Does the Severity of Mood and Anxiety Symptoms Predict Health Care Utilization?

,

Original Research

Does the Severity of Mood and Anxiety Symptoms Predict Health Care Utilization?

J Fam Pract. 1999 October;48(10):769-777

References

1. Kessler LG, Cleary PD, Burke JD. Psychiatric disorders in primary care. Arch Gen Psychiatry 1985;42:583-7.

2. Schulberg HC, Saul M, McClelland M, Ganguli M, Christy W, Frank R. Assessing depression in primary medical and psychiatric practices. Arch Gen Psychiatry 1985;42:1164-70.

3. Barrett JE, Barrett JA, Oxman TE, Gerber PD. The prevalence of psychiatric disorders in a primary care practice. Arch Gen Psychiatry 1988;45:1100-6.

4. Katon W, Schulberg HC. Epidemiology of depression in primary care. Gen Hosp Psychiatry 1992;14:237-47.

5. Coyne JC, Fechner-Bates S, Schwenk TL. Prevalence, nature, and comorbidity of depressive disorders in primary care. Gen Hosp Psychiatry 1994;16:267-76.

6. Spitzer RL, Williams JB, Kroenke K, et al. Utility of a new procedure for diagnosing mental disorders in primary care: the PRIME-MD 1000 study. JAMA 1994;272:1749-56.

7. Weissman MM, Olfson M, Leon AC, et al. Brief diagnostic interviews (SDDS-PC) for multiple mental disorders in primary care. A pilot study. Arch Fam Med 1995;4:220-7.

8. Broadhead WE, Blazer DG, George LK, et al. Depression, disability days, and days lost from work in a prospective epidemiologic survey. JAMA 1990;264:2524-8.

9. Wells K, Burnam M, Rogers W, Hays R, Camp P. The course of depression in adult outpatients: results from the medical outcomes study. Arch Gen Psychiatry 1992;49:788-94.

10. Von Korff M, Shapiro S, Burke JD, et al. Anxiety and depression in a primary care clinic. Comparison of diagnostic interview schedule, general health questionnaire, and practitioner assessments. Arch Gen Psychiatry 1987;44:152-6.

11. Gerber PD, Barrett J, Manheimer E, Whiting R, Smith R. Recognition of depression by internists in primary care: a comparison of internist and 'gold standard' psychiatric assessments. J Gen Intern Med 1989;4:7-13.

12. Coyne JC, Schwenk TL, Fechner-Bates S. Nondetection of depression by primary care physicians reconsidered. Gen Hosp Psychiatry 1995;17:3-12.

13. American Psychiatric Association. Task Force on DSM-IV. Diagnostic and statistical manual of mental disorders, 4th ed (DSM-IV). Washington, DC: American Psychiatric Association; 1994:xxvii, 886.

14. Weissman MM, Broadhead WE, Olfson M, et al. A diagnostic aid for detecting (DSM-IV) mental disorders in primary care. Gen Hosp Psychiatry 1998;20:1-11.

15. Broadhead WE, Leon AC, Weissman MM, et al. Development and validation of the SDDS-PC screen for multiple mental disorders in primary care. Arch Fam Med 1995;4:211-9.

16. Hirschfeld RM, Keller MB, Panico S, et al. The National Depressive and Manic-Depressive Association Consensus Statement on the Undertreatment of Depression. JAMA 1997;277:333-40.

17. Depression Guideline Panel. United States. Agency for Health Care Policy and Research. Depression in primary care. Rockville, Md: US Dept of Health and Human Services–Agency for Health Care Policy and Research; 1993.

18. Callahan CM, Hendrie HC, Dittus RS, Brater DC, Hui SL, Tierney WM. Improving treatment of late life depression in primary care: a randomized clinical trial. J Am Geriatr Soc 1994;42:839-46.

19. Dowrick C, Buchan I. Twelve month outcome of depression in general practice: does detection or disclosure make a difference? BMJ 1995;311:1274-6.

20. Reifler DR, Kessler HS, Bernhard EJ, Leon AC, Martin GJ. Impact of screening for mental health concerns on health service utilization and functional status in primary care patients. Arch Intern Med 1996;156:2593-9.

21. Lin EH, Simon GE, Katon WJ, et al. Can enhanced acute-phase treatment of depression improve long-term outcomes? A report of randomized trials in primary care. Am J Psychiatry 1999;156:643-5.

22. American Psychiatric Association, Work Group to Revise DSM-III. Diagnostic and statistical manual of mental disorders: Dsm-III-R. 3rd, rev. ed Washington, DC: American Psychiatric Association; 1987.

23. Nease DE, Volk RJ, Cass AR. Investigation of a severity-based classification of mood and anxiety symptoms in primary care patients. J Am Board Fam Pract 1999;12:21-31.

24. Volk R, Steinbauer J, Cantor C, Holzer C. The Alcohol Use Disorders Identification Test (AUDIT) as a screen for at-risk drinking in primary care patients of different racial/ethnic backgrounds. Addiction 1997;92:197-206.

25. Ware J, Kosinski M, Keller S. Physical and mental health summary scales: a user’s manual. Boston, Mass: The Health Institute, New England Medical Center; 1994.

26. Deyo R, Cherkin D, Ciol M. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol 1992;45:613-9.

27. Charlson M, Pompei P, Ales K, MacKenzie C. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chron Dis 1987;40:373-83.

28. Endicott J. Measurement of depression in patients with cancer. Cancer 1984;53:2243-9.

29. Kathol RG, Mutgi A, Williams J, Clamon G, Noyes R, Jr. Diagnosis of major depression in cancer patients according to four sets of criteria. Am J Psychiatry 1990;147:1021-4.

