Background
Bipolar disorder (BD) is estimated to be one of the most important causes of disability worldwide.1 2 Naturalistic follow-up studies suggest that the progressive development of BD is not prevented with the present treatment options,3 4 due to delayed intervention for prodromal depressive and manic symptoms as well as decreased adherence to mood stabiliser treatment.5 6 Non-adherence has been associated with increased risk of relapse, psychiatric hospitalisation and healthcare costs.7–12 Previous studies have reported that between 10% and 66% of patients with BD do not take their medication as prescribed, and often adherence changes over time.13–15 Variation in non-adherence between studies may be partly attributable to a lack of consensus on the best methodology for assessing adherence, the period of observation and the criteria for defining non-adherence.16 Factors such as female gender, younger age, low socioeconomic status and poor therapeutic alliance seem to be risk factors for medication non-adherence in BD.5 16
Adherence to medication refers to the extent to which a patient follows the medication prescribed by their physician.17 Monitoring and assessment of non-adherence to prescribed medication can be done by both objective approaches such as drug plasma levels, pills count, registry-based information on purchased medication and electronic monitoring of medication event monitoring systems, and subjective approaches such as self-reported, relative reported or clinician reported.18 19
Non-adherence is likely to remain a major public health concern despite treatment advances.20 21 Increasing knowledge about factors affecting adherence and leveraging novel technologies can enhance its early assessment and adequate management.15 22–26 However, more information to assess adherence in patients with BD is needed.
Today, a median of 76% of adults in 18 advanced economies report having a smartphone,27 and many people use a smartphone on a daily basis.28
No prior study has collected data on patient-evaluated daily smartphone-based measures of adherence to medication in patients with BD.
Objective
The present study aimed (1) to compare and validate patient-evaluated adherence to medication measured daily with smartphones against adherence measured using the Medication Adherence Rating Scale (MARS) questionnaire, and (2) to investigate characteristics for adherence to medication measured using smartphones including the severity of depressive and manic symptoms and functioning.
We hypothesised that (1) there would be a significant negative association between patient-evaluated daily adherence measured daily using smartphones and the MARS, and (2) that female gender, younger age, longer illness duration, higher severity of depressive and manic symptoms and lower functioning would be associated with higher non-adherence in patients with BD.5 16 29 The present study represents exploratory pooled reanalyses of data collected from two randomised controlled trials (RCT).