Effects of changing the appearance of medications in safety and adherence in chronic patients over 65 years of age in primary care. CAMBIMED Study

To study whether the changes in bioequivalent drugs with different appearances are associated with an increase in lack of adherence and medication use errors, in patients >65years old treated with antihypertensive and lipid-lowering medications. Observational longitudinal prospective cohort study with a one-year follow-up period between 1 January 2013 and 31 December 2014. Primary Healthcare Centres in the Community of Madrid. Patients ≥65years-old with a diagnosis of hypertension and/or dyslipidaemia receiving treatment with Enalapril and/or Amlodipine and/or Simvastatin. Variables collected during a Primary Care consultation by means of a personal interview were: sociodemographic (age, gender, level of education), clinical variables, adherence (Morisky-Green test and direct counting), medication errors (number and type), medication changes and number, analytical (total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides) and combined variable (error and/or adherence). There were 1 baseline and 4 quarterly visits. The study included 274 patients with a mean age 72 (6.6) years, of whom 47.8% were female. Some medication changes were observed in 134 patients (48.9%), with a median of 3 (IQR 1-5) and a maximum of 11 changes. The risk of presenting with a medication use error or decreased adherence was increased in patients exposed to changes in all visits with RR 1.14 (1.16-1.69) at one year of follow-up. The most frequent error was the loss of dose. For each change in medication, the probability of a combined event increases by 41%. The changes made in bioequivalent drugs with different appearance could increase the number of medication use errors and decrease the adherence. More studies should be carried out to assess how much this affects the control of the disease. The intervention section is not considered because it is an observational study.