Prescription Drug Expenditures Among People Aged 18 - 64 with Diabetes by Serious Psychological Distress Status, 2012 -2016
Approximately 26 million Americans have diabetes, and the number is expected to increase to 41 million people by 2030. It is well documented that people with diabetes have higher prescription drug expenditures than those who do not have diabetes. The extent to which Serious Psychological Distress(SPD) may impact prescription drug expenditures among individuals diagnosed with diabetes has been under-explored in the literature.
To examine the distribution of prescription drug expenditures among US adults aged 18 - 64 by SPD status using a large, nationally representative dataset; and, to fit a model to predict expenditures on prescription drugs among people diagnosed with diabetes, including individuals that have a usual source of care, by SPD status.
Using data from the Medical Expenditure Panel Survey, we examined prescription drug expenditures among people with diabetes by SPD status, as indicated by a Kessler-6 score of 13 or greater. Data from the household file was combined for years 2012-2016. Interaction terms were fit for year and SPD status; and, race/ethnicity and SPD status. Expenditures were adjusted to 2016 inflation levels using the Consumer Price Index-Medical Component. A generalized linear model (GLM) with gamma distribution was used to investigate prescription drug expenditures. The Andersen model of health behavior was used to select co-variates; diabetes care supplement survey weights were used.
Mean prescription drug expenditures were calculated for respondents of the diabetes care survey that confirmed a diagnosis of diabetes. In 2012, mean prescription drug expenditures for all categories of medications among those with diabetes but without SPD was $3,482.75, while diabetics with SPD had drug expenditures of $5,627.81 (p <0.01). Likewise, in 2013, 2014, and 2015, diabetics without SPD spent $4,018.06, $4,607.71, and $5,559.87, while those with SPD spent $6,516.02; $7,259.10; and $8,319.71 (p <0.05) for years 2013-15. Differences in prescription drug expenditures by SPD status were not statistically significant in 2016.
Our findings from the GLM suggest that non-Hispanic Blacks (-$1,961.54, (p <0.001)), Asians (-$2,213.00, (p <0.005)), and those born outside the US had statistically significant lower expenditures on prescription drugs (-$1,334.67, (p <0.005)). Interestingly, those with Medicaid had higher expenditures ($1,500.71, (p<0.05)) on prescription drugs than the privately insured, while the uninsured had lower prescription drug expenditures (-$1421.62 (p<0.002)). Not having a usual source of care was associated with lower prescription drug expenditures (-$2,080.89, (p<0.000)).
Our findings suggest that individuals with diabetes and SPD had higher mean prescription expenditures from 2012 to 2015, compared to those with only diabetes but no SPD. We also found that having a usual source of care was a strong predictor of higher expenditures on prescription drugs. In as much as all individuals in this sample had diabetes, having a usual source of care could be an important component of diabetes disease management. Higher prescription expenditures among the publicly insured suggest that more research is needed to determine viable strategies to manage prescription drug expenditures among people receiving publicly financed health insurance.