Chronic pelvic pain – pain catastrophizing, pelvic pain and quality of life

1 Introduction

Chronic pelvic pain (CPP) has a substantial negative effect on women, their lives and their communities. CPP is commonly described as continuous or intermittent pain in the lower abdomen, lasting for at least 6 months, and not exclusively related to the menstrual period or sexual intercourse [1]. Up to two thirds of women in the general population have been found to experience CPP, often without diagnosis and management [2]. This prevalence indicates the need for greater public education and clinical attention to CPP. Previous studies have reported significantly lower quality of life (QoL) levels in numerous categories including physical, emotional, pain and mental health, when comparing women with CPP to UK norms [3]. There is a strong association between CPP and distress, disability, poor general health, low satisfaction levels and substantial costs to health services [4, 5]. In Australia the direct health care costs of endometriosis (often considered the leading cause of CPP) is an estimated 6 billion AUD per annum [6]. Indirect costs such as loss of work productivity, loss of employment, disability and absenteeism are estimated to cost the US 760 million USD per annum [4, 7, 8]. Furthermore, CPP is the single most common indication for referral to women’s health services, accounting for 20% of all outpatient appointments and 40% of all gynecological diagnostic laparoscopies [9, 10].

Painful experiences are comprised of many dimensions including cognition, emotion, behavior and motivation that affect each individual differently [11, 12]. The pain experience is further influenced by biological, psychological and social factors [6]. A common psychological feature of pain is catastrophizing. Catastrophizing has been defined as an exaggerated negative mental set present during an actual or anticipated painful experience [12, 13]. The pain catastrophizing scale (PCS) developed in 1995, consists of a total catastrophizing score and three subscales: “rumination” about pain; “magnification” of the pain problem; and feelings of “helplessness” [14]. Since the development of the PCS, there has been growing evidence of the tendency to “catastrophize” during painful stimulation. Recent studies have associated catastrophizing with a variety of different types of pain. For example, the acute pain of venepuncture had a significant positive correlation with PCS scores [15]. In lower back pain, higher levels of pain catastrophizing were found to predict low back pain at follow up [16]. Furthermore, catastrophizing has been associated with increased pain intensity, heightened disability, illness behaviors such as longer hospital stays, post-operative pain, post-operative analgesic use and the prediction of pain and disability outcomes [12, 13, 17].

Increasing evidence suggests that CPP may be similar to other chronic pain conditions with the same psychological and contextual elements. As-Sanie et al. demonstrated that it is the presence of pelvic pain (regardless of the presence or absence of endometriosis) that predicts heightened peripheral pain sensitivity thresholds [18]. We therefore, have conducted a cross-sectional study to determine the levels of pain catastrophizing in women with CPP and to explore its association to pain levels and QoL. We hypothesized that women with higher reported pain levels will have an associated increased level of pain catastrophizing, and that higher levels of pain catastrophizing will be negatively associated with QoL.

2 Materials and methods

Following informed written consent and institutional ethics approval (Mercy Health, HREC), consecutive participants were recruited from a tertiary women’s hospital gynecology outpatient department between February 9th, 2015 and July 23rd, 2015. The gynecology department receives referrals for all areas of gynecology. Participants were included if aged between 18 and 50, with a referral of at least 6 months of pelvic pain, including dysmenorrhea, dyspareunia, non-cyclical pelvic pain, lower abdominal pain, dyschezia or dysuria. Women were excluded if they were actively trying to conceive or had a history of hysterectomy as their management was likely to be modified by these. It was accepted that given referral to gynecology outpatients had occurred, participants may or may not have had previous treatments for their pelvic pain. This study reports on a component of a larger ongoing CPP study. Of 141 eligible CPP patients (Fig. 1), 115 women participated, and 26 women did not. Reasons cited for not participating were: not interested (n = 9); unable to complete the questionnaire due to English literacy limitations (n = 9); non-receipt of questionnaire during or prior to their outpatient appointment (n = 8). The initial contact for 90/115 was in in the waiting room at their appointment. Of 25 participants who were mailed a questionnaire in advance of their appointment, 17 returned their postal questionnaire prior to their appointment and 8 were followed up in the waiting room at the time of appointment. Ninety-eight questionnaires were complete, ten questionnaires were missing a single answer, five questionnaires were missing up to four answers and two questionnaires were missing responses to the 13 PCS questions. The questionnaires with missing data were excluded from relevant correlations.

Figure 1:

Flow chart demonstrating recruitment in the study of pelvic pain, pain catastrophizing and quality of life at a tertiary women’s hospital in 2015.

3 Results

Participants (n = 115) were between 18 and 50 years, with a median age of 29.0 years [interquartile range (IQR): 23.0–38.0]. Study participants were younger than non-participants [median age of 35.0 years (IQR: 28.0–41.0)]. Of the 107 women who responded to the parity questions, 53 women had been pregnant (average of 2.7 times) and 48 had a child (average two children). Seventy-five participants stated that they were currently receiving treatment, analgesia or hormonal therapies, for their pelvic pain. Seventy-five women stated they had previously had treatment for their pelvic pain, including some of the women currently receiving treatment. Fifty-four women had previously had abdominal surgery.

