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.