These results also suggest that physician diagnosis of depression in the absence of elevated BDI scores may flag a different kind of patient presentation. Diagnosis of depression without elevated BDI scores could result from effective treatment controlling the symptoms of previously diagnosed depression, but this does not adequately explain the occurrence. Perhaps other aspects of physician–patient interaction trigger a depression diagnosis without symptoms. This group ranked highest for log-transformed charges for 5 of the 6 areas explored: only for specialty care did those with high BDI scores and diagnosis of depression rank higher in total cost. This strong association with charges implies that these patients represent diagnostic dilemmas, thereby generating more primary care visits and laboratory tests. They may be diagnosed as depressed despite their low BDI scores simply because no organic explanation can be readily identified.
BDI scores showed a trend toward predicting higher laboratory charges in our models. This finding supports the importance of depressive symptoms in influencing the process of primary care, especially laboratory testing.15,30 Perhaps the diagnosis of depression actually slowed the ordering of laboratory tests.18 Because our data did not allow a separation of charges for laboratory tests before and after the diagnosis of depression, we did not test this possibility.
The size of this sample (N = 508) and the length of time patients were followed (1 year) might not have provided adequate power to fully test the contributions of symptoms and diagnosis of depression to the 6 sets of charges. This was likely true for hospitalization charges because hospitalization was an infrequent event in this study. Previous, larger studies found indications of increased hospitalization charges for those diagnosed as depressed17 and those with symptoms of depression.15,30 Alternatively, the recent emphasis on decreasing hospitalizations to reduce medical costs may mean that hospitalization for depressive symptoms rather than for physical illness is less likely to occur.31 In addition, these observations were made by resident physicians and not by community clinicians. It is not clear whether these results would generalize to another setting, although they are consistent with community observations in previous research.
These data do suggest an intriguing interplay of the impact of physician diagnosis of depression and presence of symptoms of depression in a number of indicators of charges and utilization in primary care. Even though each element was associated with increased utilization and charges, their differential impact is unclear. Both may prove important for efforts to enhance recognition of depression; recognition of a mental health problem appeared to shift the process of care in this and previous studies.14,32 To date, there are no data indicating that the diagnosis of depression reduces utilization or costs of primary care delivery. What is known is that physicians working in primary care are more apt to accurately diagnose those with more severe symptoms of depression than those with more transient or less severe symptoms.16,33 Although introducing a screening device such as the BDI or the PRIME-MD9 likely would increase the number of patients diagnosed with depression, it is unclear what impact that would have on the process, costs, and outcomes of care. Simpler interventions such as training in communication skills such as empathy34 might provide the primary care physician with all the tools needed for identification of emotional distress and mental health problems14,30 and appropriate treatment or referral.