Prevalence of opiophobia in cancer pain treatment

ABSTRACT

BACKGROUND AND OBJECTIVES:

Pain depreciates patients' quality of life, even influencing disease recovery. This study aimed at evaluating the prevalence of pain and opiophobia as barrier for the adequate management of cancer pain.

METHODS

Participated in the study 280 cancer patients in clinical treatment, who have answered a questionnaire made up of questions related to pain and use of opioid drugs. Demographic and clinical data were obtained by reviewing medical charts. The study was individually and randomly applied by the authors during outpatient visits.

RESULTS:

Prevalence of pain was 50.3%; 19.2% of patients would refuse morphine for pain control and fear of dependence was the most reported reason. The perception that morphine is directly related to worsening the disease was reported by 67.8% of respondents.

CONCLUSION:

A high prevalence of moderate and severe pain was found among studied patients, as well as a high prevalence of opiophobia.

Keywords:
Chronic pain; Fear; Morphine; Opioid analgesics; Pain

RESUMO

JUSTIFICATIVA E OBJETIVOS:

A dor se apresenta como fator depreciativo da qualidade de vida dos pacientes, influenciando inclusive na recuperação da doença. O objetivo deste estudo foi avaliar a prevalência da dor e da opiofobia, enquanto barreira ao manuseio adequado deste sintoma em pacientes com câncer.

MÉTODOS:

Foram avaliados 280 pacientes com câncer em tratamento clínico dessa doença, que responderam a um questionário composto por questões relacionadas à dor e ao uso de fármacos opioides. Os dados demográficos e clínicos foram obtidos por meio de revisão de prontuários. O estudo foi aplicado individualmente pelos autores ao acaso, durante o atendimento ambulatorial.

Apresentado em 25 de julho de 2016. Aceito para publicação em 03 de novembro de 2016. Conflito de interesses: não há - Fontes de fomento: não há.

RESULTADOS:

A prevalência de dor encontrada foi de 50,3%; 19,2% dos pacientes recusariam a morfina como tratamento da dor e o medo da dependência foi o motivo mais relatado. A percepção de que o uso da morfina tem relação direta com o agravo da doença foi descrita por 67,8% dos entrevistados.

CONCLUSÃO:

A alta prevalência de dor moderada e intensa foi encontrada nos pacientes estudados, bem como uma elevada prevalência de opiofobia.

Descritores:
Analgésicos opioides; Dor; Dor crônica; Medo; Morfina

INTRODUCTION

The World Health Organization (WHO) has proposed that cancer pain is a world medical emergency. In this population, moderate to severe pain is present in 30% of individuals already being treated and its prevalence increases with disease progression, affecting 50 to 75% of patients¹. This negatively affects quality of life (QL) of this population, generating changes in appetite, sleep and mood, and impairing their recovery².

The understanding that pain is not only result of sensory nerve perception of a tissue injury, but rather of emotional, spiritual components and social factors, has led to cancer pain qualification as total pain³.

It is known that 60 to 80% of pain symptoms in cancer patients are attributed to the disease itself; 20 to 25% to anticancer treatment and just 5 to 10% to non-cancer causes; however, emotional and cognitive components might be responsible for symptom persistence and severity³.

In light of the above, the first National Consensus for cancer pain treatment, developed by the WHO, has determined that opioids would be the basis for the treatment. However, some studies have shown failure in managing pain in approximately 40 to 70% of patients^3,4. This has become a recurrent problem in clinical oncology services.

In light of this, three types of pain treatment barriers have been evidenced: health system barriers, professionals' barriers and patients' barriers⁴. Our study has just evaluated obstacles imposed by patients with regard to opioids, called opiophobia.

Opiophobia is the fear of using opioids. Most of the times, phobia is established by myths pursuing opium derivatives, associated to the unawareness of their systemic effects⁵. The number of factors preventing the use of the drug, described by patients and their families, is very high. Some report, for example, fear of using this type of analgesia for believing in the direct relationship of its prescription with disease evolution or imminence of death. Notwithstanding the abundance of factors, fear of dependence is the most reported one⁶. This study is inserted in this context, aiming at evaluating prevalence of pain and opiophobia in cancer patients.

