Functional Disability Outcomes Among Chronic Pain Patients Receiving Long-Term Opioid Treatment Tina Valkanoff, MSW, MPH(c)1, 2, Andrea Hessel, MS2, Stacy Sterling, MSW, MPH2, Cynthia Campbell, PhD2, Michael Von Korff, ScD3 Supported by R01 DA022557 1UC Berkeley School of Public Health, 2Kaiser Division of Research 3Center for Health Research, Group Health Cooperative

Overview Background Methods Results Discussion

Chronic vs. Acute Pain Chronic pain was traditionally defined as pain lasting more than 3 or 6 months More recently, chronic pain has been defined as ‘‘pain that extends beyond the period of tissue healing and/or with low levels of identified pathology that are insufficient to explain the presence and/or extent of pain.’’ No general consensus on the definition of chronic pain. Ballantyne 2007

Background Several million Americans receive long-term opioid therapy for chronic non-malignant pain. Little is known about long-term functional outcomes for these patients. Parsells Kelly 2008;Caudill-Slosberg 2004; Von Korff 2004; Chou 2003; Ballantyne 2008; Ballantyne 2003

Public Health Risk: Unintentional drug overdose death rates and total sales of prescription opioids by year in the U.S. Paulozzi 2005

Prevalent Episodes of Long-Term Opioid Use by Age and Gender, 1997-2005 Kaiser N California (solid lines) & Group Health (dashed lines) Males Females Females 65 + Prevalence % Long-term opioid use Females 45-64 Males 65 + Males 45-64 Females 18-44 Males 18-44 Campbell 2010

Findings on Pain and Depression Chronic pain and depression commonly co-occur Depression has been associated with more severe pain outcomes Lack of employment has been associated with worse pain outcomes and higher levels of depression Sullivan 2005; Weisner 2009; Bair 2003; Braden 2009; Berna 2010; Dolce 1986

Prevalent Episodes of Long-Term Opioid Use by Depression Dx in Prior 2 Years, 1997-2005 Kaiser N CA (solid lines) & Group Health (dashed lines) Depression Dx 7.2% annualized change 5.9% annualized change Prevalence (%) of long-term opioid use No Depression Dx 6.5% annualized change 6.9% annualized change Braden 2009

Study Overview We examined the relationship of depression and functional outcomes among non-cancer chronic pain patients who are prescribed long-term opioid therapy within two large, integrated health plans.

Short vs. Long-Term Opioid Use Patients were considered long-term users of opioid medicines if they filled at least 10 prescriptions and/or received at least 120 days supply in a one-year period prior to the sample selection date. This threshold has been shown to predict high probability of sustained and frequent use of opioids. Von Korff 2005

Research Question What measures, including depression and demographic characteristics, are associated with functional disability and employment measures among chronic pain patients receiving long-term opioid therapy?

Methods CONsortium to Study Opioid Risks and Trends (CONSORT) NIH-funded study to improve understanding of long-term opioid therapy for chronic non-cancer pain

Methods We conducted a phone survey of randomly sampled chronic pain patients, age 21-80, who were receiving long-term opioid prescriptions who were members of Group Health Cooperative (GHC) of WA & Kaiser Permanente of Northern CA (KPNC). KPNC and GHC serve about 4 million people. Selby 2005; Saunders 2005

Methods We had a response rate of 60% and a sample size of 2163 patients. The sample was 37% male, 90% white, 60% with at least some college education, and the average age was 55.

Measures: Individual Characteristics Demographics age gender ethnicity (white, other) education level (no college, at least some college).

