Posttraumatic stress disorder (PTSD) is common in primary care patients1 and is associated with psychological distress, suicide risk, and disability. Posttraumatic stress disorder also increases risk of incident and recurrent cardiovascular events,2 possibly by reducing medication adherence.3 Prior studies showing an association between PTSD and medication nonadherence3 are limited by their use of self-report to measure adherence as PTSD can bias reporting of negative behaviors.4 We evaluated the association between PTSD and antihypertensive medication adherence using electronic monitoring in primary care patients with uncontrolled hypertension.
The institutional review board of Columbia University Medical Center, New York, New York, approved the protocol. All patients provided written informed consent. We enrolled a convenience sample of patients with uncontrolled hypertension from an academic hospital-based primary care clinic in New York City. Patients were eligible if they had elevated blood pressure (BP) on 2 consecutive clinic visits prior to enrollment (BP ≥ 140/90 mm Hg or ≥ 130/80 mm Hg if they had diabetes or chronic kidney disease). Patients were ineligible if they had dementia, psychosis, active substance abuse, or resided in an institutional setting.
We evaluated PTSD using the 4-item Primary Care PTSD screen, which asks patients whether, in response to a traumatic event, they had current PTSD symptoms (reexperiencing, numbing, avoidance, and hyperarousal). A cutpoint of 3 on this screen has good sensitivity and specificity (>80%) for diagnosing PTSD compared with a clinical interview.5 We assessed medication adherence during the interval between 2 subsequent clinic visits using an electronic pillbox (MedSignals; MedSignals Corporation). Each BP medication was stored in 1 of 4 pillbox compartments. The pillbox records the date and time when each compartment is opened. Regimen adherence was calculated as the mean adherence to monitored medications, with adherence to each medication calculated as the percent of days the prescribed number of doses was taken.
Patients were categorized as nonadherent if regimen adherence was less than 80%.6 Logistic regression was used to determine whether PTSD symptoms were associated with nonadherence after adjusting for covariates commonly associated with adherence (age, sex, race, ethnicity, number of blood pressure medications, and depressive symptoms measured by the 8-item Patient Health Questionnaire).
Between November 1, 2011, and June 30, 2013, we identified 123 patients who met eligibility criteria; 114 (93%) consented and 98 (80%) had usable pillbox data. The mean (SD) age was 64 (9) years, 74 were women (76%), 79 Hispanic (81%), and 28 white (29%). Fifty-nine percent (n = 58) had no PTSD symptoms, 21% (n = 21) had 1 to 2 symptoms, and 19% (n = 19) had 3 to 4 symptoms, consistent with a positive screening result for PTSD.
The mean number of prescribed BP medications was 2.6 (0.9). Adherence was monitored for a mean (SD) of 56 (43) days. Median regimen adherence was 86% (interquartile range, 58%-97%), and 41% of the sample was nonadherent (<80% of days). In unadjusted analysis, there was a graded association between PTSD symptoms and medication nonadherence (Figure). Sixty-eight percent of patients (13 of 19) who screened positive for PTSD were nonadherent compared with 26% of patients (15 of 58) without any PTSD symptoms (P = .001). In adjusted analyses, PTSD symptoms continued to be associated with nonadherence; those who screened positive for PTSD had 5.2 (95% CI, 1.1-24.4) increased odds of nonadherence compared with those without PTSD symptoms (P = .04; Table).
In conclusion, 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. Limitations include its modest sample size, recruitment from a single urban practice, and brief assessment period. 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.
Corresponding Author: Ian M Kronish, MD, MPH, Center for Behavioral Cardiovascular Health, Columbia University Medical Center, 622 W 168th St, Room PH 9-311, New York, NY 10032 (firstname.lastname@example.org).
Published Online: December 2, 2013. doi:10.1001/jamainternmed.2013.12881.
Author Contributions: Dr Kronish had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Kronish, Edmondson.
Acquisition of data: Kronish.
Analysis and interpretation of data:All authors.
Drafting of the manuscript: Kronish, Lin, Edmondson.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Kronish, Edmondson.
Obtained funding: Kronish.
Study supervision: Voils.
Conflicts of Interest Disclosures: None reported.
Funding Support: This study was supported by grants K23 HL098359 from the National Heart, Lung, and Blood Institute (NHLBI) and by 10SDG2600321 from the American Heart Association. Dr Lin received support from grant K07 CA166462 from the National Cancer Institute; Dr Cohen received support from grant K23 HL094765 from the NHLBI; and Dr Edmondson received support from grant R01 HL117832 from the NHLBI. Drs Cohen and Voils were additionally supported by resources from the Department of Veterans Affairs.
Role of the Sponsors: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; and decision to submit the manuscript for publication.
Disclaimer: The views expressed in this article are those of the authors and do not necessarily represent the views of the Department of Veterans Affairs nor of the other sponsors of the study.
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