The validity of daily smartphone-based patient-reported anxiety and the association with stress, quality of life and functioning in bipolar disorder

Introduction: Bipolar disorder (BD) is estimated as one of the most important causes of disability worldwide. Patients with BD often report a range of additional problems, and more than half of the patients experience anxiety which is associated with aggravated long-term course of illness and impaired functioning. The experience of anxiety in patients with BD seems to precede the emergence of the first affective episodes. Today a median of 76% of adults report owning and using a smartphone. Thus, smartphones offer the opportunity to collect fine-grained data outside the clinical settings. Aims: In patients with BD the present study aimed to 1) validate daily patient-reported symptoms of anxiety measured using smartphones against clinically rated symptoms of anxiety; 2) estimate the prevalence of anxiety symptoms; and 3) investigate associations between patient-reported symptoms of anxiety and stress, quality of life and functioning, respectively. Methods: A total of 84 adults patients with BD according to ICD-10 and previously treated at the Copenhagen Clinic for Affective Disorders, Denmark were included. The patients were instructed to evaluate symptoms of anxiety daily for nine months using a smartphone-based system (the Monsenso system). The app allowed for daily evaluation of symptoms of anxiety score on a scale from 0, 1, 2. The patients were prompted to evaluate by an alarm set a self-chosen time during the day. Data on clinically evaluated symptoms of anxiety and functioning was collected rater-blinded and patient-reported questionnairebased stress and quality of life were collected at five fixed time points per patients during a follow-up period of nine months. Results: During the study patients adhered to the smartphone-based monitoring 72.6% (190 days (of the days (median 215 days, range 59-270). The patients had a mean age of 43.0 years (SD 12.3) and 61.2% (n=51) were women. The patients presented mild affective symptoms, only. A total of 87.1% of the patients had a Hamilton Depression Rating Scale score≤14 and 97.6% had a Young Mania Rating Scale score≤14. Anxiety symptoms were evaluated validly according to scores of clinically evaluated anxiety based on the two anxiety sub-items of the Hamilton Depression Rating Scale (B:0.22, 95% CI: 0.18; 0.25, p<0.0001). During followup the patients experienced symptoms of anxiety 19.3% of the time. Interestingly, there was a statistically significant association between anxiety and stress (B:0.020, 95% CI: 0.013; 0.028, p<0.0001), quality of life (B:0.-0.011, 95% CI: -0.018; -0.0057, p<0.0001) and functioning (B:0.010, 95% CI: 0.0054; 0.015, p<0.0001), respectively. Conclusions: In patients with BD during full or partly remission, daily anxiety symptoms were validly self-reported using smartphones. Anxiety was associated with increased stress, decreased quality of life and functioning even during full or partly remission. Thus, identifying anxiety symptoms has clinical impact pointing toward smartphones as a valid tool.