bs_bs_banner
Pain Medicine 2014; 15: 1902–1910 Wiley Periodicals, Inc.
OPIOIDS, SUBSTANCE ABUSE & ADDICTIONS SECTION Original Research Articles Associations Between Prescription Opioid Use and Sleep Impairment among Veterans with Chronic Pain
Benjamin J. Morasco, PhD,*†‡ Daniel O’Hearn, MD,§ Dennis C. Turk, PhD,¶ and Steven K. Dobscha, MD*†‡
Design. This is a cross-sectional study with retrospective review of patient medical records.
*Mental Health and Clinical Neurosciences Division, † Center to Improve Veteran Involvement in Care, Portland VA Medical Center, Portland, Oregon; Departments of ‡Psychiatry and §Medicine, Oregon Health & Science University, Portland, Oregon; ¶ Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
Setting. The study was performed in a single VA medical center located in the Pacific Northwest.
Reprint requests to: Benjamin J. Morasco, PhD, Portland VA Medical Center (R&D99), 3710 SW US Veterans Hospital Road, Portland, OR 97239, USA. Tel: 503-220-8262 x57625; Fax: 503-273-5367; E-mail: [email protected].
Methods. All participants completed self-report questionnaires assessing demographic characteristics, sleep parameters, pain-related variables, and psychiatric symptoms. Data on prescription opioid use were extracted from patients’ medical records.
Conflict of Interest: Dr. Turk has received in the past 12 months research grants from the National Institutes of Health and the U.S. Food & Drug Administration and consulting fees, or honoraria in the past year from Lilly, Mallincrodt, Nektar, Orexo, Ortho-McNeil Janssen, Pfizer, and Xdynia. All other authors declare that they have no potential conflicts of interest. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the Department of Veterans Affairs, National Institutes of Health, or the U.S. Food & Drug Administration.
Subjects. Participants with chronic pain and a current prescription for opioid medications (N = 72), chronic pain and no opioid prescription (N = 104), or who did not report current chronic pain or opioid prescription (N = 91) were included.
Results. In unadjusted analyses, patients with chronic pain who were prescribed opioids were more likely to have sleep apnea diagnoses in their medical record and reported more impairment on sleep global score and across four sleep parameter subscales (subjective sleep quality, sleep latency, sleep disturbance, and use of sleeping medications). In linear regression analyses controlling for demographic and clinical covariates, prescription opioid status was associated with sleep latency, and opioid dose was significantly associated with sleep latency and sleep global score.
Abstract Objective. Chronic pain is associated with impairments in sleep; however, the relationship between prescription opioid status and sleep is unclear. The primary aim of this study was to examine differences in self-reported sleep quality between groups of patients who varied based on chronic pain and prescription opioid status. 1902
Conclusions. Prescription opioid status and dose were associated with impairment in self-reported sleep. For patients with chronic pain, consideration should be given to use of nonpharmacological interventions to improve sleep. Key Words. Opioids; Sleep; Chronic Pain; Pittsburgh Sleep Quality Index
Association between Opioids and Sleep Impairment Introduction The use of opioid medications to treat patients with chronic noncancer pain continues to increase [1,2]. With this expansion in prescriptions for opioids, there have been increasing concerns and efforts to evaluate both their efficacy and safety. Common adverse effects associated with the initiation of opioids include constipation, nausea, somnolence, and vomiting [3], and up to 50% of patients discontinue opioid therapy due to intolerance or insufficient pain relief [3,4]. Patients who are maintained on chronic opioid therapy may be exposed to adverse effects, such as psychosocial and medical harms [5,6]. Higher doses of opioid medications have been associated with emergency room visits, sexual dysfunction, poorer treatment outcomes, fractures, overdose, and death [7–13]. The relationships between pain and sleep impairment have been well studied. Research demonstrates that pain often results in disruptions to sleep, and impaired sleep is itself a risk factor for pain [14–16]. In a comprehensive review of randomized trials for patients with chronic osteoarthritis, prescription opioid medications were superior to placebo in improving diverse sleep outcomes [17]. However, research on the impact of chronic opioid use on sleep is inconsistent. The known sleep effects of chronic opioids in a nonpain population largely come from patients in methadone maintenance programs, where daytime sleepiness and sleep complaints are common [18,19]. Chronic use of methadone has been associated with reduced total sleep time [20], though findings have been mixed [21]. Acute dosing of opioids may result in increased stage 2 sleep and decreased slow-wave sleep [22,23]; their impact on rapid eye movement sleep varies [22–24]. Among patients