Introduction
Chronic pain is commonly defined as pain that lasts longer than three months. Some theorists and researchers have placed the transition from acute to chronic pain at 12 months [
1]. In the US, chronic pain affects approximately 100 million adults and has an annual financial impact of about $560-635 billion (in 2010) dollars [
2]. Currently, standard regimens for management of inpatients with chronic pain comprise multimodal drug treatments. According to the three-step analgesic ladder recommended by WHO, chronic pain is initially treated with non-opioids, such as acetaminophen or ibuprofen, and then transferred to opioids, e.g., morphine, hydrocodone, or oxycodone if the pain persists [
3]. During medication, determining an individual’s compliance with analgesic treatment is important in the evaluation and management of a patient with chronic pain.
However, patients with chronic pain do not always comply with doctor’s prescriptions [
4,
5]. In the USA, analgesic prescriptions are increasing, whereas substance noncompliance is frequent among chronic pain patients [
6,
7]. Manchikanti
et al.[
8] and Ives
et al.[
9] reported that the noncompliance regarding analgesics has reached up to 45% in these patients. Therefore, the routine screening of compliance with analgesic treatment has been recommended in chronic pain patients in the US [
10]. In China, few data are available on the compliance with oral treatment of analgesics in chronic pain patients. In the present study, we investigated the compliance with oral analgesic treatment of chronic pain inpatients in the Pain Department of West China Hospital from May 2013 to October 2013. We aimed to identify the compliance status and factors related to compliance of patients.
Patients and methods
Patients
We prospectively included 100 consecutive patients with chronic pain, who were hospitalized to receive oral analgesics in the Pain Department of West China Hospital, Sichuan University from May to October in 2013. Patients aged more than 18 years with clear cognition and educated in primary school and above were included in our study. The exclusion criteria were as follows: patients with gastrointestinal ulcers or coronary heart disease, diabetes, hyperthyroidism, or tumor. Eligible patients were informed to receive oral analgesics with a written informed consent by a single doctor (Hong Zhu) in Pain Department. Visual analog scale (VAS) was used to evaluate the level of pain, and the data and cause of pain were analyzed by a specific doctor. We evaluated each patient 2 h after admission, and data were recorded. For mild pain patients, we used NSAID on time. For moderate to server pain, we chose opioid medicine. For different kinds of pain, we administered specific drugs as adjuvant therapy. We prospectively recorded the data of patient demography, including gender, age, marriage, education, profession, family income, origin of expense, and diagnosis. Written informed consent was signed by each patient who participated in this study. This study was approved by the Institutional Review Board of Sichuan University, China.
Anxiety and depression scoring
The self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were used to evaluate the anxiety and depression degrees of patients, respectively [
11]. We evaluated each patient 8 h after admission, and data were recorded. In the SAS scale, the total raw scores range from 20 to 80, which should be converted into an “anxiety index” score using the chart on the paper version of the test. The anxiety index score was then used for the following scale to determine the clinical interpretation of one’s level of anxiety: 20-44, 45-59, 60-74, and 75-80 for normal, mild to moderate anxiety, marked to severe anxiety, and extreme anxiety levels, respectively. In the SDS scale, scores range from 20 to 80, which fall into four ranges as follows: 20-44, 45-59, 60-69, and≥70 for normal, mildly depressed, moderately depressed, and severely depressed, respectively. We investigated 20 patients to evaluate the reliability and validity of the questionnaires. After the analysis, the Cronbach’s α coefficient index was 0.819 and 0.862 for SAS and SDS, and the internal consistency was 73.2% and 81.5% for SAS and SDS, respectively. Patients filled out the questionnaires by themselves. For patient who had difficulty with writing, an investigator read the questions without providing a hint to choose a certain answer.
