Use of Interventions to Overcome Medication Non-Adherence

Medication Adherence

According to Cramer et al., (2008) adherence is “the extent to which a patient acts in accordance with the prescribed interval and dose of a dosing regimen.” One of the causal factors of preventable adverse events is proper medication adherence. According to Doggrell, (2010) and George et al., (2008) the rate of medication adherence varies from 30% to 100% which are influenced by patient characteristics and diversity of socio-medical constructs. Studies showed adherence rates of 30-70% for patients with asthma, 5-90% for patients with hypertension and 20-90% for patients with schizophrenic. Ho et al., (2006) worked on diabetic patients and reported that all-cause hospitalization was 23.2% for non-adherent patients compared to 19.2% for adherent. Sokol et al., (2005) classified medication adherence rates into 5 subsets: 0-20%, 21-40%, 41-60%, 61-80%, and > 80%. The study was conducted for congestive heart failure (CHF), diabetes, hypercholesterolemia and hypertension patients below the age group of 65 years. It was found that hospitalization risk and healthcare costs was inversely correlated with each of the levels of medication adherence. The reports highlighted that hospitalization risk for diabetes was 13% for adherent and 24% for non-adherent, CHF (57% vs. 63%), hypercholesterolemia (12% vs. 14%) and hypertension (19% vs. 23%). Sullivan, (1990) attributed 2.9% to 19.5% of hospital admissions to medication non-adherence. The work of Lau & Nau, (2004) on type 2 diabetes reveal that non-adherent patients were hospitalized more frequently than adherent (≥80%) patients. Hospitalization rate for 100% adherent patients was 4.1%, which increased to 14.8% when adherence dropped below 40%. Based on Medicare and Medicaid pharmacy claims data, Esposito et al., (2009) performed a cohort study on heart failure patients’ and found that adherent patients were 13% less likely to have hospital admissions and medical costs were 15% less. Zed et al., (2008) also conducted a study in Canadian tertiary care hospital and found that 3% of Emergency Department (ED) visits were due to non-adherence.