with chronic pain, long-term opioid use has been associated with central sleep apnea [25,26] and obstructive sleep apnea [27]. Indeed, opiates may confound the response to positive airway pressure therapy for obstructive sleep apnea [28–31]. Moreover, the available intervention studies examining the associations between opioid prescriptions and impact on sleep have been limited by their short duration (usually 4–12 weeks), fixed dosing pattern, and high drop-out rates [17]. The extent to which the results from these trials generalize to long-term use in patients with mixed chronic pain diagnoses, therefore, is unclear. The primary purpose of this study was to compare selfreported sleep quality among three sets of patients: 1) patients who reported chronic pain and had a current prescription for opioid medication; 2) patients who reported chronic pain, but did not have a current prescription for opioid medication; and 3) patients who did not acknowledge current chronic pain. Examining subgroups of patients with and without pain, and with variation based on opioid prescription status, may provide valuable information regarding specific associations between the effects of pain and of opioid medications with various sleep parameters. We hypothesized that patients who were prescribed opioids for chronic pain would indicate
greater impairment in various sleep parameters than patients who reported chronic pain but who were not prescribed opioids, and that patients who acknowledged chronic pain would endorse more impairment in sleep than patients who did not endorse chronic pain. Moreover, we hypothesized that the differences in sleep quality would remain significantly associated even after controlling for demographic and clinical covariates, and that opioid dose would be negatively associated with selfreported sleep quality. Methods Participants Participants in these analyses were originally recruited for a larger study examining the relationship between chronic pain, hepatitis C virus (HCV) infection, and substance abuse [32]. Patients who had been tested for HCV were eligible to participate and a total of 284 were enrolled into the larger study. Participants were recruited by means of advertisements posted in the medical center, letters sent to patients who had scheduled primary care appointments, announcements in mental health classes, and referral from patients receiving treatment in the hospital’s Hepatology Clinic. Participants completed a single research appointment consisting of a clinical interview and completion of a set of self-report questionnaires. They received a $30 store gift card as compensation. This study was approved by the Institutional Review Board at the medical center where the study was conducted, and all participants signed informed consent to participate. Participants were included if they had a history of being tested for HCV (patients were included regardless of HCV status), age 18 years or older, and able to read and write in English. Patients with hepatitis C have high lifetime rates of chronic pain [32,33] and impairments in quality of life [34], making this a viable sample for examining relationships between pain, opioid use, and sleep. Potential participants were excluded if age was greater than 70 years, had pending litigation or disability compensation for pain, had advanced liver disease, current suicidal ideation, or current untreated schizophrenia or bipolar disorder. Although not an inclusion or exclusion criterion, there were no participants who were enrolled in a methadone maintenance program. Of these 284 participants, we additionally excluded four who had incomplete data and 13 who did not endorse a current pain diagnosis, but medical records indicated a current opioid prescription. For inclusion in these analyses, participants responded to a question of whether they had a current chronic pain condition. To be included in the group with chronic pain, participants must also have had medical record documentation of a pain-related disorder. We reviewed the electronic medical records of all participants to evaluate whether they had received prescription opioids from this hospital in the previous 90 days. Of the 267 participants, we compared those with chronic pain and a current opioid prescription (CP-OP; N = 72), chronic pain and no current 1903