Evaluation of pain and patient compliance with oral analgesic treatment
The degree of pain was scored from 0 to 10 by using VAS scale: 0-3, 4-6, and 7-10 for mild, moderate pain, and severe pain, respectively. A patient who totally completed the treatment of oral analgesics was recorded as good compliance. By contrast, a patient who only completed partly or even refused the treatment was recorded as moderate or non-compliance, respectively.
Statistical analysis
All statistical analyses were performed using the STATISTICA software package (version 10.0; STATSOFT Inc., Tulsa, OK, USA). The associations between categorical variables were analyzed by using Pearson’s χ2 test. Correlations of the variables with compliance were analyzed using a logistic regression model. The test was two-sided, and a P value of less than 0.05 was considered statistically significant.
Results
Patient characteristics
A total of 100 eligible patients with chronic pain, including 43 men and 56 women with a median age of 52.58 years (range: 18-80 years), were enrolled in this study. We sent out 100 questionnaires, and a total of 99 questionnaires were considered valuable; one questionnaire was removed because of missing information (~70%). Thus, the rate of obtaining valuable questionnaire was 99%. A total of 25, 36, 18, and 20 patients have limb or trunk pain, herpes zoster neuralgia, body pain of osteoporosis, and other non-cancer chronic pain, respectively (Table 1). A total of 54 and 45 patients were prescribed with opioid and non-opioid, respectively. As scored by VAS scale, 32, 30, and 37 patients were identified to have mild, moderate, and severe pain, respectively. The median pain score was 6.8 (range: 4.0-6.9). For the occupation, 35, 35, and 29 were farmers, employees, and unemployed patients, respectively. Meanwhile, 46 and 53 patients graduated from high school or below and from college or above, respectively. A total of 50 and 49 patients had family income of below 3000 and above 3000 CNY per month, respectively (Table 1).
Anxiety and depression states of patients
By SAS and SDS scoring, we identified 41 patients with anxiety, including 21, 11, and 9 mild, moderate, and severe patients, respectively. Meanwhile, 18 patients had depression, including 8 mild, 5 moderate, and 5 severe patients. The median scores of anxiety and depression were 42.50 (interquartile range, 6.25; average, 42.46; and standard deviation, 6.94) and 40.00 (interquartile range, 16.25; average, 41.34; and standard deviation, 11.57), respectively (Table 2).
Compliance-related factors by univariate analysis
A total of 73 (73.7%) patients completed the oral analgesic treatment and were recorded as good compliance. Meanwhile, 17 (17.1%) and 9 (9.2%) patients partially completed and refused the treatment and were recorded as moderate and non-compliance, respectively (Table 3).
We analyzed the relationship between the patient’s characteristics and the compliance to oral analgesic treatment. No significant difference in compliance was observed in gender, age, pain site, anxiety, and depression state (Table 3). We observed significantly better compliance in farmers (31/35, 88.6%) than those in employed (25/35, 71.4%) and unemployed (17/29, 58.6%) patients (P = 0.02). Significantly better compliance was also observed in patients educated in college or above (39/46, 84.8%) than those educated in middle school or below (7/46, 15.2%) (P = 0.013), as well as in patients with family income of<3000 CNY (45/50, 90.0%) than those with family income of≥3000 CNY (28/49, 57.1%) (P = 0.025). Patients with severe (32/37, 84.5%) or moderate (28/30, 93.3%) pain also had better compliance than those with mild pain (13/32, 40.6%) (P<0.001).
By using logistic regression model, we found that family income of≥3000 CNY per month (OR: 2.50, 95% CI: 1.65-4.51, P = 0.021) and mild pain (OR: 1.27, 95% CI: 1.03-3.31, P = 0.016) were associated with moderate or non-compliance with oral analgesic treatment. Meanwhile, occupation, education, and depression state were not correlated with compliance (Table 4).
