Longitudinal effects on costs and potential cost savings from improvement

OBJECTIVEdToexaminethelongitudinaleffectsofmedicationnonadherence(MNA)onkeycosts and estimate potential savings from increased adherence using a novel methodology thataccounts for shared correlation among cost categories.RESEARCH DESIGN AND METHODSdVeterans with type 2 diabetes (740,195) werefollowed from January 2002 until death, loss to follow-up, or December 2006. A novel multi-variate,generalized,linear,mixedmodelingapproachwasusedtoassessthedifferentialeffectofMNA, defined as medication possession ratio (MPR) $0.8 on healthcare costs. A sensitivityanalysis was performed to assess potential cost savings at different MNA levels using the Con-sumer Price Index to adjust estimates to 2012 dollar value.RESULTSdMean MPR for the full sample over 5 years was 0.78, with a mean of 0.93 for theadherentgroupand0.58fortheMNAgroup.Infullyadjustedmodels,allannualcostcategoriesincreased ;3%peryear(P = 0.001) during the 5-year study time period. MNA was associatedwitha37%lowerpharmacycost,7%loweroutpatientcost,and41%higherinpatientcost.Basedonsensitivityanalyses,improvingadherenceintheMNAgroupwouldresultinannualestimatedcost savings ranging from;$661 million (MPR ,0.6 vs. $0.6) to ;$1.16 billion (MPR ,1vs.1). Maximal incremental annual savings would occur by raising MPR from,0.8 to $0.8($204,530,778) among MNA subjects.CONCLUSIONSdAggressive strategies and policies are needed to achieve optimal medica-tion adherence in diabetes. Such approaches may further the so-called “triple aim” of achievingbetter health, better quality care, and lower cost.Diabetes Care 35:2533–2539, 2012