METHODS

This is a cross-sectional study with patients in exclusive clinical cancer treatment in the outpatient service of an oncologic hospital. To determine the sample, proportions sample calculation was used with 95% confidence and 5% error, and patients were randomly invited to participate in the study. Inclusion criteria were all patients in exclusive clinical cancer treatment and able to answer to the proposed questionnaire. Exclusion criteria were patients whose exclusive surgical treatment was considered resolutive, those below 18 years of age and patients with intellectual incapacity to answer to the proposed questionnaire.

All patients have signed the Free and Informed Consent Term (FICT) and then have answered to a questionnaire developed by the authors and based on Colak et al.⁵, Gunnarsdottir, Serlin and Ward⁷ and Jacobsen et al.⁸. Data were collected between April and June 2015.

Questionnaire was made up of 18 questions, most of multiple-choice, which were divided in questions related to general data, to pain symptoms and to barriers to pain control. For general information collection, questions were asked about alcoholism, smoking and constant use of drugs to induce sleep. Data regarding pain symptoms were obtained by questions about existence of pain; frequency of symptom; drugs used for its management, and intensity, classified according to pain intensity numerical scale with scores from zero to 10 (zero=no pain and 10= worst pain), being classified in mild pain (1 to 3), moderate pain (4 to 7) and severe pain (8 to 10)⁹. Finally, to identify opiophobia, patients have answered which drug they thought morphine was; whether they would use or not the drug if prescribed by their physician; the reason for not using it and whether they associated morphine to disease evolution or proximity of death. Epidemiological data, such as ethnics, age and tumor origin, were collected from medical charts.

Statistical analysis

For statistical analysis, data were recorded in Microsoft Excel^®, for further descriptive analysis of collected variables and data crossing. Descriptive analysis data were grouped in frequency tables expressed in percentages. Central trend measures were expressed in mean and standard deviation in case of Gaussian samples and in medians and inter-quartile intervals (IIQ) if non Gaussian samples. For data crossing, Chi-square and Mann-Whitney tests were used. Significance level was equal to or less than 0.05.

This study was approved by the Ethics and Research Committee, Hospital Erasto Gaertner (Curitiba - PR) under protocol 1.027.681.

RESULTS

Participated in the study 280 patients being 61.7% (173) females and 38.2% (107) males, aged between 20 and 89 years (mean of 53.1±13.9). According to reviewed medical charts, 89.6% (251) of patients were Caucasian, 10% (28) Afrodescendant and 0.3% (1) Asian.

Approximately 30% (84) of participants were smokers. Alcoholic drinks were reported by 10% (28) of patients and, of them, only seven would ingest them regularly (from twice a week to daily use). The use of sleep-inducing drugs was described by 10.3% (29).

With regard to tumor origin, there has been higher prevalence of breast and colorectal cancer, as described in table 1.

Table 1
Tumors according to organ of origin

	n	%
Cervix	11	3.93
Colorectal	33	11.79
Esophagus	4	1.42
Chronic lymphoid leukemia	9	3.21
Chronic myeloid leukemia	9	3.21
Hodgkin lymphoma	8	2.86
Non-Hodgkin lymphoma	26	9.29
Breast	71	25.36
Melanoma	5	1.78
Multiple myeloma	7	2.50
Oropharynx	9	3.21
Ovary	5	1.78
Prostate	5	1.78
Lungs	4	1.42
Testis	8	2.86
Others	66	23.57

Pain was reported by 50.3% (141) of respondents. Pain intensity has varied from 2 to 10 points in the numerical scale, with median of 7.0 (IIQ = 5.0-8.0). In 10.6% (15) of symptomatic population, pain was considered mild, in 48.9% (69) moderate and in 40.4% (57) severe. Frequency of symptom in these patients was reported as daily by 53.9% (76), between 3 and 5 days a week by 23.4% (33) and in less than 3 days a week by 22.6% (32).

Some patients, 27.1% (76) of the sample, have stated not reporting their pain to assistant physicians and 31.7% (89) have reported never having received information of such professionals about cancer pain.

Analgesic drugs used are described in table 2.

