Treatment Adherence and Quality of Life of Patients with Stable Ischemic Heart Disease in Treatment with Nicorandil: Interrelation and Interaction (According to the Results of the Observational Study NIKEA)

Aim. To assess quality of life (QoL) and its dynamics during nicorandil treatment in patients with stable ischemic heart disease, to study the relationship of treatment adherence and QoL indicators when treated with nicorandil. Material and methods. Observational program NIKEA included 590 patients with angina pectoris. Seattle Angina Questionnaire (SAQ) was used to assess QoL. Patients completed SAQ at the visit of inclusion (V0) and at the visit after 3 months of observation (V3). Potential and actual adherence to therapy was assessed by medical interviews at visits V0, V1 (1 month of observation) and V3. During the visit V0 417 people (from 590 ones enrolled into the study) completed SAQ (71% response); after 3 months (V3) SAQ was filled in by 454 of 552 people who came to this visit (82% response). According to the results of medical interviews, potential adherence (visit V0) was determined in all 590 patients, actual adherence to nicorandil (visits V1 and V3) was assessed in 552 patients who came to these visits. In accordance with the degree of adherence, all patients were divided into 3 groups: (1) adherent to treatment (taking nicorandil for the first three months), (2) non-adherent (who refused to take nicorandil), and (3) partially non-adherent (who started nicorandil, but for various reasons stopped taking the drug). Results. In all patients, regardless of their adherence to the recommended drug, there was an increase in QoL according to all five scales of the SAQ after 3 months of follow-up. Statistically significant positive dynamics of all SAQ indicators was found only in adherent patients (p< 0.0001 for all aspects). Patients, who showed good adherence to nicorandil at V1, had more severe angina at the beginning of treatment (according to " Angina Stability" and "Angina Frequency" indicators). These patients also had lower QoL "Disease Perception" score and more confidence in the doctor ("Treatment Satisfaction" score) than non-adherent patients (p< 0.05). In non-adherent patients a mild degree of angina was determined 2 times more often according to "Angina Frequency" indicator (p= 0.03). Conclusion. The results of the study confirm the interrelation and mutual influence of the QoL indicators and treatment adherence to nicorandil. Effective treatment with nicorandil in patients with lower health-related QoL indicators could increase treatment adherence. On the other hand, the mild degree of angina, the low level of confidence in the treating doctor, the side effects of the new drug reduce medication adherence of patients, which, as a result, negatively affects the QoL of these patients.