Posttraumatic stress hits stroke secondary prevention

May 30 2012

By Eleanor McDermid

Patients who develop posttraumatic stress disorder (PTSD) after stroke or transient ischemic attack (TIA) are at high risk for being nonadherent to secondary prevention medications, say researchers.

"PTSD may be putting stroke/TIA survivors at increased risk for recurrent cerebrovascular events as a result of decreased medication adherence," say Ian Kronish (Columbia University Medical Center, New York, USA) and colleagues.

Kronish et al found that patients' medication adherence fell in line with increasing PTSD severity, a relationship that persisted after accounting for co-occurring depression.

"To date, the understanding of PTSD's association with medication adherence has been confounded by its association with depressive symptoms," they write in Stroke.

The researchers report that 41% of 535 patients in their study were nonadherent to secondary prevention medications, defined as a score of 0-5 on the Morisky scale. They attribute this high rate to the large proportion of study participants with low socioeconomic status, which has previously been linked to nonadherence. But they note that this, combined with the relatively large sample size, increased their power to detect an association with PTSD.

In all, 18% of the cohort had probable PTSD, defined as a score over 50 on the PTSD Checklist Specific for a stressor (PCL-S), and 67% of this group was nonadherent to medication.

A further 56% had possible PTSD (PCL-S 25-50), of whom 42% were nonadherent. By contrast, just 20% of patients with no symptoms of PTSD were nonadherent to medication.

"Even participants with more modest elevations in PTSD symptoms were at increased risk of medication nonadherence, broadening the relevance of this risk factor for nonadherence to a large number of stroke/TIA survivors," comment Kronish et al.

PTSD remained associated with medication nonadherence after accounting for demographic and clinical predictors of nonadherence. Further adjustment for depression (≥10 points on the 8-item Patient Health Questionnaire) attenuated this association slightly, but PTSD remained significantly associated with nonadherence, with possible PTSD raising the risk 1.86-fold and probable PTSD raising it 2.69-fold.

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