Table 2
Drugs used for pain control

	n	%
Simple analgesics	79	56.02
Non-steroid anti-inflammatory drug	25	17.70
Weak opioid	43	30.04
Strong opioid	23	16.30
Anticonvulsant	10	7.09
Glucocorticoid	4	2.80
Antidepressant	1	0.70

About the knowledge of morphine, more than half the patients, 57.1% (160), have recognized the drug as "medicine" for pain, not knowing how to classify it; 23.5% (66) of patients did not know it; just 14.6% (41) knew with specificity, classifying it as opioid analgesics and remaining respondents have inadequately classified it.

Agreement to receive morphine as pain control drug, without any objection, was reported by 80.7% (226) of respondents, with three abstentions. However 19.2% (54) of patients would refuse the drug as their therapy, even if prescribed by their physicians, claiming in 65.2% of cases fear of dependence, 34.7% fear of adverse effects and 30.4% fear of tolerance.

Table 3
Perception about the use of opioids

	n	%
Associated to disease worsening	190	67.85
Associated to imminence of death	115	41.07

There has been no influence of age and gender in the decision of using morphine to control pain, when prescribed by their physicians, with p=0.07 and p=0.74, respectively. Non-adherence to injectable therapies was referred by just 3.9% (11) of respondents and the conviction that pain in cancer patients may be controlled was reported by the vast majority, 91% (255) of patients.

DISCUSSION

Pain depreciates QL and recovery of a large number of cancer patients but, in spite of that, pain is still inadequately managed in this population. Van den Beuken-van Everdingen et al.¹⁰ have shown that the prevalence of pain in severe cancer patients would be 59%. In our study there has been no major contrast with regard to this index, since the symptom was present in 50.3% of patients.

Pain indicators observed in this study, were similar to those presented by the literature, in spite of samples peculiarities. While in our study severe pain was reported by 40.4% of painful patients, Silva et al. have observed 32% of severe pain among cancer patients¹¹. In the attempt to identify barriers for inadequate pain control, this study has shown that 27% of patients would not report their pain to their assistant physicians. This attitude is due to the fact that many patients understand pain as inherent symptom to cancer and so they believe that it is uncontrollable⁸. In our study, however, just 9% of respondents have stated that cancer pain cannot be controlled.

Still about the knowledge about the drug, the study has shown that 57.1% of patients have pointed morphine as painkiller, against 15.1% of the population studied by Fiedler et al.¹². Moreover, 14.6% of patients were more aware of the drug when classifying it in the adequate category. So, our data indicate that most people are familiar with the function of the drug, which does not decrease the importance of guidance about opioids. Grant et al. have stated that even patients with partial knowledge about the drug, pose obstacles to its therapy¹³.

As to the incidence of opiophobia obtained in this sample as one more barrier to adequate pain management, some indices were evidenced. Our study has shown that 19.2% of patients would refuse morphine, even if prescribed by their physicians, versus 12% found by Colak et al.⁵. In their study, major reasons for refusal were fear of dependence (53.4%), followed by religious principles (25). Our study has observed 65.2% of phobia of dependence, followed by fear of adverse effects (34.7%). Fear of tolerance was the third most reported in both studies, appearing in 30.4% of current sample. Colak et al. have also shown the influence of gender and age in the decision of accepting morphine when prescribed by their physicians; however these factors were not important in our study.

Finally, most part of the sample relates the use of morphine with worsening of their health status (67.85%) and with proximity of death (41.07%), fact already observed by other studies^13,14.

CONCLUSION

Our study has shown that there is high prevalence of opiophobia among cancer patients, which does not suffer influence of patients' gender or age. Our study has observed high prevalence of moderate to severe pain in this population, notwithstanding the evolution of its therapy.

• Sponsoring sources: none.

REFERENCES

• ¹
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  Reid CM, Gooberman-Hill R, Hanks GW. Opioid analgesics for cancer pain: symptom control for the living or comfort for the dying? A qualitative study to investigate the factors influencing the decision to accept morphine for pain caused by cancer. Ann Oncol. 2008;19(1):44-8.

Publication Dates

• Publication in this collection
  Oct-Dec 2016

History

• Received
  25 July 2016
• Accepted
  03 Nov 2016