Working Paper: NBER ID: w21780
Authors: Gisela Hostenkamp; Frank R. Lichtenberg
Abstract: We use Danish diabetes registry and health insurance data to analyze the extent, consequences, and determinants of under-use and overuse of oral anti-diabetic drugs. \n \nLess than half of patients consume the appropriate amount of medication--between 90% and 110% of the amount prescribed by their doctors. \n \nThe life expectancy of patients consuming the appropriate amount is 2.5 years greater than that of patients consuming less than 70% of the prescribed amount, and 3.2 years greater than that of patients consuming more than 130% of the prescribed amount, controlling for time since diagnosis, insulin dependence, comorbidities, age, gender and education. Patients consuming the appropriate amount are also less likely to be hospitalized than under- or over-users. \n \nPharmaceutical innovation appears to have reduced medication under-use and overuse: patients using newer drugs are significantly more likely to consume the appropriate amount, controlling for socioeconomic factors, average number of pills and average daily out-of-pocket costs. \n \nDefined Daily Doses published by the World Health Organization substantially overstate the appropriate level of consumption of these medications. \n \nPatients who don’t adhere to recommended medication regimens may also disregard other physician instructions. Medication under-use and overuse could easily be monitored to identify patients at risk and enact interventions.
Keywords: medication adherence; diabetes; health outcomes; long-term health; pharmaceutical innovation
JEL Codes: I10; I30
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Underuse of Medications (I19) | Adverse Health Consequences (increased hospitalizations, premature mortality) (I12) |
| Overuse of Medications (I19) | Adverse Health Consequences (increased hospitalizations, premature mortality) (I12) |
| Use of Newer Drugs (L65) | Better Adherence (M37) |
| Medication Adherence (measured as deviations from prescribed dosages) (I12) | Long-term Health Outcomes (hospitalizations, mortality, life expectancy) (I12) |
| Appropriate Medication Consumption (defined as 90-110% of prescribed dosage) (I11) | Life Expectancy (J17) |
| Higher Medical Possession Ratio (MPR) (I11) | Lower Hospitalization Rates (I19) |
| Deviation from Prescribed Dosage (by more than 10%) (C46) | Lower Life Expectancy (I14) |