Probabilistic threshold technique showed that patients' preferences for specific trade-offs between pain relief and each side effect of treatment in osteoarthritis varied.
OBJECTIVE
Therapeutic decisions in osteoarthritis (OA) often involve trade-offs between accepting risks of side effects and gaining pain relief. Our objectives were (1) to determine patients' maximum acceptable risk increments (MARI) for different adverse effects from OA medication and (2) to identify the predictors of these preferences.


METHODS
MARI were measured with a probabilistic threshold technique (TT). Risk and pain levels in the TT scenarios were controlled for in a 2x2 randomized factorial design. Clinical, sociodemographic, and psychological characteristics (decisional conflict and locus of control) of the participants were assessed using a self-administered questionnaire.


RESULTS
For 196 subjects, MARI varied by type of adverse effect, level of pain relief, and baseline risk. Mean MARI ranged from 3% to 5% for heart attack/stroke, 5% to 8% for stomach bleed, 13% to 21% for hypertension, 22% to 33% for fluid retention, and 23% to 35% for dyspepsia. Age, gender, education, physical and mental health, pain, disability, and locus of control were not associated with MARI.


CONCLUSIONS
Participants varied widely in the level of risk they would accept, but their clinical, sociodemographic, and psychological characteristics did not explain this variation. These observations are important for the development of practice guidelines for physicians and patients' decision aids that can foster individualized, evidence-based yet preference-sensitive care for patients with OA.
Kopec
Jacek A
JA
Department of Health Care and Epidemiology, University of British Columbia, Vancouver, BC, Canada. jkopec@arthritisresearch.ca
Richardson
Chris G
CG
Llewellyn-Thomas
Hilary
H
Klinkhoff
Alice
A
Carswell
Anne
A
Chalmers
Andrew
A
D000368:Aged; D000700:Analgesics / Q000009:adverse effects* / Q000627:therapeutic use; D004415:Dyspepsia / Q000139:chemically induced / Q000523:psychology; D005163:Factor Analysis, Statistical; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000523:psychology; D006801:Humans; D006973:Hypertension / Q000139:chemically induced / Q000523:psychology; D007389:Internal-External Control; D007674:Kidney Diseases / Q000139:chemically induced / Q000523:psychology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000188:drug therapy / Q000523:psychology*; D017288:Pain Threshold; D017060:Patient Satisfaction; D011336:Probability; D012044:Regression Analysis; D018570:Risk Assessment; D020521:Stroke / Q000139:chemically induced / Q000523:psychology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D000700:Analgesics