Health service utilization among back pain patients with depression comorbidity

Low back pain (LBP) is a leading cause of high healthcare utilization and associated costs in the U.S. with a life-time prevalence of 50% to 85%. Depression is a major driver of healthcare utilization, co-occurring with chronic pain in 58% of primary care patients. Identifying subgroups of LBP patients who are likely to show greater utilization without necessarily evidencing better outcomes is necessary to reduce healthcare costs and direct these patients to effective treatments is needed. We sought to understand health services utilization of back pain patients in primary care with and without comorbid depression. We used electronic medical and pharmacy records of participating members at an integrated health system. Participants were ambulatory, age 18 or above, with LBP. We defined an index visit, the first visit in 2004 associated with an ICD-9 code for LBP for a total of 26,014 participants. Data was assessed six-months previous and subsequent to this index date. We defined two groups: depression or no-depression based on an ICD-9 depression code. The average patient was female (55.63%), 54.76 years old (SD = 14.97), white (79.91%), overweight (mean BMI = 31.0, SD = 7.48), and non-smoker (56%). About 16% had a depression diagnosis. Those in the Depression group had significantly higher rates of psychopathology (anxiety 20% vs. 3%; substance abuse 25% vs 12%), medical comorbidity, sedative-hypnotic prescriptions (40%), long-term opioid therapy (31%), high-dose opioid therapy (42%). Utilization indicated that the Depression group consumed more healthcare overall, including more ED visits (z = -14.36, p = <0.001), ED visit (47%), pain clinic visits (6%), medical visits (z = -34.6, p = <0.001), hospitalizations (z = -3.35, p = <0.001) and opioid prescribers (z = -18.6, p = <0.001). Patients with LBP with depression comorbidity overall consumed more health services compared to patients with LBP without depression comorbidity.