White-coat effect among older patients with suspected cognitive impairment: prevalence and clinical implications

OBJECTIVES: To evaluate the prevalence of white-coat effect (WCE), and its association with individual anxiety and insight of disease, among older patients evaluated for suspected cognitive impairment. METHODS: This prospective cohort study, conducted in an Alzheimer Evaluation Unit, involved patients aged 55 years or older with suspected cognitive impairment. WCE was defined as a difference of at least 20 mmHg in systolic or 10 mmHg in diastolic blood pressure (BP) measured either by a physician during the visit or by a nurse (before and after the visit), compared with home self-blood pressure measurement (SBPM). Severity of cognitive impairment was evaluated through the Mini-Mental State Examination (MMSE); the Clinical Insight Rating Scale (CIR) and the Guidelines for the Rating for Awareness Deficits (GRAD) were used to evaluate the subject's insight; anxiety disorder was evaluated using the seven-question Generalized Anxiety Disorder scale (GAD-7). RESULTS: Among 273 subjects, prevalence of WCE was 52%, 32.6% and 30.4%, according to physician and nurse BP measurements, respectively (p = 0.000). Prevalence of WCE did not differ between patients diagnosed with and without dementia, but was higher among patients with than in those without anxiety disorder (70.7% vs 38.2%, p = 0.000). Positive relations were observed between severity of anxiety and insight of disease, which were both inversely related with severity of cognitive impairment. CONCLUSIONS: WCE is extremely common and is correlated to individual anxiety and insight of disease among older outpatients with suspected cognitive impairment; overestimation of hypertension severity might lead to unnecessary drug treatment and greater health costs in this setting.