Evaluation of adherence to pharmacological treatments by undocumented migrants with chronic diseases: a 10-year retrospective cohort study.

OBJECTIVES:To investigate the time course of medication adherence and some of the factors involved in this process in undocumented migrants with chronic diseases. DESIGN:Retrospective cohort study. SETTING:A big non-governmental organisation in Milano, Italy, giving medical assistance to undocumented migrants. PARTICIPANTS:1918 patients, 998 females and 920 males, with at least one chronic condition (diabetes, cardiovascular diseases (CVDs), mental health disorders) seen over a period of 10 years (2011-2020). Their mean age was 49.2±13 years. RESULTS:Adherence to medications decreased over 1 year in all patients. This was more evident during the first 2 months of treatment. Patients on only one medication were less adherent than those on more than one medication; at 6 months the percentage of patients with high adherence was 33% vs 57% (p<0.0001) for diabetes, 15% vs 46% (p<0.0001) for mental disorders and 35% vs 59% (p<0.0001) for CVDs. Patients with mental disorders had the lowest adherence: 25% at 6 months and 3% at 1 year. Mental disorders, when present as comorbidities, greatly reduced the probability of being highly adherent: risk ratio (RR) 0.72 (95% CI 0.57 to 0.91; p=0.006) at 3 months, RR 0.77, (95% CI 0.59 to 1.01; p=0.06) at 6 months, RR 0.35 (95% CI 0.13 to 0.94; p=0.04) at 1 year. This was especially evident for patients with CVDs, whose percentage of high adherents decreased to 30% (p=0.0008) at 6 months and to 3% (p=0.01) at 1 year. We also noted that highly adherent patients usually were those most frequently seen by a doctor. CONCLUSIONS:Interventions to increase medication adherence of undocumented migrants with chronic diseases are necessary, particularly in the first 2 months after beginning treatment. These should be aimed at people-centred care and include more outpatient consultations. Educational interventions should especially be taken into consideration for patients on monotherapy.