4 Discussion

This study demonstrates the relationship between pain catastrophizing, pelvic pain levels and QoL in women with CPP. A PCS score of 30 corresponds to the 75th percentile in the distribution of clinical samples of chronic pain patients and has been deemed a clinically relevant “cutoff” by the University Centre for Research on Pain and Disability [13]. Previous studies of patients with soft tissue back injuries found that 70% of those who scored ≥30 on the PCS remained unemployed, 70% reported occupational disability and 66% were found to have moderate depression on the Beck Depression Inventory-II [13]. Our results illustrate comparable or higher pain catastrophizing levels in the CPP population than in other chronic pain conditions, with 60/113 participants (53%, CI: 43%–63%) having a PCS score ≥30. Previous studies have demonstrated that PCS scores between 20 and 30 are considered to be at moderate risk of developing pain chronicity, and above 30 as high risk [13]. Many studies have also used PCS or similar scales as a prediction tool for disability, pain continuation, pain outcomes, and illness behaviors such as longer hospital stays, post operative pain, post operative analgesic use, frequency of visits to health care professionals and increased use of over the counter medications [12, 17, 21]. Our findings suggest over half of the study population may be at high risk for continued chronicity of their pain with the potential risk of associated disability, unemployment and depression. This emphasizes the importance of practitioners to consider and address catastrophizing and broader psychosocial components of pain within the CPP population, including psychological support.

Associations between pain catastrophizing and heightened pain experience have been demonstrated across various pain conditions and procedures [12]. This is supported by our results of significant associations between all five pelvic pain categories and PCS scores (Table 2). The strongest correlations were demonstrated in non-cyclical pelvic pain and dysmenorrhea. These were also the two most commonly reported painful symptoms, emphasizing the prevalence and importance of catastrophizing within this cohort. Interestingly, when analysing pain levels associated with dyspareunia we found those who scored either 2/5 or 3/5 had PCS scores substantially higher than those who scored no pain, suggesting a negative coping response, as measured by the PCS, impacts at lower levels of pain scores for dyspareunia when compared to other pelvic pain categories. Previous studies have demonstrated high pain catastrophizing levels are associated with increased pain ratings and a negative impact on the experience of intercourse [11]. The higher pain catastrophizing scores at lower pain levels could be explained by increased anxiety and psychosocial implications associated with dyspareunia and sexual intercourse. In Desrochers et al. [22] study of women with superficial dyspareunia (vestibulodynia and vulvodynia), a multiple linear regression analysis established the relative contribution of validated psychological variables including catastrophizing (PCS), pain related fear, hypervigilance and self-efficacy. The total regression of all variables significantly contributed to a 15% variance in pain for the subjects [22]. However, only PCS contributed an individual variance to the prediction of dyspareunia (p = 0.046), illustrating that whilst depression, anxiety, fear of pain and hyper-vigilance are all psychological variables of dyspareunia, they contribute less than catastrophizing to pain intensity, predictions of disability, pain maintenance and chronicity of dyspareunia [11, 22].

Numerous studies have examined QoL of those suffering from CPP [4, 23, 24, 25]. Our findings of significantly lower QoL levels in the physical domain across all ages and in the psychological domain for the ages <30 and between 30 and 40 in comparison to Australian norms, support previous research. The relationship between QoL and catastrophizing is often looked at specifically in terms of treatment outcomes, and psychosocial factors. In this study, a broad QoL scale demonstrated that catastrophizing plays a role in decreasing overall QoL, illustrating the significance of catastrophizing in the experience of chronic pain and negative impact on daily life. It is difficult to delineate whether decreased QoL, secondary to pain intensity occurs first, and then results in increased pain catastrophizing. Nevertheless, the association warrants recognition in the clinical context.

Limitations of this study include reduced statistical power with a total of 115 participants, however we deemed the clinical findings and correlations sufficient to draw meaningful conclusions. The cross-sectional nature of this study is also a limitation, though it is a direct reflection of information gathering in an outpatient clinical context. As with many self-report and pain experience analyses, the subjective responses to catastrophizing, pain levels and QoL may be skewed by individual perception and experience. We view this as a reflection of the overall painful experience and sought to utilize validated questionnaires to produce accurate data. As the questions required retrospective responses, there is a potential recall bias, though this mirrors information gathering in a clinical outpatient consultation scenario. Despite parity and previous history of medical and surgical treatment influencing pain levels, all participants, regardless of previous history, were included as a single cohort, to best represent a true general gynecological outpatient population for analysis and findings. Finally, there is a potential selection bias, demonstrated by the difference in age between eligible participants who did, and did not, participate in the study. Participants’ median age was 29.0 years (IQR: 23.0–38.0) and non-participants median age was 35.0 (IQR: 28.0–41.0).

In conclusion, the perception of pain and its psychological factors varies from one individual to another. Research has shown catastrophizing to be a powerful marker for heightened pain experience. In a condition as common as CPP, it is crucial for the practitioner to consider the strong associations between pain catastrophizing, pelvic pain and QoL. Psychological domains should be of great importance to clinicians caring for women with CPP, and the possibility of catastrophizing playing a role in prediction of pain outcomes in these women warrants further assessment. Further investigation is needed to determine whether pain catastrophizing can be used as a predictor of outcomes in CPP, as has been done in research of other chronic pain conditions. We postulate that it may be possible to aid patients with higher PCS scores by implementing psychological supports and predicting post treatment pain outcomes, thus allowing for better treatment choices and planning.