Why is there variation in surgery rates?
The dramatic variation in procedure rates for preference-sensitive surgery in the United States cannot be explained by variation in the prevalence of diseases requiring surgical intervention. For example, there is no reason to believe that patients in Boston are at higher risk for developing benign prostatic hyperplasia and therefore require transurethral prostatectomy more than four times as often as patients in Rochester, Minnesota. Instead, variation in the rates of a given procedure reflects a lack of concrete evidence or an unsettled debate about the efficacy of the treatment. In other words, physicians often do not know the "right" rate for a procedure, and the more that surgeons disagree about the effectiveness of that procedure, the greater likelihood there is for geographic variation. [5]
This is also demonstrated by examining rates of knee replacement and back surgery, shown in Figures 7 and 8. Conditions associated with these orthopedic procedures (for example, knee osteoarthritis or back pain due to disc herniation) can be treated in more than one way, including analgesics, physical therapy, and surgery. When there are multiple treatment options, it is no surprise that there is marked variation in procedure rates. For example, knee replacements are performed in Salt Lake City at a rate that is more than two times that in Manhattan. The only way to ensure the rate is "right" is for clinicians to fully inform patients about treatment options and to share treatment decisions, through a process known as shared decision-making. [6]
Figure 7. Knee replacement per 1,000 Medicare enrollees (2008-10)
Figure 8. Back surgery per 1,000 Medicare enrollees (2008-10)
Unwarranted variation leads to differences in surgical training. An orthopedic resident trained in Salt Lake City is likely to learn a treatment style for osteoarthritis of the knee where surgery is more probable than a resident in New York City, who might more readily prescribe physical therapy or analgesics.