Is Cognitive Impairment Associated with Medication Adherence in Outpatients with Heart Failure

Introduction: Heart failure (HF) significantly impacts patients' quality of life, morbidity and mortality, and represents a large expenditure for VA health care. Adherence to a structured medical regimen has been shown to improve clinical outcomes; however, compliance with medications is suboptimal in patients with HF. Cognitive impairment (CI) may affect medication adherence in patients with HF; yet neither the prevalence of CI nor its association to medication adherence has been evaluated in the VA population. Hypothesis: We hypothesized that CI is a prevalent condition in veteran outpatients with HF and is associated with medication adherence. Methods: The study was designed as a prospective cohort study in a single center (VA Loma Linda Healthcare System). Outpatients with HF but without previously diagnosed CI were enrolled. Patients were screened for CI by Saint Louis Mental Status (SLUMS) Examination. Demographic and clinical data, comorbidities, Geriatric Depression Scale (GDS), and laboratory data were collected at baseline. Medication adherence was determined by a 30-day pillcount of all medications. Results: 251 subjects were enrolled in the study. Mean age was 66 years with 99% being male and 73% Caucasian. More than half of the patients had diabetes (53%), hypertension (77%) and coronary artery disease (64%); 30% had history of depression. 59% of the patients were found to have cognitive impairment based on SLUMS Exam (Table 1). CI was significantly associated with age, race, education, depression (evaluated by GDS), blood pressure and Hemoglobin. 57% of patients (n=144) completed the pillcount. On average, patients were on 8 prescription medications with 338 pills per month. Out of 338 pills, an average patient mistook 70 pills per month (either missed a dose or took an extra dose), with an average compliance of 80%. Patients who did not return to complete the pillcount were more likely to be cognitively impaired (c2=7.4, p-value 0.007). In patients who did complete the pillcount, medication adherence was associated with cognitive impairment (r=0.24, p-value 0.004). (Table presented) Conclusions: In outpatient veterans with HF, previously undiagnosed CI is surprisingly prevalent and associated with medication adherence. Further studies are needed to investigate interventional measures to improve medication adherence in this challenging population.