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tions with dynamic teachers and superb clinicians who serve as their role models. So why does interest in internal medicine decline? One factor is the internal medicine resi- dency in which students perceive the medical housestaff as being overworked and, at times, dissatis- fied with their effectiveness in the care of patients. However, I dis- agree with Dr. Glick in that I be- lieve the current economic atmo- sphere with the pressures of diag- nosis-related groups and utilization reviews is only of minor importance. Residents enjoy tak- ing care of patients, but become harried when large amounts of their time must be directed to- wards numerous nonmedical re- sponsibilities such as an inordinate amount of paperwork, drawing blood, placing intravenous lines, and even transporting patients. The internal medicine residency will be more rewarding when resi- dents can spend more time in- volved in patient care and cogni- tive skills, and less time in per- forming ancillary services.

I do agree with Dr. Glick that the shortened hospital stays for pa- tients do decrease the opportunity for interpersonal relationships be- tween housestaff and patients, and limit the diversity of illnesses that the resident will experience. De- partments of internal medicine must be willing to broaden their training of residents to allow a greater percentage of time to be spent in ambulatory care settings. In the 1988 National Resident Matching Program, the number of students entering categorical inter- nal medicine programs decreased, while an increment was observed in the primary care tracks (Graet- tinger JS: The 1988 national resi- dent matching program. Ann In- tern Med 1988; 108: 761-762), indi- cating that students are interested in the special challenges of outpa- tient medicine. However, I am not suggesting that all internal medi- cine training programs should mandate an increase in ambulatory care experience because the pro- grams may become less attractive to students interested in the hospi- tal-based subspecialties of internal medicine. Rather, there must be flexibility so that residents can shape their future career plans to coincide with the kind of lifestyle they want.

Finally, internists must ennpha- size to students the positive aspects

of a career in internal medicine. Despite its problems, I believe that most internists are satisfied with their career choice. Certainly the financial rewards for cognitive work are less than in the proce- dure-oriented specialties, but I also think that financial gain is not of major concern to most medical stu- dents who invest a large amount of time in becoming physicians. Life- style issues are more important, and students are entering special- ties that are less demanding and allow them more time for social en- deavors. Therefore, it is imperative that internists educate medical students to the diversity of options available for a career in internal medicine and alert them to the fact that our field can combine the chal- lenges in the care of patients with the opportunity for a secure life- style.

ALLANR. TUNKE$,M.D., Ph.D. University of Virgima gh;;i;i

iox 385 Charlottesville, Virginia 22908

Submitted June 1, 1988. and accepted June 16, 1988

IS BEHAVIORAL MODIFICATION A SUFFICIENT CRITERION OF THE EFFECTIVENESS OF DECISION-ANALYSIS? To the Editor: Clancy and associates (Am J Med 1988; 84: 283-288) recently showed that medical decision analysis is capable of influencing the behavior of medical decision makers. Unfor- tunately, the accompanying edito- rial by Littenberg and Sox (Am J Med 1988; 84: 289-290) confuses this demonstration of psychologic effectiveness with one of clinical ef- fectiveness. Their belief that be- havioral modification is “. . . the best measure of the usefulness . . . of decision analysis,” rests on the specious assumption that an “ . individualized decision analy- sis’ will, by definition, identify the alternative that will maximize [that individual’s] well-being.” This, in turn, assumes that the in- dividual can state-with absolute confidence-the precise range of values for every probability and utility entering into the particular analysis.

Subjective estimates regarding these singular events often defy such an explicit characterization. What is the probability that the United States and the Soviet

Union will engage in a nuclear war this year? How much would such a war reduce your own “. . . well-be- ing . . .” (on a scale of 0 to 100, for example)? What are the upper and lower bounds of your estimates? How sure are you? Perhaps the dif- ficulty encountered in attempting to answer these questions helps ex- plain why the majority of subjects in Clancy and co-workers’ study were not influenced by the decision analysis.

In the face of such uncertainty, one cannot blithely assume that decision analysis impacts positive- ly on a direct measure of clinical effectiveness-in this case, a re- duction in the incidence of hepati- tis B infection-just because it pos- sesses a demonstrable degree of psychologic effectiveness. The power of persuasion is certainly necessary to the clinical effective- ness of decision analysis, but it is not by itself sufficient. We can no more infer clinical effectiveness from psychologic effectiveness than we can infer clinical signifi- cance from statistical significance. If-as the editorialists say-any- thing worth doing is worth evaluat- ing, then anything worth evaluat- ing is worth evaluating sufficient- ly-

GEORGEA.DIAMOND,M.D. Cedars-Sinai Medical Center

Los Angeles, California 90048 Submitted March 10, 1988, and accepted June 17,

1988

The Reply: The complete evaluation of a tech- nology should include analysis of the several links in the chain from technologic possibility to improved clinical outcome. The efficacy of a technology (its usefulness under ideal circumstances) often overes- timates its effectiveness (its useful- ness in clinical use). This is partic- ularly true of information-based technologies if the information is ignored by the user. Clancy and as- sociates (Am J Med 1988; 84: 283- 288) have started the work of ex- ploring whether decision analysis can cross over from potentially effi- cacious to clinically effective. If cli- nicians will not accept decision analysis, it will never be clinically useful.

Like any new diagnostic or ther- apeutic modality, decision analysis must be evaluated against a num- ber of criteria. Does it have face va- lidity? Does it operate in accord

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with our understanding of physiol- ogy and biology? Does it address an important issue? Does it perform reliably? Does it have noxious side effects? Can it be made practical in the clinical setting? Is it acceptable to the intended users? This last cri- terion is the one addressed by Clancy and associates. The others are being addressed elsewhere; per- haps some will be found wanting.