Morasco et al. prescription for an opioid medication (CP-NO; N = 104), and those who denied having chronic pain and no opioid prescription (NP-NO; N = 91) on self-reported sleep outcome variables. Participants in the NP-NO group who denied having a current chronic pain diagnosis were also asked to rate current pain severity and function (see below). Data Collection Demographic data were obtained by self-report and included age, gender, race, marital status, years of education, and current annual income. Self-reported assessment of sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI [35]). The PSQI assesses sleep quality and disturbances over a 1-month interval and includes 19 items that generate seven component scores and a global score. The component scores include subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The seven component scores are scored on a 0–3 scale. The seven component scores are summed to yield a global PSQI score, which has a range of 0–21. Higher scores indicate poorer sleep quality. Pain severity and pain interference were evaluated with the Multidimensional Pain Inventory, a frequently utilized and well-validated measure for individuals with chronic pain [36]. Symptoms of depressed mood were assessed with the Beck Depression Inventory–2, a commonly used and well-validated 21-item self-report questionnaire [37]. Current anxiety symptoms were evaluated with the Generalized Anxiety Disorder Scale (GAD-7), a seven-item questionnaire that assesses the presence of generalized anxiety disorder [38]. Scores on the GAD-7 are also strongly correlated with measures of other anxiety disorders, including posttraumatic stress disorder, panic disorder, and social anxiety disorder [39]. All measures have been used in prior studies, including samples of patients with chronic pain, and have demonstrated good to excellent psychometric characteristics. Current substance use disorder (SUD) status was assessed with the Structured Clinical Interview for DSM-IV (SCID) [40]. A SUD was considered current if the participant met criteria for abuse or dependence to a substance within the past month. For this study, the SCID was modified slightly to assess for abuse/dependence to prescription opioids and to illicit opioid use (i.e., heroin) differentially, rather than evaluating all opioids as an entire group. SCID interviews were conducted by masters-level research clinicians or students enrolled in graduate-level clinical psychology or social work programs. All interviewers received extensive training by a licensed psychologist. Regular supervision of SCID interviews was conducted to reduce likelihood of coder drift. All participants provided a self-report of height and weight, which was used to compute body mass index (BMI). BMI data were classified as normal (BMI = 18–25), overweight (BMI = 25–30), and obese (BMI > 30). 1904
Electronic medical record data were reviewed to obtain diagnostic data for pain diagnoses, sleep apnea, and hepatitis C status. These data were extracted from the medical record using the Veterans Integrated Service Network-20 (VISN-20) Data Warehouse. The VISN-20 Data Warehouse contains extracts of data from the clinical records of regional VA facilities and national VA databases. Diagnostic data were obtained using ICD-9-CM codes listed in medical encounter data for the 5 years preceding study assessment (a portion of the participants who denied current chronic pain had a pain-related disorder documented in their medical record; this may have occurred because the self-report question queried current pain status, whereas medical record data were obtained for the past 5 years and some participants may have had a history of chronic pain). Electronic medical record data were also utilized to identify participants who had current opioid prescriptions from this hospital. We collected data on opioid type, past-year duration, and dose. Prescription opioid doses were converted to an average daily dose in morphine equivalent [41].
Statistical Analyses Participants were divided into three groups based on current chronic pain status and current prescription opioid status. Differences between the three groups were evaluated using analysis of variance (ANOVA) for linear variables and chi-square for categorical variables. For these analyses, results were considered statistically significant if P < 0.05. ANOVA was used to examine unadjusted differences between the groups on the global score and seven component scores of the PSQI. Linear regression analyses were conducted to evaluate whether prescription opioid status (yes/no) was associated with PSQI component and global scores, after controlling for the effects of covariates. Covariates included in these analyses were age, hepatitis C status, BMI, pain severity, current substance use disorder status, and severity of depressive symptoms. Covariates were selected a priori and included based on prior research suggesting an association between these variables and impaired sleep [14–16,42–44]. Pearson correlations were conducted to examine associations between opioid dose with each of the seven component scales and the global score of the PSQI; these analyses were conducted only with patients who endorsed a current chronic pain diagnosis. Linear regression analyses were conducted to evaluate the association between opioid dose and the PSQI component and global scores, after controlling for covariates. The linear regression analyses excluded participants who denied chronic pain and who were not prescribed an opioid medication (i.e., the NP-NO group). To control for multiple comparisons using the Bonferroni correction, the results from analyses with the PSQI were considered significant if P < 0.006 (0.05 divided by eight, to reflect the PSQI global score and seven subscales).
Association between Opioids and Sleep Impairment Results Of the 267 participants who completed study questionnaires, 26.9% (N = 72) reported current chronic pain and had a prescription for an opioid medication (CP-OP), 38.9% (N = 104) reported chronic pain-no opioid prescription (CP-NO), and 34.1% (N = 91) denied a current chronic pain condition and did not have a prescription for an opioid medication (NP-NO). The most common opioids prescribed included hydrocodone (63.9%), oxycodone (36.1%), and morphine (22.2%). Sixty-eight percent of participants in the opioid group had received 90 or more consecutive days of opioids and 32% were prescribed opioids for less than 90 days. The current average daily dose for participants prescribed opioid medications was 34.6 mg (SD = 54.9) per day morphine equivalent. None of the participants in the CP-NO or NP-NO groups had received a prescription for opioids any time in the 90 days prior to this assessment visit. Table 1 provides descriptive data comparing participants in the three groups. Participants were predominately male, with an average age of 54 years, and over 70% were
White, non-Hispanic. There was a statistically significant difference between the groups in current marital status. The most commonly diagnosed pain-related disorders were low back pain, arthritis, and neck or joint pain. Of participants who endorsed current chronic pain, the average duration of pain was 12.8 (SD = 11.5) years, which did not differ by prescription opioid status. There were significant differences between groups in selfreported pain severity, pain interference, and depression severity. Participants in the CP-OP group reported greater pain severity and pain interference than participants in the CP-NO group. CP-OP participants reported more symptoms of depression than NP-NO participants. There was no difference in depression severity between participants in the CP-NO and NP-NO groups. Medical record data were reviewed to identify recent diagnoses of sleep apnea. There were significant differences between the groups in the rates of diagnoses of sleep apnea; 23.0% of CP-OP patients, 9.6% of CP-NO patients, and 9.9% of NP-NO patients had been diagnosed with sleep apnea (P = 0.017).
Table 1 Comparison of demographic characteristics and psychosocial functioning among patients based on chronic pain and prescription opioid status
Age Male gender White race Marital status Single Married Separated/Divorced Widowed Years of education Income
Pain Medicine 2014; 15: 1902–1910 Wiley Periodicals, Inc.
OPIOIDS, SUBSTANCE ABUSE & ADDICTIONS SECTION Original Research Articles Associations Between Prescription Opioid Use and Sleep Impairment among Veterans with Chronic Pain
Benjamin J. Morasco, PhD,*†‡ Daniel O’Hearn, MD,§ Dennis C. Turk, PhD,¶ and Steven K. Dobscha, MD*†‡
Design. This is a cross-sectional study with retrospective review of patient medical records.
*Mental Health and Clinical Neurosciences Division, † Center to Improve Veteran Involvement in Care, Portland VA Medical Center, Portland, Oregon; Departments of ‡Psychiatry and §Medicine, Oregon Health & Science University, Portland, Oregon; ¶ Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
Setting. The study was performed in a single VA medical center located in the Pacific Northwest.
Reprint requests to: Benjamin J. Morasco, PhD, Portland VA Medical Center (R&D99), 3710 SW US Veterans Hospital Road, Portland, OR 97239, USA. Tel: 503-220-8262 x57625; Fax: 503-273-5367; E-mail: [email protected].
Methods. All participants completed self-report questionnaires assessing demographic characteristics, sleep parameters, pain-related variables, and psychiatric symptoms. Data on prescription opioid use were extracted from patients’ medical records.
Conflict of Interest: Dr. Turk has received in the past 12 months research grants from the National Institutes of Health and the U.S. Food & Drug Administration and consulting fees, or honoraria in the past year from Lilly, Mallincrodt, Nektar, Orexo, Ortho-McNeil Janssen, Pfizer, and Xdynia. All other authors declare that they have no potential conflicts of interest. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the Department of Veterans Affairs, National Institutes of Health, or the U.S. Food & Drug Administration.
Subjects. Participants with chronic pain and a current prescription for opioid medications (N = 72), chronic pain and no opioid prescription (N = 104), or who did not report current chronic pain or opioid prescription (N = 91) were included.
Results. In unadjusted analyses, patients with chronic pain who were prescribed opioids were more likely to have sleep apnea diagnoses in their medical record and reported more impairment on sleep global score and across four sleep parameter subscales (subjective sleep quality, sleep latency, sleep disturbance, and use of sleeping medications). In linear regression analyses controlling for demographic and clinical covariates, prescription opioid status was associated with sleep latency, and opioid dose was significantly associated with sleep latency and sleep global score.
Abstract Objective. Chronic pain is associated with impairments in sleep; however, the relationship between prescription opioid status and sleep is unclear. The primary aim of this study was to examine differences in self-reported sleep quality between groups of patients who varied based on chronic pain and prescription opioid status. 1902
Conclusions. Prescription opioid status and dose were associated with impairment in self-reported sleep. For patients with chronic pain, consideration should be given to use of nonpharmacological interventions to improve sleep. Key Words. Opioids; Sleep; Chronic Pain; Pittsburgh Sleep Quality Index
Association between Opioids and Sleep Impairment Introduction The use of opioid medications to treat patients with chronic noncancer pain continues to increase [1,2]. With this expansion in prescriptions for opioids, there have been increasing concerns and efforts to evaluate both their efficacy and safety. Common adverse effects associated with the initiation of opioids include constipation, nausea, somnolence, and vomiting [3], and up to 50% of patients discontinue opioid therapy due to intolerance or insufficient pain relief [3,4]. Patients who are maintained on chronic opioid therapy may be exposed to adverse effects, such as psychosocial and medical harms [5,6]. Higher doses of opioid medications have been associated with emergency room visits, sexual dysfunction, poorer treatment outcomes, fractures, overdose, and death [7–13]. The relationships between pain and sleep impairment have been well studied. Research demonstrates that pain often results in disruptions to sleep, and impaired sleep is itself a risk factor for pain [14–16]. In a comprehensive review of randomized trials for patients with chronic osteoarthritis, prescription opioid medications were superior to placebo in improving diverse sleep outcomes [17]. However, research on the impact of chronic opioid use on sleep is inconsistent. The known sleep effects of chronic opioids in a nonpain population largely come from patients in methadone maintenance programs, where daytime sleepiness and sleep complaints are common [18,19]. Chronic use of methadone has been associated with reduced total sleep time [20], though findings have been mixed [21]. Acute dosing of opioids may result in increased stage 2 sleep and decreased slow-wave sleep [22,23]; their impact on rapid eye movement sleep varies [22–24]. Among patients with chronic pain, long-term opioid use has been associated with central sleep apnea [25,26] and obstructive sleep apnea [27]. Indeed, opiates may confound the response to positive airway pressure therapy for obstructive sleep apnea [28–31]. Moreover, the available intervention studies examining the associations between opioid prescriptions and impact on sleep have been limited by their short duration (usually 4–12 weeks), fixed dosing pattern, and high drop-out rates [17]. The extent to which the results from these trials generalize to long-term use in patients with mixed chronic pain diagnoses, therefore, is unclear. The primary purpose of this study was to compare selfreported sleep quality among three sets of patients: 1) patients who reported chronic pain and had a current prescription for opioid medication; 2) patients who reported chronic pain, but did not have a current prescription for opioid medication; and 3) patients who did not acknowledge current chronic pain. Examining subgroups of patients with and without pain, and with variation based on opioid prescription status, may provide valuable information regarding specific associations between the effects of pain and of opioid medications with various sleep parameters. We hypothesized that patients who were prescribed opioids for chronic pain would indicate
greater impairment in various sleep parameters than patients who reported chronic pain but who were not prescribed opioids, and that patients who acknowledged chronic pain would endorse more impairment in sleep than patients who did not endorse chronic pain. Moreover, we hypothesized that the differences in sleep quality would remain significantly associated even after controlling for demographic and clinical covariates, and that opioid dose would be negatively associated with selfreported sleep quality. Methods Participants Participants in these analyses were originally recruited for a larger study examining the relationship between chronic pain, hepatitis C virus (HCV) infection, and substance abuse [32]. Patients who had been tested for HCV were eligible to participate and a total of 284 were enrolled into the larger study. Participants were recruited by means of advertisements posted in the medical center, letters sent to patients who had scheduled primary care appointments, announcements in mental health classes, and referral from patients receiving treatment in the hospital’s Hepatology Clinic. Participants completed a single research appointment consisting of a clinical interview and completion of a set of self-report questionnaires. They received a $30 store gift card as compensation. This study was approved