LOS ANGELES — Physicians and patients are likely to reject bisphosphonate therapy when treatment efficacy is expressed in terms of absolute risk reduction, as health literacy experts recommend, rather than relative risk reduction, Dr. Christine A. Sinsky reported at the annual meeting of the Society of General Internal Medicine.
A patient's decision to reject lifelong treatment for osteoporosis may have a negative impact on a practice's income if pay for performance is linked to compliance with clinical practice guidelines.
Those guidelines recommend the use of bisphosphonates to treat postmenopausal osteoporosis. Clinicians may deviate from these guidelines; some payers, however, link provider reimbursement for osteoporosis care to guideline adherence.
Practice guidelines, clinical trial reports, and direct to consumer advertising that recommend drug treatment for osteoporosis tend to cite relative risk reduction (RRR) when describing the benefits of therapy. Experts in health literacy, however, prefer to describe treatment benefits as absolute risk reduction (ARR), because RRR tends to overestimate risks when there is a low baseline frequency of a condition, such as hip fracture in osteoporosis. Data from the U.S. Preventive Services Task Force (USPSTF) suggest that after 5 years of treatment with bisphosphonates, the RRR for hip fracture is 35%, whereas the absolute risk of fracture in the at-risk population decreases from 3% to 2%, yield a 1% ARR (Ann. Int. Med. 2002;137:526–8).
“First, you have to get the doctors to understand the difference between RRR and ARR,” stated Dr. Sinsky, an internist in private practice in Dubuque, Iowa. She illustrated these concepts for the physician audience with a 10 by 10 grid of 100 happy faces, with three (those destined for hip fracture regardless of treatment) colored red. If treatment prevents one hip fracture out of three (roughly what the USPSTF found), one red face turned blue. If the reference class includes only the three patients who would have gotten a fracture, regardless of treatment, then the RRR is 33.3%. If the reference class includes all 100 women at risk of fracture, the ARR is 1%.
The investigators hypothesized that both patient and provider willingness to try bisphosphonate therapy for osteoporosis would be significantly lower if the efficacy were presented as ARR rather than as RRR.
The investigators administered a 10-item questionnaire to 641 consecutive female patients (aged 50 years or older) and all general medicine physicians at one university-based practice and one community practice. To assess baseline compliance with clinical practice guidelines, physicians asked patients: “You have a bone density test that indicates osteoporosis. You have full drug coverage. Are you interested in treatment?” Providers were asked: “Your 65-year-old patient has a [dual-energy x-ray absorptiometry] scan that indicates osteoporosis. The patient has full drug coverage. Would you recommend treatment?” Other scenarios presented out-of-pocket costs to the patient ranging from 0% to 90%. Subsequent questions presented similar scenarios but with efficacy of treatment presented as either RRR or ARR.
When treatment benefit was presented as RRR, 86% of patients expressed interest, compared with 57% when benefit was expressed as ARR (P < .005). Similarly, physicians were significantly more likely to recommend osteoporosis treatment for their patients when treatment benefits were presented as RRR (97%) as opposed to ARR (53%) (P < .005).
Patients were told that the cost of bisphosphonate therapy is about $1,000 per year. When the scenario stated that insurance would cover the entire cost of treatment, 81% of patients wanted therapy. In contrast, if insurance would cover only 10% of the cost, 15% of patients wanted therapy (P = .04). Under scenarios in which patients had full coverage, 100% recommended therapy; in contrast, 61% recommended therapy when insurance covered only 10% (P = .02). The data support the investigators' original hypothesis.
The data suggest that better informed patients may choose to reject lifelong drug treatment for osteoporosis.