Concerning the decision to ac- cept hepatitis B vaccination, we think the efficacy issues have been well addressed (Littenberg B, Ran- sohoff DF: Hepatitis B vaccina- tion: three decision strategies for the individual. Am J Med 1984; 77: 1023-1026) and that this decision is therefore a good proving ground for efficiency issues. There certain- ly are areas where the efficacy of decision analysis is less clear. Esti- mating probabilities and eliciting utilities, for instance, are the sub- jects of much ongoing research. We believe that many technologies have become useful in medicine without a complete understanding of their inner workings. We would not abandon the whole of cardiolo- gy, for instance, just because a thorough understanding of heart failure is not available.

Professor Diamond is aware that he is putting up a straw man when he asks if behavioral modification is a sufficient criterion of the effec- tiveness of decision analysis. In our editorial, we described it as “essen- tial” but nowhere did we say it was “sufficient.” Ongoing empiric work in decision analysis is bringing the technology closer to the bedside, where it belongs.

BENJAMIN LITTENBERG, M.D. HAROLD C. Sox, Jr., M.D.

Stanford University Veterans Administration Medical

Center Palo Alto, California

T$E; IN MINIMAL CHANGE

To the Editor: The recent article by Allon et al (Am J Med 1988; 84: 756-759) de- scribed a patient with mycosis fun- goides, minimal change glomerulo- pathy, and renal interstitial infil- trates with cells possessing T-cell markers.

As the authors suggest, their re- port lends further support to the

hypothesized primary role of the T lymphocyte in minimal change dis- ease. I would like to call their atten- tion to another case report, not re- ferred to in their discussion, which lends similar support. Varsano et al [l] have described a patient with malignant thymoma (of the lym- phocytic type), nephrotic syn- drome, and minimal change dis- ease on renal biopsy examination. Although thymomas are thought to be epithelial and not lymphocytic malignancies, their association with disorders of immunity has been well described [2]. Lauriola et al [3] have studied the lymphocytic component of 10 thymomas and have found it to be both morpho- logically and functionally similar to medullary thymocytes. Medul- lary thymocytes are steroid resis- tant in animal models, and it is in- teresting that, unlike the patient of Allon et al, Varsano and co-work- ers’ patient did not show a clinical response to a course of steroids.

Both of these case reports add in an important way to the growing body of clinical data that support a role for T cells in minimal change disease.

ERIC BROWN, M.D. Yale University School of Medicine

New Haven, Connecticut 06511

1. Varsano S. Bruderman I. Bernheim JL. Rathaus M. Griffel B: Minimal change nephropathy and malignant thymoma. Chest 1980; 77: 695-697. 2. DeVita VT, Hellman S, Rosenburg SA: Cancer: prin- ciples and practice of oncology. Philadelphia: Lippin- cott. 1985: 605-611. 3.Lauriola’L, Maggiano N, Marino M, Carbone A, Piantelli M, Musiani P: Human thymoma: immunolog- ic characteristics of the lymphocytic component. Cancer 1981; 48: 1992-1995.

Submitted June 22,1988, and accepted July 8,1988

SEIZURES AND SYNCOPE IN fW;gENT COCAINE

To the Editor: The association of acute neurologic symptoms with cocaine abuse was noted in a retrospective chart re- view of 255 patients by Lowenstein et al (Am J Med 1987; 83: 841-846) and underscored in a letter to the editor by Cregler (Am J Med 1988; 84: 978-979). Seizures were the predominant neurologic problem in the 150 patients (15 percent of 996), who had evidence of cocaine abuse as well as a neurologic com- plaint. We surveyed, by means of a written questionnaire, 336 middle- class adolescents (73 percent of the

patient population), who used co- caine one or more times and who were patients in one of seven drug- abuse treatment facilities located in five geographic areas in New En- gland, the midwest, the southeast, and the southwest. Cocaine users were subdivided into three groups: (1) light users = 203 adolescents who used cocaine less than 25 times in toto; (2) intermediate users = 107 adolescents who used cocaine 25 to 100 times but less than daily use of the drug; and (3) heavy users = 26 adolescents who used cocaine at least 100 times plus daily use. The median age of the respondents was 16.5 years, and there was no geographic difference between the three groups. Loss of conscious- ness, temporally related to the use of cocaine, was noted by 2 percent, 7 percent, and 27 percent of the pa- tients in the three groups of cocaine users, respectively (p <O.OOOl). A “brain seizure” was reported by 1 percent, 3 percent, and 4 percent of light, intermediate, and heavy us- ers of cocaine (p = not significant). The percentage of respondents who experienced syncope or sei- zures was similar in each of the five geographic areas. According to the data in our study, approximately one of four heavy cocaine users will lose consciousness, one or more times, shortly after “snorting” or freebasing cocaine. Those who use cocaine even infrequently have a I percent chance of experiencing a seizure. The combination of alco- hol and cocaine or, as is noted in California, the admixture of co- caine and phencyclidine, can be ex- pected to produce seizures even more frequently.

RICHARD H. SCHWARTZ, M.D. 410 Maple Avenue West

Vienna. Virginia 22180 TODD ES?ROFF, M.D.

Ft. Walton Beach, Florida NORMAN G. HOFFMANN. Ph.D.

St. Paul, Minnesota

Submitted June 22,1988. and accepted July8,1988

OCCULT CARBON MONOXIDE POISONING: VALIDATION OF A PREDICTION MODEL To the Editor: We read with keen interest the re- cent article by Heckerling et al (Am J Med 1988; 84: 251-256) on carbon monoxide poisoning. The authors point out the toxic effects

462 September 1988 The American Journal of Medicine Volume 85