Hypertensive patients with post-traumatic stress disorder missed significantly more doses of their blood pressure drugs than patients without PTSD, researchers found.
In a small study, 68% of hypertensive patients with positive screening results for PTSD on a primary care-oriented symptom assessment were judged to be nonadherent to their medications, versus 26% of hypertensive patients with no PTSD symptoms (P=0.001), according to Ian Kronish, MD, MPH, of Columbia University in New York City, and colleagues.
The study also showed a possible trend toward increasing nonadherence with more severe PTSD, the researchers reported online in JAMA Internal Medicine.
"To our knowledge, this study is the first to demonstrate that PTSD is an independent risk factor for nonadherence among patients with uncontrolled hypertension and offers a potential mechanism by which PTSD is associated with cardiovascular disease," Kronish and colleagues wrote.
Past research had suggested that PTSD may reduce medication adherence, the researchers indicated, but those studies had relied on patient self-reports for evaluating adherence. In the current study, participants used electronic pill containers that recorded the time and date when they were opened, providing a more objective measure.
Patients whose pill containers indicated less than 80% adherence to the prescribed dosing intervals were classified as nonadherent. Pill-taking was monitored for a mean of 56 days (SD 43). Participants were taking a mean of 2.6 prescription drugs for hypertension.
Kronish and colleagues recruited a total of 114 patients with uncontrolled hypertension, defined as blood pressure of 140/90 mm Hg or higher at their last two clinic visits (130/80 mm Hg for patients with diabetes or chronic kidney disease). Pill container data were unusable in 16 patients, leaving 98 for analysis.
The researchers evaluated PTSD with a screening instrument that simply counted the presence of four symptom types: re-experiencing traumatic memories, numbing, avoidance, and hyperarousal. No symptoms were present in 58 patients and 21 had one or two. The remaining 19 had three or four symptoms, generally considered indicative of PTSD.
After adjusting for age, sex, race, ethnicity, number of medications, and depressive symptoms (assessed with an eight-item questionnaire), patients with three or four PTSD symptoms were more than five times as likely to be nonadherent compared with patients with no symptoms, the researchers calculated (odds ratio 5.18, 95% CI 1.10-24.39).
Also, the presence of one or two PTSD symptoms was also significantly associated with nonadherence (OR 4.22, 95% CI 1.33-13.51). In those 21 patients, nearly 60% were nonadherent, the researchers found.
"Given the prevalence of PTSD and its strong association with medication nonadherence, our findings provide impetus to evaluate the benefit of enhanced screening and treatment for PTSD in medical settings to improve cardiovascular risk in these patients," Kronish and colleagues concluded.
They noted several limitations to the analysis: the small number of patients, its restriction to patients at a single clinic in New York City, and the relatively short study duration.
The study was supported by the National Heart, Lung and Blood Institute and the American Heart Association.
Study authors declared they had no relevant financial interests.
- Reviewed by F. Perry Wilson, MD, MSCE Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner