Opioid Prescribing Cap Laws Have Had Little Effect on Postsurgical Prescribing Trends

Cap laws for opioid prescribing had had little effect on postsurgical opioid prescribing practices, according to results of a study published in Health Services Research.

Investigators at Johns Hopkins Bloomberg School of Public Health sourced data from the OptumLabsÒ Data Warehouse to compare trends in 30-day postsurgical opioid prescribing in 20 states that passed prescribing cap laws without surgical exemptions with 16 states and the District of Columbia that did not have such laws. Data were stratified according to whether they were obtained before or after law passage.

The main analysis included 55,966 surgeries, 10,152 and 9569 of which were performed in cap law states before and after law passage. A total of 36,245 surgeries were from control states, 18,888 of which corresponded with the prelaw time period in 1 cohort and with the postlaw time period in another cohort, yielding 27,087 and 28,046 surgeries for individuals from control states during the prelaw and postlaw periods, respectively.

The mean age of the patient cohorts ranged from 57.3 to 61.6 years.  Approximately one-half of the participants were women; 15.3% to 17.6% had mental illness, 1.5% to 2.3% had substance use disorder, and mean Elixhauser comorbidity scores ranged from 2.69 to 3.31.

Cap laws were found to be associated with a -0.041 (95% CI, -0.054 to -0.028) change in probability of filling an opioid prescription following surgery. However, there was a negative trend in postsurgical opioid prescription filling reported in the year preceding passage of the law (-0.033 probability). Overall, no significant difference in the number of postsurgical opioid prescriptions was observed (average treatment effect on the treated [ATT], -0.011; 95% CI, -0.043 to 0.021).

No decrease in daily opioid dosing was reported following enactment of the cap laws (ATT, -0.013; 95% CI, -0.030 to 0.005). Cap laws were associated with a -0.022 (95% CI, -0.038 to -0.006) change in probability of filling a greater than 30 morphine milligram equivalent (MME) per day prescription and a -0.037 (95% CI, -0.053 to -0.021) change in probability of filling a greater than 50 MME per day prescription. However, the cap laws did not affect the probability of filling a greater than 90 MME per day (ATT, -0.006; 95% CI, -0.014 to 0.002) or a greater than 200 MME per day (ATT, 0.001; 95% CI, 0.000-0.002) prescription.

Cap laws decreased daily opioid supply by 10%, and 0.117 fewer total pills were prescribed, which exceeded trends identified during the pre-law period. Cap laws decreased the probability of filling prescriptions with a more than 3-day (ATT, -0.083; 95% CI, -0.097 to -0.069), more than 5-day (ATT, -0.066; 95% CI, -0.083 to -0.048), and more than 7-day (ATT, -0.070; 95% CI, -0.086 to -0.054) supply, but they did not decrease the probability of filling prescriptions with a than 30-day supply (ATT, -0.001; 95% CI, -0.003 to 0.001).

The results of this study are inconsistent with a prior investigation; therefore, the findings should be interpreted with caution.

This study found that opioid prescribing cap laws resulted in a minimal reduction in opioid supply but had little effect on overall postsurgical opioid prescribing practices.  The investigators concluded, “While incorporating more and stricter limits on the dosage of opioid prescriptions into the laws may lead to similarly minimal reductions in dose-related outcomes, prescribing cap laws are likely insufficient to eliminate high-risk postsurgical opioid prescribing.”