Somatic symptoms of anxiety and nonadherence to statin therapy

Abstract

Background: The association between anxiety and nonadherence to preventive therapies remains unclear. We investigated whether somatic symptoms of anxiety predict statin nonadherence.

Methods: This is a prospective cohort study of 1924 individuals who responded to a questionnaire survey on health status and initiated statin therapy after the survey during 2008-2010. We followed the cohort for nonadherence, defined as the proportion of days covered <80%, during the 365days since the first dispensation after the survey. We used log-binomial regression to estimate the predictors of nonadherence.

Results: 18% of participants reported no experience of the eight somatic symptoms of anxiety (palpitation without exercise, irregular heartbeat, chest pain upon anger or emotion, sweating without exercise, flushing, tremor of hands or voice, muscle twitching) before the statin initiation, and 16% had experienced at least one symptom on average weekly to daily. 49% of respondents were nonadherent. Weekly to daily occurrence of these symptoms predicted a 33% increase in the risk of nonadherence (risk ratio [RR] 1.33, 95% confidence interval, CI, 1.13-1.57) compared to no symptoms when adjusted for sociodemographics, lifestyle risks, cardiovascular comorbidities, and depression. Particularly, chest pain upon anger or emotion (RR 1.21, 95% CI 1.01-1.46) and muscle twitching (RR 1.24, 95% CI 1.08-1.42) predicted an increased risk of nonadherence to statin therapy. Psychological symptoms of anxiety were not associated with nonadherence when adjusted for somatic symptoms.

Conclusions: Somatic anxiety-related symptoms predicted nonadherence to statin therapy. Information on pre-existing somatic symptoms may help identifying patients at increased risk of statin nonadherence.

Keywords: Anxiety; Medication adherence; Statins; Symptoms.