) of the seventy-nine patients without elevated levels of anticardiolipin antibodies (p less than 0.001). Six of the eight survivors with persistently elevated anticardiolipin antibodies had significant residual disability following stroke (Barthel score 0-9) compared to 11 of the 62 without (p less than 0.001). Two patients with initially raised anticardiolipin antibodies who became independent at six months showed a progressive decline in the level of these antibodies to normal. The presence of high levels of anticardiolipin antibody did not correlate with other recognized prognostic indices of stroke, except for incontinence. No correlation was noted between levels of antibody to cardiolipin, antinuclear factor, antibody to double-stranded DNA and C-reactive protein, either in the stroke patients or in the elderly control population. Hypertension was significantly more common in the patients with high anticardiolipin antibodies than in the rest of the patients in the stroke population (p = 0.33). There was no correlation between levels of anticardiolipin antibody and age. Anticardiolipin antibody may be considered as an independent prognostic marker for both mortality and clinical outcome after acute stroke.