Objectives Sub-optimal adherence to prescribed medications due to cost is known to have adverse health effects over 2–4 years, but little is known about its longer run effects. Here we quantify whether and how cost-related non-adherence (CRN) influences the risk of adverse health events over a 10-year period.
Methods Nationally representative 1994–2004 data from the Health and Retirement Study, conducted by the US University of Michigan, are analyzed for 2460 adults aged 50–59 years in 1994 who were regularly taking medication(s) and had one or more chronic health conditions at baseline (hypertension, heart disease, diabetes, cancer, lung problems, arthritis or had experienced a heart attack or stroke). Regression models are estimated to quantify CRN's effects on the risk of four different adverse health events, paying careful attention to the potential endogeneity of CRN.
Key findings Patients who underused medication(s) due to cost are significantly more likely to see new chronic conditions emerge, to be hospitalized, to experience a heart attack or stroke and to see problems develop limiting their ability to work. We also find the more frequent the CRN, the more probable each of these outcomes.
Conclusions Adults in late midlife with chronic conditions who underuse medications for cost reasons place themselves at much higher risk for serious adverse events over the long run.