Risk Aversion and Costs A Comparison of Family Physicians and General Internists

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Original Research

Risk Aversion and Costs A Comparison of Family Physicians and General Internists

J Fam Pract. 2000 January;49(1):12-17

References

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Results

Table 1 shows the comparisons between family physicians and internists for the 173 physicians providing complete information. Family physicians were younger and had fewer office sessions per week. Among the psychological factors, family physicians reported less anxiety generated by uncertainty and were less risk averse; none of the other psychological factors showed specialty differences. Family physicians also had lower observed and anticipated expenditures per panel member.

After using the stepwise logistic regression Table 2, anxiety generated by uncertainty was no longer significantly associated with specialty. The receiver operator curve analysis for this logistic regression revealed an area below the curve of 0.74, indicating a good fit for the regression model for independent predictors of specialty.

In the physician-level ordinary linear regression Table 3, family physicians had observed per-panel-member expenditures that were 5.3% lower (95% confidence interval [CI], 1.8% - 9.0%) after adjustment for anticipated expenditures. None of the physician demographic or practice variables made statistically significant contributions to explaining expenditures. After adjustment for case mix, risk-averse physicians generated higher expenditures Table 3; a 1 standard deviation increase in risk aversion was associated with a 2.4% increase in expenditures (95% CI, 0.5% - 4.4%). After adjustment for case mix and risk aversion Table 3, family physicians’ costs were no longer significantly lower (3.3%; 95% CI, -1.2 to 8.1%). The effect of risk aversion remained significant; a 1 standard deviation increase in risk aversion was associated with a 2.1% increase in expenditures (95% CI, 0.1% to 4.1%). None of the other physician demographic, practice, or psychological factors were significantly associated with case-mix adjusted expenditures.

Discussion

Family physicians had significantly less anxiety generated by uncertainty, less risk aversion, and worked fewer sessions per week than internists; after multivariate adjustment, the effect of anxiety generated by uncertainty was no longer statistically significant. Consistent with previous studies,^1-5 we found that family physicians generated lower overall costs than general internists. After adjusting for patient case mix, the costs per enrolled member for family physicians were 5% lower. When the risk aversion measure was included in the regression model, the expenditures generated by family physicians were no longer significantly lower than those of internists. Risk aversion, however, was associated with significantly lower patient costs both before and after adjustment for specialty. These findings suggest that interspecialty differences in costs may be related to the greater risk aversion of internists.

Although causality cannot be established through an observational study, the findings were consistent with our hypothesis that attitude toward risk influences physician behavior. Previous studies have shown that physicians who are more averse to risk order more tests,¹⁵ refer more often,¹⁶ hospitalize more frequently,¹⁴ and generate higher overall costs.¹⁸ The aspects of risk aversion that affect utilization are not clear. There was no effect of fear of malpractice or of anxiety generated by uncertainty on costs. Although these 2 scales address some aspects of risk aversion, they were focused on medical issues. The risk aversion scale we used is not specific to clinical risk taking but taps the broader domain of attitude toward risk taking in general.

There are 2 plausible explanations for the lower risk aversion of family physicians than that of general internists: self-selection and residency training. Medical students who are less risk averse may select family medicine because of its biopsychosocial approach, attention to the health of families, and a broad focus that cuts across traditional specialties defined by age or organ system. Less risk-averse students may also be drawn to family medicine’s countercultural roots.³¹ Differences in residency training between family medicine and general internal medicine may also contribute to specialty differences in risk aversion. Historically, internal medicine residency training has been more hospital-based than family medicine and has emphasized differential diagnosis and thorough diagnostic evaluations. Much of internal medicine residency teaching is done by subspecialists who emphasize diagnosis and management of diseases that are seen less frequently in primary care. Our study cannot address the relative importance of self-selection or training in accounting for differences in risk aversion between the 2 specialties; the nature of our scale, however, suggests that self-selection plays a larger role. The scale measures attitude toward risk taking in general, and it seems less likely that residency training would influence such a broad construct. It is possible that as family medicine becomes more mainstream and general internal medicine becomes more primary care based³² cost differences between the specialties will decline.

The validity of the these findings is strengthened by our use of a community sample of board-certified physicians, a comprehensive MCO claims database, and careful case-mix adjustment. Although these findings are not necessarily generalizable to other communities, the finding of lower expenditures for family physicians than internists is consistent with results from national samples.^1,2,10,12 The finding that these differences are related to risk taking is new and warrants replication.