Measures: Individual Characteristics Depression. Patients were assessed using an 8 item version of the Patient Health Questionnaire regarding their symptoms in the last 2 weeks. We summed these responses to assess the frequency of depression symptoms. We then created a dichotomous depression variable to indicate a high or low level of depression. Kroenke 2009

Measures: Dependent Variables Three Discrete Functional Disability Measures Average Pain Interference Score Activity Limitation Days Employment Status

Average Pain Interference Score The average pain interference score is composed of three activity interference rating items: daily activities recreational, social & family activities work, including housework Patients rated how much pain interfered with activities in the last 3 months on a scale of 0 to 10. We averaged the three interference rating variables to indicate high or low pain interference. Von Korff 1992

Activity Limitation Days The activity limitation days variable asked participants how many days in the last 3 months they were kept from doing their usual activities. We chose 30 days or more to indicate a significant functional disability. Von Korff 1992

Employment Status Individuals were grouped as unemployed if they were permanently or temporarily unable to work due to health reasons Employed individuals were working full-time or part-time. Those who were retired, students, homemakers, or looking for work were not included in this analysis.

Descriptive Results The sample was mostly white, female, and middle aged. 41% of respondents had a high level of depression symptoms.

Results 60% of the sample had a high average pain interference score over the past 3 months 49% had at least 30 activity limitation days in the past 3 months 35.4% of the sample were unable to work due to health reasons. 70% of participants had at least 1 of the 3 significant functional disabilities.

Percent with Significant Disability by Depression Level

Depression & Disability Average Pain Interference Score 81% of high depression group had a high score 46% in the low depression group 30+ Activity Limitation Days 67% of high depression group 30+ limited days 37% in the low depression group Unable to Work Due to Health Reasons 52% of high depression group unable to work 22% in the low depression group Individuals with high depression symptoms had more disability outcomes

Patients with At Least One Disability

Results: At Least One Disability 79% of those employed with high depression symptoms had at least one functional disability. 43% of those employed with low depression symptoms had at least one functional disability. For high depression individuals unable to work due to health reasons, 96% had at least one functional disability compared to 84% for those with low depression symptoms. Individuals who had a low level of depression symptoms and were employed were the best off, but even 43% of them reported at least one functional disability outcome.

Multivariate Analysis We estimated and tested weighted logistic regression models for each of the three disability measures (average pain interference score, activity limitation days, and employment status) with the weighted survey logistic procedures in SAS, version 9.1.

Multivariate Logistic Regression Predicting Disability Average Pain Interference Score Activity Limitation Days Employment Status (N=2162) (N=1526) Odds Ratio of Disability (Score>5) Odds Ratio of Disability (Days>=30) Odds Ratio of Disability (Unemployed) Gender (Male vs. Female) 0.635** 0.717* 0.630** Age 1.006 1.014* 1.036*** Ethnicity (White vs. Non-white) 0.558* 1.154 0.784 Education Level (Some College vs. No College) 0.781 0.100 0.554*** Depression Symptoms (High vs. Low) 5.026*** 3.636*** 4.061*** * p< .05, ** p < .01, *** p< .001

Discussion Patients with a high level of depression symptoms had 5 times the odds of having an average pain interference score greater than 5, more than 3 times the odds of having 30 or more activity limitation days, and more than 4 times the odds of being unable to work compared to those with low depression symptoms.

Discussion We found depression to have a strong association with functional disability, consistent with others in the literature. Our findings suggest a need for careful depression screening of chronic pain patients and potential benefits of an integrated approach to depression and pain treatments.

Discussion Among those unable to work due to health reasons with high depression symptoms, more than 9 out of 10 reported a high level of interference with daily activities, suggesting that this group is highly disabled. An overwhelming majority of the study population reported at least one disability.

Study Limitations Use of an insured population, which may not be generalizeable nationally May be a bidirectional relationship between depression symptoms and being unable to work Cross-sectional study Further research should consider types of medication and types of pain

Acknowledgements We acknowledge Constance Weisner, Pain Care Study team members Barbara Pichotto, Melanie Jackson-Morris, Cynthia Perry-Baker, Gina Smith-Anderson, Martha Preble, Aikya Param, Georgina Berrios, and Jessica Duhe, and the KPNC Chronic Pain Committee. Thanks also to Agatha Hinman for project coordination and editorial assistance.

Discussion Questions Should depression screening and treatment become a routine part of chronic pain care? Why are opioid prescription rates rising so quickly without evidence of long-term functional improvement? Should treatments differ based on the gender of the patient?