| Description |
To compare patient characteristics and healthcare costs between newly-treated DPN patients receiving mono-pharmacotherapy and those receiving combination pharmacotherapy. A patient cohort was identified diagnosed with DPN during 2006-2013 in Inovalon's MORE2® registry, a healthcare data warehouse with national medical/pharmacy claims, continuously enrolled for at least 18 months. Patients were included if they were ≥18 years at the time of their first DPN prescription for a tricyclic antidepressant (TCA), opioid, duloxetine, gabapentin, pregabalin, or any route lidocaine. They were classified as having mono- or combination pharmacotherapy (time between the first and second medicine was within 30 days). If there was a 60-day prescription fill gap, the prescription was classified as discontinued. Switch or add-on groups were categorized based on continuation of the index medicine. A simple proportional hazards model was conducted for comparing time to discontinue, switch, or add on. Multiple logistic regression was used for identifying predictors of combination pharmacotherapy. There were 7,145 patients on mono-pharmacotherapy and 421 patients on combination pharmacotherapy. The top three index medicines were gabapentin (55.7%), opioids (13.1%), and pregabalin (12.9%) in the mono-pharmacotherapy group, and opioids+gabapentin (27.1%), TCAs+gabapentin (17.6%), and duloxetine+gabapentin (8.6%) in the combination group. Patients on combination pharmacotherapy were 130% iv more likely to discontinue their medications than patients on mono-pharmacotherapy. There was no statistically significant difference in time to switch (p=0.254) and add on (p=0.069) between mono- and combination pharmacotherapy. Patients who were female, with >7 co-morbidities, and who had depression or arthritis were more likely to start with combination pharmacotherapy. Patients who were older than 65 and those with hypertension were less likely to start with combination pharmacotherapy. The total post- minus pre-index cost had no statistically significant difference between mono- and combination pharmacotherapy (p=0.66). Newly-treated DPN patients should add on another medication sooner than 30 days when considering combination pharmacotherapy. Because all first-line medications have similar efficacy, the cost should be considered in the treatment decision. For this reason, gabapentin and TCAs are recommended. If considering the pre-index costs, taking combination pharmacotherapy will not cost more money; the policy maker can reimburse either gabapentin+opioid or TCA+gabapentin. |