by the Institutional Review Board at the medical center where the study was conducted, and all participants signed informed consent to participate. Participants were included if they had a history of being tested for HCV (patients were included regardless of HCV status), age 18 years or older, and able to read and write in English. Patients with hepatitis C have high lifetime rates of chronic pain [32,33] and impairments in quality of life [34], making this a viable sample for examining relationships between pain, opioid use, and sleep. Potential participants were excluded if age was greater than 70 years, had pending litigation or disability compensation for pain, had advanced liver disease, current suicidal ideation, or current untreated schizophrenia or bipolar disorder. Although not an inclusion or exclusion criterion, there were no participants who were enrolled in a methadone maintenance program. Of these 284 participants, we additionally excluded four who had incomplete data and 13 who did not endorse a current pain diagnosis, but medical records indicated a current opioid prescription. For inclusion in these analyses, participants responded to a question of whether they had a current chronic pain condition. To be included in the group with chronic pain, participants must also have had medical record documentation of a pain-related disorder. We reviewed the electronic medical records of all participants to evaluate whether they had received prescription opioids from this hospital in the previous 90 days. Of the 267 participants, we compared those with chronic pain and a current opioid prescription (CP-OP; N = 72), chronic pain and no current 1903
Morasco et al. prescription for an opioid medication (CP-NO; N = 104), and those who denied having chronic pain and no opioid prescription (NP-NO; N = 91) on self-reported sleep outcome variables. Participants in the NP-NO group who denied having a current chronic pain diagnosis were also asked to rate current pain severity and function (see below). Data Collection Demographic data were obtained by self-report and included age, gender, race, marital status, years of education, and current annual income. Self-reported assessment of sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI [35]). The PSQI assesses sleep quality and disturbances over a 1-month interval and includes 19 items that generate seven component scores and a global score. The component scores include subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The seven component scores are scored on a 0–3 scale. The seven component scores are summed to yield a global PSQI score, which has a range of 0–21. Higher scores indicate poorer sleep quality. Pain severity and pain interference were evaluated with the Multidimensional Pain Inventory, a frequently utilized and well-validated measure for individuals with chronic pain [36]. Symptoms of depressed mood were assessed with the Beck Depression Inventory–2, a commonly used and well-validated 21-item self-report questionnaire [37]. Current anxiety symptoms were evaluated with the Generalized Anxiety Disorder Scale (GAD-7), a seven-item questionnaire that assesses the presence of generalized anxiety disorder [38]. Scores on the GAD-7 are also strongly correlated with measures of other anxiety disorders, including posttraumatic stress disorder, panic disorder, and social anxiety disorder [39]. All measures have been used in prior studies, including samples of patients with chronic pain, and have demonstrated good to excellent psychometric characteristics. Current substance use disorder (SUD) status was assessed with the Structured Clinical Interview for DSM-IV (SCID) [40]. A SUD was considered current if the participant met criteria for abuse or dependence to a substance within the past month. For this study, the SCID was modified slightly to assess for abuse/dependence to prescription opioids and to illicit opioid use (i.e., heroin) differentially, rather than evaluating all opioids as an entire group. SCID interviews were conducted by masters-level research clinicians or students enrolled in graduate-level clinical psychology or social work programs. All interviewers received extensive training by a licensed psychologist. Regular supervision of SCID interviews was conducted to reduce likelihood of coder drift. All participants provided a self-report of height and weight, which was used to compute body mass index (BMI). BMI data were classified as normal (BMI = 18–25), overweight (BMI = 25–30), and obese (BMI > 30). 1904
Electronic medical record data were reviewed to obtain diagnostic data for pain diagnoses, sleep apnea, and hepatitis C status. These data were extracted from the medical record using the Veterans Integrated Service Network-20 (VISN-20) Data Warehouse. The VISN-20 Data Warehouse contains extracts of data from the clinical records of regional VA facilities and national VA databases. Diagnostic data were obtained using ICD-9-CM codes listed in medical encounter data for the 5 years preceding study assessment (a portion of the participants who denied current chronic pain had a pain-related disorder documented in their medical record; this may have occurred because the self-report question queried current pain status, whereas medical record data were obtained for the past 5 years and some participants may have had a history of chronic pain). Electronic medical record data were also utilized to identify participants who had current opioid prescriptions from this hospital. We collected data on opioid type, past-year duration, and dose. Prescription opioid doses were converted to an average daily dose in morphine equivalent [41].
