Opioid-induced respiratory depression risk factor trend analysis and opioid guideline-related risk reduction in the Department of Defense long-term opioid therapy population

Palmrose, Gregory H.
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The purpose of this study was to describe the long-term opioid therapy (LOT) patient population in the Department of Defense (DoD). This study described the incidence and prevalence of LOT in the DoD as well as opioid overdose risk factor trends from 2007 to 2017. Additionally, the demographic, geographic, clinical, and service level characteristics were described for the 2017 LOT population, and characteristics associated with high-risk for opioid overdose were evaluated using logistic regression. Risk scores were compared using the Veterans Health Agency (VHA) risk index for overdose or serious opioid-induced respiratory depression (VHA-RIOSORD) and commercially insured health plan (CIP-RIOSORD) to determine agreement of “high-risk” classification between these two scores. Finally, a segmented regression time-series analysis was performed comparing the effect of the Centers for Disease Control (CDC) Guideline for Prescribing Opioids for Chronic Pain and the Department of Veterans Affairs (VA)/DoD Management of Opioid Therapy for Chronic Pain guideline on reducing the proportion of DOD LOT patients with MEDD ≥ 90 mg and on the proportion of patients with concomitant benzodiazepines. The incidence of LOT in the DoD increased from 0.25% in 2007 to 0.34% in 2013, then declined to 0.26% in 2017. The period prevalence of LOT increased from 0.45% in 2007 to 0.70% in 2014, then declined to 0.66% in 2017. Risk factors for opioid overdose, including use of long-acting formulation, concomitant antidepressants, having ≥ 4 providers, and RIOSORD > 32 declined over the study period. Of the 21,441 LOT patients in 2017, the majority were female (11,451) and older (54.2±13.7) with 25.7% being classified as high-risk (n = 5,513). Factors associated being in the high-risk group included being associated with the Navy (OR =1.14, 95% CI = 1.06-1.24, p < 0.001) while being the TRICARE sponsor was less likely to be in the high-risk group (OR = 0.65, 95% CI = 0.57-0.72, p < 0.001). The VHA- and CIP-RIOSORD classified significantly different patients as high-risk (chi-square = 629.0, p < 0.001). Finally, the time-series analysis showed a significant effect in reducing the slope of the trend line of the proportion of patients with ≥ 90 mg MEDD of both the CDC (β₃ =-0.062, SE = 0.006, p < 0.001) and the DoD guidelines (β₅ = -0.030, SE = 0.009, p < 0.001). The time-series analysis showed a significant effect of the CDC guidelines in reducing the slope of the trend line of the proportion of LOT patients with concomitant benzodiazepines (β₃ =-0.039, SE = 0.007, p < 0.001). This study shows incidence and prevalence of LOT in the DoD is low (<1%). Additionally, trends in incidence and prevalence, as well as trends in risk factors for opioid overdose, are similar to trends reported in the general and VA populations. Also, there are significant differences in the risk identified by using the VHA- and CIP-RIOSORD tools in the LOT population. Finally, the CDC and DoD guidelines had an effect in reducing significant risk factors for overdose in the DoD LOT population