Predictors of Statin Compliance after Switching from Branded to Generic Agents among Managed-Care Beneficiaries

Abstract

OBJECTIVES:To identify patient demographics and characteristics associated with compliance to statin therapy after switching from branded to generic agents DESIGN: Retrospective cohort study using electronic health records and pharmacy claims data from Sutter Health's ambulatory-care medical network PATIENTS: Managed-care beneficiaries, ≥ 18 years of age, who were switched from branded to generic statins between 1 January 2003 and 31 December 2012 MAIN MEASURES: Compliance was calculated as days of therapy dispensed divided by days from first to last generic prescription fill over 6 months, and was defined as a medication possession ratio ≥ 0.80. We used multivariable logistic regression to assess factors associated with compliance. Adjusted ORs and 95 % CI were generated. KEY RESULTS: We identified 5,156 patients who were switched from branded to generic statins; 73 % of patients were compliant in the 6 months after switching. After statistical adjustment, higher compliance was associated with each 10-year increase in age (OR: 1.13; 95 % CI: 1.07, 1.19; p<0.001), receipt of a generic statin equivalent in potency to the prior branded statin (OR: 1.41; 95 % CI: 1.16, 1.70; p<0.001), and compliance with prior branded statin (OR: 4.68; 95 % CI: 4.07, 5.39; p<0.001). Lower compliance was seen among Hispanic patients compared to non-Hispanic white patients (OR: 0.68; 95 % CI: 0.52, 0.91; p=0.009). Also, a switch to a higher potency generic statin, regardless of prior dose/potency, was negatively associated with compliance after switching (OR: 0.87; 95 % CI: 0.80, 0.94; p=0.001). CONCLUSIONS: The majority of patients switched from branded to generic agents were compliant with therapy in the first 6 months after switching. The potential for non-compliance to generic statin therapy, particularly among younger or Hispanic patients or when dose/potency changes are made, should be considered prior to switching. For these patients, counseling or close monitoring may be required to optimize generic interchange.

Real-world Evidence for Adherence and Persistence with Atorvastatin Therapy

“…Studies of patients who switched from branded to generic atorvastatin have also shown that switching may change patients' adherence [57][58][59][60][61] (Table 1). For example, an 18-month non-interventional real-world study conducted in Greece by Tsioufis et al compared the adherence of patients who continued taking branded atorvastatin with those who switched to generic atorvastatin [58].…”

“…Studies of adherence among patients prescribed atorvastatin have demonstrated that the switch from branded to generic atorvastatin had a mixed impact on adherence [ 57 – 61 ]. For example, a 6-month retrospective study analyzed adherence in 3417 patients on statin therapy (atorvastatin, fluvastatin, lovastatin, pravastatin, simvastatin) who switched from a branded to a generic formulation [ 57 ]. Patients with a medication possession ratio (MPR; ESM Table S1) ≥ 80% were considered to be ‘adherent.’ Of those who switched from a branded to generic formulation, the majority (52.3% [ n = 1786/3417]) switched from branded to generic atorvastatin.…”

Capsule Commentary on Romanelli et al., Predictors of Statin Compliance after Switching from Branded to Generic Agents Among Managed-Care Beneficiaries

“…The investigators find that a majority of patients were compliant in the six months after switching. 1 Higher compliance was associated with equivalent potency to the prior branded statin and higher pre-switch compliance. 1 Lower compliance was seen among Hispanic patients.…”

“…1 Higher compliance was associated with equivalent potency to the prior branded statin and higher pre-switch compliance. 1 Lower compliance was seen among Hispanic patients. The authors concluded that there is a potential for non-compliance to generic statin therapy, particularly among Hispanic patients or when dose/potency is increased.…”

“…The authors concluded that there is a potential for non-compliance to generic statin therapy, particularly among Hispanic patients or when dose/potency is increased. 1 All generic drugs approved by U.S. Food and Drug Administration (FDA) have the same high quality, strength, purity and stability as brand-name drugs. 2 The generic manufacturing, packaging, and testing sites must pass the same quality standards as those of brand name drugs.…”