Discussion
Researchers have observed that compliance with drug therapy in patients with chronic pain is inadequate and more dependent on personal characteristics than on external factors [
2-
6]. However, results of different kinds of research considerably vary, even for the same disease; different survey respondents gave different results [
7]. The average compliance rate was estimated at around 70.0% in Chinese patients with chronic pain, but no investigation has been reported yet to date. In the present study, we show that the good compliance rate of hospitalized patients with chronic pain was 73.7%, which was lower than the expected 90%, but close to the estimated value. We found that patients with different careers, educations, family income amounts, and degrees of pain had significantly different compliances by univariate analysis. However, multivariate analysis showed that only family income and degrees of pain were considered independent variables that were associated with patient compliance.
In our study, adherence was found to be related to family income. Patients with monthly income of less than 3000 CNY showed better adherence to therapy than patients with higher income per month. This result was much different from the available Western data, which showed no significant difference between people with different monthly income. Such observation may also be distinct in China because analgesics are not free in the country. Patients with lower income do not always want to ask doctors for medicine, unless the pain is intolerable, and they anticipate the best efficacy with limited money. Therefore, we found better compliance with analgesic treatment among Chinese people. Meanwhile, patients with higher income are mostly educated better and more arrogant. They can obtain more information from different sources and are willing to acquire medicine through their own method. Thus, a study on different patients with different approaches should be conducted. More thorough explanation on standardization of medication is important to reduce the possibility of addiction.
Patients with worse pain would have better adherence to oral analgesic treatment than patients with less pain, but this assumption remains controversial to date. Berndt
et al. [
12] found no relationship between the intensity of pain and adherence to treatment. In our study, we showed that patients with moderate or severe pain had better compliance than patients with mild pain. Further analysis showed that the pain only lasted at the end of the treatment or until pain relief. In chronic pain, assessment that includes pain relief is difficult. The goal of chronic pain management is accompanied with improvement; that is, worsening of therapy adjustment takes a long time, and adequate control is not always achieved. Therefore, a thorough follow-up should be conducted, and patients should be informed that chronic pain may persist for a lifetime, i.e., even after standardized treatment.
Depression and anxiety are the most mentioned psychiatric illnesses in patients with chronic pain. Polatin
et al. [
13] described that 59% of patients with chronic low back pain sufficed the diagnostic criteria for psychiatric illnesses, in which depression and anxiety are two common diagnoses. Among Pakistani population, the prevalence of depression and anxiety is 55% and 48.57%, respectively [
14]. According to this result, the depression and anxiety rates of patients with chronic back or neck pain were 10% to 42%. Our data show that anxiety and depression rates are 41.4% and 18.1%, respectively. Thus, no differences were observed between adherence and these psychiatric illnesses. Possibly, routine usage of anti-depressant agents (sertralie hydrochloride and alprazolam) and therapy programs (psychological counseling, psychological hint, relief therapy, musical therapy, and rehabilitation training) help patients to be more compliant to therapy.
In conclusion, adherence to oral analgesic treatment is low in Chinese patients with chronic pain. Compliance is negatively related to the family income and degree of pain. The current data are very important in testing interventions to optimize compliance with treatment and improve management of chronic pain. Specific patients should be guided accordingly to increase their compliance and treat their pain with standardized principle. Patients should also be guided to let them fully understand pain as a disease that needs standardized treatment, thereby decreasing their tolerance to pain. Pain influences sleep, work, and any other aspects of life, and low tolerance to pain would encourage patients to avoid dangerous situations, such as severe depression, anxiety, and suicide. Furthermore, a follow-up should be conducted for patients with chronic pain after discharge from hospital to increase overall control.
Compliance with ethics guidelines
Hong Zhu, Yuzhu Zheng, Hui Gao, Zengrong Chen, Li Liu, and Lie Yang declare that they have no conflict of interest. All procedures in this study were in accordance with the ethical standards of the Institutional Review Board of Sichuan University and with the Helsinki Declaration of 1975, as revised in 2000. Informed consent was obtained from all patients included in the study.
Higher Education Press and Springer-Verlag Berlin Heidelberg
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