A qualitative study to explore how patients identify and assess symptoms as adverse drug reactions.

Purpose: To explore how Thai patients assess symptoms as adverse drug reactions (ADRs).

Methods: Out-patients at two hospitals in Thailand previously reporting suspected ADRs to statins were purposively selected to cover factors relevant to the accuracy of ADR reports. Semi-structured interviews explored the mechanisms participants used to work out whether their symptoms were related to their statin. All interviews were audio-recorded, transcribed and independently thematically analyzed by two researchers.

Results: One hundred interviews were suitable for analysis; 52 were male, age range was 36 to 77 years (mean ± S.D.: 59.83 ± 9.14) and most (92) were taking other medicines in addition to statins. Patient assessment of symptoms as ADRs fell into two major themes: medicine-related factors and external factors. Timing relationships were mentioned most frequently (74), followed by information received (55), seeing similar symptoms in others (7) and diagnosis through blood tests (4). Use of multiple medicines, consideration of the medicine versus diseases, symptoms occurring with more than one medicine or relieved through treatment reduced confidence in ADR attribution. Many participants proposed alternative explanations for symptoms, including old age. Lack of information and knowledge were obstacles to the assessment process.

Conclusions: Patients assessed possible ADRs most often by considering timing relationships. While they also used medicine information, Thai patients received inadequate information to help them assess their symptoms. Patients expressed uncertainty and difficulties in deciding attribution when concomitant medicines and diseases were involved. The findings could support the development of a patient-friendly systematic tool for identifying and assessing possible ADRs.