Influences of Pain, Insomnia, and Depression on Health Care Utilization in Older Adults with Osteoarthritis

Abstract

Background: Osteoarthritis (OA), the most common type of arthritis, is prevalent and costly. Pain is the principle reason patients with OA seek treatment. Older adults with OA often report co-existing insomnia and depression. OA pain, insomnia, and depression are prevalent and greatly increase health care utilization (HCU) in this population. Purpose: a) Describe the prevalence of pain, insomnia, and depression in older adults with OA, and b) Examine individual and combined effects of pain, insomnia, and depression on HCU. Methods: A total of 8,057 participants aged 60+ with an electronic medical record diagnosis of OA were mailed a screening survey that asked about their pain, insomnia, and depressive symptoms. Pain was assessed by the Graded Chronic Pain Scale (GCPS); Grades 2 - 4 were moderate to severe pain. Insomnia severity was measured by the Insomnia Severity Index (ISI); a score of 7 or greater indicates at least sub-threshold insomnia. Depression was measured by the Patient Health Questionnaire depression scale (PHQ-8), with a score greater than 5 representing at least sub-clinical depression. All participants were members of Group Health Cooperative (GHC), a Seattle-based health maintenance organization. HCU variables from 1 year before and 3 years after the index date were extracted from GHC medical records. Variables included medication use (opioids, sedatives, tricyclic antidepressants (TCAs), and selective serotonin reuptake inhibitors (SSRIs)), total number of office visits, length of stay (LOS) (days), inpatient and outpatient costs, and hip/knee replacement. Patient demographics (age, sex, race, marital status, employment status, and educational levels), days of enrollment in GHC, and Charlson Comorbidity Index scores were also recorded. Negative binominal, generalized linear, and logistical models were used for the data analysis. Results: A total of 2,976 participants were included in the data analysis. About half the participants reported moderate to severe level pain (47.1%), at least sub-threshold insomnia (55.05%), or at least sub-clinical depression (45.2%). About one third of participants presented moderate to severe pain and at least sub-threshold insomnia (33.9%), or moderate to severe pain and at least sub-clinical depression (28.8%). Pain individually contributed to opioids and TCAs use. Depression individually contributed to use of sedatives, TCAs, and SSRIs. Insomnia individually contributed to opioid, sedative, and SSRI use. Generally, combined effects of these symptoms on opioid, sedative, and TCA use increased with symptom severity. Combined effects on SSRI use did not change significantly regardless of insomnia and depression severity. Individual effects of pain were statistically significant across all types of the examined HCU. Insomnia and depression individually contributed only to office visits and outpatient costs. Combined effects of pain/insomnia, and pain/depression were significant across all types of HCU except for hip/knee replacement and increased with insomnia/depression severity. Conclusions: OA pain, insomnia, and depression are prevalent in older adults. Individual and combined effects of pain, insomnia, and depression on medication use are significant. Effects of pain on health care utilization in OA are significant and cost-effective strategies are needed for better pain management to reduce OA-related health care burden. Significant combined effects of pain/insomnia and pain/depression suggest the importance of inquiring about insomnia and depression as part of the routine assessment for OA and working collaboratively across specialists for improved symptom management in clinical practice in order to reduce OA-associated health care burden.