Controlled substance (CS) score: How to make an impact

Prime’s CS score is linked to health outcomes and health care costs

November 30, 2017

What was the study about?

This study sought to understand the relationship between the controlled substance (CS) score and a member’s health care utilization and total cost of care. Could a one point change of that CS score affect health care utilization and cost of care?

What did we learn?

Members with higher CS scores have higher health care utilization and costs. The relationship is:

  • Linear
  • Statistically significant and
  • Consistently increasing

As the CS score goes up, so do annual hospitalizations, ER visits, controlled substance costs and total cost of care. The data showed that a one point decrease in a CS score meant a $1,488 cost of care savings.


Prime reviewed integrated medical and pharmacy claims from 11 million commercially insured members who were continuously enrolled in all of 2012 and 2013. One million of those members were identified with a CS score of 2.5 or higher.

How is the CS score determined?

The CS score is determined using a three-month lookback of a member’s CS claims. The score assigns specific points to the following:

  • Number of CS claims
  • Number of health care professionals who prescribed the CS drugs
  • Number of pharmacies that filled the CS prescriptions
  • Rate of CS drug use


Just under half (47 percent) of members had a CS score of 2.5, indicating a single CS claim during the study period. Half of the members (51 percent) had a CS score between 3 and under 12. The remaining 2 percent (20,858 members) had a score of 12 or more.

The median 2013 total cost of care for a member with a CS score of 2.5 was $2,486. The cost of care for a member with a CS score of 20 was $17,709.

A one point increase in CS score was associated with:

  • $1,488 higher total cost of care
  • $235 higher controlled substance drug cost
  • 0.9 percent increase in hospitalization rate
  • 1.5 percent increase in emergency room visit rate


The analysis validates the linear association between increasing CS score and increasing:

  • Hospitalizations
  • ER visits
  • CS drug costs
  • Total cost of care

Interventions can decrease a member’s controlled substance score. Prime’s previous research demonstrated a 1.4 point reduction in members’ CS scores associated with a prescriber letter intervention.1

This research suggests that such a letter program could help a 10,000-life commercially insured population potentially avoid $40,800 in costs, or about 34 cents per member per month.

What does this mean for you?

Plan sponsors should use validated CS risk tools to identify members who are at risk for CS misuse/abuse. A prescriber intervention program can successfully improve quality of care and bring down costs.

Prime’s Controlled Substance Management Program uses the validated CS score tool to help plan sponsors identify CS users at risk for harm and high costs and target interventions.

1. Daubresse M, Gleason PP, Peng Y, Shah. HD, Ritter ST, Alexander CG. Impact of a Drug Utilization Review Program on High-Risk Use of Prescription Controlled Substances. Pharmacoepidemiology and Drug Safety 2014:23(4):419-27.

A Controlled Substance Score: Is It Related to Health Care Utilization and Total Cost of Care? April 2015.

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