Opioid prescriptions for chronic pain and overdose: a cohort study.
BACKGROUND
Long-term opioid therapy for chronic noncancer pain is becoming increasingly common in community practice. Concomitant with this change in practice, rates of fatal opioid overdose have increased. The extent to which overdose risks are elevated among patients receiving medically prescribed long-term opioid therapy is unknown.


OBJECTIVE
To estimate rates of opioid overdose and their association with an average prescribed daily opioid dose among patients receiving medically prescribed, long-term opioid therapy.


METHODS
Cox proportional hazards models were used to estimate overdose risk as a function of average daily opioid dose (morphine equivalents) received at the time of overdose.


METHODS
HMO.


METHODS
9940 persons who received 3 or more opioid prescriptions within 90 days for chronic noncancer pain between 1997 and 2005.


METHODS
Average daily opioid dose over the previous 90 days from automated pharmacy data. Primary outcomes--nonfatal and fatal overdoses--were identified through diagnostic codes from inpatient and outpatient care and death certificates and were confirmed by medical record review.


RESULTS
51 opioid-related overdoses were identified, including 6 deaths. Compared with patients receiving 1 to 20 mg/d of opioids (0.2% annual overdose rate), patients receiving 50 to 99 mg/d had a 3.7-fold increase in overdose risk (95% CI, 1.5 to 9.5) and a 0.7% annual overdose rate. Patients receiving 100 mg/d or more had an 8.9-fold increase in overdose risk (CI, 4.0 to 19.7) and a 1.8% annual overdose rate.


CONCLUSIONS
Increased overdose risk among patients receiving higher dose regimens may be due to confounding by patient differences and by use of opioids in ways not intended by prescribing physicians. The small number of overdoses in the study cohort is also a limitation.


CONCLUSIONS
Patients receiving higher doses of prescribed opioids are at increased risk for overdose, which underscores the need for close supervision of these patients.


BACKGROUND
National Institute of Drug Abuse.
Dunn
Kate M
KM
Group Health Research Institute, Seattle, Washington 98101, USA.
Saunders
Kathleen W
KW
Rutter
Carolyn M
CM
Banta-Green
Caleb J
CJ
Merrill
Joseph O
JO
Sullivan
Mark D
MD
Weisner
Constance M
CM
Silverberg
Michael J
MJ
Campbell
Cynthia I
CI
Psaty
Bruce M
BM
Von Korff
Michael
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000506:poisoning*; D002908:Chronic Disease; D015331:Cohort Studies; D004334:Drug Administration Schedule; D062787:Drug Overdose / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy*; D016016:Proportional Hazards Models; D012307:Risk Factors; D055815:Young Adult
D000701:Analgesics, Opioid