Adherence to pharmacological pain therapy in patients with nonmalignant pain: the role of patients' knowledge of pain medication.

Background: Nonadherence to pharmacological therapy is a common and underexposed problem in patients with chronic nonmalignant pain. It may lead to treatment failure and increased healthcare costs.

Methods: In this prospective observational study we analyzed the association between knowledge and adherence in the chronic nonmalignant pain population. We included 96 patients treated with a new pharmacological prescription. During the initial visit (T0), demographic variables, pain intensity, knowledge of the prescription (name, dose, and frequency), self-reported adherence to the prescription, and general knowledge of pharmacological pain therapy (according to the Pain Knowledge Questionnaire, Dutch Language Version (PKQ-DLV) were recorded. During two follow-up visits (T1, T2), apart from demographics, these parameters were measured again.

Results: Adherence rates were 42%, 42%, and 46% at T0, T1 and T2, respectively. 53%, 59%, and 48% of patients had knowledge of their current prescription, and mean scores on the PKQ-DLV were 56, 55, and 52 percent of the maximum scores, respectively, at T0, T1 and T2. A multivariate binary logistic regression analysis resulted in a significant contribution of knowledge of the prescription and of age to the prediction of adherence.

Conclusions: Knowledge of the analgesic prescription is associated with adherence and significantly contributes to the prediction of adherence to analgesic therapy. An interventional study is needed to determine whether increasing knowledge will improve medication adherence and therapy outcome in patients with chronic nonmalignant pain.