Objective: To evaluate the extent to which pain severity contributes to the increased medical care costs associated with depression in primary care.
Method: A systematic sample of primary care patients (N = 1028) from an urban practice were assessed between April 1, 2002, and January 16, 2003, with the DSM-IV Primary Care Evaluation of Mental Disorders Patient Health Questionnaire, the Sheehan Disability Scale, a medical illness checklist, and the Medical Outcomes Study 12-Item Short Form Health Survey, which includes a measure of pain interference with daily activities. Medical charges for inpatient, outpatient, and emergency department services were assessed for the 6-month periods preceding and following the index medical visit. Patients with and without major depressive disorder (MDD) were first compared with respect to clinical characteristics and median medical charges. Mean predicted medical care charges were then compared among 4 patient groups: (1) No MDD/ Low Pain Interference, (2) No MDD/High Pain Interference, (3) MDD/Low Pain Interference, and (4) MDD/High Pain Interference.
Results: As compared to patients without MDD (N = 821), those with MDD (N = 207) had significantly higher predicted mean medical care charges (19,838 dollars vs. 6268 dollars; t = 3.3, p = .001) after controlling for age and gender and were significantly more likely to report at least moderate pain-related interference in daily activities (MDD: 69.1% vs. no MDD: 38.6%; chi 2 = 61.3, df = 1, p < .0001). Mean predicted medical care charges of patients with MDD and at least moderate pain-related interference were on average 2.33 times (95% CI = 1.34 to 4.05) as high as those for patients with MDD and little or no pain-related interference. Among patients with at least moderate pain-related interference, MDD was associated with significantly greater mean predicted charges (mean = 28,598 dollars/ year with MDD vs. 11,031 dollars/year without MDD). However, among patients with lower levels of pain-related interference, MDD was not associated with greater mean predicted medical charges (mean = 2306 dollars/year with MDD vs. 3560 dollars/year without MDD).
Conclusion: In this urban primary care practice, major depressive disorder is associated with increased health care costs, but only among patients with moderate to extreme pain-related interference in daily activities.