Statistical Analyses Participants were divided into three groups based on current chronic pain status and current prescription opioid status. Differences between the three groups were evaluated using analysis of variance (ANOVA) for linear variables and chi-square for categorical variables. For these analyses, results were considered statistically significant if P < 0.05. ANOVA was used to examine unadjusted differences between the groups on the global score and seven component scores of the PSQI. Linear regression analyses were conducted to evaluate whether prescription opioid status (yes/no) was associated with PSQI component and global scores, after controlling for the effects of covariates. Covariates included in these analyses were age, hepatitis C status, BMI, pain severity, current substance use disorder status, and severity of depressive symptoms. Covariates were selected a priori and included based on prior research suggesting an association between these variables and impaired sleep [14–16,42–44]. Pearson correlations were conducted to examine associations between opioid dose with each of the seven component scales and the global score of the PSQI; these analyses were conducted only with patients who endorsed a current chronic pain diagnosis. Linear regression analyses were conducted to evaluate the association between opioid dose and the PSQI component and global scores, after controlling for covariates. The linear regression analyses excluded participants who denied chronic pain and who were not prescribed an opioid medication (i.e., the NP-NO group). To control for multiple comparisons using the Bonferroni correction, the results from analyses with the PSQI were considered significant if P < 0.006 (0.05 divided by eight, to reflect the PSQI global score and seven subscales).
Association between Opioids and Sleep Impairment Results Of the 267 participants who completed study questionnaires, 26.9% (N = 72) reported current chronic pain and had a prescription for an opioid medication (CP-OP), 38.9% (N = 104) reported chronic pain-no opioid prescription (CP-NO), and 34.1% (N = 91) denied a current chronic pain condition and did not have a prescription for an opioid medication (NP-NO). The most common opioids prescribed included hydrocodone (63.9%), oxycodone (36.1%), and morphine (22.2%). Sixty-eight percent of participants in the opioid group had received 90 or more consecutive days of opioids and 32% were prescribed opioids for less than 90 days. The current average daily dose for participants prescribed opioid medications was 34.6 mg (SD = 54.9) per day morphine equivalent. None of the participants in the CP-NO or NP-NO groups had received a prescription for opioids any time in the 90 days prior to this assessment visit. Table 1 provides descriptive data comparing participants in the three groups. Participants were predominately male, with an average age of 54 years, and over 70% were
White, non-Hispanic. There was a statistically significant difference between the groups in current marital status. The most commonly diagnosed pain-related disorders were low back pain, arthritis, and neck or joint pain. Of participants who endorsed current chronic pain, the average duration of pain was 12.8 (SD = 11.5) years, which did not differ by prescription opioid status. There were significant differences between groups in selfreported pain severity, pain interference, and depression severity. Participants in the CP-OP group reported greater pain severity and pain interference than participants in the CP-NO group. CP-OP participants reported more symptoms of depression than NP-NO participants. There was no difference in depression severity between participants in the CP-NO and NP-NO groups. Medical record data were reviewed to identify recent diagnoses of sleep apnea. There were significant differences between the groups in the rates of diagnoses of sleep apnea; 23.0% of CP-OP patients, 9.6% of CP-NO patients, and 9.9% of NP-NO patients had been diagnosed with sleep apnea (P = 0.017).
Table 1 Comparison of demographic characteristics and psychosocial functioning among patients based on chronic pain and prescription opioid status
Age Male gender White race Marital status Single Married Separated/Divorced Widowed Years of education Income
