Overdose Risk Score


The Overdose Risk Score (ORS) is a relative scoring system that ranges from 000-990.

The scores represents the risk of unintentional overdose death.


The ORS was developed against a case / control study of Ohio overdose deaths from 2014.

More than 70 PMP variables were evaluated using machine learning and logistic regression.


The model revealed threshold quantities of pharmacies, providers, and MME that were strongly associated with risk of overdose death.

The model also revealed that certain trends in provider, pharmacy, and MME usage were strongly associated with risk of overdose death.


The score was designed such that the risk of overdose death doubles approximately every 100pts.


An Odds Ratio for 100 point scoring groups using 000-190 as the referent group can also be used to quantify risk.

Patient’s with an ORS of 900-990 are more than 300x likely to die of an overdose than patients with a score of less than 200.

Sorting Differences

Narx Scores can at times differ markedly from the Overdose Risk Score.


Some high use patterns can have low overdose risk. Typically this means the patient is properly using medications at a high dose.

Certain low use patterns can be risky, especially when it comes to trends in usage.

Narx Scores tend to fall over time with decreased use but historical use patterns can result in persistent overdose risk and persistently elevated overdose risk scores even in the setting of zero, or reduced usage within the last year.

Future Advancements

The Overdose Risk Score is currently based on prescription monitoring program (PMP) data.

As additional data becomes available, this score will be adapted with the goal of providing comprehensive risk assessment.