30. Gallo JJ, Rabins PV, Lyketsos CG, Tien AY, Anthony JC. Depression without sadness: functional outcomes of nondysphoric depression in later life. J Am Geriatr Soc 1997;45:570-8.

31. Klinkman MS, Coyne JC, Gallo S, Schwenk TL. False positives, false negatives, and the validity of the diagnosis of major depression in primary care. Arch Fam Med. 1998;7:451-61.

32. Hamilton M. Development of a rating scale for primary depressive illness. Br J Soc Clin Psychol. 1967;6:278-96.

33. Klinkman MS, Schwenk TL, Coyne JC. Depression in primary care—more like asthma than appendicitis: the Michigan Depression Project. Can J Psychiatry. 1997;42:966-73.

34. Judd LL, Akiskal HS, Maser JD, et al. A prospective 12-year study of subsyndromal and syndromal depressive symptoms in unipolar major depressive disorders. Arch Gen Psychiatry. 1998;55:694-700.

35. Gibbons RD, Clark DC, Kupfer DJ. Exactly what does the Hamilton Depression Rating Scale measure? J Psychiatr Res. 1993;27:259-73.

36. Valenstein M, Dalack G, Blow F, Figueroa S, Standiford C, Douglass A. Screening for psychiatric illness with a combined screening and diagnostic instrument. J Gen Intern Med. 1997;12:679-85.

37. Klinkman MS, Okkes I. Mental health problems in primary care. A research agenda. J Fam Pract. 1998;47:379-84.

Study Implications

The implications of this study should be placed in the context of our earlier study. In that study we demonstrated that primary care patients might be better characterized according to the severity of their mood and anxiety symptoms rather than by a diagnostic label. The groupings that we created using cluster analysis techniques were distinguished more by their symptom severity than by whether they had symptoms that were predominately mood or anxiety related. We found these groupings very predictive of differences in HRQOL as measured by the SF-36. While DSM-III-R mood and anxiety disorder criteria also predicted HRQOL differences, the differences associated with membership in a symptom severity group were more profound.²³

This study reinforces the findings in our previous work by demonstrating health care utilization differences between symptom severity groups. Not only were significant differences measured between levels of utilization in the 3 months preceding and including the date subjects were enrolled, these differences also persisted for the entire 15 months of the study, with the exception of one 3-month period. The differences were robust to adjustment for significant covariates including age, income, medical comorbidity, ethnicity, and mood or anxiety disorder diagnosis. Except for the period from 1 to 180 days after the index visit, the presence of a mood or anxiety disorder failed to appear in our regression models as a factor that significantly influenced utilization.

This study of health care utilization is unique because it began with the severity of mood and anxiety symptoms experienced by an entire practice-based sample without selection according to symptoms, disorders, or physician recognition. The severity of the symptoms were used to derive a classification scheme that was tested for its ability to predict health care utilization. This is an important break from current classification schemes that employ methods of counting symptoms to identify patients with disorders and subsequent targeting for intervention. The importance of this approach is illustrated in the Figure 1, where we demonstrate that patients who meet specific DSM-III-R disorder criteria distribute across most (if not all) our symptom severity groups. In other words, if a primary care patient reports enough symptoms to meet criteria for a particular disorder we cannot assume that those symptoms are severe. The reverse also appears to be true; that is, patients who fail to meet criteria are not necessarily experiencing a low level of symptom severity. The severity distribution of subjects who have no disorder is strikingly similar to those who meet criteria for major depressive disorder.

Taken together, our 2 studies lay the groundwork for a reconceptualization of how primary care patients with mood and anxiety symptoms are evaluated and classified. Clues are emerging that psychiatric labels may not be adequate to fully describe the spectrum of mental health problems in primary care. Evidence from studies of cancer patients suggests that application of psychiatric criteria for major depressive disorder outside a psychiatric population results in misclassification.^28,29 Gallo and colleagues³⁰ have used the Baltimore Epidemiologic Catchment Area Program sample to demonstrate that traditional criteria for classifying depression may not be adequate to identify elderly patients who are at risk. Data from the Michigan Depression Project indicate that primary care physicians appear to recognize an overlapping but different group of patients from those identified by mental health screening tools.³¹ Our work appears to lend additional evidence that psychiatric labels describe only part of a complex picture of mental health symptomatology.

Our explorations of mood and anxiety symptom severity through cluster analysis have yielded what we have termed a “classification.” However, we believe this classification is most likely representative of an underlying severity dimension that cuts across mood and anxiety symptom types. This concept is not new. Many treatment trials of depression in primary care have already used monitoring of severity with instruments such as the Hamilton Depression Rating Scale³² as outcome measures. What is new is mood and anxiety symptom severity as an independent predictor of HRQOL and utilization outcomes beyond presence of a psychiatric disorder. This suggests a unique and independent priority for symptom severity status.

Consensus is emerging that depression is a chronic illness with periods of exacerbation and recovery.^33,34 Conceptualizing a symptom severity dimension as a predictor of HRQOL and utilization appears consistent with this idea. The presence of a mood or anxiety disorder may be similar to having asthma, with actual mood and anxiety symptom severity similar to peak flow status. Just as patients experiencing bronchospasm for any of a variety of reasons have decreased peak flow independent of an asthma diagnosis, it appears that primary care patients experience severe mood and anxiety symptoms for a variety of reasons independent of a psychiatric disorder diagnosis. Also for patients who have disorders, symptom severity may be a more important parameter to follow than DSM-III-R criteria that measure the “recovery from” or “relapse back into” a disorder.